original_kernel/tools/include/nolibc/arch-powerpc.h

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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; \
})
#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
#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)
{
#ifdef __powerpc64__
#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 */
__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 */
);
#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 */