1 files changed, 100 insertions, 0 deletions
diff --git a/vdso/syscalls.h b/vdso/syscalls.h
new file mode 100644
index 000000000..0c6a922a0
--- /dev/null
+++ b/vdso/syscalls.h
@@ -0,0 +1,100 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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>
+
+#define __stringify_1(x...) #x
+#define __stringify(x...) __stringify_1(x)
+
+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;
+}
+
+static inline void sys_rt_sigreturn(void) {
+  asm volatile("movl $" __stringify(__NR_rt_sigreturn)", %eax \n"
+               "syscall \n");
+}
+
+#elif __aarch64__
+
+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;
+}
+
+static inline void sys_rt_sigreturn(void) {
+  asm volatile("mov x8, #" __stringify(__NR_rt_sigreturn)" \n"
+               "svc #0 \n");
+}
+
+#else
+#error "unsupported architecture"
+#endif
+}  // namespace vdso
+
+#endif  // VDSO_SYSCALLS_H_