From 81d362732bac05f656cdc4bbe776ac20cfd30c45 Mon Sep 17 00:00:00 2001 From: Andrew Davis Date: Mon, 6 Mar 2023 16:47:52 -0600 Subject: [PATCH 01/72] kbuild: Disallow DTB overlays to built from .dts named source files As a follow up to the series allowing DTB overlays to built from .dtso files. Now that all overlays have been renamed, remove the ability to build from overlays from .dts files to prevent any files with the old name from accidental being added. Signed-off-by: Andrew Davis Reviewed-by: Geert Uytterhoeven Acked-by: Andy Shevchenko Signed-off-by: Masahiro Yamada --- scripts/Makefile.lib | 3 --- 1 file changed, 3 deletions(-) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 100a386fcd71..68d0134bdbf9 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -418,9 +418,6 @@ endif $(obj)/%.dtb: $(src)/%.dts $(DTC) $(DT_TMP_SCHEMA) FORCE $(call if_changed_dep,dtb) -$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE - $(call if_changed_dep,dtc) - $(obj)/%.dtbo: $(src)/%.dtso $(DTC) FORCE $(call if_changed_dep,dtc) From 64f140417d818aa374788acc9cb8328165747262 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 12 May 2023 01:24:22 +0900 Subject: [PATCH 02/72] modpost: error out if addend_*_rel() is not implemented for REL arch The section mismatch check relies on the relocation entries. For REL, the addend value is implicit, so we need some code to compute it. Currently, EM_386, EM_ARM, and EM_MIPS are supported. This commit makes sure we covered all the cases. I believe the other architectures use RELA, where the explicit r_addend field exists. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d4531d09984d..c1c523adb139 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1628,6 +1628,8 @@ static void section_rel(const char *modname, struct elf_info *elf, if (addend_mips_rel(elf, sechdr, &r)) continue; break; + default: + fatal("Please add code to calculate addend for this architecture\n"); } sym = elf->symtab_start + r_sym; /* Skip special sections */ From d0acc76a49aa917c1a455d11d32d34a01e8b2835 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:19 +0900 Subject: [PATCH 03/72] modpost: remove broken calculation of exception_table_entry size find_extable_entry_size() is completely broken. It has awesome comments about how to calculate sizeof(struct exception_table_entry). It was based on these assumptions: - struct exception_table_entry has two fields - both of the fields have the same size Then, we came up with this equation: (offset of the second field) * 2 == (size of struct) It was true for all architectures when commit 52dc0595d540 ("modpost: handle relocations mismatch in __ex_table.") was applied. Our mathematics broke when commit 548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options") introduced the third field. Now, the definition of exception_table_entry is highly arch-dependent. For x86, sizeof(struct exception_table_entry) is apparently 12, but find_extable_entry_size() sets extable_entry_size to 8. I could fix it, but I do not see much value in this code. extable_entry_size is used just for selecting a slightly different error message. If the first field ("insn") references to a non-executable section, The relocation at %s+0x%lx references section "%s" which is not executable, IOW it is not possible for the kernel to fault at that address. Something is seriously wrong and should be fixed. If the second field ("fixup") references to a non-executable section, The relocation at %s+0x%lx references section "%s" which is not executable, IOW the kernel will fault if it ever tries to jump to it. Something is seriously wrong and should be fixed. Merge the two error messages rather than adding even more complexity. Change fatal() to error() to make it continue running and catch more possible errors. Fixes: 548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 60 +++---------------------------------------- 1 file changed, 3 insertions(+), 57 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c1c523adb139..ba4577aa4f1d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1292,43 +1292,6 @@ static int is_executable_section(struct elf_info* elf, unsigned int section_inde return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); } -/* - * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() - * to know the sizeof(struct exception_table_entry) for the target architecture. - */ -static unsigned int extable_entry_size = 0; -static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) -{ - /* - * If we're currently checking the second relocation within __ex_table, - * that relocation offset tells us the offsetof(struct - * exception_table_entry, fixup) which is equal to sizeof(struct - * exception_table_entry) divided by two. We use that to our advantage - * since there's no portable way to get that size as every architecture - * seems to go with different sized types. Not pretty but better than - * hard-coding the size for every architecture.. - */ - if (!extable_entry_size) - extable_entry_size = r->r_offset * 2; -} - -static inline bool is_extable_fault_address(Elf_Rela *r) -{ - /* - * extable_entry_size is only discovered after we've handled the - * _second_ relocation in __ex_table, so only abort when we're not - * handling the first reloc and extable_entry_size is zero. - */ - if (r->r_offset && extable_entry_size == 0) - fatal("extable_entry size hasn't been discovered!\n"); - - return ((r->r_offset == 0) || - (r->r_offset % extable_entry_size == 0)); -} - -#define is_second_extable_reloc(Start, Cur, Sec) \ - (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) - static void report_extable_warnings(const char* modname, struct elf_info* elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, @@ -1384,22 +1347,9 @@ static void extable_mismatch_handler(const char* modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (!is_executable_section(elf, get_secindex(elf, sym))) { - if (is_extable_fault_address(r)) - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "it is not possible for the kernel to fault\n" - "at that address. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); - else - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "the kernel will fault if it ever tries to\n" - "jump to it. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); - } + else if (!is_executable_section(elf, get_secindex(elf, sym))) + error("%s+0x%lx references non-executable section '%s'\n", + fromsec, (long)r->r_offset, tosec); } static void check_section_mismatch(const char *modname, struct elf_info *elf, @@ -1574,8 +1524,6 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - if (is_second_extable_reloc(start, rela, fromsec)) - find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } @@ -1635,8 +1583,6 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - if (is_second_extable_reloc(start, rel, fromsec)) - find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } From 6c90d36be3e5140c93d3af360d012fa26966304a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:20 +0900 Subject: [PATCH 04/72] modpost: remove fromsym info in __ex_table section mismatch warning report_extable_warnings() prints "from" in a pretty form, but we know it is always located in the __ex_table section, i.e. a collection of struct exception_table_entry. It is very likely to fail to get the symbol name and ends up with meaningless message: ... in reference from the (unknown reference) (unknown) to ... Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ba4577aa4f1d..bbe066f7adbc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1297,23 +1297,16 @@ static void report_extable_warnings(const char* modname, struct elf_info* elf, Elf_Rela* r, Elf_Sym* sym, const char* fromsec, const char* tosec) { - Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); - const char* fromsym_name = sym_name(elf, fromsym); Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); const char* tosym_name = sym_name(elf, tosym); - const char* from_pretty_name; - const char* from_pretty_name_p; const char* to_pretty_name; const char* to_pretty_name_p; - get_pretty_name(is_function(fromsym), - &from_pretty_name, &from_pretty_name_p); get_pretty_name(is_function(tosym), &to_pretty_name, &to_pretty_name_p); - warn("%s(%s+0x%lx): Section mismatch in reference from the %s %s%s to the %s %s:%s%s\n", - modname, fromsec, (long)r->r_offset, from_pretty_name, - fromsym_name, from_pretty_name_p, + warn("%s(%s+0x%lx): Section mismatch in reference to the %s %s:%s%s\n", + modname, fromsec, (long)r->r_offset, to_pretty_name, tosec, tosym_name, to_pretty_name_p); if (!match(tosec, mismatch->bad_tosec) && From 6691e6f5fc3e9fa76c9a50970fa851829df7d9f2 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:21 +0900 Subject: [PATCH 05/72] modpost: remove get_prettyname() This is the last user of get_pretty_name() - it is just used to distinguish whether the symbol is a function or not. It is not valuable information. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 27 ++------------------------- 1 file changed, 2 insertions(+), 25 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bbe066f7adbc..371891d67175 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,23 +1207,6 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } -static int is_function(Elf_Sym *sym) -{ - if (sym) - return ELF_ST_TYPE(sym->st_info) == STT_FUNC; - else - return -1; -} - -static inline void get_pretty_name(int is_func, const char** name, const char** name_p) -{ - switch (is_func) { - case 0: *name = "variable"; *name_p = ""; break; - case 1: *name = "function"; *name_p = "()"; break; - default: *name = "(unknown reference)"; *name_p = ""; break; - } -} - /* * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. @@ -1299,15 +1282,9 @@ static void report_extable_warnings(const char* modname, struct elf_info* elf, { Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); const char* tosym_name = sym_name(elf, tosym); - const char* to_pretty_name; - const char* to_pretty_name_p; - get_pretty_name(is_function(tosym), - &to_pretty_name, &to_pretty_name_p); - - warn("%s(%s+0x%lx): Section mismatch in reference to the %s %s:%s%s\n", - modname, fromsec, (long)r->r_offset, - to_pretty_name, tosec, tosym_name, to_pretty_name_p); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym_name); if (!match(tosec, mismatch->bad_tosec) && is_executable_section(elf, get_secindex(elf, sym))) From faee9defd8fc376864efb39b87d59f667deeb488 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:22 +0900 Subject: [PATCH 06/72] modpost: squash report_extable_warnings() into extable_mismatch_handler() Collect relevant code into one place to clarify all the cases are covered by 'if () ... else if ... else ...'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 40 ++++++++++++++-------------------------- 1 file changed, 14 insertions(+), 26 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 371891d67175..7a9a3ef8ca0d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1275,40 +1275,19 @@ static int is_executable_section(struct elf_info* elf, unsigned int section_inde return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); } -static void report_extable_warnings(const char* modname, struct elf_info* elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char* fromsec, const char* tosec) -{ - Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); - const char* tosym_name = sym_name(elf, tosym); - - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym_name); - - if (!match(tosec, mismatch->bad_tosec) && - is_executable_section(elf, get_secindex(elf, sym))) - fprintf(stderr, - "The relocation at %s+0x%lx references\n" - "section \"%s\" which is not in the list of\n" - "authorized sections. If you're adding a new section\n" - "and/or if this reference is valid, add \"%s\" to the\n" - "list of authorized sections to jump to on fault.\n" - "This can be achieved by adding \"%s\" to \n" - "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); -} - static void extable_mismatch_handler(const char* modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, const char *fromsec) { const char* tosec = sec_name(elf, get_secindex(elf, sym)); + Elf_Sym *tosym = find_elf_symbol(elf, r->r_addend, sym); + const char *tosym_name = sym_name(elf, tosym); sec_mismatch_count++; - report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym_name); if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" @@ -1317,7 +1296,16 @@ static void extable_mismatch_handler(const char* modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (!is_executable_section(elf, get_secindex(elf, sym))) + else if (is_executable_section(elf, get_secindex(elf, sym))) + warn("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not in the list of\n" + "authorized sections. If you're adding a new section\n" + "and/or if this reference is valid, add \"%s\" to the\n" + "list of authorized sections to jump to on fault.\n" + "This can be achieved by adding \"%s\" to\n" + "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", + fromsec, (long)r->r_offset, tosec, tosec, tosec); + else error("%s+0x%lx references non-executable section '%s'\n", fromsec, (long)r->r_offset, tosec); } From fc5fa862c49a4d9e23617fbda7d249d2c1b72e56 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:23 +0900 Subject: [PATCH 07/72] modpost: squash report_sec_mismatch() into default_mismatch_handler() report_sec_mismatch() and default_mismatch_handler() are small enough to be merged together. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 55 ++++++++++++++++--------------------------- 1 file changed, 20 insertions(+), 35 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 7a9a3ef8ca0d..bb7d1d87bae7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,17 +1207,27 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } -/* - * Print a warning about a section mismatch. - * Try to find symbols near it so user can find it. - * Check whitelist before warning - it may be a false positive. - */ -static void report_sec_mismatch(const char *modname, - const struct sectioncheck *mismatch, - const char *fromsec, - const char *fromsym, - const char *tosec, const char *tosym) +static void default_mismatch_handler(const char *modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { + const char *tosec; + Elf_Sym *to; + Elf_Sym *from; + const char *tosym; + const char *fromsym; + + from = find_elf_symbol2(elf, r->r_offset, fromsec); + fromsym = sym_name(elf, from); + + tosec = sec_name(elf, get_secindex(elf, sym)); + to = find_elf_symbol(elf, r->r_addend, sym); + tosym = sym_name(elf, to); + + /* check whitelist - we may ignore it */ + if (!secref_whitelist(mismatch, fromsec, fromsym, tosec, tosym)) + return; + sec_mismatch_count++; switch (mismatch->mismatch) { @@ -1242,31 +1252,6 @@ static void report_sec_mismatch(const char *modname, } } -static void default_mismatch_handler(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) -{ - const char *tosec; - Elf_Sym *to; - Elf_Sym *from; - const char *tosym; - const char *fromsym; - - from = find_elf_symbol2(elf, r->r_offset, fromsec); - fromsym = sym_name(elf, from); - - tosec = sec_name(elf, get_secindex(elf, sym)); - to = find_elf_symbol(elf, r->r_addend, sym); - tosym = sym_name(elf, to); - - /* check whitelist - we may ignore it */ - if (secref_whitelist(mismatch, - fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, mismatch, - fromsec, fromsym, tosec, tosym); - } -} - static int is_executable_section(struct elf_info* elf, unsigned int section_index) { if (section_index > elf->num_sections) From f4c35484e7f11458c1834b88ee55b746cdabbb09 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:24 +0900 Subject: [PATCH 08/72] modpost: clean up is_executable_section() SHF_EXECINSTR is a bit flag (#define SHF_EXECINSTR 0x4). Compare the masked flag to '!= 0'. There is no good reason to stop modpost immediately even if a special section index is given. You will get a section mismatch error anyway. Also, change the return type to bool. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bb7d1d87bae7..0bda2f22c985 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,6 +1207,14 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } +static bool is_executable_section(struct elf_info *elf, unsigned int secndx) +{ + if (secndx > elf->num_sections) + return false; + + return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0; +} + static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela *r, Elf_Sym *sym, const char *fromsec) @@ -1252,14 +1260,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } -static int is_executable_section(struct elf_info* elf, unsigned int section_index) -{ - if (section_index > elf->num_sections) - fatal("section_index is outside elf->num_sections!\n"); - - return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); -} - static void extable_mismatch_handler(const char* modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, From 856567d5599e7df75d7cad1fef1311d7c1854200 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:25 +0900 Subject: [PATCH 09/72] modpost: squash extable_mismatch_handler() into default_mismatch_handler() Merging these two reduces several lines of code. The extable section mismatch is already distinguished by EXTABLE_TO_NON_TEXT. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 84 ++++++++++++++----------------------------- 1 file changed, 26 insertions(+), 58 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 0bda2f22c985..49357a716519 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -881,27 +881,14 @@ enum mismatch { * targeting sections in this array (white-list). Can be empty. * * @mismatch: Type of mismatch. - * - * @handler: Specific handler to call when a match is found. If NULL, - * default_mismatch_handler() will be called. - * */ struct sectioncheck { const char *fromsec[20]; const char *bad_tosec[20]; const char *good_tosec[20]; enum mismatch mismatch; - void (*handler)(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec); - }; -static void extable_mismatch_handler(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, - const char *fromsec); - static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data @@ -974,7 +961,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { ".altinstr_replacement", NULL }, .good_tosec = {ALL_TEXT_SECTIONS , NULL}, .mismatch = EXTABLE_TO_NON_TEXT, - .handler = extable_mismatch_handler, } }; @@ -1255,60 +1241,42 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, modname, tosym, tosec); break; case EXTABLE_TO_NON_TEXT: - fatal("There's a special handler for this mismatch type, we should never get here.\n"); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym); + + if (match(tosec, mismatch->bad_tosec)) + fatal("The relocation at %s+0x%lx references\n" + "section \"%s\" which is black-listed.\n" + "Something is seriously wrong and should be fixed.\n" + "You might get more information about where this is\n" + "coming from by using scripts/check_extable.sh %s\n", + fromsec, (long)r->r_offset, tosec, modname); + else if (is_executable_section(elf, get_secindex(elf, sym))) + warn("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not in the list of\n" + "authorized sections. If you're adding a new section\n" + "and/or if this reference is valid, add \"%s\" to the\n" + "list of authorized sections to jump to on fault.\n" + "This can be achieved by adding \"%s\" to\n" + "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", + fromsec, (long)r->r_offset, tosec, tosec, tosec); + else + error("%s+0x%lx references non-executable section '%s'\n", + fromsec, (long)r->r_offset, tosec); break; } } -static void extable_mismatch_handler(const char* modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char *fromsec) -{ - const char* tosec = sec_name(elf, get_secindex(elf, sym)); - Elf_Sym *tosym = find_elf_symbol(elf, r->r_addend, sym); - const char *tosym_name = sym_name(elf, tosym); - - sec_mismatch_count++; - - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym_name); - - if (match(tosec, mismatch->bad_tosec)) - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is black-listed.\n" - "Something is seriously wrong and should be fixed.\n" - "You might get more information about where this is\n" - "coming from by using scripts/check_extable.sh %s\n", - fromsec, (long)r->r_offset, tosec, modname); - else if (is_executable_section(elf, get_secindex(elf, sym))) - warn("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not in the list of\n" - "authorized sections. If you're adding a new section\n" - "and/or if this reference is valid, add \"%s\" to the\n" - "list of authorized sections to jump to on fault.\n" - "This can be achieved by adding \"%s\" to\n" - "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); - else - error("%s+0x%lx references non-executable section '%s'\n", - fromsec, (long)r->r_offset, tosec); -} - static void check_section_mismatch(const char *modname, struct elf_info *elf, Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); - if (mismatch) { - if (mismatch->handler) - mismatch->handler(modname, elf, mismatch, - r, sym, fromsec); - else - default_mismatch_handler(modname, elf, mismatch, - r, sym, fromsec); - } + if (!mismatch) + return; + + default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec); } static unsigned int *reloc_location(struct elf_info *elf, From dbf7cc2e4e78dfecad02ff17ff5c9971b42da462 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:26 +0900 Subject: [PATCH 10/72] modpost: pass 'tosec' down to default_mismatch_handler() default_mismatch_handler() does not need to compute 'tosec' because it is calculated by the caller. Pass it down to default_mismatch_handler() instead of calling sec_name() twice. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 49357a716519..2cc9c2a4aadc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1203,9 +1203,9 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) + Elf_Rela *r, Elf_Sym *sym, const char *fromsec, + const char *tosec) { - const char *tosec; Elf_Sym *to; Elf_Sym *from; const char *tosym; @@ -1214,7 +1214,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, from = find_elf_symbol2(elf, r->r_offset, fromsec); fromsym = sym_name(elf, from); - tosec = sec_name(elf, get_secindex(elf, sym)); to = find_elf_symbol(elf, r->r_addend, sym); tosym = sym_name(elf, to); @@ -1276,7 +1275,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec); + default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec, tosec); } static unsigned int *reloc_location(struct elf_info *elf, From 9990ca35870b7c57d39f8b325d676dfd028035b4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:27 +0900 Subject: [PATCH 11/72] modpost: pass section index to find_elf_symbol2() find_elf_symbol2() converts the section index to the section name, then compares the two strings in each iteration. This is slow. It is faster to compare the section indices (i.e. integers) directly. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2cc9c2a4aadc..3b7b78e69137 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1169,19 +1169,14 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, * it is, but this works for now. **/ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, - const char *sec) + unsigned int secndx) { Elf_Sym *sym; Elf_Sym *near = NULL; Elf_Addr distance = ~0; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - const char *symsec; - - if (is_shndx_special(sym->st_shndx)) - continue; - symsec = sec_name(elf, get_secindex(elf, sym)); - if (strcmp(symsec, sec) != 0) + if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; @@ -1203,7 +1198,8 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec, + Elf_Rela *r, Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec, const char *tosec) { Elf_Sym *to; @@ -1211,7 +1207,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, const char *tosym; const char *fromsym; - from = find_elf_symbol2(elf, r->r_offset, fromsec); + from = find_elf_symbol2(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); to = find_elf_symbol(elf, r->r_addend, sym); @@ -1267,7 +1263,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) + Elf_Rela *r, Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); @@ -1275,7 +1272,8 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec, tosec); + default_mismatch_handler(modname, elf, mismatch, r, sym, fsecndx, fromsec, + tosec); } static unsigned int *reloc_location(struct elf_info *elf, @@ -1390,12 +1388,11 @@ static void section_rela(const char *modname, struct elf_info *elf, Elf_Rela *rela; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rela *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; @@ -1434,7 +1431,7 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fromsec); + check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); } } @@ -1445,12 +1442,11 @@ static void section_rel(const char *modname, struct elf_info *elf, Elf_Rel *rel; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rel *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; @@ -1493,7 +1489,7 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fromsec); + check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); } } From ac263349b91bf34b7c8419f5645c84b4f88de846 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:28 +0900 Subject: [PATCH 12/72] modpost: rename find_elf_symbol() and find_elf_symbol2() find_elf_symbol() and find_elf_symbol2() are not good names. Rename them to find_tosym(), find_fromsym(), respectively. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3b7b78e69137..0d2c2aff2c03 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1124,8 +1124,8 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ -static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, + Elf_Sym *relsym) { Elf_Sym *sym; Elf_Sym *near = NULL; @@ -1168,8 +1168,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, * The ELF format may have a better way to detect what type of symbol * it is, but this works for now. **/ -static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx) +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) { Elf_Sym *sym; Elf_Sym *near = NULL; @@ -1207,10 +1207,10 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, const char *tosym; const char *fromsym; - from = find_elf_symbol2(elf, r->r_offset, fsecndx); + from = find_fromsym(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); - to = find_elf_symbol(elf, r->r_addend, sym); + to = find_tosym(elf, r->r_addend, sym); tosym = sym_name(elf, to); /* check whitelist - we may ignore it */ From e1b37563caffc410bb4b55f153ccb14dede66815 Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Mon, 15 May 2023 19:32:16 +0200 Subject: [PATCH 13/72] scripts/tags.sh: Resolve gtags empty index generation gtags considers any file outside of its current working directory "outside the source tree" and refuses to index it. For O= kernel builds, or when "make" is invoked from a directory other then the kernel source tree, gtags ignores the entire kernel source and generates an empty index. Force-set gtags current working directory to the kernel source tree. Due to commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), if the kernel build is done in a sub-directory of the kernel source tree, the kernel Makefile will set the kernel's $srctree to ".." for shorter compile-time and run-time warnings. Consequently, the list of files to be indexed will be in the "../*" form, rendering all such paths invalid once gtags switches to the kernel source tree as its current working directory. If gtags indexing is requested and the build directory is not the kernel source tree, index all files in absolute-path form. Note, indexing in absolute-path form will not affect the generated index, as paths in gtags indices are always relative to the gtags "root directory" anyway (as evidenced by "gtags --dump"). Signed-off-by: Ahmed S. Darwish Cc: Signed-off-by: Masahiro Yamada --- scripts/tags.sh | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/scripts/tags.sh b/scripts/tags.sh index ea31640b2671..f6b3c7cd39c7 100755 --- a/scripts/tags.sh +++ b/scripts/tags.sh @@ -32,6 +32,13 @@ else tree=${srctree}/ fi +# gtags(1) refuses to index any file outside of its current working dir. +# If gtags indexing is requested and the build output directory is not +# the kernel source tree, index all files in absolute-path form. +if [[ "$1" == "gtags" && -n "${tree}" ]]; then + tree=$(realpath "$tree")/ +fi + # Detect if ALLSOURCE_ARCHS is set. If not, we assume SRCARCH if [ "${ALLSOURCE_ARCHS}" = "" ]; then ALLSOURCE_ARCHS=${SRCARCH} @@ -131,7 +138,7 @@ docscope() dogtags() { - all_target_sources | gtags -i -f - + all_target_sources | gtags -i -C "${tree:-.}" -f - "$PWD" } # Basic regular expressions with an optional /kind-spec/ for ctags and From b230235b386589d8f0d631b1c77a95ca79bb0732 Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Mon, 15 May 2023 19:32:17 +0200 Subject: [PATCH 14/72] docs: Set minimal gtags / GNU GLOBAL version to 6.6.5 Kernel build now uses the gtags "-C (--directory)" option, available since GNU GLOBAL v6.6.5. Update the documentation accordingly. Signed-off-by: Ahmed S. Darwish Cc: Link: https://lists.gnu.org/archive/html/info-global/2020-09/msg00000.html Signed-off-by: Masahiro Yamada --- Documentation/process/changes.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index ef540865ad22..a9ef00509c9b 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -60,6 +60,7 @@ openssl & libcrypto 1.0.0 openssl version bc 1.06.95 bc --version Sphinx\ [#f1]_ 1.7 sphinx-build --version cpio any cpio --version +gtags (optional) 6.6.5 gtags --version ====================== =============== ======================================== .. [#f1] Sphinx is needed only to build the Kernel documentation @@ -174,6 +175,12 @@ You will need openssl to build kernels 3.7 and higher if module signing is enabled. You will also need openssl development packages to build kernels 4.3 and higher. +gtags / GNU GLOBAL (optional) +----------------------------- + +The kernel build requires GNU GLOBAL version 6.6.5 or later to generate +tag files through ``make gtags``. This is due to its use of the gtags +``-C (--directory)`` flag. System utilities **************** From 49c386ebbb43394ff4773ce24f726f6afc4c30c8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 21 May 2023 22:23:35 +0900 Subject: [PATCH 15/72] Revert "kheaders: substituting --sort in archive creation" This reverts commit 700dea5a0bea9f64eba89fae7cb2540326fdfdc1. The reason for that commit was --sort=ORDER introduced in tar 1.28 (2014). More than 3 years have passed since then. Requiring GNU tar 1.28 should be fine now because we require GCC 5.1 (2015). Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- kernel/gen_kheaders.sh | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh index 1ef9a87511f5..6d443ea22bb7 100755 --- a/kernel/gen_kheaders.sh +++ b/kernel/gen_kheaders.sh @@ -83,12 +83,9 @@ find $cpio_dir -type f -print0 | xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;' # Create archive and try to normalize metadata for reproducibility. -# For compatibility with older versions of tar, files are fed to tar -# pre-sorted, as --sort=name might not be available. -find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \ - tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ - --owner=0 --group=0 --numeric-owner --no-recursion \ - -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null +tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \ + --owner=0 --group=0 --sort=name --numeric-owner \ + -I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null echo $headers_md5 > kernel/kheaders.md5 echo "$this_file_md5" >> kernel/kheaders.md5 From c584476d477e7617478dc9a305350629aa155f5c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 21 May 2023 22:23:36 +0900 Subject: [PATCH 16/72] doc: Add tar requirement to changes.rst tar is used to build the kernel with CONFIG_IKHEADERS. GNU tar 1.28 or later is required. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Documentation/process/changes.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index a9ef00509c9b..3c0074214d75 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -60,6 +60,7 @@ openssl & libcrypto 1.0.0 openssl version bc 1.06.95 bc --version Sphinx\ [#f1]_ 1.7 sphinx-build --version cpio any cpio --version +GNU tar 1.28 tar --version gtags (optional) 6.6.5 gtags --version ====================== =============== ======================================== @@ -175,6 +176,12 @@ You will need openssl to build kernels 3.7 and higher if module signing is enabled. You will also need openssl development packages to build kernels 4.3 and higher. +Tar +--- + +GNU tar is needed if you want to enable access to the kernel headers via sysfs +(CONFIG_IKHEADERS). + gtags / GNU GLOBAL (optional) ----------------------------- From 17b53f10aba7c17e92bcf713179bc577cba059b7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:06 +0900 Subject: [PATCH 17/72] Revert "modpost: skip ELF local symbols during section mismatch check" This reverts commit a4d26f1a0958bb1c2b60c6f1e67c6f5d43e2647b. The variable 'fromsym' never starts with ".L" since commit 87e5b1e8f257 ("module: Sync code of is_arm_mapping_symbol()"). In other words, Pattern 6 is now dead code. Previously, the .LANCHOR1 hid the symbols listed in Pattern 2. 87e5b1e8f257 provided a better solution. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 0d2c2aff2c03..71de14544432 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1034,14 +1034,6 @@ static const struct sectioncheck *section_mismatch( * fromsec = text section * refsymname = *.constprop.* * - * Pattern 6: - * Hide section mismatch warnings for ELF local symbols. The goal - * is to eliminate false positive modpost warnings caused by - * compiler-generated ELF local symbol names such as ".LANCHOR1". - * Autogenerated symbol names bypass modpost's "Pattern 2" - * whitelisting, which relies on pattern-matching against symbol - * names to work. (One situation where gcc can autogenerate ELF - * local symbols is when "-fsection-anchors" is used.) **/ static int secref_whitelist(const struct sectioncheck *mismatch, const char *fromsec, const char *fromsym, @@ -1092,10 +1084,6 @@ static int secref_whitelist(const struct sectioncheck *mismatch, match(fromsym, optim_symbols)) return 0; - /* Check for pattern 6 */ - if (strstarts(fromsym, ".L")) - return 0; - return 1; } From 05bb0704672dec59cbdc6b901130098ecfe7a846 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:09 +0900 Subject: [PATCH 18/72] modpost: remove unused argument from secref_whitelist() secref_whitelist() does not use the argument 'mismatch'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 71de14544432..c0b262b68d50 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1035,8 +1035,7 @@ static const struct sectioncheck *section_mismatch( * refsymname = *.constprop.* * **/ -static int secref_whitelist(const struct sectioncheck *mismatch, - const char *fromsec, const char *fromsym, +static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ @@ -1202,7 +1201,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, tosym = sym_name(elf, to); /* check whitelist - we may ignore it */ - if (!secref_whitelist(mismatch, fromsec, fromsym, tosec, tosym)) + if (!secref_whitelist(fromsec, fromsym, tosec, tosym)) return; sec_mismatch_count++; From a23e7584ecf33df2b27ac176185c7b030ab0736f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:11 +0900 Subject: [PATCH 19/72] modpost: unify 'sym' and 'to' in default_mismatch_handler() find_tosym() takes 'sym' and stores the return value to another variable 'to'. You can use the same variable because we want to replace the original one when appropriate. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c0b262b68d50..9290e0f804cf 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1185,11 +1185,10 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, + Elf_Rela *r, Elf_Sym *tsym, unsigned int fsecndx, const char *fromsec, const char *tosec) { - Elf_Sym *to; Elf_Sym *from; const char *tosym; const char *fromsym; @@ -1197,8 +1196,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, from = find_fromsym(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); - to = find_tosym(elf, r->r_addend, sym); - tosym = sym_name(elf, to); + tsym = find_tosym(elf, r->r_addend, tsym); + tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ if (!secref_whitelist(fromsec, fromsym, tosec, tosym)) @@ -1233,7 +1232,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (is_executable_section(elf, get_secindex(elf, sym))) + else if (is_executable_section(elf, get_secindex(elf, tsym))) warn("The relocation at %s+0x%lx references\n" "section \"%s\" which is not in the list of\n" "authorized sections. If you're adding a new section\n" From 04ed3b476306c1b4c6e544e40d10f477c8193435 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:12 +0900 Subject: [PATCH 20/72] modpost: replace r->r_offset, r->r_addend with faddr, taddr r_offset/r_addend holds the offset address from/to which a symbol is referenced. It is unclear unless you are familiar with ELF. Rename them to faddr, taddr, respectively. The prefix 'f' means 'from', 't' means 'to'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 9290e0f804cf..c339d9eda402 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1185,18 +1185,18 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *tsym, - unsigned int fsecndx, const char *fromsec, - const char *tosec) + Elf_Sym *tsym, + unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, + const char *tosec, Elf_Addr taddr) { Elf_Sym *from; const char *tosym; const char *fromsym; - from = find_fromsym(elf, r->r_offset, fsecndx); + from = find_fromsym(elf, faddr, fsecndx); fromsym = sym_name(elf, from); - tsym = find_tosym(elf, r->r_addend, tsym); + tsym = find_tosym(elf, taddr, tsym); tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ @@ -1223,7 +1223,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, break; case EXTABLE_TO_NON_TEXT: warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym); + modname, fromsec, (long)faddr, tosec, tosym); if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" @@ -1231,7 +1231,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "Something is seriously wrong and should be fixed.\n" "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", - fromsec, (long)r->r_offset, tosec, modname); + fromsec, (long)faddr, tosec, modname); else if (is_executable_section(elf, get_secindex(elf, tsym))) warn("The relocation at %s+0x%lx references\n" "section \"%s\" which is not in the list of\n" @@ -1240,17 +1240,18 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "list of authorized sections to jump to on fault.\n" "This can be achieved by adding \"%s\" to\n" "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); + fromsec, (long)faddr, tosec, tosec, tosec); else error("%s+0x%lx references non-executable section '%s'\n", - fromsec, (long)r->r_offset, tosec); + fromsec, (long)faddr, tosec); break; } } static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, - unsigned int fsecndx, const char *fromsec) + Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec, + Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); @@ -1258,8 +1259,9 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fsecndx, fromsec, - tosec); + default_mismatch_handler(modname, elf, mismatch, sym, + fsecndx, fromsec, faddr, + tosec, taddr); } static unsigned int *reloc_location(struct elf_info *elf, @@ -1417,7 +1419,8 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); + check_section_mismatch(modname, elf, sym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1475,7 +1478,8 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); + check_section_mismatch(modname, elf, sym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } From a9bb3e5d57293773d7f925dd07e45f6e13e94947 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:13 +0900 Subject: [PATCH 21/72] modpost: remove is_shndx_special() check from section_rel(a) This check is unneeded. Without it, sec_name() will returns the null string "", then section_mismatch() will return immediately. Anyway, special section indices rarely appear in these loops. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 16 ++++------------ scripts/mod/modpost.h | 5 ----- 2 files changed, 4 insertions(+), 17 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c339d9eda402..1018cd9ced71 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1372,7 +1372,6 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) static void section_rela(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rela *rela; Elf_Rela r; unsigned int r_sym; @@ -1415,11 +1414,8 @@ static void section_rela(const char *modname, struct elf_info *elf, continue; break; } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - check_section_mismatch(modname, elf, sym, + + check_section_mismatch(modname, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1427,7 +1423,6 @@ static void section_rela(const char *modname, struct elf_info *elf, static void section_rel(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rel *rel; Elf_Rela r; unsigned int r_sym; @@ -1474,11 +1469,8 @@ static void section_rel(const char *modname, struct elf_info *elf, default: fatal("Please add code to calculate addend for this architecture\n"); } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - check_section_mismatch(modname, elf, sym, + + check_section_mismatch(modname, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 1178f40a73f3..b1e2d95f8047 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -151,11 +151,6 @@ struct elf_info { Elf32_Word *symtab_shndx_stop; }; -static inline int is_shndx_special(unsigned int i) -{ - return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE; -} - /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ static inline unsigned int get_secindex(const struct elf_info *info, const Elf_Sym *sym) From d4323e83505247d2aca1e2488f69da9aab8ad03f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:21 +0900 Subject: [PATCH 22/72] modpost: merge fromsec=DATA_SECTIONS entries in sectioncheck table You can merge these entries. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 1018cd9ced71..21417a4a7655 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -900,12 +900,7 @@ static const struct sectioncheck sectioncheck[] = { }, { .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_INIT, }, { From abc23979ac90396c5a5dff03dcea198b5bd0c50d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:22 +0900 Subject: [PATCH 23/72] modpost: merge bad_tosec=ALL_EXIT_SECTIONS entries in sectioncheck table There is no distinction between TEXT_TO_ANY_EXIT and DATA_TO_ANY_EXIT. Just merge them. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 21417a4a7655..cc4cf40a360f 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -859,8 +859,7 @@ static const char *const optim_symbols[] = { "*.constprop.*", NULL }; enum mismatch { TEXT_TO_ANY_INIT, DATA_TO_ANY_INIT, - TEXT_TO_ANY_EXIT, - DATA_TO_ANY_EXIT, + TEXTDATA_TO_ANY_EXIT, XXXINIT_TO_SOME_INIT, XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, @@ -904,14 +903,9 @@ static const struct sectioncheck sectioncheck[] = { .mismatch = DATA_TO_ANY_INIT, }, { - .fromsec = { TEXT_SECTIONS, NULL }, + .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_EXIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_EXIT, + .mismatch = TEXTDATA_TO_ANY_EXIT, }, /* Do not reference init code/data from meminit code/data */ { @@ -1203,8 +1197,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, switch (mismatch->mismatch) { case TEXT_TO_ANY_INIT: case DATA_TO_ANY_INIT: - case TEXT_TO_ANY_EXIT: - case DATA_TO_ANY_EXIT: + case TEXTDATA_TO_ANY_EXIT: case XXXINIT_TO_SOME_INIT: case XXXEXIT_TO_SOME_EXIT: case ANY_INIT_TO_ANY_EXIT: From 1df380ff3018521bd1b129dff60984b61ade8cee Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:23 +0900 Subject: [PATCH 24/72] modpost: remove *_sections[] arrays Use PATTERNS() macros to remove unneeded array definitions. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 36 +++++++++--------------------------- 1 file changed, 9 insertions(+), 27 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index cc4cf40a360f..7031e5da62e5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -838,24 +838,6 @@ static void check_section(const char *modname, struct elf_info *elf, #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ TEXT_SECTIONS, OTHER_TEXT_SECTIONS -/* init data sections */ -static const char *const init_data_sections[] = - { ALL_INIT_DATA_SECTIONS, NULL }; - -/* all init sections */ -static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; - -/* all text sections */ -static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; - -/* data section */ -static const char *const data_sections[] = { DATA_SECTIONS, NULL }; - -static const char *const head_sections[] = { ".head.text*", NULL }; -static const char *const linker_symbols[] = - { "__init_begin", "_sinittext", "_einittext", NULL }; -static const char *const optim_symbols[] = { "*.constprop.*", NULL }; - enum mismatch { TEXT_TO_ANY_INIT, DATA_TO_ANY_INIT, @@ -1028,14 +1010,14 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ - if (match(tosec, init_data_sections) && - match(fromsec, data_sections) && + if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) && + match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param")) return 0; /* Check for pattern 1a */ if (strcmp(tosec, ".init.text") == 0 && - match(fromsec, data_sections) && + match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param_ops_")) return 0; @@ -1058,18 +1040,18 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, return 0; /* Check for pattern 3 */ - if (match(fromsec, head_sections) && - match(tosec, init_sections)) + if (strstarts(fromsec, ".head.text") && + match(tosec, PATTERNS(ALL_INIT_SECTIONS))) return 0; /* Check for pattern 4 */ - if (match(tosym, linker_symbols)) + if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext"))) return 0; /* Check for pattern 5 */ - if (match(fromsec, text_sections) && - match(tosec, init_sections) && - match(fromsym, optim_symbols)) + if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) && + match(tosec, PATTERNS(ALL_INIT_SECTIONS)) && + match(fromsym, PATTERNS("*.constprop.*"))) return 0; return 1; From b7c63520f6703a25eebb4f8138fed764fcae1c6f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:55 +0900 Subject: [PATCH 25/72] modpost: fix section mismatch message for R_ARM_ABS32 addend_arm_rel() processes R_ARM_ABS32 in a wrong way. Here, test code. [test code 1] #include int __initdata foo; int get_foo(void) { return foo; } If you compile it with ARM versatile_defconfig, modpost will show the symbol name, (unknown). WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> (unknown) (section: .init.data) (You need to use GNU linker instead of LLD to reproduce it.) If you compile it for other architectures, modpost will show the correct symbol name. WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data) For R_ARM_ABS32, addend_arm_rel() sets r->r_addend to a wrong value. I just mimicked the code in arch/arm/kernel/module.c. However, there is more difficulty for ARM. Here, test code. [test code 2] #include int __initdata foo; int get_foo(void) { return foo; } int __initdata bar; int get_bar(void) { return bar; } With this commit applied, modpost will show the following messages for ARM versatile_defconfig: WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data) WARNING: modpost: vmlinux.o: section mismatch in reference: get_bar (section: .text) -> foo (section: .init.data) The reference from 'get_bar' to 'foo' seems wrong. I have no solution for this because it is true in assembly level. In the following output, relocation at 0x1c is no longer associated with 'bar'. The two relocation entries point to the same symbol, and the offset to 'bar' is encoded in the instruction 'r0, [r3, #4]'. Disassembly of section .text: 00000000 : 0: e59f3004 ldr r3, [pc, #4] @ c 4: e5930000 ldr r0, [r3] 8: e12fff1e bx lr c: 00000000 .word 0x00000000 00000010 : 10: e59f3004 ldr r3, [pc, #4] @ 1c 14: e5930004 ldr r0, [r3, #4] 18: e12fff1e bx lr 1c: 00000000 .word 0x00000000 Relocation section '.rel.text' at offset 0x244 contains 2 entries: Offset Info Type Sym.Value Sym. Name 0000000c 00000c02 R_ARM_ABS32 00000000 .init.data 0000001c 00000c02 R_ARM_ABS32 00000000 .init.data When find_elf_symbol() gets into a situation where relsym->st_name is zero, there is no guarantee to get the symbol name as written in C. I am keeping the current logic because it is useful in many architectures, but the symbol name is not always correct depending on the optimization. I left some comments in find_tosym(). Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 7031e5da62e5..c68dad45ace2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1094,6 +1094,10 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, if (relsym->st_name != 0) return relsym; + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ relsym_secindex = get_secindex(elf, relsym); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != relsym_secindex) @@ -1276,12 +1280,14 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); + Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); + void *loc = reloc_location(elf, sechdr, r); + uint32_t inst; switch (r_typ) { case R_ARM_ABS32: - /* From ARM ABI: (S + A) | T */ - r->r_addend = (int)(long) - (elf->symtab_start + ELF_R_SYM(r->r_info)); + inst = TO_NATIVE(*(uint32_t *)loc); + r->r_addend = inst + sym->st_value; break; case R_ARM_PC24: case R_ARM_CALL: From 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:56 +0900 Subject: [PATCH 26/72] modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24} addend_arm_rel() processes R_ARM_PC24, R_ARM_CALL, R_ARM_JUMP24 in a wrong way. Here, test code. [test code for R_ARM_JUMP24] .section .init.text,"ax" bar: bx lr .section .text,"ax" .globl foo foo: b bar [test code for R_ARM_CALL] .section .init.text,"ax" bar: bx lr .section .text,"ax" .globl foo foo: push {lr} bl bar pop {pc} If you compile it with ARM multi_v7_defconfig, modpost will show the symbol name, (unknown). WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text) (You need to use GNU linker instead of LLD to reproduce it.) Fix the code to make modpost show the correct symbol name. I imported (with adjustment) sign_extend32() from include/linux/bitops.h. The '+8' is the compensation for pc-relative instruction. It is documented in "ELF for the Arm Architecture" [1]. "If the relocation is pc-relative then compensation for the PC bias (the PC value is 8 bytes ahead of the executing instruction in Arm state and 4 bytes in Thumb state) must be encoded in the relocation by the object producer." [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm") Fixes: 6e2e340b59d2 ("ARM: 7324/1: modpost: Fix section warnings for ARM for many compilers") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c68dad45ace2..e47bba7cfad2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1277,12 +1277,20 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_ARM_THM_JUMP19 51 #endif +static int32_t sign_extend32(int32_t value, int index) +{ + uint8_t shift = 31 - index; + + return (int32_t)(value << shift) >> shift; +} + static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); uint32_t inst; + int32_t offset; switch (r_typ) { case R_ARM_ABS32: @@ -1292,6 +1300,10 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: + inst = TO_NATIVE(*(uint32_t *)loc); + offset = sign_extend32((inst & 0x00ffffff) << 2, 25); + r->r_addend = offset + sym->st_value + 8; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: case R_ARM_THM_JUMP19: From 12ca2c67d742d390c0aa1f8c1cfc49469df55ddf Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:57 +0900 Subject: [PATCH 27/72] modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS} For ARM defconfig (i.e. multi_v7_defconfig), modpost fails to detect some types of section mismatches. [test code] #include int __initdata foo; int get_foo(void) { return foo; } It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.text' at offset 0x200 contains 2 entries: Offset Info Type Sym.Value Sym. Name 00000000 0000062b R_ARM_MOVW_ABS_NC 00000000 .LANCHOR0 00000004 0000062c R_ARM_MOVT_ABS 00000000 .LANCHOR0 Currently, R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS are just skipped. Add code to handle them. I checked arch/arm/kernel/module.c to learn how the offset is encoded in the instruction. The referenced symbol in relocation might be a local anchor. If is_valid_name() returns false, let's search for a better symbol name. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e47bba7cfad2..5a5e802b160c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1078,7 +1078,7 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) /** * Find symbol based on relocation record info. * In some cases the symbol supplied is a valid symbol so - * return refsym. If st_name != 0 we assume this is a valid symbol. + * return refsym. If is_valid_name() == true, we assume this is a valid symbol. * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ @@ -1091,7 +1091,7 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, Elf64_Sword d; unsigned int relsym_secindex; - if (relsym->st_name != 0) + if (is_valid_name(elf, relsym)) return relsym; /* @@ -1297,6 +1297,13 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) inst = TO_NATIVE(*(uint32_t *)loc); r->r_addend = inst + sym->st_value; break; + case R_ARM_MOVW_ABS_NC: + case R_ARM_MOVT_ABS: + inst = TO_NATIVE(*(uint32_t *)loc); + offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff), + 15); + r->r_addend = offset + sym->st_value; + break; case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: From b1a9651d48b42f3eddf095123c09f93e4df23060 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:58 +0900 Subject: [PATCH 28/72] modpost: refactor find_fromsym() and find_tosym() find_fromsym() and find_tosym() are similar - both of them iterate in the .symtab section and return the nearest symbol. The difference between them is that find_tosym() allows a negative distance, but the distance must be less than 20. Factor out the common part into find_nearest_sym(). Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 95 ++++++++++++++++--------------------------- 1 file changed, 36 insertions(+), 59 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 5a5e802b160c..32d56efe3f3b 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1075,81 +1075,58 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) return !is_mapping_symbol(name); } -/** - * Find symbol based on relocation record info. - * In some cases the symbol supplied is a valid symbol so - * return refsym. If is_valid_name() == true, we assume this is a valid symbol. - * In other cases the symbol needs to be looked up in the symbol table - * based on section and address. - * **/ -static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +/* Look up the nearest symbol based on the section and the address */ +static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf64_Sword distance = 20; - Elf64_Sword d; - unsigned int relsym_secindex; - - if (is_valid_name(elf, relsym)) - return relsym; - - /* - * Strive to find a better symbol name, but the resulting name may not - * match the symbol referenced in the original code. - */ - relsym_secindex = get_secindex(elf, relsym); - for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (get_secindex(elf, sym) != relsym_secindex) - continue; - if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) - continue; - if (!is_valid_name(elf, sym)) - continue; - if (sym->st_value == addr) - return sym; - /* Find a symbol nearby - addr are maybe negative */ - d = sym->st_value - addr; - if (d < 0) - d = addr - sym->st_value; - if (d < distance) { - distance = d; - near = sym; - } - } - /* We need a close match */ - if (distance < 20) - return near; - else - return NULL; -} - -/* - * Find symbols before or equal addr and after addr - in the section sec. - * If we find two symbols with equal offset prefer one with a valid name. - * The ELF format may have a better way to detect what type of symbol - * it is, but this works for now. - **/ -static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx) -{ - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr distance = ~0; + Elf_Addr distance; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; - if (sym->st_value <= addr && addr - sym->st_value <= distance) { + + if (addr >= sym->st_value) distance = addr - sym->st_value; + else if (allow_negative) + distance = sym->st_value - addr; + else + continue; + + if (distance <= min_distance) { + min_distance = distance; near = sym; } + + if (min_distance == 0) + break; } return near; } +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) +{ + return find_nearest_sym(elf, addr, secndx, false, ~0); +} + +static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) +{ + /* If the supplied symbol has a valid name, return it */ + if (is_valid_name(elf, sym)) + return sym; + + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ + return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); +} + static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { if (secndx > elf->num_sections) From cd1824fb7a377882497e8b87a6f3a9ec19be3623 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:59 +0900 Subject: [PATCH 29/72] modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS} When CONFIG_THUMB2_KERNEL is enabled, modpost fails to detect some types of section mismatches. [test code] #include int __initdata foo; int get_foo(void) { return foo; } It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.text' at offset 0x1e8 contains 2 entries: Offset Info Type Sym.Value Sym. Name 00000000 0000052f R_ARM_THM_MOVW_AB 00000000 .LANCHOR0 00000004 00000530 R_ARM_THM_MOVT_AB 00000000 .LANCHOR0 Currently, R_ARM_THM_MOVW_ABS_NC and R_ARM_THM_MOVT_ABS are just skipped. Add code to handle them. I checked arch/arm/kernel/module.c to learn how the offset is encoded in the instruction. One more thing to note for Thumb instructions - the st_value is an odd value, so you need to mask the bit 0 to get the offset. Otherwise, you will get an off-by-one error in the nearest symbol look-up. It is documented in "ELF for the ARM Architecture" [1]: In addition to the normal rules for symbol values the following rules shall also apply to symbols of type STT_FUNC: * If the symbol addresses an Arm instruction, its value is the address of the instruction (in a relocatable object, the offset of the instruction from the start of the section containing it). * If the symbol addresses a Thumb instruction, its value is the address of the instruction with bit zero set (in a relocatable object, the section offset with bit zero set). * For the purposes of relocation the value used shall be the address of the instruction (st_value & ~1). [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 32d56efe3f3b..ec16f4d7e55a 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1082,7 +1082,8 @@ static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf_Addr distance; + Elf_Addr sym_addr, distance; + bool is_arm = (elf->hdr->e_machine == EM_ARM); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != secndx) @@ -1090,10 +1091,19 @@ static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, if (!is_valid_name(elf, sym)) continue; - if (addr >= sym->st_value) - distance = addr - sym->st_value; + sym_addr = sym->st_value; + + /* + * For ARM Thumb instruction, the bit 0 of st_value is set + * if the symbol is STT_FUNC type. Mask it to get the address. + */ + if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC) + sym_addr &= ~1; + + if (addr >= sym_addr) + distance = addr - sym_addr; else if (allow_negative) - distance = sym->st_value - addr; + distance = sym_addr - addr; else continue; @@ -1266,7 +1276,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); - uint32_t inst; + uint32_t inst, upper, lower; int32_t offset; switch (r_typ) { @@ -1288,6 +1298,17 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) offset = sign_extend32((inst & 0x00ffffff) << 2, 25); r->r_addend = offset + sym->st_value + 8; break; + case R_ARM_THM_MOVW_ABS_NC: + case R_ARM_THM_MOVT_ABS: + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + offset = sign_extend32(((upper & 0x000f) << 12) | + ((upper & 0x0400) << 1) | + ((lower & 0x7000) >> 4) | + (lower & 0x00ff), + 15); + r->r_addend = offset + sym->st_value; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: case R_ARM_THM_JUMP19: From 3310bae805250aec227eb056e8e61a246678f28a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:10:00 +0900 Subject: [PATCH 30/72] modpost: fix section_mismatch message for R_ARM_THM_{CALL,JUMP24,JUMP19} MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit addend_arm_rel() processes R_ARM_THM_CALL, R_ARM_THM_JUMP24, R_ARM_THM_JUMP19 in a wrong way. Here, test code. [test code for R_ARM_THM_JUMP24]   .section .init.text,"ax"   bar:           bx      lr   .section .text,"ax"   .globl foo   foo:           b       bar [test code for R_ARM_THM_CALL]   .section .init.text,"ax"   bar:           bx      lr   .section .text,"ax"   .globl foo   foo:           push    {lr}           bl      bar           pop     {pc} If you compile it with CONFIG_THUMB2_KERNEL=y, modpost will show the symbol name, (unknown).   WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text) (You need to use GNU linker instead of LLD to reproduce it.) Fix the code to make modpost show the correct symbol name. I checked arch/arm/kernel/module.c to learn the encoding of R_ARM_THM_CALL and R_ARM_THM_JUMP24. The module does not support R_ARM_THM_JUMP19, but I checked its encoding in ARM ARM. The '+4' is the compensation for pc-relative instruction. It is documented in "ELF for the Arm Architecture" [1].   "If the relocation is pc-relative then compensation for the PC bias   (the PC value is 8 bytes ahead of the executing instruction in Arm   state and 4 bytes in Thumb state) must be encoded in the relocation   by the object producer." [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Fixes: c9698e5cd6ad ("ARM: 7964/1: Detect section mismatches in thumb relocations") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 53 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 6 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ec16f4d7e55a..4e911ab711d4 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1276,7 +1276,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); - uint32_t inst, upper, lower; + uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; switch (r_typ) { @@ -1309,13 +1309,54 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 15); r->r_addend = offset + sym->st_value; break; + case R_ARM_THM_JUMP19: + /* + * Encoding T3: + * S = upper[10] + * imm6 = upper[5:0] + * J1 = lower[13] + * J2 = lower[11] + * imm11 = lower[10:0] + * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0') + */ + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + + sign = (upper >> 10) & 1; + j1 = (lower >> 13) & 1; + j2 = (lower >> 11) & 1; + offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) | + ((upper & 0x03f) << 12) | + ((lower & 0x07ff) << 1), + 20); + r->r_addend = offset + sym->st_value + 4; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: - case R_ARM_THM_JUMP19: - /* From ARM ABI: ((S + A) | T) - P */ - r->r_addend = (int)(long)(elf->hdr + - sechdr->sh_offset + - (r->r_offset - sechdr->sh_addr)); + /* + * Encoding T4: + * S = upper[10] + * imm10 = upper[9:0] + * J1 = lower[13] + * J2 = lower[11] + * imm11 = lower[10:0] + * I1 = NOT(J1 XOR S) + * I2 = NOT(J2 XOR S) + * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0') + */ + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + + sign = (upper >> 10) & 1; + j1 = (lower >> 13) & 1; + j2 = (lower >> 11) & 1; + offset = sign_extend32((sign << 24) | + ((~(j1 ^ sign) & 1) << 23) | + ((~(j2 ^ sign) & 1) << 22) | + ((upper & 0x03ff) << 12) | + ((lower & 0x07ff) << 1), + 24); + r->r_addend = offset + sym->st_value + 4; break; default: return 1; From 2cb749466d179e3ccfe83eb8a52dc002d07b08af Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:10:01 +0900 Subject: [PATCH 31/72] modpost: detect section mismatch for R_ARM_REL32 For ARM, modpost fails to detect some types of section mismatches. [test code] .section .init.data,"aw" bar: .long 0 .section .data,"aw" .globl foo foo: .long bar - . It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.data' at offset 0xe8 contains 1 entry: Offset Info Type Sym.Value Sym. Name 00000000 00000403 R_ARM_REL32 00000000 .init.data Currently, R_ARM_REL32 is just skipped. Handle it like R_ARM_ABS32. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 1 + 1 file changed, 1 insertion(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 4e911ab711d4..d10f5bdcb753 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1281,6 +1281,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) switch (r_typ) { case R_ARM_ABS32: + case R_ARM_REL32: inst = TO_NATIVE(*(uint32_t *)loc); r->r_addend = inst + sym->st_value; break; From 08f6554ff90ef189e6b8f0303e57005bddfdd6a7 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 1 Jun 2023 11:38:24 -0700 Subject: [PATCH 32/72] mips: Include KBUILD_CPPFLAGS in CHECKFLAGS invocation A future change will move CLANG_FLAGS from KBUILD_{A,C}FLAGS to KBUILD_CPPFLAGS so that '--target' is available while preprocessing. When that occurs, the following error appears when building ARCH=mips with clang (tip of tree error shown): clang: error: unsupported option '-mabi=' for target 'x86_64-pc-linux-gnu' Add KBUILD_CPPFLAGS in the CHECKFLAGS invocation to keep everything working after the move. Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- arch/mips/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..ef7b05ae92ce 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -346,7 +346,7 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_LDFLAGS += -m $(ld-emul) ifdef CONFIG_MIPS -CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \ +CHECKFLAGS += $(shell $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \ grep -E -vw '__GNUC_(MINOR_|PATCHLEVEL_)?_' | \ sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g') endif From a7e5eb53bf9b800d086e2ebcfebd9a3bb16bd1b0 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 1 Jun 2023 11:46:33 -0700 Subject: [PATCH 33/72] powerpc/vdso: Include CLANG_FLAGS explicitly in ldflags-y A future change will move CLANG_FLAGS from KBUILD_{A,C}FLAGS to KBUILD_CPPFLAGS so that '--target' is available while preprocessing. When that occurs, the following error appears when building the compat PowerPC vDSO: clang: error: unsupported option '-mbig-endian' for target 'x86_64-pc-linux-gnu' make[3]: *** [.../arch/powerpc/kernel/vdso/Makefile:76: arch/powerpc/kernel/vdso/vdso32.so.dbg] Error 1 Explicitly add CLANG_FLAGS to ldflags-y, so that '--target' will always be present. Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- arch/powerpc/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index 4c3f34485f08..23d3caf27d6d 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -54,7 +54,7 @@ KASAN_SANITIZE := n KCSAN_SANITIZE := n ccflags-y := -fno-common -fno-builtin -ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack +ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS) ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld) # Filter flags that clang will warn are unused for linking ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS)) From cff6e7f50bd315e5b39c4e46c704ac587ceb965f Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 1 Jun 2023 12:50:39 -0700 Subject: [PATCH 34/72] kbuild: Add CLANG_FLAGS to as-instr A future change will move CLANG_FLAGS from KBUILD_{A,C}FLAGS to KBUILD_CPPFLAGS so that '--target' is available while preprocessing. When that occurs, the following errors appear multiple times when building ARCH=powerpc powernv_defconfig: ld.lld: error: vmlinux.a(arch/powerpc/kernel/head_64.o):(.text+0x12d4): relocation R_PPC64_ADDR16_HI out of range: -4611686018409717520 is not in [-2147483648, 2147483647]; references '__start___soft_mask_table' ld.lld: error: vmlinux.a(arch/powerpc/kernel/head_64.o):(.text+0x12e8): relocation R_PPC64_ADDR16_HI out of range: -4611686018409717392 is not in [-2147483648, 2147483647]; references '__stop___soft_mask_table' Diffing the .o.cmd files reveals that -DHAVE_AS_ATHIGH=1 is not present anymore, because as-instr only uses KBUILD_AFLAGS, which will no longer contain '--target'. Mirror Kconfig's as-instr and add CLANG_FLAGS explicitly to the invocation to ensure the target information is always present. Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- scripts/Makefile.compiler | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index 7aa1fbc4aafe..437013f8def3 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -38,7 +38,7 @@ as-option = $(call try-run,\ # Usage: aflags-y += $(call as-instr,instr,option1,option2) as-instr = $(call try-run,\ - printf "%b\n" "$(1)" | $(CC) -Werror $(KBUILD_AFLAGS) -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3)) + printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3)) # __cc-option # Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586) From feb843a469fb0ab00d2d23cfb9bcc379791011bb Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 9 Apr 2023 23:53:57 +0900 Subject: [PATCH 35/72] kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS When preprocessing arch/*/kernel/vmlinux.lds.S, the target triple is not passed to $(CPP) because we add it only to KBUILD_{C,A}FLAGS. As a result, the linker script is preprocessed with predefined macros for the build host instead of the target. Assuming you use an x86 build machine, compare the following: $ clang -dM -E -x c /dev/null $ clang -dM -E -x c /dev/null -target aarch64-linux-gnu There is no actual problem presumably because our linker scripts do not rely on such predefined macros, but it is better to define correct ones. Move $(CLANG_FLAGS) to KBUILD_CPPFLAGS, so that all *.c, *.S, *.lds.S will be processed with the proper target triple. [Note] After the patch submission, we got an actual problem that needs this commit. (CBL issue 1859) Link: https://github.com/ClangBuiltLinux/linux/issues/1859 Reported-by: Tom Rini Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor --- scripts/Makefile.clang | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 9076cc939e87..058a4c0f864e 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -34,6 +34,5 @@ CLANG_FLAGS += -Werror=unknown-warning-option CLANG_FLAGS += -Werror=ignored-optimization-argument CLANG_FLAGS += -Werror=option-ignored CLANG_FLAGS += -Werror=unused-command-line-argument -KBUILD_CFLAGS += $(CLANG_FLAGS) -KBUILD_AFLAGS += $(CLANG_FLAGS) +KBUILD_CPPFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS From 7f8256ae0efba344a9b113036b1d545a1f6cdaa7 Mon Sep 17 00:00:00 2001 From: Benjamin Gray Date: Tue, 6 Jun 2023 16:17:41 +1000 Subject: [PATCH 36/72] initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP gen_initramfs.sh has an internal dependency on KBUILD_BUILD_TIMESTAMP for generating file mtimes that is not exposed to make, so changing KBUILD_BUILD_TIMESTAMP will not trigger a rebuild of the archive. Declare the mtime date as a new parameter to gen_initramfs.sh to encode KBUILD_BUILD_TIMESTAMP in the shell command, thereby making make aware of the dependency. It will rebuild if KBUILD_BUILD_TIMESTAMP changes or is newly set/unset. It will _not_ rebuild if KBUILD_BUILD_TIMESTAMP is unset before and after. This should be fine for anyone who doesn't care about setting specific build times in the first place. Reviewed-by: Andrew Donnellan Tested-by: Andrew Donnellan Signed-off-by: Benjamin Gray Reviewed-by: Nicolas Schier Signed-off-by: Masahiro Yamada --- usr/Makefile | 1 + usr/gen_initramfs.sh | 16 +++++++++------- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/usr/Makefile b/usr/Makefile index 59d9e8b07a01..f8e1ad19e05c 100644 --- a/usr/Makefile +++ b/usr/Makefile @@ -64,6 +64,7 @@ quiet_cmd_initfs = GEN $@ $(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d \ $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \ $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID)) \ + $(if $(KBUILD_BUILD_TIMESTAMP), -d "$(KBUILD_BUILD_TIMESTAMP)") \ $(ramfs-input) # We rebuild initramfs_data.cpio if: diff --git a/usr/gen_initramfs.sh b/usr/gen_initramfs.sh index 63476bb70b41..14b5782f961a 100755 --- a/usr/gen_initramfs.sh +++ b/usr/gen_initramfs.sh @@ -23,6 +23,7 @@ $0 [-o ] [-l ] [-u ] [-g ] {-d | } ... -g Group ID to map to group ID 0 (root). is only meaningful if is a directory. "squash" forces all files to gid 0. + -d Use date for all file mtime values File list or directory for cpio archive. If is a .cpio file it will be used as direct input to initramfs. @@ -190,6 +191,7 @@ prog=$0 root_uid=0 root_gid=0 dep_list= +timestamp= cpio_list=$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX) output="/dev/stdout" @@ -218,6 +220,13 @@ while [ $# -gt 0 ]; do [ "$root_gid" = "-1" ] && root_gid=$(id -g || echo 0) shift ;; + "-d") # date for file mtimes + timestamp="$(date -d"$1" +%s || :)" + if test -n "$timestamp"; then + timestamp="-t $timestamp" + fi + shift + ;; "-h") usage exit 0 @@ -237,11 +246,4 @@ done # If output_file is set we will generate cpio archive # we are careful to delete tmp files -timestamp= -if test -n "$KBUILD_BUILD_TIMESTAMP"; then - timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)" - if test -n "$timestamp"; then - timestamp="-t $timestamp" - fi -fi usr/gen_init_cpio $timestamp $cpio_list > $output From 20ff36856fe00879f82de71fe6f1482ca1b72334 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 6 Jun 2023 18:41:59 +0900 Subject: [PATCH 37/72] modpost: propagate W=1 build option to modpost "No build warning" is a strong requirement these days, so you must fix all issues before enabling a new warning flag. We often add a new warning to W=1 first so that the kbuild test robot blocks new breakages. This commit allows modpost to show extra warnings only when W=1 (or KBUILD_EXTRA_WARN=1) is given. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/Makefile.modpost | 1 + scripts/mod/modpost.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 0980c58d8afc..074e27c0c140 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -47,6 +47,7 @@ modpost-args = \ $(if $(KBUILD_MODPOST_WARN),-w) \ $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ + $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \ -o $@ modpost-deps := $(MODPOST) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d10f5bdcb753..3ea5eb2b1029 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -42,6 +42,8 @@ static bool allow_missing_ns_imports; static bool error_occurred; +static bool extra_warn; + /* * Cut off the warnings when there are too many. This typically occurs when * vmlinux is missing. ('make modules' without building vmlinux.) @@ -2199,7 +2201,7 @@ int main(int argc, char **argv) LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; - while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:o:aWwENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2224,6 +2226,9 @@ int main(int argc, char **argv) case 'T': files_source = optarg; break; + case 'W': + extra_warn = true; + break; case 'w': warn_unresolved = true; break; From ec336aa83162fe0f3d554baed2d4e2589b69ec6e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?= Date: Tue, 6 Jun 2023 17:35:53 +0000 Subject: [PATCH 38/72] scripts/mksysmap: Fix badly escaped '$' MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The backslash characters escaping '$' in the command to sed (intended to prevent it from interpreting '$' as "end-of-line") are currently being consumed by the Shell (where they mean that sh should not evaluate what follows '$' as a variable name). This means that sed -e "/ \$/d" executes the script / $/d instead of the intended / \$/d So escape twice in mksysmap any '$' that actually needs to reach sed escaped so that the backslash survives the Shell. Fixes: c4802044a0a7 ("scripts/mksysmap: use sed with in-line comments") Fixes: 320e7c9d4494 ("scripts/kallsyms: move compiler-generated symbol patterns to mksysmap") Signed-off-by: Pierre-Clément Tosi Signed-off-by: Masahiro Yamada --- scripts/mksysmap | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scripts/mksysmap b/scripts/mksysmap index cb3b1fff3eee..ec3338526102 100755 --- a/scripts/mksysmap +++ b/scripts/mksysmap @@ -32,7 +32,7 @@ ${NM} -n ${1} | sed >${2} -e " # (do not forget a space before each pattern) # local symbols for ARM, MIPS, etc. -/ \$/d +/ \\$/d # local labels, .LBB, .Ltmpxxx, .L__unnamed_xx, .LASANPC, etc. / \.L/d @@ -41,7 +41,7 @@ ${NM} -n ${1} | sed >${2} -e " / __efistub_/d # arm64 local symbols in non-VHE KVM namespace -/ __kvm_nvhe_\$/d +/ __kvm_nvhe_\\$/d / __kvm_nvhe_\.L/d # arm64 lld From 200dd957a7a72278363a8f2a49d2e90491bdb1b4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?= Date: Tue, 6 Jun 2023 18:19:36 +0000 Subject: [PATCH 39/72] scripts/mksysmap: Ignore __pi_ local arm64 symbols MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Similarly to "__kvm_nvhe_", filter out any local symbol that was prefixed with "__pi_" (generated when CONFIG_RANDOMIZE_BASE=y) when compiling System.map and in kallsyms. Signed-off-by: Pierre-Clément Tosi Acked-by: Ard Biesheuvel Signed-off-by: Masahiro Yamada --- scripts/mksysmap | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/scripts/mksysmap b/scripts/mksysmap index ec3338526102..26f39772f7a5 100755 --- a/scripts/mksysmap +++ b/scripts/mksysmap @@ -40,6 +40,10 @@ ${NM} -n ${1} | sed >${2} -e " # arm64 EFI stub namespace / __efistub_/d +# arm64 local symbols in PIE namespace +/ __pi_\\$/d +/ __pi_\.L/d + # arm64 local symbols in non-VHE KVM namespace / __kvm_nvhe_\\$/d / __kvm_nvhe_\.L/d From 43fc0a99906e04792786edf8534d8d58d1e9de0c Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 6 Jun 2023 15:40:35 -0700 Subject: [PATCH 40/72] kbuild: Add KBUILD_CPPFLAGS to as-option invocation After commit feb843a469fb ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS"), there is an error while building certain PowerPC assembly files with clang: arch/powerpc/lib/copypage_power7.S: Assembler messages: arch/powerpc/lib/copypage_power7.S:34: Error: junk at end of line: `0b01000' arch/powerpc/lib/copypage_power7.S:35: Error: junk at end of line: `0b01010' arch/powerpc/lib/copypage_power7.S:37: Error: junk at end of line: `0b01000' arch/powerpc/lib/copypage_power7.S:38: Error: junk at end of line: `0b01010' arch/powerpc/lib/copypage_power7.S:40: Error: junk at end of line: `0b01010' clang: error: assembler command failed with exit code 1 (use -v to see invocation) as-option only uses KBUILD_AFLAGS, so after removing CLANG_FLAGS from KBUILD_AFLAGS, there is no more '--target=' or '--prefix=' flags. As a result of those missing flags, the host target will be tested during as-option calls and likely fail, meaning necessary flags may not get added when building assembly files, resulting in errors like seen above. Add KBUILD_CPPFLAGS to as-option invocations to clear up the errors. This should have been done in commit d5c8d6e0fa61 ("kbuild: Update assembler calls to use proper flags and language target"), which switched from using the assembler target to the assembler-with-cpp target, so flags that affect preprocessing are passed along in all relevant tests. as-option now mirrors cc-option. Fixes: feb843a469fb ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS") Reported-by: Linux Kernel Functional Testing Closes: https://lore.kernel.org/CA+G9fYs=koW9WardsTtora+nMgLR3raHz-LSLr58tgX4T5Mxag@mail.gmail.com/ Signed-off-by: Nathan Chancellor Tested-by: Naresh Kamboju Signed-off-by: Masahiro Yamada --- scripts/Makefile.compiler | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index 437013f8def3..e31f18625fcf 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -32,7 +32,7 @@ try-run = $(shell set -e; \ # Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,) as-option = $(call try-run,\ - $(CC) -Werror $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2)) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2)) # as-instr # Usage: aflags-y += $(call as-instr,instr,option1,option2) From 98d7c7544a3a9f2713dc0f729bca4ab05fbc6e7f Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 7 Jun 2023 08:14:17 +0200 Subject: [PATCH 41/72] streamline_config.pl: handle also ${CONFIG_FOO} streamline_config.pl currently searches for CONFIG options in Kconfig files as $(CONFIG_FOO). But some Kconfigs (e.g. thunderbolt) use ${CONFIG_FOO}. So fix up the regex to accept both. This fixes: $ make LSMOD=`pwd/`/lsmod localmodconfig using config: '.config' thunderbolt config not found!! Signed-off-by: Jiri Slaby Reviewed-by: Mika Westerberg Acked-by: Steven Rostedt (Google) Signed-off-by: Masahiro Yamada --- scripts/kconfig/streamline_config.pl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl index 3387ad7508f7..d51cd7ac15d2 100755 --- a/scripts/kconfig/streamline_config.pl +++ b/scripts/kconfig/streamline_config.pl @@ -317,7 +317,7 @@ foreach my $makefile (@makefiles) { $_ = convert_vars($_, %make_vars); # collect objects after obj-$(CONFIG_FOO_BAR) - if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) { + if (/obj-\$[({](CONFIG_[^})]*)[)}]\s*[+:]?=\s*(.*)/) { $var = $1; $objs = $2; From 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 8 Jun 2023 11:23:40 +0300 Subject: [PATCH 42/72] modpost: fix off by one in is_executable_section() The > comparison should be >= to prevent an out of bounds array access. Fixes: 52dc0595d540 ("modpost: handle relocations mismatch in __ex_table.") Signed-off-by: Dan Carpenter Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3ea5eb2b1029..8decf04633bc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1141,7 +1141,7 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { - if (secndx > elf->num_sections) + if (secndx >= elf->num_sections) return false; return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0; From 56b0f453db74207633019f83758b4c11c66b75d0 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 9 Jun 2023 10:46:41 +0200 Subject: [PATCH 43/72] kernel-doc: don't let V=1 change outcome The kernel-doc script currently reports a number of issues only in "verbose" mode, but that's initialized from V=1 (via KBUILD_VERBOSE), so if you use KDOC_WERROR=1 then adding V=1 might actually break the build. This is rather unexpected. Change kernel-doc to not change its behaviour wrt. errors (or warnings) when verbose mode is enabled, but rather add separate warning flags (and -Wall) for it. Allow enabling those flags via environment/make variables in the kernel's build system for easier user use, but to not have to parse them in the script itself. Signed-off-by: Johannes Berg Acked-by: Jonathan Corbet Signed-off-by: Masahiro Yamada --- Documentation/kbuild/kbuild.rst | 6 ++++++ scripts/Makefile.build | 2 +- scripts/kernel-doc | 28 +++++++++++++++++++++++----- 3 files changed, 30 insertions(+), 6 deletions(-) diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst index 2a22ddb1b848..bd906407e307 100644 --- a/Documentation/kbuild/kbuild.rst +++ b/Documentation/kbuild/kbuild.rst @@ -150,6 +150,12 @@ the UTS_MACHINE variable, and on some architectures also the kernel config. The value of KBUILD_DEBARCH is assumed (not checked) to be a valid Debian architecture. +KDOCFLAGS +--------- +Specify extra (warning/error) flags for kernel-doc checks during the build, +see scripts/kernel-doc for which flags are supported. Note that this doesn't +(currently) apply to documentation builds. + ARCH ---- Set ARCH to the architecture to be built. diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 9f94fc83f086..a0b4fb58201c 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -101,7 +101,7 @@ else ifeq ($(KBUILD_CHECKSRC),2) endif ifneq ($(KBUILD_EXTRA_WARN),) - cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< + cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) $< endif # Compile C sources (.c) diff --git a/scripts/kernel-doc b/scripts/kernel-doc index 2486689ffc7b..8f8440870a0f 100755 --- a/scripts/kernel-doc +++ b/scripts/kernel-doc @@ -23,7 +23,7 @@ kernel-doc - Print formatted kernel documentation to stdout =head1 SYNOPSIS - kernel-doc [-h] [-v] [-Werror] + kernel-doc [-h] [-v] [-Werror] [-Wall] [-Wreturn] [-Wshort-description] [-Wcontents-before-sections] [ -man | -rst [-sphinx-version VERSION] [-enable-lineno] | -none @@ -133,6 +133,9 @@ my $dohighlight = ""; my $verbose = 0; my $Werror = 0; +my $Wreturn = 0; +my $Wshort_desc = 0; +my $Wcontents_before_sections = 0; my $output_mode = "rst"; my $output_preformatted = 0; my $no_doc_sections = 0; @@ -187,9 +190,14 @@ if (defined($ENV{'KCFLAGS'})) { } } +# reading this variable is for backwards compat just in case +# someone was calling it with the variable from outside the +# kernel's build system if (defined($ENV{'KDOC_WERROR'})) { $Werror = "$ENV{'KDOC_WERROR'}"; } +# other environment variables are converted to command-line +# arguments in cmd_checkdoc in the build system # Generated docbook code is inserted in a template at a point where # docbook v3.1 requires a non-zero sequence of RefEntry's; see: @@ -318,6 +326,16 @@ while ($ARGV[0] =~ m/^--?(.*)/) { $verbose = 1; } elsif ($cmd eq "Werror") { $Werror = 1; + } elsif ($cmd eq "Wreturn") { + $Wreturn = 1; + } elsif ($cmd eq "Wshort-desc") { + $Wshort_desc = 1; + } elsif ($cmd eq "Wcontents-before-sections") { + $Wcontents_before_sections = 1; + } elsif ($cmd eq "Wall") { + $Wreturn = 1; + $Wshort_desc = 1; + $Wcontents_before_sections = 1; } elsif (($cmd eq "h") || ($cmd eq "help")) { pod2usage(-exitval => 0, -verbose => 2); } elsif ($cmd eq 'no-doc-sections') { @@ -1748,9 +1766,9 @@ sub dump_function($$) { # This check emits a lot of warnings at the moment, because many # functions don't have a 'Return' doc section. So until the number # of warnings goes sufficiently down, the check is only performed in - # verbose mode. + # -Wreturn mode. # TODO: always perform the check. - if ($verbose && !$noret) { + if ($Wreturn && !$noret) { check_return_section($file, $declaration_name, $return_type); } @@ -2054,7 +2072,7 @@ sub process_name($$) { $state = STATE_NORMAL; } - if (($declaration_purpose eq "") && $verbose) { + if (($declaration_purpose eq "") && $Wshort_desc) { emit_warning("${file}:$.", "missing initial short description on line:\n$_"); } @@ -2103,7 +2121,7 @@ sub process_body($$) { } if (($contents ne "") && ($contents ne "\n")) { - if (!$in_doc_sect && $verbose) { + if (!$in_doc_sect && $Wcontents_before_sections) { emit_warning("${file}:$.", "contents before sections\n"); } dump_section($file, $section, $contents); From dd203fefd9c9e28bc141d144e032e263804c90bb Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 9 Jun 2023 10:46:42 +0200 Subject: [PATCH 44/72] kbuild: enable kernel-doc -Wall for W=2 For W=2, we can enable more kernel-doc warnings, such as missing return value descriptions etc. Signed-off-by: Johannes Berg Signed-off-by: Masahiro Yamada --- scripts/Makefile.build | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a0b4fb58201c..ddd644bd032d 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -101,7 +101,9 @@ else ifeq ($(KBUILD_CHECKSRC),2) endif ifneq ($(KBUILD_EXTRA_WARN),) - cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) $< + cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) \ + $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \ + $< endif # Compile C sources (.c) From 8635e8df477bc77837886da206f4915576f88fec Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 10 Jun 2023 18:13:10 +0900 Subject: [PATCH 45/72] Revert "[PATCH] uml: export symbols added by GCC hardened" This reverts commit cead61a6717a9873426b08d73a34a325e3546f5d. It exported __stack_smash_handler and __guard, while they may not be defined by anyone. The code *declares* __stack_smash_handler and __guard. It does not create weak symbols. If no external library is linked, they are left undefined, but yet exported. If a loadable module tries to access non-existing symbols, bad things (a page fault, NULL pointer dereference, etc.) will happen. So, the current code is wrong and dangerous. If the code were written as follows, it would *define* them as weak symbols so modules would be able to get access to them. void (*__stack_smash_handler)(void *) __attribute__((weak)); EXPORT_SYMBOL(__stack_smash_handler); long __guard __attribute__((weak)); EXPORT_SYMBOL(__guard); In fact, modpost forbids exporting undefined symbols. It shows an error message if it detects such a mistake. ERROR: modpost: "..." [...] was exported without definition Unfortunately, it is checked only when the code is built as modular. The problem described above has been unnoticed for a long time because arch/um/os-Linux/user_syms.c is always built-in. With a planned change in Kbuild, exporting undefined symbols will always result in a build error instead of a run-time error. It is a good thing, but we need to fix the breakage in advance. One fix is to define weak symbols as shown above. An alternative is to export them conditionally as follows: #ifdef CONFIG_STACKPROTECTOR extern void __stack_smash_handler(void *); EXPORT_SYMBOL(__stack_smash_handler); external long __guard; EXPORT_SYMBOL(__guard); #endif This is what other architectures do; EXPORT_SYMBOL(__stack_chk_guard) is guarded by #ifdef CONFIG_STACKPROTECTOR. However, adding the #ifdef guard is not sensible because UML cannot enable the stack-protector in the first place! (Please note UML does not select HAVE_STACKPROTECTOR in Kconfig.) So, the code is already broken (and unused) in multiple ways. Just remove. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- arch/um/os-Linux/user_syms.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c index 9b62a9d352b3..a310ae27b479 100644 --- a/arch/um/os-Linux/user_syms.c +++ b/arch/um/os-Linux/user_syms.c @@ -37,13 +37,6 @@ EXPORT_SYMBOL(vsyscall_ehdr); EXPORT_SYMBOL(vsyscall_end); #endif -/* Export symbols used by GCC for the stack protector. */ -extern void __stack_smash_handler(void *) __attribute__((weak)); -EXPORT_SYMBOL(__stack_smash_handler); - -extern long __guard __attribute__((weak)); -EXPORT_SYMBOL(__guard); - #ifdef _FORTIFY_SOURCE extern int __sprintf_chk(char *str, int flag, size_t len, const char *format); EXPORT_SYMBOL(__sprintf_chk); From 92e74fb6e6196d642505ae2b74a8e327202afef9 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 5 Jun 2023 21:04:00 +0900 Subject: [PATCH 46/72] scripts/kallsyms: constify long_options getopt_long() does not modify this. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- scripts/kallsyms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 0d2db41177b2..8e97ac7b38a6 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -806,7 +806,7 @@ static void record_relative_base(void) int main(int argc, char **argv) { while (1) { - static struct option long_options[] = { + static const struct option long_options[] = { {"all-symbols", no_argument, &all_symbols, 1}, {"absolute-percpu", no_argument, &absolute_percpu, 1}, {"base-relative", no_argument, &base_relative, 1}, From 1c975da56a6f89a3e610cc86d92f65de3da7bd61 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 5 Jun 2023 21:26:04 +0900 Subject: [PATCH 47/72] scripts/kallsyms: remove KSYM_NAME_LEN_BUFFER You do not need to decide the buffer size statically. Use getline() to grow the line buffer as needed. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- scripts/kallsyms.c | 61 ++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 29 deletions(-) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 8e97ac7b38a6..d387c9381650 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -19,6 +19,7 @@ * */ +#include #include #include #include @@ -29,24 +30,8 @@ #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0])) -#define _stringify_1(x) #x -#define _stringify(x) _stringify_1(x) - #define KSYM_NAME_LEN 512 -/* - * A substantially bigger size than the current maximum. - * - * It cannot be defined as an expression because it gets stringified - * for the fscanf() format string. Therefore, a _Static_assert() is - * used instead to maintain the relationship with KSYM_NAME_LEN. - */ -#define KSYM_NAME_LEN_BUFFER 2048 -_Static_assert( - KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4, - "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN" -); - struct sym_entry { unsigned long long addr; unsigned int len; @@ -136,24 +121,40 @@ static void check_symbol_range(const char *sym, unsigned long long addr, } } -static struct sym_entry *read_symbol(FILE *in) +static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) { - char name[KSYM_NAME_LEN_BUFFER+1], type; + char *name, type, *p; unsigned long long addr; - unsigned int len; + size_t len; + ssize_t readlen; struct sym_entry *sym; - int rc; - rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name); - if (rc != 3) { - if (rc != EOF && fgets(name, ARRAY_SIZE(name), in) == NULL) - fprintf(stderr, "Read error or end of file.\n"); + readlen = getline(buf, buf_len, in); + if (readlen < 0) { + if (errno) { + perror("read_symbol"); + exit(EXIT_FAILURE); + } return NULL; } - if (strlen(name) >= KSYM_NAME_LEN) { + + if ((*buf)[readlen - 1] == '\n') + (*buf)[readlen - 1] = 0; + + addr = strtoull(*buf, &p, 16); + + if (*buf == p || *p++ != ' ' || !isascii((type = *p++)) || *p++ != ' ') { + fprintf(stderr, "line format error\n"); + exit(EXIT_FAILURE); + } + + name = p; + len = strlen(name); + + if (len >= KSYM_NAME_LEN) { fprintf(stderr, "Symbol %s too long for kallsyms (%zu >= %d).\n" "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n", - name, strlen(name), KSYM_NAME_LEN); + name, len, KSYM_NAME_LEN); return NULL; } @@ -169,8 +170,7 @@ static struct sym_entry *read_symbol(FILE *in) /* include the type field in the symbol name, so that it gets * compressed together */ - - len = strlen(name) + 1; + len++; sym = malloc(sizeof(*sym) + len + 1); if (!sym) { @@ -257,6 +257,8 @@ static void read_map(const char *in) { FILE *fp; struct sym_entry *sym; + char *buf = NULL; + size_t buflen = 0; fp = fopen(in, "r"); if (!fp) { @@ -265,7 +267,7 @@ static void read_map(const char *in) } while (!feof(fp)) { - sym = read_symbol(fp); + sym = read_symbol(fp, &buf, &buflen); if (!sym) continue; @@ -284,6 +286,7 @@ static void read_map(const char *in) table[table_cnt++] = sym; } + free(buf); fclose(fp); } From 92e2921eeafdfca9acd9b83f07d2b7ca099bac24 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:50 +0900 Subject: [PATCH 48/72] ARC: define ASM_NL and __ALIGN(_STR) outside #ifdef __ASSEMBLY__ guard ASM_NL is useful not only in *.S files but also in .c files for using inline assembler in C code. On ARC, however, ASM_NL is evaluated inconsistently. It is expanded to a backquote (`) in *.S files, but a semicolon (;) in *.c files because arch/arc/include/asm/linkage.h defines it inside #ifdef __ASSEMBLY__, so the definition for C code falls back to the default value defined in include/linux/linkage.h. If ASM_NL is used in inline assembler in .c files, it will result in wrong assembly code because a semicolon is not an instruction separator, but the start of a comment for ARC. Move ASM_NL (also __ALIGN and __ALIGN_STR) out of the #ifdef. Fixes: 9df62f054406 ("arch: use ASM_NL instead of ';' for assembler new line character in the macro") Fixes: 8d92e992a785 ("ARC: define __ALIGN_STR and __ALIGN symbols for ARC") Signed-off-by: Masahiro Yamada --- arch/arc/include/asm/linkage.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arc/include/asm/linkage.h b/arch/arc/include/asm/linkage.h index c9434ff3aa4c..8a3fb71e9cfa 100644 --- a/arch/arc/include/asm/linkage.h +++ b/arch/arc/include/asm/linkage.h @@ -8,6 +8,10 @@ #include +#define ASM_NL ` /* use '`' to mark new line in macro */ +#define __ALIGN .align 4 +#define __ALIGN_STR __stringify(__ALIGN) + #ifdef __ASSEMBLY__ .macro ST2 e, o, off @@ -28,10 +32,6 @@ #endif .endm -#define ASM_NL ` /* use '`' to mark new line in macro */ -#define __ALIGN .align 4 -#define __ALIGN_STR __stringify(__ALIGN) - /* annotation for data we want in DCCM - if enabled in .config */ .macro ARCFP_DATA nm #ifdef CONFIG_ARC_HAS_DCCM From 94d6cb68124b7a63f24fcc345795ba5f9a27e694 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:51 +0900 Subject: [PATCH 49/72] modpost: pass struct module pointer to check_section_mismatch() The next commit will use it. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 8decf04633bc..403ba4d923f5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1211,7 +1211,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } -static void check_section_mismatch(const char *modname, struct elf_info *elf, +static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) @@ -1222,7 +1222,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, sym, + default_mismatch_handler(mod->name, elf, mismatch, sym, fsecndx, fromsec, faddr, tosec, taddr); } @@ -1406,7 +1406,7 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_LARCH_SUB32 55 #endif -static void section_rela(const char *modname, struct elf_info *elf, +static void section_rela(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { Elf_Rela *rela; @@ -1452,12 +1452,12 @@ static void section_rela(const char *modname, struct elf_info *elf, break; } - check_section_mismatch(modname, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } -static void section_rel(const char *modname, struct elf_info *elf, +static void section_rel(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { Elf_Rel *rel; @@ -1507,7 +1507,7 @@ static void section_rel(const char *modname, struct elf_info *elf, fatal("Please add code to calculate addend for this architecture\n"); } - check_section_mismatch(modname, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1524,19 +1524,19 @@ static void section_rel(const char *modname, struct elf_info *elf, * to find all references to a section that reference a section that will * be discarded and warns about it. **/ -static void check_sec_ref(const char *modname, struct elf_info *elf) +static void check_sec_ref(struct module *mod, struct elf_info *elf) { int i; Elf_Shdr *sechdrs = elf->sechdrs; /* Walk through all sections */ for (i = 0; i < elf->num_sections; i++) { - check_section(modname, elf, &elf->sechdrs[i]); + check_section(mod->name, elf, &elf->sechdrs[i]); /* We want to process only relocation sections and not .init */ if (sechdrs[i].sh_type == SHT_RELA) - section_rela(modname, elf, &elf->sechdrs[i]); + section_rela(mod, elf, &elf->sechdrs[i]); else if (sechdrs[i].sh_type == SHT_REL) - section_rel(modname, elf, &elf->sechdrs[i]); + section_rel(mod, elf, &elf->sechdrs[i]); } } @@ -1707,7 +1707,7 @@ static void read_symbols(const char *modname) sym_get_data(&info, sym)); } - check_sec_ref(modname, &info); + check_sec_ref(mod, &info); if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); From ddb5cdbafaaad6b99d7007ae1740403124502d03 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:52 +0900 Subject: [PATCH 50/72] kbuild: generate KSYMTAB entries by modpost Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way whether the EXPORT_SYMBOL() is placed in *.c or *.S. For further cleanups, this commit applies a similar approach to the entire data structure of EXPORT_SYMBOL(). The EXPORT_SYMBOL() compilation is split into two stages. When a source file is compiled, EXPORT_SYMBOL() will be converted into a dummy symbol in the .export_symbol section. For example, EXPORT_SYMBOL(foo); EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE); will be encoded into the following assembly code: .section ".export_symbol","a" __export_symbol_foo: .asciz "" /* license */ .asciz "" /* name space */ .balign 8 .quad foo /* symbol reference */ .previous .section ".export_symbol","a" __export_symbol_bar: .asciz "GPL" /* license */ .asciz "BAR_NAMESPACE" /* name space */ .balign 8 .quad bar /* symbol reference */ .previous They are mere markers to tell modpost the name, license, and namespace of the symbols. They will be dropped from the final vmlinux and modules because the *(.export_symbol) will go into /DISCARD/ in the linker script. Then, modpost extracts all the information about EXPORT_SYMBOL() from the .export_symbol section, and generates the final C code: KSYMTAB_FUNC(foo, "", ""); KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE"); KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct kernel_symbol that will be linked to the vmlinux or a module. With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S files, providing the following benefits. [1] Deprecate EXPORT_DATA_SYMBOL() In the old days, EXPORT_SYMBOL() was only available in C files. To export a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file. arch/arm/kernel/armksyms.c is one example written in the classic manner. Commit 22823ab419d8 ("EXPORT_SYMBOL() for asm") removed this limitation. Since then, EXPORT_SYMBOL() can be placed close to the symbol definition in *.S files. It was a nice improvement. However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL() for data objects on some architectures. In the new approach, modpost checks symbol's type (STT_FUNC or not), and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly. There are only two users of EXPORT_DATA_SYMBOL: EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S) EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S) They are transformed as follows and output into .vmlinux.export.c KSYMTAB_DATA(empty_zero_page, "_gpl", ""); KSYMTAB_DATA(ia64_ivt, "", ""); The other EXPORT_SYMBOL users in ia64 assembly are output as KSYMTAB_FUNC(). EXPORT_DATA_SYMBOL() is now deprecated. [2] merge and There are two similar header implementations: include/linux/export.h for .c files include/asm-generic/export.h for .S files Ideally, the functionality should be consistent between them, but they tend to diverge. Commit 8651ec01daed ("module: add support for symbol namespaces.") did not support the namespace for *.S files. This commit shifts the essential implementation part to C, which supports EXPORT_SYMBOL_NS() for *.S files. and will remain as a wrapper of for a while. They will be removed after #include directives are all replaced with #include . [3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit) When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. We can do this better now; modpost can selectively emit KSYMTAB entries that are really used by modules. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- arch/ia64/include/asm/Kbuild | 1 + arch/ia64/include/asm/export.h | 3 - include/asm-generic/export.h | 84 ++--------------------- include/asm-generic/vmlinux.lds.h | 1 + include/linux/export-internal.h | 49 ++++++++++++++ include/linux/export.h | 101 ++++++++++++---------------- include/linux/pm.h | 4 +- kernel/module/internal.h | 12 ++++ scripts/Makefile.build | 8 +-- scripts/check-local-export | 4 +- scripts/mod/modpost.c | 106 ++++++++++++++++++++---------- scripts/mod/modpost.h | 1 + 12 files changed, 190 insertions(+), 184 deletions(-) delete mode 100644 arch/ia64/include/asm/export.h diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index aefae2efde9f..33733245f42b 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 generated-y += syscall_table.h generic-y += agp.h +generic-y += export.h generic-y += kvm_para.h generic-y += mcs_spinlock.h generic-y += vtime.h diff --git a/arch/ia64/include/asm/export.h b/arch/ia64/include/asm/export.h deleted file mode 100644 index ad18c6583252..000000000000 --- a/arch/ia64/include/asm/export.h +++ /dev/null @@ -1,3 +0,0 @@ -/* EXPORT_DATA_SYMBOL != EXPORT_SYMBOL here */ -#define KSYM_FUNC(name) @fptr(name) -#include diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 5e4b1f2369d2..0ae9f38a904c 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -3,86 +3,12 @@ #define __ASM_GENERIC_EXPORT_H /* - * This comment block is used by fixdep. Please do not remove. - * - * When CONFIG_MODVERSIONS is changed from n to y, all source files having - * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a - * side effect of the *.o build rule. + * and are deprecated. + * Please include directly. */ +#include -#ifndef KSYM_FUNC -#define KSYM_FUNC(x) x -#endif -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define KSYM_ALIGN 4 -#elif defined(CONFIG_64BIT) -#define KSYM_ALIGN 8 -#else -#define KSYM_ALIGN 4 -#endif - -.macro __put, val, name -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS - .long \val - ., \name - ., 0 -#elif defined(CONFIG_64BIT) - .quad \val, \name, 0 -#else - .long \val, \name, 0 -#endif -.endm - -/* - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ - -.macro ___EXPORT_SYMBOL name,val,sec -#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS) - .section ___ksymtab\sec+\name,"a" - .balign KSYM_ALIGN -__ksymtab_\name: - __put \val, __kstrtab_\name - .previous - .section __ksymtab_strings,"aMS",%progbits,1 -__kstrtab_\name: - .asciz "\name" - .previous -#endif -.endm - -#if defined(CONFIG_TRIM_UNUSED_KSYMS) - -#include -#include - -.macro __ksym_marker sym - .section ".discard.ksym","a" -__ksym_marker_\sym: - .previous -.endm - -#define __EXPORT_SYMBOL(sym, val, sec) \ - __ksym_marker sym; \ - __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym)) -#define __cond_export_sym(sym, val, sec, conf) \ - ___cond_export_sym(sym, val, sec, conf) -#define ___cond_export_sym(sym, val, sec, enabled) \ - __cond_export_sym_##enabled(sym, val, sec) -#define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#define __cond_export_sym_0(sym, val, sec) /* nothing */ - -#else -#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#endif - -#define EXPORT_SYMBOL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name),) -#define EXPORT_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name), _gpl) -#define EXPORT_DATA_SYMBOL(name) \ - __EXPORT_SYMBOL(name, name,) -#define EXPORT_DATA_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, name,_gpl) +#define EXPORT_DATA_SYMBOL(name) EXPORT_SYMBOL(name) +#define EXPORT_DATA_SYMBOL_GPL(name) EXPORT_SYMBOL_GPL(name) #endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..e65d55e8819c 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -1006,6 +1006,7 @@ PATCHABLE_DISCARDS \ *(.discard) \ *(.discard.*) \ + *(.export_symbol) \ *(.modinfo) \ /* ld.bfd warns about .gnu.version* even when not emitted */ \ *(.gnu.version*) \ diff --git a/include/linux/export-internal.h b/include/linux/export-internal.h index fe7e6ba918f1..1c849db953a5 100644 --- a/include/linux/export-internal.h +++ b/include/linux/export-internal.h @@ -10,6 +10,55 @@ #include #include +#if defined(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS) +/* + * relative reference: this reduces the size by half on 64-bit architectures, + * and eliminates the need for absolute relocations that require runtime + * processing on relocatable kernels. + */ +#define __KSYM_REF(sym) ".long " #sym "- ." +#elif defined(CONFIG_64BIT) +#define __KSYM_REF(sym) ".quad " #sym +#else +#define __KSYM_REF(sym) ".long " #sym +#endif + +/* + * For every exported symbol, do the following: + * + * - Put the name of the symbol and namespace (empty string "" for none) in + * __ksymtab_strings. + * - Place a struct kernel_symbol entry in the __ksymtab section. + * + * Note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) + * section flag requires it. Use '%progbits' instead of '@progbits' since the + * former apparently works on all arches according to the binutils source. + */ +#define __KSYMTAB(name, sym, sec, ns) \ + asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1" "\n" \ + "__kstrtab_" #name ":" "\n" \ + " .asciz \"" #name "\"" "\n" \ + "__kstrtabns_" #name ":" "\n" \ + " .asciz \"" ns "\"" "\n" \ + " .previous" "\n" \ + " .section \"___ksymtab" sec "+" #name "\", \"a\"" "\n" \ + " .balign 4" "\n" \ + "__ksymtab_" #name ":" "\n" \ + __KSYM_REF(sym) "\n" \ + __KSYM_REF(__kstrtab_ ##name) "\n" \ + __KSYM_REF(__kstrtabns_ ##name) "\n" \ + " .previous" "\n" \ + ) + +#ifdef CONFIG_IA64 +#define KSYM_FUNC(name) @fptr(name) +#else +#define KSYM_FUNC(name) name +#endif + +#define KSYMTAB_FUNC(name, sec, ns) __KSYMTAB(name, KSYM_FUNC(name), sec, ns) +#define KSYMTAB_DATA(name, sec, ns) __KSYMTAB(name, name, sec, ns) + #define SYMBOL_CRC(sym, crc, sec) \ asm(".section \"___kcrctab" sec "+" #sym "\",\"a\"" "\n" \ "__crc_" #sym ":" "\n" \ diff --git a/include/linux/export.h b/include/linux/export.h index 3f31ced0d977..a01868136717 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -2,6 +2,8 @@ #ifndef _LINUX_EXPORT_H #define _LINUX_EXPORT_H +#include +#include #include /* @@ -28,72 +30,41 @@ extern struct module __this_module; #else #define THIS_MODULE ((struct module *)0) #endif +#endif /* __ASSEMBLY__ */ -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#include -/* - * Emit the ksymtab entry as a pair of relative references: this reduces - * the size by half on 64-bit architectures, and eliminates the need for - * absolute relocations that require runtime processing on relocatable - * kernels. - */ -#define __KSYMTAB_ENTRY(sym, sec) \ - __ADDRESSABLE(sym) \ - asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ - " .balign 4 \n" \ - "__ksymtab_" #sym ": \n" \ - " .long " #sym "- . \n" \ - " .long __kstrtab_" #sym "- . \n" \ - " .long __kstrtabns_" #sym "- . \n" \ - " .previous \n") - -struct kernel_symbol { - int value_offset; - int name_offset; - int namespace_offset; -}; +#ifdef CONFIG_64BIT +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 8 ASM_NL \ + .quad sym #else -#define __KSYMTAB_ENTRY(sym, sec) \ - static const struct kernel_symbol __ksymtab_##sym \ - __attribute__((section("___ksymtab" sec "+" #sym), used)) \ - __aligned(sizeof(void *)) \ - = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } - -struct kernel_symbol { - unsigned long value; - const char *name; - const char *namespace; -}; +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 4 ASM_NL \ + .long sym #endif +#define ____EXPORT_SYMBOL(sym, license, ns) \ + .section ".export_symbol","a" ASM_NL \ + __export_symbol_##sym: ASM_NL \ + .asciz license ASM_NL \ + .asciz ns ASM_NL \ + __EXPORT_SYMBOL_REF(sym) ASM_NL \ + .previous + #ifdef __GENKSYMS__ #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) +#elif defined(__ASSEMBLY__) + +#define ___EXPORT_SYMBOL(sym, license, ns) \ + ____EXPORT_SYMBOL(sym, license, ns) + #else -/* - * For every exported symbol, do the following: - * - * - Put the name of the symbol and namespace (empty string "" for none) in - * __ksymtab_strings. - * - Place a struct kernel_symbol entry in the __ksymtab section. - * - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ -#define ___EXPORT_SYMBOL(sym, sec, ns) \ - extern typeof(sym) sym; \ - extern const char __kstrtab_##sym[]; \ - extern const char __kstrtabns_##sym[]; \ - asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ - "__kstrtab_" #sym ": \n" \ - " .asciz \"" #sym "\" \n" \ - "__kstrtabns_" #sym ": \n" \ - " .asciz \"" ns "\" \n" \ - " .previous \n"); \ - __KSYMTAB_ENTRY(sym, sec) +#define ___EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) #endif @@ -117,9 +88,21 @@ struct kernel_symbol { * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are * discarded in the final link stage. */ + +#ifdef __ASSEMBLY__ + +#define __ksym_marker(sym) \ + .section ".discard.ksym","a" ; \ +__ksym_marker_##sym: ; \ + .previous + +#else + #define __ksym_marker(sym) \ static int __ksym_marker_##sym[0] __section(".discard.ksym") __used +#endif + #define __EXPORT_SYMBOL(sym, sec, ns) \ __ksym_marker(sym); \ __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) @@ -148,10 +131,8 @@ struct kernel_symbol { #endif #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") -#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") +#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL") #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns)) -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", __stringify(ns)) - -#endif /* !__ASSEMBLY__ */ +#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", __stringify(ns)) #endif /* _LINUX_EXPORT_H */ diff --git a/include/linux/pm.h b/include/linux/pm.h index 035d9649eba4..f615193587d2 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -389,9 +389,9 @@ const struct dev_pm_ops name = { \ #endif #define EXPORT_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "", "") -#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "_gpl", "") +#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "GPL", "") #define EXPORT_NS_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "", #ns) -#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "_gpl", #ns) +#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "GPL", #ns) /* * Use this if you want to use the same suspend and resume callbacks for suspend diff --git a/kernel/module/internal.h b/kernel/module/internal.h index dc7b0160c480..c8b7b4dcf782 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -32,6 +32,18 @@ /* Maximum number of characters written by module_flags() */ #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) +struct kernel_symbol { +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS + int value_offset; + int name_offset; + int namespace_offset; +#else + unsigned long value; + const char *name; + const char *namespace; +#endif +}; + extern struct mutex module_mutex; extern struct list_head modules; diff --git a/scripts/Makefile.build b/scripts/Makefile.build index ddd644bd032d..4119e737fe87 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -163,7 +163,7 @@ quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ ifdef CONFIG_MODVERSIONS # When module versioning is enabled the following steps are executed: # o compile a .o from .c -# o if .o doesn't contain a __ksymtab version, i.e. does +# o if .o doesn't contain a __export_symbol_*, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old # genksyms on the preprocessed source and dump them into the .cmd file. @@ -171,7 +171,7 @@ ifdef CONFIG_MODVERSIONS # be compiled and linked to the kernel and/or modules. gen_symversions = \ - if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ + if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ >> $(dot-target).cmd; \ fi @@ -342,9 +342,7 @@ $(obj)/%.ll: $(src)/%.rs FORCE cmd_gensymtypes_S = \ { echo "\#include " ; \ echo "\#include " ; \ - $(CPP) $(a_flags) $< | \ - grep "\<___EXPORT_SYMBOL\>" | \ - sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ + $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ diff --git a/scripts/check-local-export b/scripts/check-local-export index f90b5a9c67b3..86ad94647164 100755 --- a/scripts/check-local-export +++ b/scripts/check-local-export @@ -46,9 +46,9 @@ BEGIN { { symbol_types[$3]=$2 } # append the exported symbol to the array -($3 ~ /^__ksymtab_/) { +($3 ~ /^__export_symbol_.*/) { export_symbols[i] = $3 - sub(/^__ksymtab_/, "", export_symbols[i]) + sub(/^__export_symbol_/, "", export_symbols[i]) i++ } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 403ba4d923f5..ce37e6de5df7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -217,6 +217,7 @@ struct symbol { unsigned int crc; bool crc_valid; bool weak; + bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ char name[]; }; @@ -533,6 +534,8 @@ static int parse_elf(struct elf_info *info, const char *filename) fatal("%s has NOBITS .modinfo\n", filename); info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; + } else if (!strcmp(secname, ".export_symbol")) { + info->export_symbol_secndx = i; } if (sechdrs[i].sh_type == SHT_SYMTAB) { @@ -655,18 +658,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info, ELF_ST_BIND(sym->st_info) == STB_WEAK); break; default: - /* All exported symbols */ - if (strstarts(symname, "__ksymtab_")) { - const char *name, *secname; - - name = symname + strlen("__ksymtab_"); - secname = sec_name(info, get_secindex(info, sym)); - - if (strstarts(secname, "___ksymtab_gpl+")) - sym_add_exported(name, mod, true); - else if (strstarts(secname, "___ksymtab+")) - sym_add_exported(name, mod, false); - } if (strcmp(symname, "init_module") == 0) mod->has_init = true; if (strcmp(symname, "cleanup_module") == 0) @@ -848,7 +839,6 @@ enum mismatch { XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, - EXPORT_TO_INIT_EXIT, EXTABLE_TO_NON_TEXT, }; @@ -920,12 +910,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, -/* Do not export init/exit functions or data */ -{ - .fromsec = { "___ksymtab*", NULL }, - .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, - .mismatch = EXPORT_TO_INIT_EXIT, -}, { .fromsec = { "__ex_table", NULL }, /* If you're adding any new black-listed sections in here, consider @@ -1180,10 +1164,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", modname, fromsym, fromsec, tosym, tosec); break; - case EXPORT_TO_INIT_EXIT: - warn("%s: EXPORT_SYMBOL used for init/exit symbol: %s (section: %s)\n", - modname, tosym, tosec); - break; case EXTABLE_TO_NON_TEXT: warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", modname, fromsec, (long)faddr, tosec, tosym); @@ -1211,14 +1191,75 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } +static void check_export_symbol(struct module *mod, struct elf_info *elf, + Elf_Addr faddr, const char *secname, + Elf_Sym *sym) +{ + static const char *prefix = "__export_symbol_"; + const char *label_name, *name, *data; + Elf_Sym *label; + struct symbol *s; + bool is_gpl; + + label = find_fromsym(elf, faddr, elf->export_symbol_secndx); + label_name = sym_name(elf, label); + + if (!strstarts(label_name, prefix)) { + error("%s: .export_symbol section contains strange symbol '%s'\n", + mod->name, label_name); + return; + } + + name = sym_name(elf, sym); + if (strcmp(label_name + strlen(prefix), name)) { + error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", + mod->name, name); + return; + } + + data = sym_get_data(elf, label); /* license */ + if (!strcmp(data, "GPL")) { + is_gpl = true; + } else if (!strcmp(data, "")) { + is_gpl = false; + } else { + error("%s: unknown license '%s' was specified for '%s'\n", + mod->name, data, name); + return; + } + + data += strlen(data) + 1; /* namespace */ + s = sym_add_exported(name, mod, is_gpl); + sym_update_namespace(name, data); + + /* + * We need to be aware whether we are exporting a function or + * a data on some architectures. + */ + s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC); + + if (match(secname, PATTERNS(INIT_SECTIONS))) + warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", + mod->name, name); + else if (match(secname, PATTERNS(EXIT_SECTIONS))) + warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", + mod->name, name); +} + static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); - const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); + const struct sectioncheck *mismatch; + if (elf->export_symbol_secndx == fsecndx) { + check_export_symbol(mod, elf, faddr, tosec, sym); + return; + } + + mismatch = section_mismatch(fromsec, tosec); if (!mismatch) return; @@ -1698,15 +1739,6 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } - for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - symname = remove_dot(info.strtab + sym->st_name); - - /* Apply symbol namespaces from __kstrtabns_ entries. */ - if (strstarts(symname, "__kstrtabns_")) - sym_update_namespace(symname + strlen("__kstrtabns_"), - sym_get_data(&info, sym)); - } - check_sec_ref(mod, &info); if (!mod->is_vmlinux) { @@ -1890,6 +1922,14 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; + /* generate struct for exported symbols */ + buf_printf(buf, "\n"); + list_for_each_entry(sym, &mod->exported_symbols, list) + buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", + sym->is_func ? "FUNC" : "DATA", sym->name, + sym->is_gpl_only ? "_gpl" : "", + sym->namespace ?: ""); + if (!modversions) return; diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index b1e2d95f8047..dfdb9484e325 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -137,6 +137,7 @@ struct elf_info { Elf_Shdr *sechdrs; Elf_Sym *symtab_start; Elf_Sym *symtab_stop; + unsigned int export_symbol_secndx; /* .export_symbol section */ char *strtab; char *modinfo; unsigned int modinfo_len; From 7d59313f19df0b55db6b31c5e4d4e828aa77d584 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:53 +0900 Subject: [PATCH 51/72] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* With the previous refactoring, you can always use EXPORT_SYMBOL*. Replace two instances in ia64, then remove EXPORT_DATA_SYMBOL*. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- arch/ia64/kernel/head.S | 2 +- arch/ia64/kernel/ivt.S | 2 +- include/asm-generic/export.h | 3 --- 3 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S index f22469f1c1fc..c096500590e9 100644 --- a/arch/ia64/kernel/head.S +++ b/arch/ia64/kernel/head.S @@ -170,7 +170,7 @@ RestRR: \ __PAGE_ALIGNED_DATA .global empty_zero_page -EXPORT_DATA_SYMBOL_GPL(empty_zero_page) +EXPORT_SYMBOL_GPL(empty_zero_page) empty_zero_page: .skip PAGE_SIZE diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S index d6d4229b28db..7a418e324d30 100644 --- a/arch/ia64/kernel/ivt.S +++ b/arch/ia64/kernel/ivt.S @@ -87,7 +87,7 @@ .align 32768 // align on 32KB boundary .global ia64_ivt - EXPORT_DATA_SYMBOL(ia64_ivt) + EXPORT_SYMBOL(ia64_ivt) ia64_ivt: ///////////////////////////////////////////////////////////////////////////////////////// // 0x0000 Entry 0 (size 64 bundles) VHPT Translation (8,20,47) diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 0ae9f38a904c..570cd4da7210 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -8,7 +8,4 @@ */ #include -#define EXPORT_DATA_SYMBOL(name) EXPORT_SYMBOL(name) -#define EXPORT_DATA_SYMBOL_GPL(name) EXPORT_SYMBOL_GPL(name) - #endif From 6d62b1c46b1e6e1686a0cf6617c96c80d4ab5cd5 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:54 +0900 Subject: [PATCH 52/72] modpost: check static EXPORT_SYMBOL* by modpost again Commit 31cb50b5590f ("kbuild: check static EXPORT_SYMBOL* by script instead of modpost") moved the static EXPORT_SYMBOL* check from the mostpost to a shell script because I thought it must be checked per compilation unit to avoid false negatives. I came up with an idea to do this in modpost, against combined ELF files. The relocation entries in ELF will find the correct exported symbol even if there exist symbols with the same name in different compilation units. Again, the same sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} Then, modpost can catch it correctly. MODPOST Module.symvers ERROR: modpost: vmlinux: local symbol 'foo' was exported Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/Makefile.build | 4 --- scripts/check-local-export | 70 -------------------------------------- scripts/mod/modpost.c | 7 ++++ 3 files changed, 7 insertions(+), 74 deletions(-) delete mode 100755 scripts/check-local-export diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 4119e737fe87..210142c3ff00 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -222,8 +222,6 @@ cmd_gen_ksymdeps = \ $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd endif -cmd_check_local_export = $(srctree)/scripts/check-local-export $@ - ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) endif @@ -231,7 +229,6 @@ endif define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) $(call cmd,gen_ksymdeps) - $(call cmd,check_local_export) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) @@ -243,7 +240,6 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) $(call cmd,gen_ksymdeps) - $(call cmd,check_local_export) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) $(call cmd,warn_shared_object) diff --git a/scripts/check-local-export b/scripts/check-local-export deleted file mode 100755 index 86ad94647164..000000000000 --- a/scripts/check-local-export +++ /dev/null @@ -1,70 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only -# -# Copyright (C) 2022 Masahiro Yamada -# Copyright (C) 2022 Owen Rafferty -# -# Exit with error if a local exported symbol is found. -# EXPORT_SYMBOL should be used for global symbols. - -set -e -pid=$$ - -# If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows -# 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by -# '2>/dev/null'. However, it suppresses real error messages as well. Add a -# hand-crafted error message here. -# -# TODO: -# Use --quiet instead of 2>/dev/null when we upgrade the minimum version of -# binutils to 2.37, llvm to 13.0.0. -# Then, the following line will be simpler: -# { ${NM} --quiet ${1} || kill 0; } | - -{ ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; kill $pid; } } | -${AWK} -v "file=${1}" ' -BEGIN { - i = 0 -} - -# Skip the line if the number of fields is less than 3. -# -# case 1) -# For undefined symbols, the first field (value) is empty. -# The outout looks like this: -# " U _printk" -# It is unneeded to record undefined symbols. -# -# case 2) -# For Clang LTO, llvm-nm outputs a line with type t but empty name: -# "---------------- t" -!length($3) { - next -} - -# save (name, type) in the associative array -{ symbol_types[$3]=$2 } - -# append the exported symbol to the array -($3 ~ /^__export_symbol_.*/) { - export_symbols[i] = $3 - sub(/^__export_symbol_/, "", export_symbols[i]) - i++ -} - -END { - exit_code = 0 - for (j = 0; j < i; ++j) { - name = export_symbols[j] - # nm(3) says "If lowercase, the symbol is usually local" - if (symbol_types[name] ~ /[a-z]/) { - printf "%s: error: local symbol %s was exported\n", - file, name | "cat 1>&2" - exit_code = 1 - } - } - - exit exit_code -}' - -exit $? diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ce37e6de5df7..6c1f95d18515 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1210,6 +1210,13 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, return; } + if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && + ELF_ST_BIND(sym->st_info) != STB_WEAK) { + error("%s: local symbol '%s' was exported\n", mod->name, + label_name + strlen(prefix)); + return; + } + name = sym_name(elf, sym); if (strcmp(label_name + strlen(prefix), name)) { error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", From 6e7611c485315a0e4e36c763d0810677e1f26ecd Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:55 +0900 Subject: [PATCH 53/72] modpost: squash sym_update_namespace() into sym_add_exported() Pass a set of the name, license, and namespace to sym_add_exported(). sym_update_namespace() is unneeded. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6c1f95d18515..bc9ef40ac620 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -355,26 +355,8 @@ static const char *sec_name(const struct elf_info *info, unsigned int secindex) #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) -static void sym_update_namespace(const char *symname, const char *namespace) -{ - struct symbol *s = find_symbol(symname); - - /* - * That symbol should have been created earlier and thus this is - * actually an assertion. - */ - if (!s) { - error("Could not update namespace(%s) for symbol %s\n", - namespace, symname); - return; - } - - free(s->namespace); - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; -} - static struct symbol *sym_add_exported(const char *name, struct module *mod, - bool gpl_only) + bool gpl_only, const char *namespace) { struct symbol *s = find_symbol(name); @@ -387,6 +369,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; + s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); @@ -1236,8 +1219,7 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, } data += strlen(data) + 1; /* namespace */ - s = sym_add_exported(name, mod, is_gpl); - sym_update_namespace(name, data); + s = sym_add_exported(name, mod, is_gpl, data); /* * We need to be aware whether we are exporting a function or @@ -2180,9 +2162,8 @@ static void read_dump(const char *fname) mod = new_module(modname, strlen(modname)); mod->from_dump = true; } - s = sym_add_exported(symname, mod, gpl_only); + s = sym_add_exported(symname, mod, gpl_only, namespace); sym_set_crc(s, crc); - sym_update_namespace(symname, namespace); } free(buf); return; From 700c48b439921b67715e25380e0f67e6e490d7b8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:56 +0900 Subject: [PATCH 54/72] modpost: use null string instead of NULL pointer for default namespace The default namespace is the null string, "". When set, the null string "" is converted to NULL: s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; When printed, the NULL pointer is get back to the null string: sym->namespace ?: "" This saves 1 byte memory allocated for "", but loses the readability. In kernel-space, we strive to save memory, but modpost is a userspace tool used to build the kernel. On modern systems, such small piece of memory is not a big deal. Handle the namespace string as is. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bc9ef40ac620..a7c979b0ea21 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -300,6 +300,13 @@ static bool contains_namespace(struct list_head *head, const char *namespace) { struct namespace_list *list; + /* + * The default namespace is null string "", which is always implicitly + * contained. + */ + if (!namespace[0]) + return true; + list_for_each_entry(list, head, list) { if (!strcmp(list->namespace, namespace)) return true; @@ -369,7 +376,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; + s->namespace = NOFAIL(strdup(namespace)); list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); @@ -1829,8 +1836,7 @@ static void check_exports(struct module *mod) else basename = mod->name; - if (exp->namespace && - !contains_namespace(&mod->imported_namespaces, exp->namespace)) { + if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) { modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR, "module %s uses symbol %s from namespace %s, but does not import it.\n", basename, exp->name, exp->namespace); @@ -1916,8 +1922,7 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) list_for_each_entry(sym, &mod->exported_symbols, list) buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, - sym->is_gpl_only ? "_gpl" : "", - sym->namespace ?: ""); + sym->is_gpl_only ? "_gpl" : "", sym->namespace); if (!modversions) return; @@ -2185,7 +2190,7 @@ static void write_dump(const char *fname) buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", - sym->namespace ?: ""); + sym->namespace); } } write_buf(&buf, fname); From 5e9e95cc9148b82074a5eae283e63bce3f1aacfe Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:57 +0900 Subject: [PATCH 55/72] kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada --- .gitignore | 2 - Makefile | 22 ++--------- include/linux/export.h | 67 +++++----------------------------- scripts/Makefile.build | 15 +------- scripts/Makefile.modpost | 7 ++++ scripts/adjust_autoksyms.sh | 73 ------------------------------------- scripts/basic/fixdep.c | 3 +- scripts/gen_autoksyms.sh | 62 ------------------------------- scripts/gen_ksymdeps.sh | 30 --------------- scripts/mod/modpost.c | 57 ++++++++++++++++++++++++++--- scripts/remove-stale-files | 4 ++ 11 files changed, 78 insertions(+), 264 deletions(-) delete mode 100755 scripts/adjust_autoksyms.sh delete mode 100755 scripts/gen_autoksyms.sh delete mode 100755 scripts/gen_ksymdeps.sh diff --git a/.gitignore b/.gitignore index 7f86e0837909..c3ce78ca20d2 100644 --- a/.gitignore +++ b/.gitignore @@ -51,7 +51,6 @@ *.symversions *.tab.[ch] *.tar -*.usyms *.xz *.zst Module.symvers @@ -112,7 +111,6 @@ modules.order # /include/config/ /include/generated/ -/include/ksym/ /arch/*/include/generated/ # stgit generated dirs diff --git a/Makefile b/Makefile index f836936fb4d8..cc3fe09c4dec 100644 --- a/Makefile +++ b/Makefile @@ -1193,28 +1193,12 @@ endif export KBUILD_VMLINUX_LIBS export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds -# Recurse until adjust_autoksyms.sh is satisfied -PHONY += autoksyms_recursive ifdef CONFIG_TRIM_UNUSED_KSYMS # For the kernel to actually contain only the needed exported symbols, # we have to build modules as well to determine what those symbols are. -# (this can be evaluated only once include/config/auto.conf has been included) KBUILD_MODULES := 1 - -autoksyms_recursive: $(build-dir) modules.order - $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \ - "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive" endif -autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h) - -quiet_cmd_autoksyms_h = GEN $@ - cmd_autoksyms_h = mkdir -p $(dir $@); \ - $(CONFIG_SHELL) $(srctree)/scripts/gen_autoksyms.sh $@ - -$(autoksyms_h): - $(call cmd,autoksyms_h) - # '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14 quiet_cmd_ar_vmlinux.a = AR $@ cmd_ar_vmlinux.a = \ @@ -1223,7 +1207,7 @@ quiet_cmd_ar_vmlinux.a = AR $@ $(AR) mPiT $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt) targets += vmlinux.a -vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt autoksyms_recursive FORCE +vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE $(call if_changed,ar_vmlinux.a) PHONY += vmlinux_o @@ -1279,7 +1263,7 @@ scripts: scripts_basic scripts_dtc PHONY += prepare archprepare archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \ - asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h \ + asm-generic $(version_h) include/generated/utsrelease.h \ include/generated/compile.h include/generated/autoconf.h remove-stale-files prepare0: archprepare @@ -2039,7 +2023,7 @@ clean: $(clean-dirs) -o -name '*.dtb.S' -o -name '*.dtbo.S' \ -o -name '*.dt.yaml' \ -o -name '*.dwo' -o -name '*.lst' \ - -o -name '*.su' -o -name '*.mod' -o -name '*.usyms' \ + -o -name '*.su' -o -name '*.mod' \ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \ -o -name '*.lex.c' -o -name '*.tab.[ch]' \ -o -name '*.asn1.[ch]' \ diff --git a/include/linux/export.h b/include/linux/export.h index a01868136717..1de600734071 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -42,7 +42,7 @@ extern struct module __this_module; .long sym #endif -#define ____EXPORT_SYMBOL(sym, license, ns) \ +#define ___EXPORT_SYMBOL(sym, license, ns) \ .section ".export_symbol","a" ASM_NL \ __export_symbol_##sym: ASM_NL \ .asciz license ASM_NL \ @@ -50,24 +50,6 @@ extern struct module __this_module; __EXPORT_SYMBOL_REF(sym) ASM_NL \ .previous -#ifdef __GENKSYMS__ - -#define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) - -#elif defined(__ASSEMBLY__) - -#define ___EXPORT_SYMBOL(sym, license, ns) \ - ____EXPORT_SYMBOL(sym, license, ns) - -#else - -#define ___EXPORT_SYMBOL(sym, license, ns) \ - extern typeof(sym) sym; \ - __ADDRESSABLE(sym) \ - asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) - -#endif - #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) /* @@ -77,50 +59,21 @@ extern struct module __this_module; */ #define __EXPORT_SYMBOL(sym, sec, ns) -#elif defined(CONFIG_TRIM_UNUSED_KSYMS) +#elif defined(__GENKSYMS__) -#include +#define __EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) -/* - * For fine grained build dependencies, we want to tell the build system - * about each possible exported symbol even if they're not actually exported. - * We use a symbol pattern __ksym_marker_ that the build system filters - * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are - * discarded in the final link stage. - */ +#elif defined(__ASSEMBLY__) -#ifdef __ASSEMBLY__ - -#define __ksym_marker(sym) \ - .section ".discard.ksym","a" ; \ -__ksym_marker_##sym: ; \ - .previous +#define __EXPORT_SYMBOL(sym, license, ns) \ + ___EXPORT_SYMBOL(sym, license, ns) #else -#define __ksym_marker(sym) \ - static int __ksym_marker_##sym[0] __section(".discard.ksym") __used - -#endif - -#define __EXPORT_SYMBOL(sym, sec, ns) \ - __ksym_marker(sym); \ - __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) -#define __cond_export_sym(sym, sec, ns, conf) \ - ___cond_export_sym(sym, sec, ns, conf) -#define ___cond_export_sym(sym, sec, ns, enabled) \ - __cond_export_sym_##enabled(sym, sec, ns) -#define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) - -#ifdef __GENKSYMS__ -#define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) -#else -#define __cond_export_sym_0(sym, sec, ns) /* nothing */ -#endif - -#else - -#define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) +#define __EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + asm(__stringify(___EXPORT_SYMBOL(sym, license, ns))) #endif /* CONFIG_MODULES */ diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 210142c3ff00..4735b958097a 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -82,7 +82,7 @@ ifdef need-builtin targets-for-builtin += $(obj)/built-in.a endif -targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ +targets-for-modules := $(foreach x, o mod, \ $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) ifdef need-modorder @@ -217,18 +217,12 @@ is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetar $(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) -ifdef CONFIG_TRIM_UNUSED_KSYMS -cmd_gen_ksymdeps = \ - $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd -endif - ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) endif define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) - $(call cmd,gen_ksymdeps) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) @@ -239,7 +233,6 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) - $(call cmd,gen_ksymdeps) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) $(call cmd,warn_shared_object) @@ -258,12 +251,6 @@ cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ $(obj)/%.mod: FORCE $(call if_changed,mod) -# List module undefined symbols -cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ - -$(obj)/%.usyms: $(obj)/%.o FORCE - $(call if_changed,undefined_syms) - quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 074e27c0c140..39472e834b63 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -91,6 +91,13 @@ targets += .vmlinux.objs .vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE $(call if_changed,vmlinux_objs) +ifdef CONFIG_TRIM_UNUSED_KSYMS +ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST) +ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl) +modpost-args += -t $(addprefix -u , $(ksym-wl)) +modpost-deps += $(ksym-wl) +endif + ifeq ($(wildcard vmlinux.o),) missing-input := vmlinux.o output-symdump := modules-only.symvers diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh deleted file mode 100755 index f1b5ac818411..000000000000 --- a/scripts/adjust_autoksyms.sh +++ /dev/null @@ -1,73 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only - -# Script to update include/generated/autoksyms.h and dependency files -# -# Copyright: (C) 2016 Linaro Limited -# Created by: Nicolas Pitre, January 2016 -# - -# Update the include/generated/autoksyms.h file. -# -# For each symbol being added or removed, the corresponding dependency -# file's timestamp is updated to force a rebuild of the affected source -# file. All arguments passed to this script are assumed to be a command -# to be exec'd to trigger a rebuild of those files. - -set -e - -cur_ksyms_file="include/generated/autoksyms.h" -new_ksyms_file="include/generated/autoksyms.h.tmpnew" - -info() { - if [ "$quiet" != "silent_" ]; then - printf " %-7s %s\n" "$1" "$2" - fi -} - -info "CHK" "$cur_ksyms_file" - -# Use "make V=1" to debug this script. -case "$KBUILD_VERBOSE" in -*1*) - set -x - ;; -esac - -# Generate a new symbol list file -$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh --modorder "$new_ksyms_file" - -# Extract changes between old and new list and touch corresponding -# dependency files. -changed=$( -count=0 -sort "$cur_ksyms_file" "$new_ksyms_file" | uniq -u | -sed -n 's/^#define __KSYM_\(.*\) 1/\1/p' | -while read sympath; do - if [ -z "$sympath" ]; then continue; fi - depfile="include/ksym/${sympath}" - mkdir -p "$(dirname "$depfile")" - touch "$depfile" - # Filesystems with coarse time precision may create timestamps - # equal to the one from a file that was very recently built and that - # needs to be rebuild. Let's guard against that by making sure our - # dep files are always newer than the first file we created here. - while [ ! "$depfile" -nt "$new_ksyms_file" ]; do - touch "$depfile" - done - echo $((count += 1)) -done | tail -1 ) -changed=${changed:-0} - -if [ $changed -gt 0 ]; then - # Replace the old list with tne new one - old=$(grep -c "^#define __KSYM_" "$cur_ksyms_file" || true) - new=$(grep -c "^#define __KSYM_" "$new_ksyms_file" || true) - info "KSYMS" "symbols: before=$old, after=$new, changed=$changed" - info "UPD" "$cur_ksyms_file" - mv -f "$new_ksyms_file" "$cur_ksyms_file" - # Then trigger a rebuild of affected source files - exec $@ -else - rm -f "$new_ksyms_file" -fi diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c index fa562806c2be..84b6efa849f4 100644 --- a/scripts/basic/fixdep.c +++ b/scripts/basic/fixdep.c @@ -246,8 +246,7 @@ static void *read_file(const char *filename) /* Ignore certain dependencies */ static int is_ignored_file(const char *s, int len) { - return str_ends_with(s, len, "include/generated/autoconf.h") || - str_ends_with(s, len, "include/generated/autoksyms.h"); + return str_ends_with(s, len, "include/generated/autoconf.h"); } /* Do not parse these files */ diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh deleted file mode 100755 index 12bcfae940ee..000000000000 --- a/scripts/gen_autoksyms.sh +++ /dev/null @@ -1,62 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only - -# Create an autoksyms.h header file from the list of all module's needed symbols -# as recorded in *.usyms files and the user-provided symbol whitelist. - -set -e - -# Use "make V=1" to debug this script. -case "$KBUILD_VERBOSE" in -*1*) - set -x - ;; -esac - -read_modorder= - -if [ "$1" = --modorder ]; then - shift - read_modorder=1 -fi - -output_file="$1" - -needed_symbols= - -# Special case for modversions (see modpost.c) -if grep -q "^CONFIG_MODVERSIONS=y$" include/config/auto.conf; then - needed_symbols="$needed_symbols module_layout" -fi - -ksym_wl=$(sed -n 's/^CONFIG_UNUSED_KSYMS_WHITELIST=\(.*\)$/\1/p' include/config/auto.conf) -if [ -n "$ksym_wl" ]; then - [ "${ksym_wl}" != "${ksym_wl#/}" ] || ksym_wl="$abs_srctree/$ksym_wl" - if [ ! -f "$ksym_wl" ] || [ ! -r "$ksym_wl" ]; then - echo "ERROR: '$ksym_wl' whitelist file not found" >&2 - exit 1 - fi -fi - -# Generate a new ksym list file with symbols needed by the current -# set of modules. -cat > "$output_file" << EOT -/* - * Automatically generated file; DO NOT EDIT. - */ - -EOT - -{ - [ -n "${read_modorder}" ] && sed 's/o$/usyms/' modules.order | xargs cat - echo "$needed_symbols" - [ -n "$ksym_wl" ] && cat "$ksym_wl" -} | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' | -# Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry -# point addresses. -sed -e 's/^\.//' | -sort -u | -# Ignore __this_module. It's not an exported symbol, and will be resolved -# when the final .ko's are linked. -grep -v '^__this_module$' | -sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file" diff --git a/scripts/gen_ksymdeps.sh b/scripts/gen_ksymdeps.sh deleted file mode 100755 index 8ee533f33659..000000000000 --- a/scripts/gen_ksymdeps.sh +++ /dev/null @@ -1,30 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0 - -set -e - -# List of exported symbols -# -# If the object has no symbol, $NM warns 'no symbols'. -# Suppress the stderr. -# TODO: -# Use -q instead of 2>/dev/null when we upgrade the minimum version of -# binutils to 2.37, llvm to 13.0.0. -ksyms=$($NM $1 2>/dev/null | sed -n 's/.*__ksym_marker_\(.*\)/\1/p') - -if [ -z "$ksyms" ]; then - exit 0 -fi - -echo -echo "ksymdeps_$1 := \\" - -for s in $ksyms -do - printf ' $(wildcard include/ksym/%s) \\\n' "$s" -done - -echo -echo "$1: \$(ksymdeps_$1)" -echo -echo "\$(ksymdeps_$1):" diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index a7c979b0ea21..3d9f3e2b2a2d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -35,6 +35,9 @@ static bool warn_unresolved; static int sec_mismatch_count; static bool sec_mismatch_warn_only = true; +/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */ +static bool trim_unused_exports; + /* ignore missing files */ static bool ignore_missing_files; /* If set to 1, only warn (instead of error) about missing ns imports */ @@ -219,6 +222,7 @@ struct symbol { bool weak; bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ + bool used; /* there exists a user of this symbol */ char name[]; }; @@ -1826,6 +1830,7 @@ static void check_exports(struct module *mod) continue; } + exp->used = true; s->module = exp->module; s->crc_valid = exp->crc_valid; s->crc = exp->crc; @@ -1849,6 +1854,23 @@ static void check_exports(struct module *mod) } } +static void handle_white_list_exports(const char *white_list) +{ + char *buf, *p, *name; + + buf = read_text_file(white_list); + p = buf; + + while ((name = strsep(&p, "\n"))) { + struct symbol *sym = find_symbol(name); + + if (sym) + sym->used = true; + } + + free(buf); +} + static void check_modname_len(struct module *mod) { const char *mod_name; @@ -1919,10 +1941,14 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) /* generate struct for exported symbols */ buf_printf(buf, "\n"); - list_for_each_entry(sym, &mod->exported_symbols, list) + list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, sym->is_gpl_only ? "_gpl" : "", sym->namespace); + } if (!modversions) return; @@ -1930,6 +1956,9 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) /* record CRCs for exported symbols */ buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + if (!sym->crc_valid) warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" "Is \"%s\" prototyped in ?\n", @@ -2093,9 +2122,6 @@ static void write_mod_c_file(struct module *mod) char fname[PATH_MAX]; int ret; - check_modname_len(mod); - check_exports(mod); - add_header(&buf, mod); add_exported_symbols(&buf, mod); add_versions(&buf, mod); @@ -2187,6 +2213,9 @@ static void write_dump(const char *fname) if (mod->from_dump) continue; list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", @@ -2229,12 +2258,13 @@ int main(int argc, char **argv) { struct module *mod; char *missing_namespace_deps = NULL; + char *unused_exports_white_list = NULL; char *dump_write = NULL, *files_source = NULL; int opt; LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; - while ((opt = getopt(argc, argv, "ei:mnT:o:aWwENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:to:au:WwENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2259,6 +2289,12 @@ int main(int argc, char **argv) case 'T': files_source = optarg; break; + case 't': + trim_unused_exports = true; + break; + case 'u': + unused_exports_white_list = optarg; + break; case 'W': extra_warn = true; break; @@ -2291,6 +2327,17 @@ int main(int argc, char **argv) if (files_source) read_symbols_from_files(files_source); + list_for_each_entry(mod, &modules, list) { + if (mod->from_dump || mod->is_vmlinux) + continue; + + check_modname_len(mod); + check_exports(mod); + } + + if (unused_exports_white_list) + handle_white_list_exports(unused_exports_white_list); + list_for_each_entry(mod, &modules, list) { if (mod->from_dump) continue; diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files index 7f432900671a..f3659ea0335b 100755 --- a/scripts/remove-stale-files +++ b/scripts/remove-stale-files @@ -33,3 +33,7 @@ rm -f rust/target.json rm -f scripts/bin2c rm -f .scmversion + +rm -rf include/ksym + +find . -name '*.usyms' | xargs rm -f From 78dac1a22944910ba5c1475c384309d30c99afaa Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:58 +0900 Subject: [PATCH 56/72] modpost: merge two similar section mismatch warnings In case of section mismatch, modpost shows slightly different messages. For extable section mismatch: "%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n" For the other cases: "%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n" They are similar. Merge them. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3d9f3e2b2a2d..c7faa455f978 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1147,21 +1147,10 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, sec_mismatch_count++; - switch (mismatch->mismatch) { - case TEXT_TO_ANY_INIT: - case DATA_TO_ANY_INIT: - case TEXTDATA_TO_ANY_EXIT: - case XXXINIT_TO_SOME_INIT: - case XXXEXIT_TO_SOME_EXIT: - case ANY_INIT_TO_ANY_EXIT: - case ANY_EXIT_TO_ANY_INIT: - warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", - modname, fromsym, fromsec, tosym, tosec); - break; - case EXTABLE_TO_NON_TEXT: - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)faddr, tosec, tosym); + warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", + modname, fromsym, fromsec, tosym, tosec); + if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) { if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" "section \"%s\" which is black-listed.\n" @@ -1181,7 +1170,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, else error("%s+0x%lx references non-executable section '%s'\n", fromsec, (long)faddr, tosec); - break; } } From f234627898d7644998e28938390fa3d63efeefb7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:59 +0900 Subject: [PATCH 57/72] modpost: show offset from symbol for section mismatch warnings Currently, modpost only shows the symbol names and section names, so it repeats the same message if there are multiple relocations in the same symbol. It is common the relocation spans across multiple instructions. It is better to show the offset from the symbol. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c7faa455f978..39cf43d61d51 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1147,8 +1147,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, sec_mismatch_count++; - warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", - modname, fromsym, fromsec, tosym, tosec); + warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n", + modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec); if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) { if (match(tosec, mismatch->bad_tosec)) From 8ed7e33a685a679c04cfe5ffdbb3b4c396ac8076 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:51:00 +0900 Subject: [PATCH 58/72] linux/export.h: rename 'sec' argument to 'license' Now, EXPORT_SYMBOL() is populated in two stages. In the first stage, all of EXPORT_SYMBOL/EXPORT_SYMBOL_GPL go into the same section, '.export_symbol'. 'sec' does not make sense any more. Rename it to 'license'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- include/linux/export.h | 8 ++++---- include/linux/pm.h | 6 +++--- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/include/linux/export.h b/include/linux/export.h index 1de600734071..beed8387e0a4 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -57,11 +57,11 @@ extern struct module __this_module; * be reused in other execution contexts such as the UEFI stub or the * decompressor. */ -#define __EXPORT_SYMBOL(sym, sec, ns) +#define __EXPORT_SYMBOL(sym, license, ns) #elif defined(__GENKSYMS__) -#define __EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) +#define __EXPORT_SYMBOL(sym, license, ns) __GENKSYMS_EXPORT_SYMBOL(sym) #elif defined(__ASSEMBLY__) @@ -78,9 +78,9 @@ extern struct module __this_module; #endif /* CONFIG_MODULES */ #ifdef DEFAULT_SYMBOL_NAMESPACE -#define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) +#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, __stringify(DEFAULT_SYMBOL_NAMESPACE)) #else -#define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") +#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, "") #endif #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") diff --git a/include/linux/pm.h b/include/linux/pm.h index f615193587d2..badad7d11f4f 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -375,14 +375,14 @@ const struct dev_pm_ops name = { \ } #ifdef CONFIG_PM -#define _EXPORT_DEV_PM_OPS(name, sec, ns) \ +#define _EXPORT_DEV_PM_OPS(name, license, ns) \ const struct dev_pm_ops name; \ - __EXPORT_SYMBOL(name, sec, ns); \ + __EXPORT_SYMBOL(name, license, ns); \ const struct dev_pm_ops name #define EXPORT_PM_FN_GPL(name) EXPORT_SYMBOL_GPL(name) #define EXPORT_PM_FN_NS_GPL(name, ns) EXPORT_SYMBOL_NS_GPL(name, ns) #else -#define _EXPORT_DEV_PM_OPS(name, sec, ns) \ +#define _EXPORT_DEV_PM_OPS(name, license, ns) \ static __maybe_unused const struct dev_pm_ops __static_##name #define EXPORT_PM_FN_GPL(name) #define EXPORT_PM_FN_NS_GPL(name, ns) From 8ae071fc216a25f4f797f33c56857f4dd6b4408e Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 15 Jun 2023 20:17:43 +0900 Subject: [PATCH 59/72] kbuild: make modules_install copy modules.builtin(.modinfo) Josh Triplett reports that initramfs-tools needs modules.builtin and modules.builtin.modinfo to create a working initramfs for a non-modular kernel. If this is a general tooling issue not limited to Debian, I think it makes sense to change modules_install. This commit changes the targets as follows when CONFIG_MODULES=n. In-tree builds: make modules -> no-op make modules_install -> install modules.builtin(.modinfo) External module builds: make modules -> show error message like before make modules_install -> show error message like before Link: https://lore.kernel.org/lkml/36a4014c73a52af27d930d3ca31d362b60f4461c.1686356364.git.josh@joshtriplett.org/ Reported-by: Josh Triplett Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nicolas Schier Reviewed-by: Josh Triplett Tested-by: Josh Triplett --- Makefile | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/Makefile b/Makefile index cc3fe09c4dec..f18d59c81241 100644 --- a/Makefile +++ b/Makefile @@ -1545,6 +1545,8 @@ modules_sign_only := y endif endif +endif # CONFIG_MODULES + modinst_pre := ifneq ($(filter modules_install,$(MAKECMDGOALS)),) modinst_pre := __modinst_pre @@ -1555,18 +1557,18 @@ PHONY += __modinst_pre __modinst_pre: @rm -rf $(MODLIB)/kernel @rm -f $(MODLIB)/source - @mkdir -p $(MODLIB)/kernel + @mkdir -p $(MODLIB) +ifdef CONFIG_MODULES @ln -s $(abspath $(srctree)) $(MODLIB)/source @if [ ! $(objtree) -ef $(MODLIB)/build ]; then \ rm -f $(MODLIB)/build ; \ ln -s $(CURDIR) $(MODLIB)/build ; \ fi @sed 's:^\(.*\)\.o$$:kernel/\1.ko:' modules.order > $(MODLIB)/modules.order +endif @cp -f modules.builtin $(MODLIB)/ @cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/ -endif # CONFIG_MODULES - ### # Cleaning is done on three levels. # make clean Delete most generated files @@ -1908,6 +1910,13 @@ help: @echo ' clean - remove generated files in module directory only' @echo '' +__external_modules_error: + @echo >&2 '***' + @echo >&2 '*** The present kernel disabled CONFIG_MODULES.' + @echo >&2 '*** You cannot build or install external modules.' + @echo >&2 '***' + @false + endif # KBUILD_EXTMOD # --------------------------------------------------------------------------- @@ -1944,13 +1953,10 @@ else # CONFIG_MODULES # Modules not configured # --------------------------------------------------------------------------- -modules modules_install: - @echo >&2 '***' - @echo >&2 '*** The present kernel configuration has modules disabled.' - @echo >&2 '*** To use the module feature, please run "make menuconfig" etc.' - @echo >&2 '*** to enable CONFIG_MODULES.' - @echo >&2 '***' - @exit 1 +PHONY += __external_modules_error + +modules modules_install: __external_modules_error + @: KBUILD_MODULES := From 1fffe7a34c89b12b58f88b280bc10ce034477c3a Mon Sep 17 00:00:00 2001 From: Vincenzo Palazzo Date: Fri, 16 Jun 2023 01:40:37 +0200 Subject: [PATCH 60/72] script: modpost: emit a warning when the description is missing Emit a warning when the mod description is missed and only when the W=1 is enabled. Reported-by: Roland Kletzing Link: https://bugzilla.kernel.org/show_bug.cgi?id=10770 Signed-off-by: Vincenzo Palazzo Tested-by: Nicolas Schier Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 39cf43d61d51..983f507a47ad 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1720,6 +1720,8 @@ static void read_symbols(const char *modname) } } + if (extra_warn && !get_modinfo(&info, "description")) + warn("missing MODULE_DESCRIPTION() in %s\n", modname); for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = remove_dot(info.strtab + sym->st_name); From 3602906019a68c340b69991bb4020e10374fb0d0 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 18 Jun 2023 00:30:25 +0900 Subject: [PATCH 61/72] kbuild: make clean rule robust against too long argument error Commit cd968b97c492 ("kbuild: make built-in.a rule robust against too long argument error") made a build rule robust against "Argument list too long" error. Eugeniu Rosca reported the same error occurred when cleaning an external module. The $(obj)/ prefix can be a very long path for external modules. Apply a similar solution to 'make clean'. Reported-by: Eugeniu Rosca Signed-off-by: Masahiro Yamada Reviewed-by: Eugeniu Rosca Tested-by: Eugeniu Rosca --- scripts/Makefile.clean | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean index 3649900696dd..f2cb4d7ffd96 100644 --- a/scripts/Makefile.clean +++ b/scripts/Makefile.clean @@ -37,8 +37,10 @@ __clean-files := $(wildcard $(addprefix $(obj)/, $(__clean-files))) # ========================================================================== +# To make this rule robust against "Argument list too long" error, +# remove $(obj)/ prefix, and restore it by a shell command. quiet_cmd_clean = CLEAN $(obj) - cmd_clean = rm -rf $(__clean-files) + cmd_clean = printf '$(obj)/%s ' $(patsubst $(obj)/%,%,$(__clean-files)) | xargs rm -rf __clean: $(subdir-ymn) ifneq ($(strip $(__clean-files)),) From ddf56288eebd1fe82c46fc9f693b5b18045cddb6 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 23 Jun 2023 00:11:42 +0000 Subject: [PATCH 62/72] kbuild: Fix CFI failures with GCOV With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, and the functions are indirectly called during boot. However, when code is injected to object files that are not part of vmlinux.o, it's also not processed by objtool, which breaks CFI hash randomization as the hashes in these files won't be included in the .cfi_sites section and thus won't be randomized. Similarly to commit 42633ed852de ("kbuild: Fix CFI hash randomization with KASAN"), disable GCOV for .vmlinux.export.o and init/version-timestamp.o to avoid emitting unnecessary functions to object files that don't otherwise have executable code. Fixes: 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization") Reported-by: Joe Fradley Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada --- init/Makefile | 1 + scripts/Makefile.vmlinux | 1 + 2 files changed, 2 insertions(+) diff --git a/init/Makefile b/init/Makefile index 26de459006c4..ec557ada3c12 100644 --- a/init/Makefile +++ b/init/Makefile @@ -60,3 +60,4 @@ include/generated/utsversion.h: FORCE $(obj)/version-timestamp.o: include/generated/utsversion.h CFLAGS_version-timestamp.o := -include include/generated/utsversion.h KASAN_SANITIZE_version-timestamp.o := n +GCOV_PROFILE_version-timestamp.o := n diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 10176dec97ea..3cd6ca15f390 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -19,6 +19,7 @@ quiet_cmd_cc_o_c = CC $@ ifdef CONFIG_MODULES KASAN_SANITIZE_.vmlinux.export.o := n +GCOV_PROFILE_.vmlinux.export.o := n targets += .vmlinux.export.o vmlinux: .vmlinux.export.o endif From 25a21fbb934a0d989e1858f83c2ddf4cfb2ebe30 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 23 Jun 2023 00:11:43 +0000 Subject: [PATCH 63/72] kbuild: Disable GCOV for *.mod.o With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, including the *.mod.o. As we filter out CC_FLAGS_CFI for *.mod.o, the compiler won't generate type hashes for the injected functions, and therefore indirectly calling them during module loading trips indirect call checking. Enabling CFI for *.mod.o isn't sufficient to fix this issue after commit 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization"), as *.mod.o aren't processed by objtool, which means any hashes emitted there won't be randomized. Therefore, in addition to disabling CFI for *.mod.o, also disable GCOV, as the object files don't otherwise contain any executable code. Fixes: cf68fffb66d6 ("add support for Clang CFI") Reported-by: Joe Fradley Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada --- scripts/Makefile.modfinal | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 4703f652c009..fc19f67039bd 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -23,7 +23,7 @@ modname = $(notdir $(@:.mod.o=)) part-of-module = y quiet_cmd_cc_o_c = CC [M] $@ - cmd_cc_o_c = $(CC) $(filter-out $(CC_FLAGS_CFI), $(c_flags)) -c -o $@ $< + cmd_cc_o_c = $(CC) $(filter-out $(CC_FLAGS_CFI) $(CFLAGS_GCOV), $(c_flags)) -c -o $@ $< %.mod.o: %.mod.c FORCE $(call if_changed_dep,cc_o_c) From b31db651f745604371e4d3304f5b16fc3d9d0110 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:19 +0900 Subject: [PATCH 64/72] modpost: factor out inst location calculation to section_rel() All the addend_*_rel() functions calculate the instruction location in the same way. Factor out the similar code to the caller. Squash reloc_location() too. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 983f507a47ad..40fdc1a69483 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1256,16 +1256,9 @@ static void check_section_mismatch(struct module *mod, struct elf_info *elf, tosec, taddr); } -static unsigned int *reloc_location(struct elf_info *elf, - Elf_Shdr *sechdr, Elf_Rela *r) -{ - return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset); -} - -static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_386_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); switch (r_typ) { case R_386_32: @@ -1302,11 +1295,10 @@ static int32_t sign_extend32(int32_t value, int index) return (int32_t)(value << shift) >> shift; } -static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_arm_rel(void *loc, struct elf_info *elf, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); - void *loc = reloc_location(elf, sechdr, r); uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; @@ -1396,11 +1388,10 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) return 0; } -static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_mips_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); - unsigned int inst; + uint32_t inst; if (r_typ == R_MIPS_HI16) return 1; /* skip this */ @@ -1502,6 +1493,8 @@ static void section_rel(struct module *mod, struct elf_info *elf, return; for (rel = start; rel < stop; rel++) { + void *loc; + r.r_offset = TO_NATIVE(rel->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (elf->hdr->e_machine == EM_MIPS) { @@ -1519,17 +1512,20 @@ static void section_rel(struct module *mod, struct elf_info *elf, r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = 0; + + loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); + switch (elf->hdr->e_machine) { case EM_386: - if (addend_386_rel(elf, sechdr, &r)) + if (addend_386_rel(loc, &r)) continue; break; case EM_ARM: - if (addend_arm_rel(elf, sechdr, &r)) + if (addend_arm_rel(loc, elf, &r)) continue; break; case EM_MIPS: - if (addend_mips_rel(elf, sechdr, &r)) + if (addend_mips_rel(loc, &r)) continue; break; default: From 8aa00e2c3da470c82148f64b6a3cac2d79bb9d16 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:20 +0900 Subject: [PATCH 65/72] modpost: factor out Elf_Sym pointer calculation to section_rel() Pass the Elf_Sym pointer to addend_arm_rel() as well as to check_section_mismatch(). Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 40fdc1a69483..bfe26b835db2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1295,10 +1295,9 @@ static int32_t sign_extend32(int32_t value, int index) return (int32_t)(value << shift) >> shift; } -static int addend_arm_rel(void *loc, struct elf_info *elf, Elf_Rela *r) +static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; @@ -1493,6 +1492,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, return; for (rel = start; rel < stop; rel++) { + Elf_Sym *tsym; void *loc; r.r_offset = TO_NATIVE(rel->r_offset); @@ -1514,6 +1514,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, r.r_addend = 0; loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); + tsym = elf->symtab_start + ELF_R_SYM(r.r_info); switch (elf->hdr->e_machine) { case EM_386: @@ -1521,7 +1522,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, continue; break; case EM_ARM: - if (addend_arm_rel(loc, elf, &r)) + if (addend_arm_rel(loc, tsym, &r)) continue; break; case EM_MIPS: @@ -1532,7 +1533,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, fatal("Please add code to calculate addend for this architecture\n"); } - check_section_mismatch(mod, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, tsym, fsecndx, fromsec, r.r_offset, r.r_addend); } } From 8e86ebefdd5ca15458fcb3a03da89ab9cad6382b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:21 +0900 Subject: [PATCH 66/72] modpost: continue even with unknown relocation type Currently, unknown relocation types are just skipped. The value of r_addend is only needed to get the symbol name in case is_valid_name(elf, sym) returns false. Even if we do not know how to calculate r_addend, we should continue. At worst, we will get "(unknown)" as the symbol name, but it is better than failing to detect section mismatches. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bfe26b835db2..73f4f5588b67 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1267,6 +1267,8 @@ static int addend_386_rel(uint32_t *location, Elf_Rela *r) case R_386_PC32: r->r_addend = TO_NATIVE(*location) + 4; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1382,7 +1384,7 @@ static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r) r->r_addend = offset + sym->st_value + 4; break; default: - return 1; + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1392,8 +1394,6 @@ static int addend_mips_rel(uint32_t *location, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); uint32_t inst; - if (r_typ == R_MIPS_HI16) - return 1; /* skip this */ inst = TO_NATIVE(*location); switch (r_typ) { case R_MIPS_LO16: @@ -1405,6 +1405,8 @@ static int addend_mips_rel(uint32_t *location, Elf_Rela *r) case R_MIPS_32: r->r_addend = inst; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1514,20 +1516,17 @@ static void section_rel(struct module *mod, struct elf_info *elf, r.r_addend = 0; loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); - tsym = elf->symtab_start + ELF_R_SYM(r.r_info); + tsym = elf->symtab_start + r_sym; switch (elf->hdr->e_machine) { case EM_386: - if (addend_386_rel(loc, &r)) - continue; + addend_386_rel(loc, &r); break; case EM_ARM: - if (addend_arm_rel(loc, tsym, &r)) - continue; + addend_arm_rel(loc, tsym, &r); break; case EM_MIPS: - if (addend_mips_rel(loc, &r)) - continue; + addend_mips_rel(loc, &r); break; default: fatal("Please add code to calculate addend for this architecture\n"); From 4243afdb932677a03770753be8c54b3190a512e8 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Thu, 22 Jun 2023 12:19:53 -0700 Subject: [PATCH 67/72] kbuild: builddeb: always make modules_install, to install modules.builtin* Even for a non-modular kernel, the kernel builds modules.builtin and modules.builtin.modinfo, with information about the built-in modules. Tools such as initramfs-tools need these files to build a working initramfs on some systems, such as those requiring firmware. Now that `make modules_install` works even in non-modular kernels and installs these files, unconditionally invoke it when building a Debian package. Signed-off-by: Josh Triplett Reviewed-by: Nicolas Schier Signed-off-by: Masahiro Yamada --- scripts/package/builddeb | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/package/builddeb b/scripts/package/builddeb index 252faaa5561c..f500e3910158 100755 --- a/scripts/package/builddeb +++ b/scripts/package/builddeb @@ -62,8 +62,8 @@ install_linux_image () { ${MAKE} -f ${srctree}/Makefile INSTALL_DTBS_PATH="${pdir}/usr/lib/linux-image-${KERNELRELEASE}" dtbs_install fi + ${MAKE} -f ${srctree}/Makefile INSTALL_MOD_PATH="${pdir}" modules_install if is_enabled CONFIG_MODULES; then - ${MAKE} -f ${srctree}/Makefile INSTALL_MOD_PATH="${pdir}" modules_install rm -f "${pdir}/lib/modules/${KERNELRELEASE}/build" rm -f "${pdir}/lib/modules/${KERNELRELEASE}/source" if [ "${SRCARCH}" = um ] ; then From 1240dabe8d58b4eff09e7edf1560da0360f997aa Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 26 Jun 2023 03:16:23 +0900 Subject: [PATCH 68/72] kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb When CONFIG_MODULES is disabled for ARCH=um, 'make (bin)deb-pkg' fails with an error like follows: cp: cannot create regular file 'debian/linux-image/usr/lib/uml/modules/6.4.0-rc2+/System.map': No such file or directory Remove the CONFIG_MODULES check completely so ${pdir}/usr/lib/uml/modules will always be created and modules.builtin.(modinfo) will be installed under it for ARCH=um. Fixes: b611daae5efc ("kbuild: deb-pkg: split image and debug objects staging out into functions") Signed-off-by: Masahiro Yamada --- scripts/package/builddeb | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/scripts/package/builddeb b/scripts/package/builddeb index f500e3910158..032774eb061e 100755 --- a/scripts/package/builddeb +++ b/scripts/package/builddeb @@ -63,17 +63,13 @@ install_linux_image () { fi ${MAKE} -f ${srctree}/Makefile INSTALL_MOD_PATH="${pdir}" modules_install - if is_enabled CONFIG_MODULES; then - rm -f "${pdir}/lib/modules/${KERNELRELEASE}/build" - rm -f "${pdir}/lib/modules/${KERNELRELEASE}/source" - if [ "${SRCARCH}" = um ] ; then - mkdir -p "${pdir}/usr/lib/uml/modules" - mv "${pdir}/lib/modules/${KERNELRELEASE}" "${pdir}/usr/lib/uml/modules/${KERNELRELEASE}" - fi - fi + rm -f "${pdir}/lib/modules/${KERNELRELEASE}/build" + rm -f "${pdir}/lib/modules/${KERNELRELEASE}/source" # Install the kernel if [ "${ARCH}" = um ] ; then + mkdir -p "${pdir}/usr/lib/uml/modules" + mv "${pdir}/lib/modules/${KERNELRELEASE}" "${pdir}/usr/lib/uml/modules/${KERNELRELEASE}" mkdir -p "${pdir}/usr/bin" "${pdir}/usr/share/doc/${pname}" cp System.map "${pdir}/usr/lib/uml/modules/${KERNELRELEASE}/System.map" cp ${KCONFIG_CONFIG} "${pdir}/usr/share/doc/${pname}/config" From 71025b8565a383223ea2d94325db37cdabbcc453 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?= Date: Mon, 26 Jun 2023 12:29:46 +0000 Subject: [PATCH 69/72] scripts/mksysmap: Ignore prefixed KCFI symbols MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The (relatively) new KCFI feature in LLVM/Clang encodes type information for C functions by generating symbols named __kcfi_typeid_, which can then be referenced from assembly. However, some custom build rules (e.g. nVHE or early PIE on arm64) use objcopy to add a prefix to all the symbols in their object files, making mksysmap's ignore filter miss those KCFI symbols. Therefore, explicitly list those twice-prefixed KCFI symbols as ignored. Alternatively, this could also be achieved in a less verbose way by ignoring any symbol containing the string "__kcfi_typeid_". However, listing the combined prefixes explicitly saves us from running the small risk of ignoring symbols that should be kept. Signed-off-by: Pierre-Clément Tosi Reviewed-by: Sami Tolvanen Signed-off-by: Masahiro Yamada --- scripts/mksysmap | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/mksysmap b/scripts/mksysmap index 26f39772f7a5..9ba1c9da0a40 100755 --- a/scripts/mksysmap +++ b/scripts/mksysmap @@ -62,6 +62,8 @@ ${NM} -n ${1} | sed >${2} -e " # CFI type identifiers / __kcfi_typeid_/d +/ __kvm_nvhe___kcfi_typeid_/d +/ __pi___kcfi_typeid_/d # CRC from modversions / __crc_/d From 5fa94ceb793e93870541dc5a1235aec87b0871bc Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 27 Jun 2023 08:30:12 +0900 Subject: [PATCH 70/72] kbuild: set correct abs_srctree and abs_objtree for package builds When you run 'make rpm-pkg', the rpmbuild tool builds the kernel in rpmbuild/BUILD, but $(abs_srctree) and $(abs_objtree) point to the directory path where make was started, not the kernel is actually being built. The same applies to 'make snap-pkg'. Fix it. Signed-off-by: Masahiro Yamada --- Makefile | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/Makefile b/Makefile index f18d59c81241..70b314059d8b 100644 --- a/Makefile +++ b/Makefile @@ -38,6 +38,10 @@ __all: # descending is started. They are now explicitly listed as the # prepare rule. +this-makefile := $(lastword $(MAKEFILE_LIST)) +export abs_srctree := $(realpath $(dir $(this-makefile))) +export abs_objtree := $(CURDIR) + ifneq ($(sub_make_done),1) # Do not use make's built-in rules and variables @@ -185,8 +189,6 @@ $(if $(abs_objtree),, \ # $(realpath ...) resolves symlinks abs_objtree := $(realpath $(abs_objtree)) -else -abs_objtree := $(CURDIR) endif # ifneq ($(KBUILD_OUTPUT),) ifeq ($(abs_objtree),$(CURDIR)) @@ -196,9 +198,6 @@ else need-sub-make := 1 endif -this-makefile := $(lastword $(MAKEFILE_LIST)) -abs_srctree := $(realpath $(dir $(this-makefile))) - ifneq ($(words $(subst :, ,$(abs_srctree))), 1) $(error source directory cannot contain spaces or colons) endif @@ -211,7 +210,6 @@ need-sub-make := 1 $(this-makefile): ; endif -export abs_srctree abs_objtree export sub_make_done := 1 ifeq ($(need-sub-make),1) From 5fc10e76fa2a96d0207ed4d0cc9d16fb61371f71 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 27 Jun 2023 08:30:13 +0900 Subject: [PATCH 71/72] kbuild: revive "Entering directory" for Make >= 4.4.1 With commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), compiler messages in out-of-tree builds include relative paths, which are relative to the build directory, not the directory where make was started. To help IDEs/editors find the source files, Kbuild lets GNU Make print "Entering directory ..." when it changes the working directory. It has been working fine for a long time, but David reported it is broken with the latest GNU Make. The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537] Fix setting -w in makefiles"). Previously, setting --no-print-directory to MAKEFLAGS only affected child makes, but it is now interpreted in the current make as soon as it is set. [test code] $ cat /tmp/Makefile ifneq ($(SUBMAKE),1) MAKEFLAGS += --no-print-directory all: ; $(MAKE) SUBMAKE=1 else all: ; : endif [before 8f9e7722ff0f] $ make -C /tmp make: Entering directory '/tmp' make SUBMAKE=1 : make: Leaving directory '/tmp' [after 8f9e7722ff0f] $ make -C /tmp make SUBMAKE=1 : Previously, the effect of --no-print-directory was delayed until Kbuild started the directory descending, but it is no longer true with GNU Make 4.4.1. This commit adds one more recursion to cater to GNU Make >= 4.4.1. When Kbuild needs to change the working directory, __submake will be executed twice. __submake without --no-print-directory --> show "Entering directory ..." __submake with --no-print-directory --> parse the rest of Makefile We end up with one more recursion than needed for GNU Make < 4.4.1, but I do not want to complicate the version check. Reported-by: David Howells Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/ Signed-off-by: Masahiro Yamada Tested-by: Nicolas Schier --- Makefile | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-) diff --git a/Makefile b/Makefile index 70b314059d8b..7edb00603b7e 100644 --- a/Makefile +++ b/Makefile @@ -191,13 +191,6 @@ $(if $(abs_objtree),, \ abs_objtree := $(realpath $(abs_objtree)) endif # ifneq ($(KBUILD_OUTPUT),) -ifeq ($(abs_objtree),$(CURDIR)) -# Suppress "Entering directory ..." unless we are changing the work directory. -MAKEFLAGS += --no-print-directory -else -need-sub-make := 1 -endif - ifneq ($(words $(subst :, ,$(abs_srctree))), 1) $(error source directory cannot contain spaces or colons) endif @@ -212,6 +205,23 @@ endif export sub_make_done := 1 +endif # sub_make_done + +ifeq ($(abs_objtree),$(CURDIR)) +# Suppress "Entering directory ..." if we are at the final work directory. +no-print-directory := --no-print-directory +else +# Recursion to show "Entering directory ..." +need-sub-make := 1 +endif + +ifeq ($(filter --no-print-directory, $(MAKEFLAGS)),) +# If --no-print-directory is unset, recurse once again to set it. +# You may end up recursing into __sub-make twice. This is needed due to the +# behavior change in GNU Make 4.4.1. +need-sub-make := 1 +endif + ifeq ($(need-sub-make),1) PHONY += $(MAKECMDGOALS) __sub-make @@ -221,18 +231,12 @@ $(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make # Invoke a second make in the output directory, passing relevant variables __sub-make: - $(Q)$(MAKE) -C $(abs_objtree) -f $(abs_srctree)/Makefile $(MAKECMDGOALS) + $(Q)$(MAKE) $(no-print-directory) -C $(abs_objtree) \ + -f $(abs_srctree)/Makefile $(MAKECMDGOALS) -endif # need-sub-make -endif # sub_make_done +else # need-sub-make # We process the rest of the Makefile if this is the final invocation of make -ifeq ($(need-sub-make),) - -# Do not print "Entering directory ...", -# but we want to display it when entering to the output directory -# so that IDEs/editors are able to understand relative filenames. -MAKEFLAGS += --no-print-directory ifeq ($(abs_srctree),$(abs_objtree)) # building in the source tree From f5983dab0ead92dc2690d147f0604a0badcac6a8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 28 Jun 2023 01:32:05 +0900 Subject: [PATCH 72/72] modpost: define more R_ARM_* for old distributions On CentOS 7, the following build error occurs. scripts/mod/modpost.c: In function 'addend_arm_rel': scripts/mod/modpost.c:1312:7: error: 'R_ARM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_MOVW_ABS_NC: ^~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1312:7: note: each undeclared identifier is reported only once for each function it appears in scripts/mod/modpost.c:1313:7: error: 'R_ARM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_MOVT_ABS: ^~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1326:7: error: 'R_ARM_THM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_THM_MOVW_ABS_NC: ^~~~~~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1327:7: error: 'R_ARM_THM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_THM_MOVT_ABS: ^~~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 Fixes: 12ca2c67d742 ("modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS}") Fixes: cd1824fb7a37 ("modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS}") Reported-by: Tetsuo Handa Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 73f4f5588b67..603a4f9587a4 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1286,6 +1286,23 @@ static int addend_386_rel(uint32_t *location, Elf_Rela *r) #ifndef R_ARM_THM_JUMP24 #define R_ARM_THM_JUMP24 30 #endif + +#ifndef R_ARM_MOVW_ABS_NC +#define R_ARM_MOVW_ABS_NC 43 +#endif + +#ifndef R_ARM_MOVT_ABS +#define R_ARM_MOVT_ABS 44 +#endif + +#ifndef R_ARM_THM_MOVW_ABS_NC +#define R_ARM_THM_MOVW_ABS_NC 47 +#endif + +#ifndef R_ARM_THM_MOVT_ABS +#define R_ARM_THM_MOVT_ABS 48 +#endif + #ifndef R_ARM_THM_JUMP19 #define R_ARM_THM_JUMP19 51 #endif