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// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// System call support for the VDSO.
//
// Provides fallback system call interfaces for getcpu()
// and clock_gettime().
#ifndef VDSO_SYSCALLS_H_
#define VDSO_SYSCALLS_H_
#include <asm/unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <sys/types.h>
namespace vdso {
#if __x86_64__
struct getcpu_cache;
static inline int sys_clock_gettime(clockid_t clock, struct timespec* ts) {
int num = __NR_clock_gettime;
asm volatile("syscall\n"
: "+a"(num)
: "D"(clock), "S"(ts)
: "rcx", "r11", "memory");
return num;
}
static inline int sys_getcpu(unsigned* cpu, unsigned* node,
struct getcpu_cache* cache) {
int num = __NR_getcpu;
asm volatile("syscall\n"
: "+a"(num)
: "D"(cpu), "S"(node), "d"(cache)
: "rcx", "r11", "memory");
return num;
}
#elif __aarch64__
static inline int sys_rt_sigreturn(void) {
int num = __NR_rt_sigreturn;
asm volatile(
"mov x8, %0\n"
"svc #0 \n"
: "+r"(num)
:
:);
return num;
}
static inline int sys_clock_gettime(clockid_t _clkid, struct timespec *_ts) {
register struct timespec *ts asm("x1") = _ts;
register clockid_t clkid asm("x0") = _clkid;
register long ret asm("x0");
register long nr asm("x8") = __NR_clock_gettime;
asm volatile("svc #0\n"
: "=r"(ret)
: "r"(clkid), "r"(ts), "r"(nr)
: "memory");
return ret;
}
static inline int sys_clock_getres(clockid_t _clkid, struct timespec *_ts) {
register struct timespec *ts asm("x1") = _ts;
register clockid_t clkid asm("x0") = _clkid;
register long ret asm("x0");
register long nr asm("x8") = __NR_clock_getres;
asm volatile("svc #0\n"
: "=r"(ret)
: "r"(clkid), "r"(ts), "r"(nr)
: "memory");
return ret;
}
#else
#error "unsupported architecture"
#endif
} // namespace vdso
#endif // VDSO_SYSCALLS_H_
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