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| -rw-r--r-- | tools/include/nolibc/arch-x86_64.h | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h new file mode 100644 index 000000000000..0e1e9eb8545d --- /dev/null +++ b/tools/include/nolibc/arch-x86_64.h @@ -0,0 +1,215 @@ +/* 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 |