// 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>

struct getcpu_cache;

namespace vdso {

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;
}

}  // namespace vdso

#endif  // VDSO_SYSCALLS_H_