mirror of
https://github.com/torvalds/linux.git
synced 2024-12-02 17:11:33 +00:00
1590c59836
Building with clang yields the following error: ``` <inline asm>:3:1: error: _start changed binding to STB_GLOBAL .global _start ^ 1 error generated. ``` Make sure only specify one between `.global _start` and `.weak _start`. Remove `.global _start`. Cc: llvm@lists.linux.dev Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
216 lines
11 KiB
C
216 lines
11 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
|
|
/*
|
|
* x86_64 specific definitions for NOLIBC
|
|
* Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
|
|
*/
|
|
|
|
#ifndef _NOLIBC_ARCH_X86_64_H
|
|
#define _NOLIBC_ARCH_X86_64_H
|
|
|
|
/* O_* macros for fcntl/open are architecture-specific */
|
|
#define O_RDONLY 0
|
|
#define O_WRONLY 1
|
|
#define O_RDWR 2
|
|
#define O_CREAT 0x40
|
|
#define O_EXCL 0x80
|
|
#define O_NOCTTY 0x100
|
|
#define O_TRUNC 0x200
|
|
#define O_APPEND 0x400
|
|
#define O_NONBLOCK 0x800
|
|
#define O_DIRECTORY 0x10000
|
|
|
|
/* The struct returned by the stat() syscall, equivalent to stat64(). The
|
|
* syscall returns 116 bytes and stops in the middle of __unused.
|
|
*/
|
|
struct sys_stat_struct {
|
|
unsigned long st_dev;
|
|
unsigned long st_ino;
|
|
unsigned long st_nlink;
|
|
unsigned int st_mode;
|
|
unsigned int st_uid;
|
|
|
|
unsigned int st_gid;
|
|
unsigned int __pad0;
|
|
unsigned long st_rdev;
|
|
long st_size;
|
|
long st_blksize;
|
|
|
|
long st_blocks;
|
|
unsigned long st_atime;
|
|
unsigned long st_atime_nsec;
|
|
unsigned long st_mtime;
|
|
|
|
unsigned long st_mtime_nsec;
|
|
unsigned long st_ctime;
|
|
unsigned long st_ctime_nsec;
|
|
long __unused[3];
|
|
};
|
|
|
|
/* Syscalls for x86_64 :
|
|
* - registers are 64-bit
|
|
* - syscall number is passed in rax
|
|
* - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively
|
|
* - the system call is performed by calling the syscall instruction
|
|
* - syscall return comes in rax
|
|
* - rcx and r11 are clobbered, others are preserved.
|
|
* - 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.
|
|
* - the syscall number is always specified last in order to allow to force
|
|
* some registers before (gcc refuses a %-register at the last position).
|
|
* - see also x86-64 ABI section A.2 AMD64 Linux Kernel Conventions, A.2.1
|
|
* Calling Conventions.
|
|
*
|
|
* Link x86-64 ABI: https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/home
|
|
*
|
|
*/
|
|
|
|
#define my_syscall0(num) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall1(num, arg1) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), \
|
|
"0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall2(num, arg1, arg2) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
register long _arg2 __asm__ ("rsi") = (long)(arg2); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), "r"(_arg2), \
|
|
"0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall3(num, arg1, arg2, arg3) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
register long _arg2 __asm__ ("rsi") = (long)(arg2); \
|
|
register long _arg3 __asm__ ("rdx") = (long)(arg3); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
|
|
"0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
register long _arg2 __asm__ ("rsi") = (long)(arg2); \
|
|
register long _arg3 __asm__ ("rdx") = (long)(arg3); \
|
|
register long _arg4 __asm__ ("r10") = (long)(arg4); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
|
|
"0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
register long _arg2 __asm__ ("rsi") = (long)(arg2); \
|
|
register long _arg3 __asm__ ("rdx") = (long)(arg3); \
|
|
register long _arg4 __asm__ ("r10") = (long)(arg4); \
|
|
register long _arg5 __asm__ ("r8") = (long)(arg5); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
|
|
"0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
|
|
({ \
|
|
long _ret; \
|
|
register long _num __asm__ ("rax") = (num); \
|
|
register long _arg1 __asm__ ("rdi") = (long)(arg1); \
|
|
register long _arg2 __asm__ ("rsi") = (long)(arg2); \
|
|
register long _arg3 __asm__ ("rdx") = (long)(arg3); \
|
|
register long _arg4 __asm__ ("r10") = (long)(arg4); \
|
|
register long _arg5 __asm__ ("r8") = (long)(arg5); \
|
|
register long _arg6 __asm__ ("r9") = (long)(arg6); \
|
|
\
|
|
__asm__ volatile ( \
|
|
"syscall\n" \
|
|
: "=a"(_ret) \
|
|
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
|
|
"r"(_arg6), "0"(_num) \
|
|
: "rcx", "r11", "memory", "cc" \
|
|
); \
|
|
_ret; \
|
|
})
|
|
|
|
/* startup code */
|
|
/*
|
|
* x86-64 System V ABI mandates:
|
|
* 1) %rsp must be 16-byte aligned right before the function call.
|
|
* 2) The deepest stack frame should be zero (the %rbp).
|
|
*
|
|
*/
|
|
__asm__ (".section .text\n"
|
|
".weak _start\n"
|
|
"_start:\n"
|
|
"pop %rdi\n" // argc (first arg, %rdi)
|
|
"mov %rsp, %rsi\n" // argv[] (second arg, %rsi)
|
|
"lea 8(%rsi,%rdi,8),%rdx\n" // then a NULL then envp (third arg, %rdx)
|
|
"xor %ebp, %ebp\n" // zero the stack frame
|
|
"and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned before call
|
|
"call main\n" // main() returns the status code, we'll exit with it.
|
|
"mov %eax, %edi\n" // retrieve exit code (32 bit)
|
|
"mov $60, %eax\n" // NR_exit == 60
|
|
"syscall\n" // really exit
|
|
"hlt\n" // ensure it does not return
|
|
"");
|
|
|
|
#endif // _NOLIBC_ARCH_X86_64_H
|