tools/include/nolibc/arch-loongarch.h

   1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
   2 /*
   3  * LoongArch specific definitions for NOLIBC
   4  * Copyright (C) 2023 Loongson Technology Corporation Limited
   5  */
   6
   7 #ifndef _NOLIBC_ARCH_LOONGARCH_H
   8 #define _NOLIBC_ARCH_LOONGARCH_H
   9
  10 #include "compiler.h"
  11 #include "crt.h"
  12
  13 /* Syscalls for LoongArch :
  14  *   - stack is 16-byte aligned
  15  *   - syscall number is passed in a7
  16  *   - arguments are in a0, a1, a2, a3, a4, a5
  17  *   - the system call is performed by calling "syscall 0"
  18  *   - syscall return comes in a0
  19  *   - the arguments are cast to long and assigned into the target
  20  *     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 == 32
 146 #define LONG_BSTRINS "bstrins.w"
 147 #else /* __loongarch_grlen == 64 */
 148 #define LONG_BSTRINS "bstrins.d"
 149 #endif
 150
 151 /* startup code */
 152 void __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 */