| | 1 | /* |
| | 2 | * Copyright (c) 2015 Apple Inc. All rights reserved. |
| | 3 | * |
| | 4 | * @APPLE_LICENSE_HEADER_START@ |
| | 5 | * |
| | 6 | * This file contains Original Code and/or Modifications of Original Code |
| | 7 | * as defined in and that are subject to the Apple Public Source License |
| | 8 | * Version 2.0 (the 'License'). You may not use this file except in |
| | 9 | * compliance with the License. Please obtain a copy of the License at |
| | 10 | * http://www.opensource.apple.com/apsl/ and read it before using this |
| | 11 | * file. |
| | 12 | * |
| | 13 | * The Original Code and all software distributed under the License are |
| | 14 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
| | 15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| | 16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
| | 17 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
| | 18 | * Please see the License for the specific language governing rights and |
| | 19 | * limitations under the License. |
| | 20 | * |
| | 21 | * @APPLE_LICENSE_HEADER_END@ |
| | 22 | */ |
| | 23 | #include <stdbool.h> |
| | 24 | #include <sys/types.h> |
| | 25 | #include <sys/time.h> |
| | 26 | #include <mach/mach_time.h> |
| | 27 | #include <sys/time.h> |
| | 28 | #include <machine/cpu_capabilities.h> |
| | 29 | |
| | 30 | // From __commpage_gettimeofday.c |
| | 31 | extern int __commpage_gettimeofday_internal(struct timeval *tp, uint64_t *tbr_out); |
| | 32 | extern kern_return_t _mach_continuous_time(uint64_t* absolute_time, uint64_t* cont_time); |
| | 33 | // From mach_continuous_time.c |
| | 34 | extern uint64_t _mach_continuous_time_base(void); |
| | 35 | // Underlying syscall stub |
| | 36 | extern int __gettimeofday_with_mach(struct timeval *, struct timezone *, uint64_t *); |
| | 37 | |
| | 38 | kern_return_t |
| | 39 | mach_get_times(uint64_t* absolute_time, uint64_t* cont_time, struct timespec *tp) { |
| | 40 | if (tp == NULL) { |
| | 41 | return _mach_continuous_time(absolute_time, cont_time); |
| | 42 | } |
| | 43 | |
| | 44 | uint64_t continuous_time_base_prior = -1, continuous_time_base_post = -1; |
| | 45 | uint64_t tbr; |
| | 46 | struct timeval tv; |
| | 47 | |
| | 48 | do { |
| | 49 | /* |
| | 50 | * We need to capture the result of gettimeofday without our continuous |
| | 51 | * time base changing. Once we have that, and the value for absolute |
| | 52 | * time that was used to compute the timespec, we can just add the base |
| | 53 | * to get the accompanying continuous time. |
| | 54 | */ |
| | 55 | continuous_time_base_prior = _mach_continuous_time_base(); |
| | 56 | |
| | 57 | /* |
| | 58 | * This call has the necessary memory barriers for this retry loop, |
| | 59 | * since it is implemented with a retry loop of its own. |
| | 60 | */ |
| | 61 | if (__commpage_gettimeofday_internal(&tv, &tbr)) { |
| | 62 | tbr = 0; |
| | 63 | if (__gettimeofday_with_mach(&tv, NULL, &tbr) < 0) { |
| | 64 | return KERN_FAILURE; |
| | 65 | } else if (tbr == 0) { |
| | 66 | // On an old kernel, likely chroot'ed. (remove next year) |
| | 67 | tbr = mach_absolute_time(); |
| | 68 | } |
| | 69 | } |
| | 70 | |
| | 71 | continuous_time_base_post = _mach_continuous_time_base(); |
| | 72 | } while (__builtin_expect(continuous_time_base_prior != continuous_time_base_post, 0)); |
| | 73 | |
| | 74 | if (absolute_time) *absolute_time = tbr; |
| | 75 | if (cont_time) *cont_time = continuous_time_base_prior + tbr; |
| | 76 | tp->tv_sec = tv.tv_sec; |
| | 77 | tp->tv_nsec = tv.tv_usec * NSEC_PER_USEC; |
| | 78 | |
| | 79 | return KERN_SUCCESS; |
| | 80 | } |
projects / apple / xnu.git / blame_incremental