163 lines · c
1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */2/*3 * LoongArch specific definitions for NOLIBC4 * Copyright (C) 2023 Loongson Technology Corporation Limited5 */6 7#ifndef _NOLIBC_ARCH_LOONGARCH_H8#define _NOLIBC_ARCH_LOONGARCH_H9 10#include "compiler.h"11#include "crt.h"12 13/* Syscalls for LoongArch :14 * - stack is 16-byte aligned15 * - syscall number is passed in a716 * - arguments are in a0, a1, a2, a3, a4, a517 * - the system call is performed by calling "syscall 0"18 * - syscall return comes in a019 * - the arguments are cast to long and assigned into the target20 * registers which are then simply passed as registers to the asm code,21 * so that we don't have to experience issues with register constraints.22 */23 24#define _NOLIBC_SYSCALL_CLOBBERLIST \25 "memory", "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8"26 27#define my_syscall0(num) \28({ \29 register long _num __asm__ ("a7") = (num); \30 register long _arg1 __asm__ ("a0"); \31 \32 __asm__ volatile ( \33 "syscall 0\n" \34 : "=r"(_arg1) \35 : "r"(_num) \36 : _NOLIBC_SYSCALL_CLOBBERLIST \37 ); \38 _arg1; \39})40 41#define my_syscall1(num, arg1) \42({ \43 register long _num __asm__ ("a7") = (num); \44 register long _arg1 __asm__ ("a0") = (long)(arg1); \45 \46 __asm__ volatile ( \47 "syscall 0\n" \48 : "+r"(_arg1) \49 : "r"(_num) \50 : _NOLIBC_SYSCALL_CLOBBERLIST \51 ); \52 _arg1; \53})54 55#define my_syscall2(num, arg1, arg2) \56({ \57 register long _num __asm__ ("a7") = (num); \58 register long _arg1 __asm__ ("a0") = (long)(arg1); \59 register long _arg2 __asm__ ("a1") = (long)(arg2); \60 \61 __asm__ volatile ( \62 "syscall 0\n" \63 : "+r"(_arg1) \64 : "r"(_arg2), \65 "r"(_num) \66 : _NOLIBC_SYSCALL_CLOBBERLIST \67 ); \68 _arg1; \69})70 71#define my_syscall3(num, arg1, arg2, arg3) \72({ \73 register long _num __asm__ ("a7") = (num); \74 register long _arg1 __asm__ ("a0") = (long)(arg1); \75 register long _arg2 __asm__ ("a1") = (long)(arg2); \76 register long _arg3 __asm__ ("a2") = (long)(arg3); \77 \78 __asm__ volatile ( \79 "syscall 0\n" \80 : "+r"(_arg1) \81 : "r"(_arg2), "r"(_arg3), \82 "r"(_num) \83 : _NOLIBC_SYSCALL_CLOBBERLIST \84 ); \85 _arg1; \86})87 88#define my_syscall4(num, arg1, arg2, arg3, arg4) \89({ \90 register long _num __asm__ ("a7") = (num); \91 register long _arg1 __asm__ ("a0") = (long)(arg1); \92 register long _arg2 __asm__ ("a1") = (long)(arg2); \93 register long _arg3 __asm__ ("a2") = (long)(arg3); \94 register long _arg4 __asm__ ("a3") = (long)(arg4); \95 \96 __asm__ volatile ( \97 "syscall 0\n" \98 : "+r"(_arg1) \99 : "r"(_arg2), "r"(_arg3), "r"(_arg4), \100 "r"(_num) \101 : _NOLIBC_SYSCALL_CLOBBERLIST \102 ); \103 _arg1; \104})105 106#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \107({ \108 register long _num __asm__ ("a7") = (num); \109 register long _arg1 __asm__ ("a0") = (long)(arg1); \110 register long _arg2 __asm__ ("a1") = (long)(arg2); \111 register long _arg3 __asm__ ("a2") = (long)(arg3); \112 register long _arg4 __asm__ ("a3") = (long)(arg4); \113 register long _arg5 __asm__ ("a4") = (long)(arg5); \114 \115 __asm__ volatile ( \116 "syscall 0\n" \117 : "+r"(_arg1) \118 : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \119 "r"(_num) \120 : _NOLIBC_SYSCALL_CLOBBERLIST \121 ); \122 _arg1; \123})124 125#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \126({ \127 register long _num __asm__ ("a7") = (num); \128 register long _arg1 __asm__ ("a0") = (long)(arg1); \129 register long _arg2 __asm__ ("a1") = (long)(arg2); \130 register long _arg3 __asm__ ("a2") = (long)(arg3); \131 register long _arg4 __asm__ ("a3") = (long)(arg4); \132 register long _arg5 __asm__ ("a4") = (long)(arg5); \133 register long _arg6 __asm__ ("a5") = (long)(arg6); \134 \135 __asm__ volatile ( \136 "syscall 0\n" \137 : "+r"(_arg1) \138 : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \139 "r"(_num) \140 : _NOLIBC_SYSCALL_CLOBBERLIST \141 ); \142 _arg1; \143})144 145#if __loongarch_grlen == 32146#define LONG_BSTRINS "bstrins.w"147#else /* __loongarch_grlen == 64 */148#define LONG_BSTRINS "bstrins.d"149#endif150 151/* startup code */152void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)153{154 __asm__ volatile (155 "move $a0, $sp\n" /* save stack pointer to $a0, as arg1 of _start_c */156 LONG_BSTRINS " $sp, $zero, 3, 0\n" /* $sp must be 16-byte aligned */157 "bl _start_c\n" /* transfer to c runtime */158 );159 __nolibc_entrypoint_epilogue();160}161 162#endif /* _NOLIBC_ARCH_LOONGARCH_H */163