/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ /* * LoongArch specific definitions for NOLIBC * Copyright (C) 2023 Loongson Technology Corporation Limited */ #ifndef _NOLIBC_ARCH_LOONGARCH_H #define _NOLIBC_ARCH_LOONGARCH_H #include "compiler.h" /* Syscalls for LoongArch : * - stack is 16-byte aligned * - syscall number is passed in a7 * - arguments are in a0, a1, a2, a3, a4, a5 * - the system call is performed by calling "syscall 0" * - syscall return comes in a0 * - 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. * * On LoongArch, select() is not implemented so we have to use pselect6(). */ #define __ARCH_WANT_SYS_PSELECT6 #define my_syscall0(num) \ ({ \ register long _num __asm__ ("a7") = (num); \ register long _arg1 __asm__ ("a0"); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "=r"(_arg1) \ : "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall1(num, arg1) \ ({ \ register long _num __asm__ ("a7") = (num); \ register long _arg1 __asm__ ("a0") = (long)(arg1); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall2(num, arg1, arg2) \ ({ \ register long _num __asm__ ("a7") = (num); \ register long _arg1 __asm__ ("a0") = (long)(arg1); \ register long _arg2 __asm__ ("a1") = (long)(arg2); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_arg2), \ "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall3(num, arg1, arg2, arg3) \ ({ \ register long _num __asm__ ("a7") = (num); \ register long _arg1 __asm__ ("a0") = (long)(arg1); \ register long _arg2 __asm__ ("a1") = (long)(arg2); \ register long _arg3 __asm__ ("a2") = (long)(arg3); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_arg2), "r"(_arg3), \ "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall4(num, arg1, arg2, arg3, arg4) \ ({ \ register long _num __asm__ ("a7") = (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 ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_arg2), "r"(_arg3), "r"(_arg4), \ "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ ({ \ register long _num __asm__ ("a7") = (num); \ register long _arg1 __asm__ ("a0") = (long)(arg1); \ register long _arg2 __asm__ ("a1") = (long)(arg2); \ register long _arg3 __asm__ ("a2") = (long)(arg3); \ register long _arg4 __asm__ ("a3") = (long)(arg4); \ register long _arg5 __asm__ ("a4") = (long)(arg5); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ ({ \ register long _num __asm__ ("a7") = (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 __asm__ ("a4") = (long)(arg5); \ register long _arg6 __asm__ ("a5") = (long)(arg6); \ \ __asm__ volatile ( \ "syscall 0\n" \ : "+r"(_arg1) \ : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \ "r"(_num) \ : "memory", "$t0", "$t1", "$t2", "$t3", \ "$t4", "$t5", "$t6", "$t7", "$t8" \ ); \ _arg1; \ }) char **environ __attribute__((weak)); const unsigned long *_auxv __attribute__((weak)); #if __loongarch_grlen == 32 #define LONGLOG "2" #define SZREG "4" #define REG_L "ld.w" #define LONG_S "st.w" #define LONG_ADD "add.w" #define LONG_ADDI "addi.w" #define LONG_SLL "slli.w" #define LONG_BSTRINS "bstrins.w" #else /* __loongarch_grlen == 64 */ #define LONGLOG "3" #define SZREG "8" #define REG_L "ld.d" #define LONG_S "st.d" #define LONG_ADD "add.d" #define LONG_ADDI "addi.d" #define LONG_SLL "slli.d" #define LONG_BSTRINS "bstrins.d" #endif /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector _start(void) { __asm__ volatile ( #ifdef _NOLIBC_STACKPROTECTOR "bl __stack_chk_init\n" /* initialize stack protector */ #endif REG_L " $a0, $sp, 0\n" /* argc (a0) was in the stack */ LONG_ADDI " $a1, $sp, "SZREG"\n" /* argv (a1) = sp + SZREG */ LONG_SLL " $a2, $a0, "LONGLOG"\n" /* envp (a2) = SZREG*argc ... */ LONG_ADDI " $a2, $a2, "SZREG"\n" /* + SZREG (skip null) */ LONG_ADD " $a2, $a2, $a1\n" /* + argv */ "move $a3, $a2\n" /* iterate a3 over envp to find auxv (after NULL) */ "0:\n" /* do { */ REG_L " $a4, $a3, 0\n" /* a4 = *a3; */ LONG_ADDI " $a3, $a3, "SZREG"\n" /* a3 += sizeof(void*); */ "bne $a4, $zero, 0b\n" /* } while (a4); */ "la.pcrel $a4, _auxv\n" /* a4 = &_auxv */ LONG_S " $a3, $a4, 0\n" /* store a3 into _auxv */ "la.pcrel $a3, environ\n" /* a3 = &environ */ LONG_S " $a2, $a3, 0\n" /* store envp(a2) into environ */ LONG_BSTRINS " $sp, $zero, 3, 0\n" /* sp must be 16-byte aligned */ "bl main\n" /* main() returns the status code, we'll exit with it. */ "li.w $a7, 93\n" /* NR_exit == 93 */ "syscall 0\n" ); __builtin_unreachable(); } #endif /* _NOLIBC_ARCH_LOONGARCH_H */