137 lines
3.4 KiB
C
137 lines
3.4 KiB
C
/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Alex Smith <alex.smith@imgtec.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
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{
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const ELF(Ehdr) *ehdr = vdso;
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void *shdrs;
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ELF(Shdr) *shdr;
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char *shstrtab, *name;
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uint16_t sh_count, sh_entsize, i;
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shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
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sh_count = swap_uint16(ehdr->e_shnum);
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sh_entsize = swap_uint16(ehdr->e_shentsize);
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shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
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shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
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for (i = 0; i < sh_count; i++) {
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shdr = shdrs + (i * sh_entsize);
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name = shstrtab + swap_uint32(shdr->sh_name);
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/*
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* Ensure there are no relocation sections - ld.so does not
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* relocate the VDSO so if there are relocations things will
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* break.
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*/
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switch (swap_uint32(shdr->sh_type)) {
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case SHT_REL:
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case SHT_RELA:
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fprintf(stderr,
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"%s: '%s' contains relocation sections\n",
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program_name, path);
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return false;
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}
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/* Check for existing sections. */
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if (strcmp(name, ".MIPS.abiflags") == 0) {
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fprintf(stderr,
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"%s: '%s' already contains a '.MIPS.abiflags' section\n",
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program_name, path);
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return false;
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}
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if (strcmp(name, ".mips_abiflags") == 0) {
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strcpy(name, ".MIPS.abiflags");
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shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS);
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shdr->sh_entsize = shdr->sh_size;
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}
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}
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return true;
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}
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static inline bool FUNC(get_symbols)(const char *path, void *vdso)
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{
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const ELF(Ehdr) *ehdr = vdso;
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void *shdrs, *symtab;
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ELF(Shdr) *shdr;
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const ELF(Sym) *sym;
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char *strtab, *name;
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uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
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uint64_t offset;
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uint32_t flags;
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shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
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sh_count = swap_uint16(ehdr->e_shnum);
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sh_entsize = swap_uint16(ehdr->e_shentsize);
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for (i = 0; i < sh_count; i++) {
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shdr = shdrs + (i * sh_entsize);
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if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
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break;
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}
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if (i == sh_count) {
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fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
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path);
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return false;
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}
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/* Get flags */
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flags = swap_uint32(ehdr->e_flags);
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if (elf_class == ELFCLASS64)
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elf_abi = ABI_N64;
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else if (flags & EF_MIPS_ABI2)
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elf_abi = ABI_N32;
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else
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elf_abi = ABI_O32;
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/* Get symbol table. */
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symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
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st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
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st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
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/* Get string table. */
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shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
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strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
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/* Write offsets for symbols needed by the kernel. */
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for (i = 0; vdso_symbols[i].name; i++) {
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if (!(vdso_symbols[i].abis & elf_abi))
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continue;
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for (j = 0; j < st_count; j++) {
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sym = symtab + (j * st_entsize);
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name = strtab + swap_uint32(sym->st_name);
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if (!strcmp(name, vdso_symbols[i].name)) {
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offset = FUNC(swap_uint)(sym->st_value);
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fprintf(out_file,
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"\t.%s = 0x%" PRIx64 ",\n",
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vdso_symbols[i].offset_name, offset);
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break;
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}
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}
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if (j == st_count) {
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fprintf(stderr,
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"%s: '%s' is missing required symbol '%s'\n",
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program_name, path, vdso_symbols[i].name);
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return false;
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}
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}
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return true;
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}
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