mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-05 16:54:27 +00:00
cc6dc5fbec
This remained the only exception to the kernel's architectures organization and it's always a bit cumbersome to deal with. Let's merge i386 and x86_64 into x86. This will result in a single arch-x86.h file by default, and we'll no longer need to merge the two manually during installation. Requesting either i386 or x86_64 will also result in installing x86. Acked-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Willy Tarreau <w@1wt.eu>
387 lines
18 KiB
C
387 lines
18 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* x86 specific definitions for NOLIBC (both 32- and 64-bit)
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* Copyright (C) 2017-2025 Willy Tarreau <w@1wt.eu>
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*/
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#ifndef _NOLIBC_ARCH_X86_H
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#define _NOLIBC_ARCH_X86_H
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#include "compiler.h"
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#include "crt.h"
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#if !defined(__x86_64__)
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/* Syscalls for i386 :
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* - mostly similar to x86_64
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* - registers are 32-bit
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* - syscall number is passed in eax
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* - arguments are in ebx, ecx, edx, esi, edi, ebp respectively
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* - all registers are preserved (except eax of course)
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* - the system call is performed by calling int $0x80
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* - syscall return comes in eax
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* - the arguments are cast to long and assigned into the target registers
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* which are then simply passed as registers to the asm code, so that we
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* don't have to experience issues with register constraints.
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* - the syscall number is always specified last in order to allow to force
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* some registers before (gcc refuses a %-register at the last position).
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*
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* Also, i386 supports the old_select syscall if newselect is not available
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*/
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#define __ARCH_WANT_SYS_OLD_SELECT
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#define my_syscall0(num) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall1(num, arg1) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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register long _arg1 __asm__ ("ebx") = (long)(arg1); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "r"(_arg1), \
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"0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall2(num, arg1, arg2) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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register long _arg1 __asm__ ("ebx") = (long)(arg1); \
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register long _arg2 __asm__ ("ecx") = (long)(arg2); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "r"(_arg1), "r"(_arg2), \
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"0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall3(num, arg1, arg2, arg3) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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register long _arg1 __asm__ ("ebx") = (long)(arg1); \
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register long _arg2 __asm__ ("ecx") = (long)(arg2); \
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register long _arg3 __asm__ ("edx") = (long)(arg3); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
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"0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall4(num, arg1, arg2, arg3, arg4) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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register long _arg1 __asm__ ("ebx") = (long)(arg1); \
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register long _arg2 __asm__ ("ecx") = (long)(arg2); \
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register long _arg3 __asm__ ("edx") = (long)(arg3); \
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register long _arg4 __asm__ ("esi") = (long)(arg4); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
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"0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
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({ \
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long _ret; \
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register long _num __asm__ ("eax") = (num); \
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register long _arg1 __asm__ ("ebx") = (long)(arg1); \
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register long _arg2 __asm__ ("ecx") = (long)(arg2); \
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register long _arg3 __asm__ ("edx") = (long)(arg3); \
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register long _arg4 __asm__ ("esi") = (long)(arg4); \
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register long _arg5 __asm__ ("edi") = (long)(arg5); \
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\
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__asm__ volatile ( \
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"int $0x80\n" \
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: "=a" (_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
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"0"(_num) \
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: "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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long _eax = (long)(num); \
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long _arg6 = (long)(arg6); /* Always in memory */ \
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__asm__ volatile ( \
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"pushl %[_arg6]\n\t" \
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"pushl %%ebp\n\t" \
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"movl 4(%%esp),%%ebp\n\t" \
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"int $0x80\n\t" \
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"popl %%ebp\n\t" \
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"addl $4,%%esp\n\t" \
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: "+a"(_eax) /* %eax */ \
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: "b"(arg1), /* %ebx */ \
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"c"(arg2), /* %ecx */ \
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"d"(arg3), /* %edx */ \
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"S"(arg4), /* %esi */ \
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"D"(arg5), /* %edi */ \
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[_arg6]"m"(_arg6) /* memory */ \
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: "memory", "cc" \
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); \
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_eax; \
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})
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/* startup code */
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/*
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* i386 System V ABI mandates:
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* 1) last pushed argument must be 16-byte aligned.
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* 2) The deepest stack frame should be set to zero
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*
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*/
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void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
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{
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__asm__ volatile (
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"xor %ebp, %ebp\n" /* zero the stack frame */
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"mov %esp, %eax\n" /* save stack pointer to %eax, as arg1 of _start_c */
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"sub $12, %esp\n" /* sub 12 to keep it aligned after the push %eax */
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"push %eax\n" /* push arg1 on stack to support plain stack modes too */
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"call _start_c\n" /* transfer to c runtime */
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"hlt\n" /* ensure it does not return */
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);
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__nolibc_entrypoint_epilogue();
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}
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#else /* !defined(__x86_64__) */
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/* Syscalls for x86_64 :
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* - registers are 64-bit
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* - syscall number is passed in rax
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* - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively
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* - the system call is performed by calling the syscall instruction
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* - syscall return comes in rax
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* - rcx and r11 are clobbered, others are preserved.
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* - the arguments are cast to long and assigned into the target registers
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* which are then simply passed as registers to the asm code, so that we
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* don't have to experience issues with register constraints.
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* - the syscall number is always specified last in order to allow to force
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* some registers before (gcc refuses a %-register at the last position).
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* - see also x86-64 ABI section A.2 AMD64 Linux Kernel Conventions, A.2.1
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* Calling Conventions.
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*
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* Link x86-64 ABI: https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/home
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*
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*/
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#define my_syscall0(num) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall1(num, arg1) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), \
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"0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall2(num, arg1, arg2) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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register long _arg2 __asm__ ("rsi") = (long)(arg2); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), "r"(_arg2), \
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"0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall3(num, arg1, arg2, arg3) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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register long _arg2 __asm__ ("rsi") = (long)(arg2); \
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register long _arg3 __asm__ ("rdx") = (long)(arg3); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
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"0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall4(num, arg1, arg2, arg3, arg4) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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register long _arg2 __asm__ ("rsi") = (long)(arg2); \
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register long _arg3 __asm__ ("rdx") = (long)(arg3); \
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register long _arg4 __asm__ ("r10") = (long)(arg4); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
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"0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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register long _arg2 __asm__ ("rsi") = (long)(arg2); \
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register long _arg3 __asm__ ("rdx") = (long)(arg3); \
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register long _arg4 __asm__ ("r10") = (long)(arg4); \
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register long _arg5 __asm__ ("r8") = (long)(arg5); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
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"0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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long _ret; \
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register long _num __asm__ ("rax") = (num); \
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register long _arg1 __asm__ ("rdi") = (long)(arg1); \
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register long _arg2 __asm__ ("rsi") = (long)(arg2); \
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register long _arg3 __asm__ ("rdx") = (long)(arg3); \
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register long _arg4 __asm__ ("r10") = (long)(arg4); \
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register long _arg5 __asm__ ("r8") = (long)(arg5); \
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register long _arg6 __asm__ ("r9") = (long)(arg6); \
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\
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__asm__ volatile ( \
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"syscall\n" \
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: "=a"(_ret) \
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: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
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"r"(_arg6), "0"(_num) \
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: "rcx", "r11", "memory", "cc" \
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); \
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_ret; \
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})
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/* startup code */
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/*
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* x86-64 System V ABI mandates:
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* 1) %rsp must be 16-byte aligned right before the function call.
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* 2) The deepest stack frame should be zero (the %rbp).
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*
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*/
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void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
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{
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__asm__ volatile (
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"xor %ebp, %ebp\n" /* zero the stack frame */
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"mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _start_c */
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"call _start_c\n" /* transfer to c runtime */
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"hlt\n" /* ensure it does not return */
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);
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__nolibc_entrypoint_epilogue();
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}
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#define NOLIBC_ARCH_HAS_MEMMOVE
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void *memmove(void *dst, const void *src, size_t len);
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#define NOLIBC_ARCH_HAS_MEMCPY
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void *memcpy(void *dst, const void *src, size_t len);
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#define NOLIBC_ARCH_HAS_MEMSET
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void *memset(void *dst, int c, size_t len);
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__asm__ (
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".section .text.nolibc_memmove_memcpy\n"
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".weak memmove\n"
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".weak memcpy\n"
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"memmove:\n"
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"memcpy:\n"
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"movq %rdx, %rcx\n\t"
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"movq %rdi, %rax\n\t"
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"movq %rdi, %rdx\n\t"
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"subq %rsi, %rdx\n\t"
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"cmpq %rcx, %rdx\n\t"
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"jb 1f\n\t"
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"rep movsb\n\t"
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"retq\n"
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"1:" /* backward copy */
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"leaq -1(%rdi, %rcx, 1), %rdi\n\t"
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"leaq -1(%rsi, %rcx, 1), %rsi\n\t"
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"std\n\t"
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"rep movsb\n\t"
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"cld\n\t"
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"retq\n"
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".section .text.nolibc_memset\n"
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".weak memset\n"
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"memset:\n"
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"xchgl %eax, %esi\n\t"
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"movq %rdx, %rcx\n\t"
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"pushq %rdi\n\t"
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"rep stosb\n\t"
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"popq %rax\n\t"
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"retq\n"
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);
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#endif /* !defined(__x86_64__) */
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#endif /* _NOLIBC_ARCH_X86_H */
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