blob: bdddba65e13beb509395b8a497f222c7d07ad5a6 [file] [log] [blame]
// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "private.h"
#ifdef __x86_64__
#include <x86intrin.h>
__EXPORT zx_ticks_t _zx_ticks_get(void) {
#if __aarch64__
// read the virtual counter
zx_ticks_t ticks;
__asm__ volatile("mrs %0, cntvct_el0" : "=r"(ticks));
return ticks;
#elif __x86_64__
return __rdtsc();
#error Unsupported architecture
// Note: See alternates.ld for a definition of CODE_ticks_get_via_kernel, which
// is an alias for SYSCALL_zx_ticks_get_via_kernel. This is a version of
// zx_ticks_get which goes through a forced syscall. It is selected by the vDSO
// builder at runtiem for use on platforms where the hardware tick counter is
// not directly accessible by user mode code.