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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* MIPS specific definitions for NOLIBC
* Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
*/
#ifndef _NOLIBC_ARCH_MIPS_H
#define _NOLIBC_ARCH_MIPS_H
#include "compiler.h"
/* The struct returned by the stat() syscall. 88 bytes are returned by the
* syscall.
*/
struct sys_stat_struct {
unsigned int st_dev;
long st_pad1[3];
unsigned long st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned int st_uid;
unsigned int st_gid;
unsigned int st_rdev;
long st_pad2[2];
long st_size;
long st_pad3;
long st_atime;
long st_atime_nsec;
long st_mtime;
long st_mtime_nsec;
long st_ctime;
long st_ctime_nsec;
long st_blksize;
long st_blocks;
long st_pad4[14];
};
/* Syscalls for MIPS ABI O32 :
* - WARNING! there's always a delayed slot!
* - WARNING again, the syntax is different, registers take a '$' and numbers
* do not.
* - registers are 32-bit
* - stack is 8-byte aligned
* - syscall number is passed in v0 (starts at 0xfa0).
* - arguments are in a0, a1, a2, a3, then the stack. The caller needs to
* leave some room in the stack for the callee to save a0..a3 if needed.
* - Many registers are clobbered, in fact only a0..a2 and s0..s8 are
* preserved. See: https://www.linux-mips.org/wiki/Syscall as well as
* scall32-o32.S in the kernel sources.
* - the system call is performed by calling "syscall"
* - syscall return comes in v0, and register a3 needs to be checked to know
* if an error occurred, in which case errno is in v0.
* - 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.
*/
#define my_syscall0(num) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg4 __asm__ ("a3"); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "r"(_num) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg4 __asm__ ("a3"); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg4 __asm__ ("a3"); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3"); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r" (_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num __asm__ ("v0") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
register long _arg5 = (long)(arg5); \
\
__asm__ volatile ( \
"addiu $sp, $sp, -32\n" \
"sw %7, 16($sp)\n" \
"syscall\n " \
"addiu $sp, $sp, 32\n" \
: "=r" (_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));
/* startup code, note that it's called __start on MIPS */
void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector __start(void)
{
__asm__ volatile (
/*".set nomips16\n"*/
".set push\n"
".set noreorder\n"
".option pic0\n"
#ifdef _NOLIBC_STACKPROTECTOR
"jal __stack_chk_init\n" /* initialize stack protector */
"nop\n" /* delayed slot */
#endif
/*".ent __start\n"*/
/*"__start:\n"*/
"lw $a0,($sp)\n" /* argc was in the stack */
"addiu $a1, $sp, 4\n" /* argv = sp + 4 */
"sll $a2, $a0, 2\n" /* a2 = argc * 4 */
"add $a2, $a2, $a1\n" /* envp = argv + 4*argc ... */
"addiu $a2, $a2, 4\n" /* ... + 4 */
"lui $a3, %hi(environ)\n" /* load environ into a3 (hi) */
"addiu $a3, %lo(environ)\n" /* load environ into a3 (lo) */
"sw $a2,($a3)\n" /* store envp(a2) into environ */
"move $t0, $a2\n" /* iterate t0 over envp, look for NULL */
"0:" /* do { */
"lw $a3, ($t0)\n" /* a3=*(t0); */
"bne $a3, $0, 0b\n" /* } while (a3); */
"addiu $t0, $t0, 4\n" /* delayed slot: t0+=4; */
"lui $a3, %hi(_auxv)\n" /* load _auxv into a3 (hi) */
"addiu $a3, %lo(_auxv)\n" /* load _auxv into a3 (lo) */
"sw $t0, ($a3)\n" /* store t0 into _auxv */
"li $t0, -8\n"
"and $sp, $sp, $t0\n" /* sp must be 8-byte aligned */
"addiu $sp,$sp,-16\n" /* the callee expects to save a0..a3 there! */
"jal main\n" /* main() returns the status code, we'll exit with it. */
"nop\n" /* delayed slot */
"move $a0, $v0\n" /* retrieve 32-bit exit code from v0 */
"li $v0, 4001\n" /* NR_exit == 4001 */
"syscall\n"
/*".end __start\n"*/
".set pop\n"
);
__builtin_unreachable();
}
#endif /* _NOLIBC_ARCH_MIPS_H */
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