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-rw-r--r--kernel/power/smp.c89
1 files changed, 34 insertions, 55 deletions
diff --git a/kernel/power/smp.c b/kernel/power/smp.c
index 457c2302ed42..bbe23079c62c 100644
--- a/kernel/power/smp.c
+++ b/kernel/power/smp.c
@@ -13,73 +13,52 @@
13#include <linux/interrupt.h> 13#include <linux/interrupt.h>
14#include <linux/suspend.h> 14#include <linux/suspend.h>
15#include <linux/module.h> 15#include <linux/module.h>
16#include <linux/cpu.h>
16#include <asm/atomic.h> 17#include <asm/atomic.h>
17#include <asm/tlbflush.h> 18#include <asm/tlbflush.h>
18 19
19static atomic_t cpu_counter, freeze; 20/* This is protected by pm_sem semaphore */
20 21static cpumask_t frozen_cpus;
21
22static void smp_pause(void * data)
23{
24 struct saved_context ctxt;
25 __save_processor_state(&ctxt);
26 printk("Sleeping in:\n");
27 dump_stack();
28 atomic_inc(&cpu_counter);
29 while (atomic_read(&freeze)) {
30 /* FIXME: restore takes place at random piece inside this.
31 This should probably be written in assembly, and
32 preserve general-purpose registers, too
33
34 What about stack? We may need to move to new stack here.
35
36 This should better be ran with interrupts disabled.
37 */
38 cpu_relax();
39 barrier();
40 }
41 atomic_dec(&cpu_counter);
42 __restore_processor_state(&ctxt);
43}
44
45static cpumask_t oldmask;
46 22
47void disable_nonboot_cpus(void) 23void disable_nonboot_cpus(void)
48{ 24{
49 oldmask = current->cpus_allowed; 25 int cpu, error;
50 set_cpus_allowed(current, cpumask_of_cpu(0));
51 printk("Freezing CPUs (at %d)", raw_smp_processor_id());
52 current->state = TASK_INTERRUPTIBLE;
53 schedule_timeout(HZ);
54 printk("...");
55 BUG_ON(raw_smp_processor_id() != 0);
56
57 /* FIXME: for this to work, all the CPUs must be running
58 * "idle" thread (or we deadlock). Is that guaranteed? */
59 26
60 atomic_set(&cpu_counter, 0); 27 error = 0;
61 atomic_set(&freeze, 1); 28 cpus_clear(frozen_cpus);
62 smp_call_function(smp_pause, NULL, 0, 0); 29 printk("Freezing cpus ...\n");
63 while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) { 30 for_each_online_cpu(cpu) {
64 cpu_relax(); 31 if (cpu == 0)
65 barrier(); 32 continue;
33 error = cpu_down(cpu);
34 if (!error) {
35 cpu_set(cpu, frozen_cpus);
36 printk("CPU%d is down\n", cpu);
37 continue;
38 }
39 printk("Error taking cpu %d down: %d\n", cpu, error);
66 } 40 }
67 printk("ok\n"); 41 BUG_ON(smp_processor_id() != 0);
42 if (error)
43 panic("cpus not sleeping");
68} 44}
69 45
70void enable_nonboot_cpus(void) 46void enable_nonboot_cpus(void)
71{ 47{
72 printk("Restarting CPUs"); 48 int cpu, error;
73 atomic_set(&freeze, 0);
74 while (atomic_read(&cpu_counter)) {
75 cpu_relax();
76 barrier();
77 }
78 printk("...");
79 set_cpus_allowed(current, oldmask);
80 schedule();
81 printk("ok\n");
82 49
50 printk("Thawing cpus ...\n");
51 for_each_cpu_mask(cpu, frozen_cpus) {
52 error = smp_prepare_cpu(cpu);
53 if (!error)
54 error = cpu_up(cpu);
55 if (!error) {
56 printk("CPU%d is up\n", cpu);
57 continue;
58 }
59 printk("Error taking cpu %d up: %d\n", cpu, error);
60 panic("Not enough cpus");
61 }
62 cpus_clear(frozen_cpus);
83} 63}
84 64
85