| /* 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" |
| #include "crt.h" |
| |
| #if !defined(_ABIO32) |
| #error Unsupported MIPS ABI |
| #endif |
| |
| /* 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 _NOLIBC_SYSCALL_CLOBBERLIST \ |
| "memory", "cc", "at", "v1", "hi", "lo", \ |
| "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" |
| |
| #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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _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) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _arg4 ? -_num : _num; \ |
| }) |
| |
| #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ |
| ({ \ |
| 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); \ |
| register long _arg6 = (long)(arg6); \ |
| \ |
| __asm__ volatile ( \ |
| "addiu $sp, $sp, -32\n" \ |
| "sw %7, 16($sp)\n" \ |
| "sw %8, 20($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), \ |
| "r"(_arg6) \ |
| : _NOLIBC_SYSCALL_CLOBBERLIST \ |
| ); \ |
| _arg4 ? -_num : _num; \ |
| }) |
| |
| /* startup code, note that it's called __start on MIPS */ |
| void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector __start(void) |
| { |
| __asm__ volatile ( |
| ".set push\n" |
| ".set noreorder\n" |
| "bal 1f\n" /* prime $ra for .cpload */ |
| "nop\n" |
| "1:\n" |
| ".cpload $ra\n" |
| "move $a0, $sp\n" /* save stack pointer to $a0, as arg1 of _start_c */ |
| "addiu $sp, $sp, -4\n" /* space for .cprestore to store $gp */ |
| ".cprestore 0\n" |
| "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 */ |
| "lui $t9, %hi(_start_c)\n" /* ABI requires current function address in $t9 */ |
| "ori $t9, %lo(_start_c)\n" |
| "jalr $t9\n" /* transfer to c runtime */ |
| " nop\n" /* delayed slot */ |
| ".set pop\n" |
| ); |
| __nolibc_entrypoint_epilogue(); |
| } |
| |
| #endif /* _NOLIBC_ARCH_MIPS_H */ |
