gems-kernel/source/THIRDPARTY/xnu/bsd/kern/kern_synch.c
2024-06-03 11:29:39 -05:00

478 lines
11 KiB
C

/*
* Copyright (c) 2000-2020 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@
*/
/*
* Mach Operating System
* Copyright (c) 1987 Carnegie-Mellon University
* All rights reserved. The CMU software License Agreement specifies
* the terms and conditions for use and redistribution.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/user.h>
#include <sys/file_internal.h>
#include <sys/vnode.h>
#include <sys/kernel.h>
#include <kern/queue.h>
#include <sys/lock.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/ast.h>
#include <kern/cpu_number.h>
#include <vm/vm_kern.h>
#include <kern/task.h>
#include <mach/time_value.h>
#include <kern/locks.h>
#include <kern/policy_internal.h>
#include <sys/systm.h> /* for unix_syscall_return() */
#include <libkern/OSAtomic.h>
extern void compute_averunnable(void *); /* XXX */
__attribute__((noreturn))
static void
_sleep_continue( __unused void *parameter, wait_result_t wresult)
{
struct proc *p = current_proc();
thread_t self = current_thread();
struct uthread * ut;
int sig, catch;
int error = 0;
int dropmutex, spinmutex;
ut = get_bsdthread_info(self);
catch = ut->uu_pri & PCATCH;
dropmutex = ut->uu_pri & PDROP;
spinmutex = ut->uu_pri & PSPIN;
switch (wresult) {
case THREAD_TIMED_OUT:
error = EWOULDBLOCK;
break;
case THREAD_AWAKENED:
/*
* Posix implies any signal should be delivered
* first, regardless of whether awakened due
* to receiving event.
*/
if (!catch) {
break;
}
OS_FALLTHROUGH;
case THREAD_INTERRUPTED:
if (catch) {
if (thread_should_abort(self)) {
error = EINTR;
} else if (SHOULDissignal(p, ut)) {
if ((sig = CURSIG(p)) != 0) {
if (p->p_sigacts.ps_sigintr & sigmask(sig)) {
error = EINTR;
} else {
error = ERESTART;
}
}
if (thread_should_abort(self)) {
error = EINTR;
}
} else if ((ut->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
/* due to thread cancel */
error = EINTR;
}
} else {
error = EINTR;
}
break;
}
if (error == EINTR || error == ERESTART) {
act_set_astbsd(self);
}
if (ut->uu_mtx && !dropmutex) {
if (spinmutex) {
lck_mtx_lock_spin(ut->uu_mtx);
} else {
lck_mtx_lock(ut->uu_mtx);
}
}
ut->uu_wchan = NULL;
ut->uu_wmesg = NULL;
unix_syscall_return((*ut->uu_continuation)(error));
}
/*
* Give up the processor till a wakeup occurs
* on chan, at which time the process
* enters the scheduling queue at priority pri.
* The most important effect of pri is that when
* pri<=PZERO a signal cannot disturb the sleep;
* if pri>PZERO signals will be processed.
* If pri&PCATCH is set, signals will cause sleep
* to return 1, rather than longjmp.
* Callers of this routine must be prepared for
* premature return, and check that the reason for
* sleeping has gone away.
*
* if msleep was the entry point, than we have a mutex to deal with
*
* The mutex is unlocked before the caller is blocked, and
* relocked before msleep returns unless the priority includes the PDROP
* flag... if PDROP is specified, _sleep returns with the mutex unlocked
* regardless of whether it actually blocked or not.
*/
static int
_sleep(
caddr_t chan,
int pri,
const char *wmsg,
u_int64_t abstime,
int (*continuation)(int),
lck_mtx_t *mtx)
{
struct proc *p;
thread_t self = current_thread();
struct uthread * ut;
int sig, catch;
int dropmutex = pri & PDROP;
int spinmutex = pri & PSPIN;
int wait_result;
int error = 0;
ut = get_bsdthread_info(self);
p = current_proc();
p->p_priority = pri & PRIMASK;
/* It can still block in proc_exit() after the teardown. */
if (p->p_stats != NULL) {
OSIncrementAtomicLong(&p->p_stats->p_ru.ru_nvcsw);
}
if (pri & PCATCH) {
catch = THREAD_ABORTSAFE;
} else {
catch = THREAD_UNINT;
}
/* set wait message & channel */
ut->uu_wchan = chan;
ut->uu_wmesg = wmsg ? wmsg : "unknown";
if (mtx != NULL && chan != NULL && continuation == NULL) {
int flags;
if (dropmutex) {
flags = LCK_SLEEP_UNLOCK;
} else {
flags = LCK_SLEEP_DEFAULT;
}
if (spinmutex) {
flags |= LCK_SLEEP_SPIN;
}
if (abstime) {
wait_result = lck_mtx_sleep_deadline(mtx, flags, chan, catch, abstime);
} else {
wait_result = lck_mtx_sleep(mtx, flags, chan, catch);
}
} else {
if (chan != NULL) {
assert_wait_deadline(chan, catch, abstime);
}
if (mtx) {
lck_mtx_unlock(mtx);
}
if (catch == THREAD_ABORTSAFE) {
if (SHOULDissignal(p, ut)) {
if ((sig = CURSIG(p)) != 0) {
if (clear_wait(self, THREAD_INTERRUPTED) == KERN_FAILURE) {
goto block;
}
if (p->p_sigacts.ps_sigintr & sigmask(sig)) {
error = EINTR;
} else {
error = ERESTART;
}
if (mtx && !dropmutex) {
if (spinmutex) {
lck_mtx_lock_spin(mtx);
} else {
lck_mtx_lock(mtx);
}
}
goto out;
}
}
if (thread_should_abort(self)) {
if (clear_wait(self, THREAD_INTERRUPTED) == KERN_FAILURE) {
goto block;
}
error = EINTR;
if (mtx && !dropmutex) {
if (spinmutex) {
lck_mtx_lock_spin(mtx);
} else {
lck_mtx_lock(mtx);
}
}
goto out;
}
}
block:
if (continuation != NULL) {
ut->uu_continuation = continuation;
ut->uu_pri = (uint16_t)pri;
ut->uu_mtx = mtx;
(void) thread_block(_sleep_continue);
/* NOTREACHED */
}
wait_result = thread_block(THREAD_CONTINUE_NULL);
if (mtx && !dropmutex) {
if (spinmutex) {
lck_mtx_lock_spin(mtx);
} else {
lck_mtx_lock(mtx);
}
}
}
switch (wait_result) {
case THREAD_TIMED_OUT:
error = EWOULDBLOCK;
break;
case THREAD_AWAKENED:
case THREAD_RESTART:
/*
* Posix implies any signal should be delivered
* first, regardless of whether awakened due
* to receiving event.
*/
if (catch != THREAD_ABORTSAFE) {
break;
}
OS_FALLTHROUGH;
case THREAD_INTERRUPTED:
if (catch == THREAD_ABORTSAFE) {
if (thread_should_abort(self)) {
error = EINTR;
} else if (SHOULDissignal(p, ut)) {
if ((sig = CURSIG(p)) != 0) {
if (p->p_sigacts.ps_sigintr & sigmask(sig)) {
error = EINTR;
} else {
error = ERESTART;
}
}
if (thread_should_abort(self)) {
error = EINTR;
}
} else if ((ut->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
/* due to thread cancel */
error = EINTR;
}
} else {
error = EINTR;
}
break;
}
out:
if (error == EINTR || error == ERESTART) {
act_set_astbsd(self);
}
ut->uu_wchan = NULL;
ut->uu_wmesg = NULL;
return error;
}
int
sleep(
void *chan,
int pri)
{
return _sleep((caddr_t)chan, pri, (char *)NULL, 0, (int (*)(int))0, (lck_mtx_t *)0);
}
int
msleep0(
void *chan,
lck_mtx_t *mtx,
int pri,
const char *wmsg,
int timo,
int (*continuation)(int))
{
u_int64_t abstime = 0;
if (timo) {
clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
}
return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, mtx);
}
int
msleep(
void *chan,
lck_mtx_t *mtx,
int pri,
const char *wmsg,
struct timespec *ts)
{
u_int64_t abstime = 0;
if (ts && (ts->tv_sec || ts->tv_nsec)) {
nanoseconds_to_absolutetime((uint64_t)ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec, &abstime );
clock_absolutetime_interval_to_deadline( abstime, &abstime );
}
return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, mtx);
}
int
msleep1(
void *chan,
lck_mtx_t *mtx,
int pri,
const char *wmsg,
u_int64_t abstime)
{
return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, mtx);
}
int
tsleep(
void *chan,
int pri,
const char *wmsg,
int timo)
{
u_int64_t abstime = 0;
if (timo) {
clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
}
return _sleep((caddr_t)chan, pri, wmsg, abstime, (int (*)(int))0, (lck_mtx_t *)0);
}
int
tsleep0(
void *chan,
int pri,
const char *wmsg,
int timo,
int (*continuation)(int))
{
u_int64_t abstime = 0;
if (timo) {
clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
}
return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, (lck_mtx_t *)0);
}
int
tsleep1(
void *chan,
int pri,
const char *wmsg,
u_int64_t abstime,
int (*continuation)(int))
{
return _sleep((caddr_t)chan, pri, wmsg, abstime, continuation, (lck_mtx_t *)0);
}
/*
* Wake up all processes sleeping on chan.
*/
void
wakeup(void *chan)
{
thread_wakeup((caddr_t)chan);
}
/*
* Wake up the first process sleeping on chan.
*
* Be very sure that the first process is really
* the right one to wakeup.
*/
void
wakeup_one(caddr_t chan)
{
thread_wakeup_one((caddr_t)chan);
}
/*
* Compute the priority of a process when running in user mode.
* Arrange to reschedule if the resulting priority is better
* than that of the current process.
*/
void
resetpriority(struct proc *p)
{
(void)task_importance(proc_task(p), -p->p_nice);
}
struct loadavg averunnable =
{ {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
/*
* Constants for averages over 1, 5, and 15 minutes
* when sampling at 5 second intervals.
*/
static fixpt_t cexp[3] = {
(fixpt_t)(0.9200444146293232 * FSCALE), /* exp(-1/12) */
(fixpt_t)(0.9834714538216174 * FSCALE), /* exp(-1/60) */
(fixpt_t)(0.9944598480048967 * FSCALE), /* exp(-1/180) */
};
void
compute_averunnable(void *arg)
{
unsigned int nrun = *(unsigned int *)arg;
struct loadavg *avg = &averunnable;
int i;
for (i = 0; i < 3; i++) {
avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
}
}