86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
/*
|
|
* drivers/power/smp.c - Functions for stopping other CPUs.
|
|
*
|
|
* Copyright 2004 Pavel Machek <pavel@suse.cz>
|
|
* Copyright (C) 2002-2003 Nigel Cunningham <ncunningham@clear.net.nz>
|
|
*
|
|
* This file is released under the GPLv2.
|
|
*/
|
|
|
|
#undef DEBUG
|
|
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/suspend.h>
|
|
#include <linux/module.h>
|
|
#include <asm/atomic.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
static atomic_t cpu_counter, freeze;
|
|
|
|
|
|
static void smp_pause(void * data)
|
|
{
|
|
struct saved_context ctxt;
|
|
__save_processor_state(&ctxt);
|
|
printk("Sleeping in:\n");
|
|
dump_stack();
|
|
atomic_inc(&cpu_counter);
|
|
while (atomic_read(&freeze)) {
|
|
/* FIXME: restore takes place at random piece inside this.
|
|
This should probably be written in assembly, and
|
|
preserve general-purpose registers, too
|
|
|
|
What about stack? We may need to move to new stack here.
|
|
|
|
This should better be ran with interrupts disabled.
|
|
*/
|
|
cpu_relax();
|
|
barrier();
|
|
}
|
|
atomic_dec(&cpu_counter);
|
|
__restore_processor_state(&ctxt);
|
|
}
|
|
|
|
static cpumask_t oldmask;
|
|
|
|
void disable_nonboot_cpus(void)
|
|
{
|
|
oldmask = current->cpus_allowed;
|
|
set_cpus_allowed(current, cpumask_of_cpu(0));
|
|
printk("Freezing CPUs (at %d)", raw_smp_processor_id());
|
|
current->state = TASK_INTERRUPTIBLE;
|
|
schedule_timeout(HZ);
|
|
printk("...");
|
|
BUG_ON(raw_smp_processor_id() != 0);
|
|
|
|
/* FIXME: for this to work, all the CPUs must be running
|
|
* "idle" thread (or we deadlock). Is that guaranteed? */
|
|
|
|
atomic_set(&cpu_counter, 0);
|
|
atomic_set(&freeze, 1);
|
|
smp_call_function(smp_pause, NULL, 0, 0);
|
|
while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) {
|
|
cpu_relax();
|
|
barrier();
|
|
}
|
|
printk("ok\n");
|
|
}
|
|
|
|
void enable_nonboot_cpus(void)
|
|
{
|
|
printk("Restarting CPUs");
|
|
atomic_set(&freeze, 0);
|
|
while (atomic_read(&cpu_counter)) {
|
|
cpu_relax();
|
|
barrier();
|
|
}
|
|
printk("...");
|
|
set_cpus_allowed(current, oldmask);
|
|
schedule();
|
|
printk("ok\n");
|
|
|
|
}
|
|
|
|
|