libc/src/__support/OSUtil/linux/riscv/syscall.h

   1 //===--------- inline implementation of riscv syscalls ------------* C++ *-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_RISCV_SYSCALL_H
  10 #define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_RISCV_SYSCALL_H
  11
  12 #include "src/__support/common.h"
  13
  14 #define REGISTER_DECL_0                                                        \
  15   register long a7 __asm__("a7") = number;                                     \
  16   register long a0 __asm__("a0");
  17 #define REGISTER_DECL_1                                                        \
  18   register long a7 __asm__("a7") = number;                                     \
  19   register long a0 __asm__("a0") = arg1;
  20 #define REGISTER_DECL_2 REGISTER_DECL_1 register long a1 __asm__("a1") = arg2;
  21 #define REGISTER_DECL_3                                                        \
  22   REGISTER_DECL_2                                                              \
  23   register long a2 __asm__("a2") = arg3;
  24 #define REGISTER_DECL_4                                                        \
  25   REGISTER_DECL_3                                                              \
  26   register long a3 __asm__("a3") = arg4;
  27 #define REGISTER_DECL_5                                                        \
  28   REGISTER_DECL_4                                                              \
  29   register long a4 __asm__("a4") = arg5;
  30 #define REGISTER_DECL_6                                                        \
  31   REGISTER_DECL_5                                                              \
  32   register long a5 __asm__("a5") = arg6;
  33
  34 #define REGISTER_CONSTRAINT_0 "r"(a7)
  35 #define REGISTER_CONSTRAINT_1 REGISTER_CONSTRAINT_0, "r"(a0)
  36 #define REGISTER_CONSTRAINT_2 REGISTER_CONSTRAINT_1, "r"(a1)
  37 #define REGISTER_CONSTRAINT_3 REGISTER_CONSTRAINT_2, "r"(a2)
  38 #define REGISTER_CONSTRAINT_4 REGISTER_CONSTRAINT_3, "r"(a3)
  39 #define REGISTER_CONSTRAINT_5 REGISTER_CONSTRAINT_4, "r"(a4)
  40 #define REGISTER_CONSTRAINT_6 REGISTER_CONSTRAINT_5, "r"(a5)
  41
  42 #define SYSCALL_INSTR(input_constraint)                                        \
  43   LIBC_INLINE_ASM("ecall\n\t" : "=r"(a0) : input_constraint : "memory")
  44
  45 namespace LIBC_NAMESPACE {
  46
  47 LIBC_INLINE long syscall_impl(long number) {
  48   REGISTER_DECL_0;
  49   SYSCALL_INSTR(REGISTER_CONSTRAINT_0);
  50   return a0;
  51 }
  52
  53 LIBC_INLINE long syscall_impl(long number, long arg1) {
  54   REGISTER_DECL_1;
  55   SYSCALL_INSTR(REGISTER_CONSTRAINT_1);
  56   return a0;
  57 }
  58
  59 LIBC_INLINE long syscall_impl(long number, long arg1, long arg2) {
  60   REGISTER_DECL_2;
  61   SYSCALL_INSTR(REGISTER_CONSTRAINT_2);
  62   return a0;
  63 }
  64
  65 LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3) {
  66   REGISTER_DECL_3;
  67   SYSCALL_INSTR(REGISTER_CONSTRAINT_3);
  68   return a0;
  69 }
  70
  71 LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
  72                               long arg4) {
  73   REGISTER_DECL_4;
  74   SYSCALL_INSTR(REGISTER_CONSTRAINT_4);
  75   return a0;
  76 }
  77
  78 LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
  79                               long arg4, long arg5) {
  80   REGISTER_DECL_5;
  81   SYSCALL_INSTR(REGISTER_CONSTRAINT_5);
  82   return a0;
  83 }
  84
  85 LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
  86                               long arg4, long arg5, long arg6) {
  87   REGISTER_DECL_6;
  88   SYSCALL_INSTR(REGISTER_CONSTRAINT_6);
  89   return a0;
  90 }
  91
  92 } // namespace LIBC_NAMESPACE
  93
  94 #undef REGISTER_DECL_0
  95 #undef REGISTER_DECL_1
  96 #undef REGISTER_DECL_2
  97 #undef REGISTER_DECL_3
  98 #undef REGISTER_DECL_4
  99 #undef REGISTER_DECL_5
 100 #undef REGISTER_DECL_6
 101
 102 #undef REGISTER_CONSTRAINT_0
 103 #undef REGISTER_CONSTRAINT_1
 104 #undef REGISTER_CONSTRAINT_2
 105 #undef REGISTER_CONSTRAINT_3
 106 #undef REGISTER_CONSTRAINT_4
 107 #undef REGISTER_CONSTRAINT_5
 108 #undef REGISTER_CONSTRAINT_6
 109
 110 #endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_RISCV_SYSCALL_H