FILE
arch-x86.h
File preview with syntax highlighting.
linux-6.19.14/tools/include/nolibc/arch-x86.h
1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ 2/* 3 * x86 specific definitions for NOLIBC (both 32- and 64-bit) 4 * Copyright (C) 2017-2025 Willy Tarreau <w@1wt.eu> 5 */ 6 7#ifndef _NOLIBC_ARCH_X86_H 8#define _NOLIBC_ARCH_X86_H 9 10#include "compiler.h" 11#include "crt.h" 12 13#if !defined(__x86_64__) 14 15/* Syscalls for i386 : 16 * - mostly similar to x86_64 17 * - registers are 32-bit 18 * - syscall number is passed in eax 19 * - arguments are in ebx, ecx, edx, esi, edi, ebp respectively 20 * - all registers are preserved (except eax of course) 21 * - the system call is performed by calling int $0x80 22 * - syscall return comes in eax 23 * - the arguments are cast to long and assigned into the target registers 24 * which are then simply passed as registers to the asm code, so that we 25 * don't have to experience issues with register constraints. 26 * - the syscall number is always specified last in order to allow to force 27 * some registers before (gcc refuses a %-register at the last position). 28 * 29 * Also, i386 supports the old_select syscall if newselect is not available 30 */ 31#define __ARCH_WANT_SYS_OLD_SELECT 32 33#define my_syscall0(num) \ 34({ \ 35 long _ret; \ 36 register long _num __asm__ ("eax") = (num); \ 37 \ 38 __asm__ volatile ( \ 39 "int $0x80\n" \ 40 : "=a" (_ret) \ 41 : "0"(_num) \ 42 : "memory", "cc" \ 43 ); \ 44 _ret; \ 45}) 46 47#define my_syscall1(num, arg1) \ 48({ \ 49 long _ret; \ 50 register long _num __asm__ ("eax") = (num); \ 51 register long _arg1 __asm__ ("ebx") = (long)(arg1); \ 52 \ 53 __asm__ volatile ( \ 54 "int $0x80\n" \ 55 : "=a" (_ret) \ 56 : "r"(_arg1), \ 57 "0"(_num) \ 58 : "memory", "cc" \ 59 ); \ 60 _ret; \ 61}) 62 63#define my_syscall2(num, arg1, arg2) \ 64({ \ 65 long _ret; \ 66 register long _num __asm__ ("eax") = (num); \ 67 register long _arg1 __asm__ ("ebx") = (long)(arg1); \ 68 register long _arg2 __asm__ ("ecx") = (long)(arg2); \ 69 \ 70 __asm__ volatile ( \ 71 "int $0x80\n" \ 72 : "=a" (_ret) \ 73 : "r"(_arg1), "r"(_arg2), \ 74 "0"(_num) \ 75 : "memory", "cc" \ 76 ); \ 77 _ret; \ 78}) 79 80#define my_syscall3(num, arg1, arg2, arg3) \ 81({ \ 82 long _ret; \ 83 register long _num __asm__ ("eax") = (num); \ 84 register long _arg1 __asm__ ("ebx") = (long)(arg1); \ 85 register long _arg2 __asm__ ("ecx") = (long)(arg2); \ 86 register long _arg3 __asm__ ("edx") = (long)(arg3); \ 87 \ 88 __asm__ volatile ( \ 89 "int $0x80\n" \ 90 : "=a" (_ret) \ 91 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \ 92 "0"(_num) \ 93 : "memory", "cc" \ 94 ); \ 95 _ret; \ 96}) 97 98#define my_syscall4(num, arg1, arg2, arg3, arg4) \ 99({ \ 100 long _ret; \ 101 register long _num __asm__ ("eax") = (num); \ 102 register long _arg1 __asm__ ("ebx") = (long)(arg1); \ 103 register long _arg2 __asm__ ("ecx") = (long)(arg2); \ 104 register long _arg3 __asm__ ("edx") = (long)(arg3); \ 105 register long _arg4 __asm__ ("esi") = (long)(arg4); \ 106 \ 107 __asm__ volatile ( \ 108 "int $0x80\n" \ 109 : "=a" (_ret) \ 110 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ 111 "0"(_num) \ 112 : "memory", "cc" \ 113 ); \ 114 _ret; \ 115}) 116 117#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ 118({ \ 119 long _ret; \ 120 register long _num __asm__ ("eax") = (num); \ 121 register long _arg1 __asm__ ("ebx") = (long)(arg1); \ 122 register long _arg2 __asm__ ("ecx") = (long)(arg2); \ 123 register long _arg3 __asm__ ("edx") = (long)(arg3); \ 124 register long _arg4 __asm__ ("esi") = (long)(arg4); \ 125 register long _arg5 __asm__ ("edi") = (long)(arg5); \ 126 \ 127 __asm__ volatile ( \ 128 "int $0x80\n" \ 129 : "=a" (_ret) \ 130 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ 131 "0"(_num) \ 132 : "memory", "cc" \ 133 ); \ 134 _ret; \ 135}) 136 137#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ 138({ \ 139 long _eax = (long)(num); \ 140 long _arg6 = (long)(arg6); /* Always in memory */ \ 141 __asm__ volatile ( \ 142 "pushl %[_arg6]\n\t" \ 143 "pushl %%ebp\n\t" \ 144 "movl 4(%%esp),%%ebp\n\t" \ 145 "int $0x80\n\t" \ 146 "popl %%ebp\n\t" \ 147 "addl $4,%%esp\n\t" \ 148 : "+a"(_eax) /* %eax */ \ 149 : "b"(arg1), /* %ebx */ \ 150 "c"(arg2), /* %ecx */ \ 151 "d"(arg3), /* %edx */ \ 152 "S"(arg4), /* %esi */ \ 153 "D"(arg5), /* %edi */ \ 154 [_arg6]"m"(_arg6) /* memory */ \ 155 : "memory", "cc" \ 156 ); \ 157 _eax; \ 158}) 159 160#ifndef NOLIBC_NO_RUNTIME 161/* startup code */ 162/* 163 * i386 System V ABI mandates: 164 * 1) last pushed argument must be 16-byte aligned. 165 * 2) The deepest stack frame should be set to zero 166 * 167 */ 168void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void) 169{ 170 __asm__ volatile ( 171 "xor %ebp, %ebp\n" /* zero the stack frame */ 172 "mov %esp, %eax\n" /* save stack pointer to %eax, as arg1 of _start_c */ 173 "sub $12, %esp\n" /* sub 12 to keep it aligned after the push %eax */ 174 "push %eax\n" /* push arg1 on stack to support plain stack modes too */ 175 "call _start_c\n" /* transfer to c runtime */ 176 "hlt\n" /* ensure it does not return */ 177 ); 178 __nolibc_entrypoint_epilogue(); 179} 180#endif /* NOLIBC_NO_RUNTIME */ 181 182#else /* !defined(__x86_64__) */ 183 184/* Syscalls for x86_64 : 185 * - registers are 64-bit 186 * - syscall number is passed in rax 187 * - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively 188 * - the system call is performed by calling the syscall instruction 189 * - syscall return comes in rax 190 * - rcx and r11 are clobbered, others are preserved. 191 * - the arguments are cast to long and assigned into the target registers 192 * which are then simply passed as registers to the asm code, so that we 193 * don't have to experience issues with register constraints. 194 * - the syscall number is always specified last in order to allow to force 195 * some registers before (gcc refuses a %-register at the last position). 196 * - see also x86-64 ABI section A.2 AMD64 Linux Kernel Conventions, A.2.1 197 * Calling Conventions. 198 * 199 * Link x86-64 ABI: https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/home 200 * 201 */ 202 203#define my_syscall0(num) \ 204({ \ 205 long _ret; \ 206 register long _num __asm__ ("rax") = (num); \ 207 \ 208 __asm__ volatile ( \ 209 "syscall\n" \ 210 : "=a"(_ret) \ 211 : "0"(_num) \ 212 : "rcx", "r11", "memory", "cc" \ 213 ); \ 214 _ret; \ 215}) 216 217#define my_syscall1(num, arg1) \ 218({ \ 219 long _ret; \ 220 register long _num __asm__ ("rax") = (num); \ 221 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 222 \ 223 __asm__ volatile ( \ 224 "syscall\n" \ 225 : "=a"(_ret) \ 226 : "r"(_arg1), \ 227 "0"(_num) \ 228 : "rcx", "r11", "memory", "cc" \ 229 ); \ 230 _ret; \ 231}) 232 233#define my_syscall2(num, arg1, arg2) \ 234({ \ 235 long _ret; \ 236 register long _num __asm__ ("rax") = (num); \ 237 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 238 register long _arg2 __asm__ ("rsi") = (long)(arg2); \ 239 \ 240 __asm__ volatile ( \ 241 "syscall\n" \ 242 : "=a"(_ret) \ 243 : "r"(_arg1), "r"(_arg2), \ 244 "0"(_num) \ 245 : "rcx", "r11", "memory", "cc" \ 246 ); \ 247 _ret; \ 248}) 249 250#define my_syscall3(num, arg1, arg2, arg3) \ 251({ \ 252 long _ret; \ 253 register long _num __asm__ ("rax") = (num); \ 254 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 255 register long _arg2 __asm__ ("rsi") = (long)(arg2); \ 256 register long _arg3 __asm__ ("rdx") = (long)(arg3); \ 257 \ 258 __asm__ volatile ( \ 259 "syscall\n" \ 260 : "=a"(_ret) \ 261 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \ 262 "0"(_num) \ 263 : "rcx", "r11", "memory", "cc" \ 264 ); \ 265 _ret; \ 266}) 267 268#define my_syscall4(num, arg1, arg2, arg3, arg4) \ 269({ \ 270 long _ret; \ 271 register long _num __asm__ ("rax") = (num); \ 272 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 273 register long _arg2 __asm__ ("rsi") = (long)(arg2); \ 274 register long _arg3 __asm__ ("rdx") = (long)(arg3); \ 275 register long _arg4 __asm__ ("r10") = (long)(arg4); \ 276 \ 277 __asm__ volatile ( \ 278 "syscall\n" \ 279 : "=a"(_ret) \ 280 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ 281 "0"(_num) \ 282 : "rcx", "r11", "memory", "cc" \ 283 ); \ 284 _ret; \ 285}) 286 287#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ 288({ \ 289 long _ret; \ 290 register long _num __asm__ ("rax") = (num); \ 291 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 292 register long _arg2 __asm__ ("rsi") = (long)(arg2); \ 293 register long _arg3 __asm__ ("rdx") = (long)(arg3); \ 294 register long _arg4 __asm__ ("r10") = (long)(arg4); \ 295 register long _arg5 __asm__ ("r8") = (long)(arg5); \ 296 \ 297 __asm__ volatile ( \ 298 "syscall\n" \ 299 : "=a"(_ret) \ 300 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ 301 "0"(_num) \ 302 : "rcx", "r11", "memory", "cc" \ 303 ); \ 304 _ret; \ 305}) 306 307#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ 308({ \ 309 long _ret; \ 310 register long _num __asm__ ("rax") = (num); \ 311 register long _arg1 __asm__ ("rdi") = (long)(arg1); \ 312 register long _arg2 __asm__ ("rsi") = (long)(arg2); \ 313 register long _arg3 __asm__ ("rdx") = (long)(arg3); \ 314 register long _arg4 __asm__ ("r10") = (long)(arg4); \ 315 register long _arg5 __asm__ ("r8") = (long)(arg5); \ 316 register long _arg6 __asm__ ("r9") = (long)(arg6); \ 317 \ 318 __asm__ volatile ( \ 319 "syscall\n" \ 320 : "=a"(_ret) \ 321 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ 322 "r"(_arg6), "0"(_num) \ 323 : "rcx", "r11", "memory", "cc" \ 324 ); \ 325 _ret; \ 326}) 327 328#ifndef NOLIBC_NO_RUNTIME 329/* startup code */ 330/* 331 * x86-64 System V ABI mandates: 332 * 1) %rsp must be 16-byte aligned right before the function call. 333 * 2) The deepest stack frame should be zero (the %rbp). 334 * 335 */ 336void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void) 337{ 338 __asm__ volatile ( 339 "xor %ebp, %ebp\n" /* zero the stack frame */ 340 "mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _start_c */ 341 "call _start_c\n" /* transfer to c runtime */ 342 "hlt\n" /* ensure it does not return */ 343 ); 344 __nolibc_entrypoint_epilogue(); 345} 346#endif /* NOLIBC_NO_RUNTIME */ 347 348#define NOLIBC_ARCH_HAS_MEMMOVE 349void *memmove(void *dst, const void *src, size_t len); 350 351#define NOLIBC_ARCH_HAS_MEMCPY 352void *memcpy(void *dst, const void *src, size_t len); 353 354#define NOLIBC_ARCH_HAS_MEMSET 355void *memset(void *dst, int c, size_t len); 356 357__asm__ ( 358".pushsection .text.nolibc_memmove_memcpy\n" 359".weak memmove\n" 360".weak memcpy\n" 361"memmove:\n" 362"memcpy:\n" 363 "movq %rdx, %rcx\n\t" 364 "movq %rdi, %rax\n\t" 365 "movq %rdi, %rdx\n\t" 366 "subq %rsi, %rdx\n\t" 367 "cmpq %rcx, %rdx\n\t" 368 "jb 1f\n\t" 369 "rep movsb\n\t" 370 "retq\n" 371"1:" /* backward copy */ 372 "leaq -1(%rdi, %rcx, 1), %rdi\n\t" 373 "leaq -1(%rsi, %rcx, 1), %rsi\n\t" 374 "std\n\t" 375 "rep movsb\n\t" 376 "cld\n\t" 377 "retq\n" 378".popsection\n" 379 380".pushsection .text.nolibc_memset\n" 381".weak memset\n" 382"memset:\n" 383 "xchgl %eax, %esi\n\t" 384 "movq %rdx, %rcx\n\t" 385 "pushq %rdi\n\t" 386 "rep stosb\n\t" 387 "popq %rax\n\t" 388 "retq\n" 389".popsection\n" 390); 391 392#endif /* !defined(__x86_64__) */ 393#endif /* _NOLIBC_ARCH_X86_H */
~/
Read-only file preview.