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tools/nolibc: add support for powerpc Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:39:26 +08:00
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* PowerPC specific definitions for NOLIBC
* Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
*/
#ifndef _NOLIBC_ARCH_POWERPC_H
#define _NOLIBC_ARCH_POWERPC_H
#include "compiler.h"
#include "crt.h"
/* Syscalls for PowerPC :
* - stack is 16-byte aligned
* - syscall number is passed in r0
* - arguments are in r3, r4, r5, r6, r7, r8, r9
* - the system call is performed by calling "sc"
* - syscall return comes in r3, and the summary overflow bit is checked
* to know if an error occurred, in which case errno is in r3.
* - the arguments are cast to long and assigned into the target
* registers which are then simply passed as registers to the asm code,
* so that we don't have to experience issues with register constraints.
*/
#define _NOLIBC_SYSCALL_CLOBBERLIST \
"memory", "cr0", "r12", "r11", "r10", "r9"
#define my_syscall0(num) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num) \
: \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \
); \
_ret; \
})
#define my_syscall1(num, arg1) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \
); \
_ret; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
register long _arg2 __asm__ ("r4") = (long)(arg2); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num), "+r"(_arg2) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5" \
); \
_ret; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
register long _arg2 __asm__ ("r4") = (long)(arg2); \
register long _arg3 __asm__ ("r5") = (long)(arg3); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6" \
); \
_ret; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
register long _arg2 __asm__ ("r4") = (long)(arg2); \
register long _arg3 __asm__ ("r5") = (long)(arg3); \
register long _arg4 __asm__ ("r6") = (long)(arg4); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
"+r"(_arg4) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7" \
); \
_ret; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
register long _arg2 __asm__ ("r4") = (long)(arg2); \
register long _arg3 __asm__ ("r5") = (long)(arg3); \
register long _arg4 __asm__ ("r6") = (long)(arg4); \
register long _arg5 __asm__ ("r7") = (long)(arg5); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
"+r"(_arg4), "+r"(_arg5) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST, "r8" \
); \
_ret; \
})
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
register long _ret __asm__ ("r3"); \
register long _num __asm__ ("r0") = (num); \
register long _arg1 __asm__ ("r3") = (long)(arg1); \
register long _arg2 __asm__ ("r4") = (long)(arg2); \
register long _arg3 __asm__ ("r5") = (long)(arg3); \
register long _arg4 __asm__ ("r6") = (long)(arg4); \
register long _arg5 __asm__ ("r7") = (long)(arg5); \
register long _arg6 __asm__ ("r8") = (long)(arg6); \
\
__asm__ volatile ( \
" sc\n" \
" bns+ 1f\n" \
" neg %0, %0\n" \
"1:\n" \
: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
"+r"(_arg4), "+r"(_arg5), "+r"(_arg6) \
: "0"(_arg1) \
: _NOLIBC_SYSCALL_CLOBBERLIST \
); \
_ret; \
})
tools/nolibc: add support for powerpc64 This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new ABI for little-endian PowerPC64 Design & Implementation" [2] and the musl code in arch/powerpc64/crt_arch.h. First, stdu and clrrdi are used instead of stwu and clrrwi for powerpc64. Second, the stack frame size is increased to 32 bytes for powerpc64, 32 bytes is the minimal stack frame size supported described in [2]. Besides, the TOC pointer (GOT pointer) must be saved to r2. This works on both little endian and big endian 64-bit PowerPC. [1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf [2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:40:31 +08:00
#ifndef __powerpc64__
tools/nolibc: add support for powerpc Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:39:26 +08:00
/* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0),
* "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but
* works with __attribute__((__optimize__("-fno-stack-protector")))
*/
#ifdef __no_stack_protector
#undef __no_stack_protector
#define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
#endif
tools/nolibc: add support for powerpc64 This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new ABI for little-endian PowerPC64 Design & Implementation" [2] and the musl code in arch/powerpc64/crt_arch.h. First, stdu and clrrdi are used instead of stwu and clrrwi for powerpc64. Second, the stack frame size is increased to 32 bytes for powerpc64, 32 bytes is the minimal stack frame size supported described in [2]. Besides, the TOC pointer (GOT pointer) must be saved to r2. This works on both little endian and big endian 64-bit PowerPC. [1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf [2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:40:31 +08:00
#endif /* !__powerpc64__ */
tools/nolibc: add support for powerpc Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:39:26 +08:00
/* startup code */
void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
{
tools/nolibc: add support for powerpc64 This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new ABI for little-endian PowerPC64 Design & Implementation" [2] and the musl code in arch/powerpc64/crt_arch.h. First, stdu and clrrdi are used instead of stwu and clrrwi for powerpc64. Second, the stack frame size is increased to 32 bytes for powerpc64, 32 bytes is the minimal stack frame size supported described in [2]. Besides, the TOC pointer (GOT pointer) must be saved to r2. This works on both little endian and big endian 64-bit PowerPC. [1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf [2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:40:31 +08:00
#ifdef __powerpc64__
tools/nolibc: silence ppc64 compile warnings Silence the following warnings reported by the new -Wall -Wextra options with pure assembly code. In file included from sysroot/powerpc/include/stdio.h:13, from nolibc-test.c:13: sysroot/powerpc/include/arch.h: In function '_start': sysroot/powerpc/include/arch.h:192:32: warning: unused variable 'r2' [-Wunused-variable] 192 | register volatile long r2 __asm__ ("r2") = (void *)&TOC - (void *)_start; | ^~ sysroot/powerpc/include/arch.h:187:97: warning: optimization may eliminate reads and/or writes to register variables [-Wvolatile-register-var] 187 | void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void) | ^~~~~~ Since only elfv2 ABI requires to save the TOC/GOT pointer to r2 register, when using elfv1 ABI, the old C code is simply ignored by the compiler, but the compiler can not ignore the inline assembly code and will introduce build failure or running segfaults. So, let's further only add the new assembly code for elfv2 ABI with the checking of _CALL_ELF == 2. Link: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf Link: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-07 19:00:48 +08:00
#if _CALL_ELF == 2
/* with -mabi=elfv2, save TOC/GOT pointer to r2
* r12 is global entry pointer, we use it to compute TOC from r12
* https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf
* https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf
*/
__asm__ volatile (
"addis 2, 12, .TOC. - _start@ha\n"
"addi 2, 2, .TOC. - _start@l\n"
);
#endif /* _CALL_ELF == 2 */
tools/nolibc: add support for powerpc64 This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new ABI for little-endian PowerPC64 Design & Implementation" [2] and the musl code in arch/powerpc64/crt_arch.h. First, stdu and clrrdi are used instead of stwu and clrrwi for powerpc64. Second, the stack frame size is increased to 32 bytes for powerpc64, 32 bytes is the minimal stack frame size supported described in [2]. Besides, the TOC pointer (GOT pointer) must be saved to r2. This works on both little endian and big endian 64-bit PowerPC. [1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf [2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:40:31 +08:00
__asm__ volatile (
"mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
"clrrdi 1, 1, 4\n" /* align the stack to 16 bytes */
"li 0, 0\n" /* zero the frame pointer */
"stdu 1, -32(1)\n" /* the initial stack frame */
"bl _start_c\n" /* transfer to c runtime */
);
#else
tools/nolibc: add support for powerpc Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:39:26 +08:00
__asm__ volatile (
"mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
"clrrwi 1, 1, 4\n" /* align the stack to 16 bytes */
"li 0, 0\n" /* zero the frame pointer */
"stwu 1, -16(1)\n" /* the initial stack frame */
"bl _start_c\n" /* transfer to c runtime */
);
tools/nolibc: add support for powerpc64 This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new ABI for little-endian PowerPC64 Design & Implementation" [2] and the musl code in arch/powerpc64/crt_arch.h. First, stdu and clrrdi are used instead of stwu and clrrwi for powerpc64. Second, the stack frame size is increased to 32 bytes for powerpc64, 32 bytes is the minimal stack frame size supported described in [2]. Besides, the TOC pointer (GOT pointer) must be saved to r2. This works on both little endian and big endian 64-bit PowerPC. [1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf [2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:40:31 +08:00
#endif
tools/nolibc: add support for powerpc Both syscall declarations and _start code definition are added for powerpc to nolibc. Like mips, powerpc uses a register (exactly, the summary overflow bit) to record the error occurred, and uses another register to return the value [1]. So, the return value of every syscall declaration must be normalized to match the __sysret() helper, return -value when there is an error, otheriwse, return value directly. Glibc and musl use different methods to check the summary overflow bit, glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register to r0 at first, and then check the summary overflow bit in cr0: mfcr r0 r0 & (1 << 28) ? -r3 : r3 --> 10003c14: 7c 00 00 26 mfcr r0 10003c18: 74 09 10 00 andis. r9,r0,4096 10003c1c: 41 82 00 08 beq 0x10003c24 10003c20: 7c 63 00 d0 neg r3,r3 Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow bit with the 'bns' instruction, it is smaller: /* no summary overflow bit means no error, return value directly */ bns+ 1f /* otherwise, return negated value */ neg r3, r3 1: --> 10000418: 40 a3 00 08 bns 0x10000420 1000041c: 7c 63 00 d0 neg r3,r3 Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the same method for do_syscall_2() too. Here applies the second method to get smaller size. [1]: https://man7.org/linux/man-pages/man2/syscall.2.html Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-06 02:39:26 +08:00
__builtin_unreachable();
}
#endif /* _NOLIBC_ARCH_POWERPC_H */