/* * Copyright (c) 2016 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #ifndef REMOTE_TIME_H #define REMOTE_TIME_H #include <sys/cdefs.h> #include <stdint.h> #include <os/overflow.h> __BEGIN_DECLS /* bt_params is an ABI for tracing tools */ struct bt_params { double rate; uint64_t base_local_ts; uint64_t base_remote_ts; }; /* local_ts_ns should be in nanoseconds */ static inline uint64_t mach_bridge_compute_timestamp(uint64_t local_ts_ns, struct bt_params *params) { if (!params || params->rate == 0.0) { return 0; } /* * Formula to compute remote_timestamp * remote_timestamp = (bt_params.rate * (local_ts_ns - bt_params.base_local_ts)) * + bt_params.base_remote_ts */ int64_t remote_ts = 0; int64_t rate_prod = 0; /* To avoid precision loss due to typecasting from int64_t to double */ if (params->rate != 1.0) { rate_prod = (int64_t)(params->rate * (double)((int64_t)local_ts_ns - (int64_t)params->base_local_ts)); } else { rate_prod = (int64_t)local_ts_ns - (int64_t)params->base_local_ts; } if (os_add_overflow((int64_t)params->base_remote_ts, rate_prod, &remote_ts)) { return 0; } return (uint64_t)remote_ts; } uint64_t mach_bridge_remote_time(uint64_t); #if XNU_KERNEL_PRIVATE #include <kern/locks.h> extern lck_spin_t bt_maintenance_lock; extern lck_spin_t bt_spin_lock; extern lck_spin_t bt_ts_conversion_lock; #endif __END_DECLS #endif /* REMOTE_TIME_H */