/*
* 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 */