/*
* Start up the first thread on a CPU.
* First thread is specified for the master CPU.
*/
void
cpu_launch_first_thread(
register thread_t th)
{
register int mycpu;
mycpu = cpu_number();
#if MACH_ASSERT
if (watchacts & WA_BOOT)
printf("cpu_launch_first_thread(%x) cpu=%d\n", th, mycpu);
#endif /* MACH_ASSERT */
cpu_up(mycpu);
start_timer(&kernel_timer[mycpu]);
/*
* Block all interrupts for choose_thread.
*/
(void) splhigh();
if (th == THREAD_NULL) {
th = cpu_to_processor(mycpu)->idle_thread;
if (th == THREAD_NULL || !rem_runq(th))
panic("cpu_launch_first_thread");
}
rtclock_reset(); /* start realtime clock ticking */
PMAP_ACTIVATE_KERNEL(mycpu);
thread_machine_set_current(th);
thread_lock(th);
th->state &= ~TH_UNINT;
thread_unlock(th);
timer_switch(&th->system_timer);
PMAP_ACTIVATE_USER(th->top_act, mycpu);
assert(mycpu == cpu_number());
/* The following is necessary to keep things balanced */
disable_preemption();
load_context(th);
/*NOTREACHED*/
}
/*
* thread_switch:
*
* Context switch. User may supply thread hint.
*
* Fixed priority threads that call this get what they asked for
* even if that violates priority order.
*/
kern_return_t thread_switch(
mach_port_t thread_name,
int option,
mach_msg_timeout_t option_time)
{
thread_t cur_thread = current_thread();
processor_t myprocessor;
ipc_port_t port;
/*
* Process option.
*/
switch (option) {
case SWITCH_OPTION_NONE:
/*
* Nothing to do.
*/
break;
case SWITCH_OPTION_DEPRESS:
/*
* Depress priority for given time.
*/
thread_depress_priority(cur_thread, option_time);
break;
case SWITCH_OPTION_WAIT:
thread_will_wait_with_timeout(cur_thread, option_time);
break;
default:
return(KERN_INVALID_ARGUMENT);
}
#ifndef MIGRATING_THREADS /* XXX thread_run defunct */
/*
* Check and act on thread hint if appropriate.
*/
if ((thread_name != 0) &&
(ipc_port_translate_send(cur_thread->task->itk_space,
thread_name, &port) == KERN_SUCCESS)) {
/* port is locked, but it might not be active */
/*
* Get corresponding thread.
*/
if (ip_active(port) && (ip_kotype(port) == IKOT_THREAD)) {
thread_t thread;
spl_t s;
thread = (thread_t) port->ip_kobject;
/*
* Check if the thread is in the right pset. Then
* pull it off its run queue. If it
* doesn't come, then it's not eligible.
*/
s = splsched();
thread_lock(thread);
if ((thread->processor_set == cur_thread->processor_set)
&& (rem_runq(thread) != RUN_QUEUE_NULL)) {
/*
* Hah, got it!!
*/
thread_unlock(thread);
(void) splx(s);
ip_unlock(port);
/* XXX thread might disappear on us now? */
#if MACH_FIXPRI
if (thread->policy == POLICY_FIXEDPRI) {
myprocessor = current_processor();
myprocessor->quantum = thread->sched_data;
myprocessor->first_quantum = TRUE;
}
#endif /* MACH_FIXPRI */
counter(c_thread_switch_handoff++);
thread_run(thread_switch_continue, thread);
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}
thread_unlock(thread);
(void) splx(s);
}
ip_unlock(port);
}
#endif /* not MIGRATING_THREADS */
/*
* No handoff hint supplied, or hint was wrong. Call thread_block() in
* hopes of running something else. If nothing else is runnable,
* thread_block will detect this. WARNING: thread_switch with no
* option will not do anything useful if the thread calling it is the
* highest priority thread (can easily happen with a collection
* of timesharing threads).
*/
#if NCPUS > 1
myprocessor = current_processor();
if (myprocessor->processor_set->runq.count > 0 ||
myprocessor->runq.count > 0)
#endif /* NCPUS > 1 */
{
counter(c_thread_switch_block++);
thread_block(thread_switch_continue);
}
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}
