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1//===-- sanitizer_syscall_linux_riscv64.inc ---------------------*- 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-exception6//7//===----------------------------------------------------------------------===//8//9// Implementations of internal_syscall and internal_iserror for Linux/riscv64.10//11//===----------------------------------------------------------------------===//12 13// About local register variables:14// https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html#Local-Register-Variables15//16// Kernel ABI...17// To my surprise I haven't found much information regarding it.18// Kernel source and internet browsing shows that:19// syscall number is passed in a720// (http://man7.org/linux/man-pages/man2/syscall.2.html) results are return in21// a0 and a1 (http://man7.org/linux/man-pages/man2/syscall.2.html) arguments22// are passed in: a0-a7 (see below)23//24// Regarding the arguments. The only "documentation" I could find is25// this comment (!!!) by Bruce Hold on google forums (!!!):26// https://groups.google.com/a/groups.riscv.org/forum/#!topic/sw-dev/exbrzM3GZDQ27// Confirmed by inspecting glibc sources.28// Great way to document things.29#define SYSCALL(name) __NR_##name30 31#define INTERNAL_SYSCALL_CLOBBERS "memory"32 33static uptr __internal_syscall(u64 nr) {34 register u64 a7 asm("a7") = nr;35 register u64 a0 asm("a0");36 __asm__ volatile("ecall\n\t"37 : "=r"(a0)38 : "r"(a7)39 : INTERNAL_SYSCALL_CLOBBERS);40 return a0;41}42#define __internal_syscall0(n) (__internal_syscall)(n)43 44static uptr __internal_syscall(u64 nr, u64 arg1) {45 register u64 a7 asm("a7") = nr;46 register u64 a0 asm("a0") = arg1;47 __asm__ volatile("ecall\n\t"48 : "+r"(a0)49 : "r"(a7)50 : INTERNAL_SYSCALL_CLOBBERS);51 return a0;52}53#define __internal_syscall1(n, a1) (__internal_syscall)(n, (u64)(a1))54 55static uptr __internal_syscall(u64 nr, u64 arg1, long arg2) {56 register u64 a7 asm("a7") = nr;57 register u64 a0 asm("a0") = arg1;58 register u64 a1 asm("a1") = arg2;59 __asm__ volatile("ecall\n\t"60 : "+r"(a0)61 : "r"(a7), "r"(a1)62 : INTERNAL_SYSCALL_CLOBBERS);63 return a0;64}65#define __internal_syscall2(n, a1, a2) \66 (__internal_syscall)(n, (u64)(a1), (long)(a2))67 68static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3) {69 register u64 a7 asm("a7") = nr;70 register u64 a0 asm("a0") = arg1;71 register u64 a1 asm("a1") = arg2;72 register u64 a2 asm("a2") = arg3;73 __asm__ volatile("ecall\n\t"74 : "+r"(a0)75 : "r"(a7), "r"(a1), "r"(a2)76 : INTERNAL_SYSCALL_CLOBBERS);77 return a0;78}79#define __internal_syscall3(n, a1, a2, a3) \80 (__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3))81 82static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3,83 u64 arg4) {84 register u64 a7 asm("a7") = nr;85 register u64 a0 asm("a0") = arg1;86 register u64 a1 asm("a1") = arg2;87 register u64 a2 asm("a2") = arg3;88 register u64 a3 asm("a3") = arg4;89 __asm__ volatile("ecall\n\t"90 : "+r"(a0)91 : "r"(a7), "r"(a1), "r"(a2), "r"(a3)92 : INTERNAL_SYSCALL_CLOBBERS);93 return a0;94}95#define __internal_syscall4(n, a1, a2, a3, a4) \96 (__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4))97 98static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,99 long arg5) {100 register u64 a7 asm("a7") = nr;101 register u64 a0 asm("a0") = arg1;102 register u64 a1 asm("a1") = arg2;103 register u64 a2 asm("a2") = arg3;104 register u64 a3 asm("a3") = arg4;105 register u64 a4 asm("a4") = arg5;106 __asm__ volatile("ecall\n\t"107 : "+r"(a0)108 : "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4)109 : INTERNAL_SYSCALL_CLOBBERS);110 return a0;111}112#define __internal_syscall5(n, a1, a2, a3, a4, a5) \113 (__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \114 (u64)(a5))115 116static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,117 long arg5, long arg6) {118 register u64 a7 asm("a7") = nr;119 register u64 a0 asm("a0") = arg1;120 register u64 a1 asm("a1") = arg2;121 register u64 a2 asm("a2") = arg3;122 register u64 a3 asm("a3") = arg4;123 register u64 a4 asm("a4") = arg5;124 register u64 a5 asm("a5") = arg6;125 __asm__ volatile("ecall\n\t"126 : "+r"(a0)127 : "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5)128 : INTERNAL_SYSCALL_CLOBBERS);129 return a0;130}131#define __internal_syscall6(n, a1, a2, a3, a4, a5, a6) \132 (__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \133 (u64)(a5), (long)(a6))134 135static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,136 long arg5, long arg6, long arg7) {137 register u64 a7 asm("a7") = nr;138 register u64 a0 asm("a0") = arg1;139 register u64 a1 asm("a1") = arg2;140 register u64 a2 asm("a2") = arg3;141 register u64 a3 asm("a3") = arg4;142 register u64 a4 asm("a4") = arg5;143 register u64 a5 asm("a5") = arg6;144 register u64 a6 asm("a6") = arg7;145 __asm__ volatile("ecall\n\t"146 : "+r"(a0)147 : "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5),148 "r"(a6)149 : INTERNAL_SYSCALL_CLOBBERS);150 return a0;151}152#define __internal_syscall7(n, a1, a2, a3, a4, a5, a6, a7) \153 (__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \154 (u64)(a5), (long)(a6), (long)(a7))155 156#define __SYSCALL_NARGS_X(a1, a2, a3, a4, a5, a6, a7, a8, n, ...) n157#define __SYSCALL_NARGS(...) \158 __SYSCALL_NARGS_X(__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0, )159#define __SYSCALL_CONCAT_X(a, b) a##b160#define __SYSCALL_CONCAT(a, b) __SYSCALL_CONCAT_X(a, b)161#define __SYSCALL_DISP(b, ...) \162 __SYSCALL_CONCAT(b, __SYSCALL_NARGS(__VA_ARGS__))(__VA_ARGS__)163 164#define internal_syscall(...) __SYSCALL_DISP(__internal_syscall, __VA_ARGS__)165 166// Helper function used to avoid clobbering of errno.167bool internal_iserror(uptr retval, int *rverrno) {168 if (retval >= (uptr)-4095) {169 if (rverrno)170 *rverrno = -retval;171 return true;172 }173 return false;174}175