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//===-- sanitizer_syscall_linux_riscv64.inc ---------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Implementations of internal_syscall and internal_iserror for Linux/riscv64.
//
//===----------------------------------------------------------------------===//
// About local register variables:
// https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html#Local-Register-Variables
//
// Kernel ABI...
// To my surprise I haven't found much information regarding it.
// Kernel source and internet browsing shows that:
// syscall number is passed in a7
// (http://man7.org/linux/man-pages/man2/syscall.2.html) results are return in
// a0 and a1 (http://man7.org/linux/man-pages/man2/syscall.2.html) arguments
// are passed in: a0-a7 (see below)
//
// Regarding the arguments. The only "documentation" I could find is
// this comment (!!!) by Bruce Hold on google forums (!!!):
// https://groups.google.com/a/groups.riscv.org/forum/#!topic/sw-dev/exbrzM3GZDQ
// Confirmed by inspecting glibc sources.
// Great way to document things.
#define SYSCALL(name) __NR_##name
#define INTERNAL_SYSCALL_CLOBBERS "memory"
static uptr __internal_syscall(u64 nr) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0");
__asm__ volatile("ecall\n\t"
: "=r"(a0)
: "r"(a7)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall0(n) (__internal_syscall)(n)
static uptr __internal_syscall(u64 nr, u64 arg1) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall1(n, a1) (__internal_syscall)(n, (u64)(a1))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall2(n, a1, a2) \
(__internal_syscall)(n, (u64)(a1), (long)(a2))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
register u64 a2 asm("a2") = arg3;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1), "r"(a2)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall3(n, a1, a2, a3) \
(__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3,
u64 arg4) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
register u64 a2 asm("a2") = arg3;
register u64 a3 asm("a3") = arg4;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1), "r"(a2), "r"(a3)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall4(n, a1, a2, a3, a4) \
(__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,
long arg5) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
register u64 a2 asm("a2") = arg3;
register u64 a3 asm("a3") = arg4;
register u64 a4 asm("a4") = arg5;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall5(n, a1, a2, a3, a4, a5) \
(__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \
(u64)(a5))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,
long arg5, long arg6) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
register u64 a2 asm("a2") = arg3;
register u64 a3 asm("a3") = arg4;
register u64 a4 asm("a4") = arg5;
register u64 a5 asm("a5") = arg6;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall6(n, a1, a2, a3, a4, a5, a6) \
(__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \
(u64)(a5), (long)(a6))
static uptr __internal_syscall(u64 nr, u64 arg1, long arg2, long arg3, u64 arg4,
long arg5, long arg6, long arg7) {
register u64 a7 asm("a7") = nr;
register u64 a0 asm("a0") = arg1;
register u64 a1 asm("a1") = arg2;
register u64 a2 asm("a2") = arg3;
register u64 a3 asm("a3") = arg4;
register u64 a4 asm("a4") = arg5;
register u64 a5 asm("a5") = arg6;
register u64 a6 asm("a6") = arg7;
__asm__ volatile("ecall\n\t"
: "+r"(a0)
: "r"(a7), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5),
"r"(a6)
: INTERNAL_SYSCALL_CLOBBERS);
return a0;
}
#define __internal_syscall7(n, a1, a2, a3, a4, a5, a6, a7) \
(__internal_syscall)(n, (u64)(a1), (long)(a2), (long)(a3), (long)(a4), \
(u64)(a5), (long)(a6), (long)(a7))
#define __SYSCALL_NARGS_X(a1, a2, a3, a4, a5, a6, a7, a8, n, ...) n
#define __SYSCALL_NARGS(...) \
__SYSCALL_NARGS_X(__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0, )
#define __SYSCALL_CONCAT_X(a, b) a##b
#define __SYSCALL_CONCAT(a, b) __SYSCALL_CONCAT_X(a, b)
#define __SYSCALL_DISP(b, ...) \
__SYSCALL_CONCAT(b, __SYSCALL_NARGS(__VA_ARGS__))(__VA_ARGS__)
#define internal_syscall(...) __SYSCALL_DISP(__internal_syscall, __VA_ARGS__)
// Helper function used to avoid clobbering of errno.
bool internal_iserror(uptr retval, int *rverrno) {
if (retval >= (uptr)-4095) {
if (rverrno)
*rverrno = -retval;
return true;
}
return false;
}
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