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/* 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__
/* 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__ */
/* 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
__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
__builtin_unreachable();
}
#endif /* _NOLIBC_ARCH_POWERPC_H */
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