/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ /* * ARM specific definitions for NOLIBC * Copyright (C) 2017-2022 Willy Tarreau */ #ifndef _NOLIBC_ARCH_ARM_H #define _NOLIBC_ARCH_ARM_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 0x4000 /* The struct returned by the stat() syscall, 32-bit only, the syscall returns * exactly 56 bytes (stops before the unused array). In big endian, the format * differs as devices are returned as short only. */ struct sys_stat_struct { #if defined(__ARMEB__) unsigned short st_dev; unsigned short __pad1; #else unsigned long st_dev; #endif unsigned long st_ino; unsigned short st_mode; unsigned short st_nlink; unsigned short st_uid; unsigned short st_gid; #if defined(__ARMEB__) unsigned short st_rdev; unsigned short __pad2; #else unsigned long st_rdev; #endif unsigned long st_size; unsigned long st_blksize; unsigned 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; unsigned long __unused[2]; }; /* 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). * * Also, ARM supports the old_select syscall if newselect is not available */ #define __ARCH_WANT_SYS_OLD_SELECT #define my_syscall0(num) \ ({ \ register long _num asm("r7") = (num); \ register long _arg1 asm("r0"); \ \ asm volatile ( \ "svc #0\n" \ : "=r"(_arg1) \ : "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) #define my_syscall1(num, arg1) \ ({ \ register long _num asm("r7") = (num); \ register long _arg1 asm("r0") = (long)(arg1); \ \ asm volatile ( \ "svc #0\n" \ : "=r"(_arg1) \ : "r"(_arg1), \ "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) #define my_syscall2(num, arg1, arg2) \ ({ \ register long _num asm("r7") = (num); \ register long _arg1 asm("r0") = (long)(arg1); \ register long _arg2 asm("r1") = (long)(arg2); \ \ asm volatile ( \ "svc #0\n" \ : "=r"(_arg1) \ : "r"(_arg1), "r"(_arg2), \ "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) #define my_syscall3(num, arg1, arg2, arg3) \ ({ \ register long _num asm("r7") = (num); \ register long _arg1 asm("r0") = (long)(arg1); \ register long _arg2 asm("r1") = (long)(arg2); \ register long _arg3 asm("r2") = (long)(arg3); \ \ asm volatile ( \ "svc #0\n" \ : "=r"(_arg1) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), \ "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) #define my_syscall4(num, arg1, arg2, arg3, arg4) \ ({ \ register long _num asm("r7") = (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 ( \ "svc #0\n" \ : "=r"(_arg1) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ ({ \ register long _num asm("r7") = (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 ( \ "svc #0\n" \ : "=r" (_arg1) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ }) /* startup code */ asm(".section .text\n" ".weak _start\n" ".global _start\n" "_start:\n" #if defined(__THUMBEB__) || defined(__THUMBEL__) /* We enter here in 32-bit mode but if some previous functions were in * 16-bit mode, the assembler cannot know, so we need to tell it we're in * 32-bit now, then switch to 16-bit (is there a better way to do it than * adding 1 by hand ?) and tell the asm we're now in 16-bit mode so that * it generates correct instructions. Note that we do not support thumb1. */ ".code 32\n" "add r0, pc, #1\n" "bx r0\n" ".code 16\n" #endif "pop {%r0}\n" // argc was in the stack "mov %r1, %sp\n" // argv = sp "add %r2, %r1, %r0, lsl #2\n" // envp = argv + 4*argc ... "add %r2, %r2, $4\n" // ... + 4 "and %r3, %r1, $-8\n" // AAPCS : sp must be 8-byte aligned in the "mov %sp, %r3\n" // callee, an bl doesn't push (lr=pc) "bl main\n" // main() returns the status code, we'll exit with it. "movs r7, $1\n" // NR_exit == 1 "svc $0x00\n" ""); #endif // _NOLIBC_ARCH_ARM_H