| /* SPDX-License-Identifier: LGPL-2.1 OR MIT */ | |
| /* | |
| * ARM specific definitions for NOLIBC | |
| * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu> | |
| */ | |
| #ifndef _NOLIBC_ARCH_ARM_H | |
| #define _NOLIBC_ARCH_ARM_H | |
| #include <linux/unistd.h> | |
| #include "compiler.h" | |
| #include "crt.h" | |
| #include "std.h" | |
| /* Syscalls for ARM in ARM or Thumb modes : | |
| * - registers are 32-bit | |
| * - stack is 8-byte aligned | |
| * ( http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka4127.html) | |
| * - syscall number is passed in r7 | |
| * - arguments are in r0, r1, r2, r3, r4, r5 | |
| * - the system call is performed by calling svc #0 | |
| * - syscall return comes in r0. | |
| * - only lr is clobbered. | |
| * - 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). | |
| * - in thumb mode without -fomit-frame-pointer, r7 is also used to store the | |
| * frame pointer, and we cannot directly assign it as a register variable, | |
| * nor can we clobber it. Instead we assign the r6 register and swap it | |
| * with r7 before calling svc, and r6 is marked as clobbered. | |
| * We're just using any regular register which we assign to r7 after saving | |
| * it. | |
| */ | |
| #if (defined(__THUMBEB__) || defined(__THUMBEL__)) && \ | |
| !defined(NOLIBC_OMIT_FRAME_POINTER) | |
| /* swap r6,r7 needed in Thumb mode since we can't use nor clobber r7 */ | |
| #define _NOLIBC_SYSCALL_REG "r6" | |
| #define _NOLIBC_THUMB_SET_R7 "eor r7, r6\neor r6, r7\neor r7, r6\n" | |
| #define _NOLIBC_THUMB_RESTORE_R7 "mov r7, r6\n" | |
| #else /* we're in ARM mode */ | |
| /* in Arm mode we can directly use r7 */ | |
| #define _NOLIBC_SYSCALL_REG "r7" | |
| #define _NOLIBC_THUMB_SET_R7 "" | |
| #define _NOLIBC_THUMB_RESTORE_R7 "" | |
| #endif /* end THUMB */ | |
| #define __nolibc_syscall0(num) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0"); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r"(_num) \ | |
| : "r"(_arg1), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall1(num, arg1) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall2(num, arg1, arg2) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| register long _arg2 __asm__ ("r1") = (long)(arg2); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), "r"(_arg2), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall3(num, arg1, arg2, arg3) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| register long _arg2 __asm__ ("r1") = (long)(arg2); \ | |
| register long _arg3 __asm__ ("r2") = (long)(arg3); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), "r"(_arg2), "r"(_arg3), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall4(num, arg1, arg2, arg3, arg4) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| register long _arg2 __asm__ ("r1") = (long)(arg2); \ | |
| register long _arg3 __asm__ ("r2") = (long)(arg3); \ | |
| register long _arg4 __asm__ ("r3") = (long)(arg4); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| register long _arg2 __asm__ ("r1") = (long)(arg2); \ | |
| register long _arg3 __asm__ ("r2") = (long)(arg3); \ | |
| register long _arg4 __asm__ ("r3") = (long)(arg4); \ | |
| register long _arg5 __asm__ ("r4") = (long)(arg5); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ | |
| "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ | |
| ({ \ | |
| register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ | |
| register long _arg1 __asm__ ("r0") = (long)(arg1); \ | |
| register long _arg2 __asm__ ("r1") = (long)(arg2); \ | |
| register long _arg3 __asm__ ("r2") = (long)(arg3); \ | |
| register long _arg4 __asm__ ("r3") = (long)(arg4); \ | |
| register long _arg5 __asm__ ("r4") = (long)(arg5); \ | |
| register long _arg6 __asm__ ("r5") = (long)(arg6); \ | |
| \ | |
| __asm__ volatile ( \ | |
| _NOLIBC_THUMB_SET_R7 \ | |
| "svc #0\n" \ | |
| _NOLIBC_THUMB_RESTORE_R7 \ | |
| : "=r"(_arg1), "=r" (_num) \ | |
| : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ | |
| "r"(_arg6), "r"(_num) \ | |
| : "memory", "cc", "lr" \ | |
| ); \ | |
| _arg1; \ | |
| }) | |
| #ifndef NOLIBC_NO_RUNTIME | |
| /* startup code */ | |
| void __attribute__((weak, noreturn)) __nolibc_entrypoint __nolibc_no_stack_protector _start(void) | |
| { | |
| __asm__ volatile ( | |
| "mov r0, sp\n" /* save stack pointer to %r0, as arg1 of _start_c */ | |
| "bl _start_c\n" /* transfer to c runtime */ | |
| ); | |
| __nolibc_entrypoint_epilogue(); | |
| } | |
| #endif /* NOLIBC_NO_RUNTIME */ | |
| static __attribute__((unused)) | |
| int _sys_ftruncate64(int fd, uint32_t length0, uint32_t length1) | |
| { | |
| return __nolibc_syscall4(__NR_ftruncate64, fd, 0, length0, length1); | |
| } | |
| #define _sys_ftruncate64 _sys_ftruncate64 | |
| #endif /* _NOLIBC_ARCH_ARM_H */ |