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powerpc/kdump: Only save CPU state first time through the secondary CPU capture code 

We might enter the secondary CPU capture code twice, eg if we have to
unstick some CPUs with a system reset. In this case we don't want to
overwrite the state on CPUs that had made it into the capture code OK,
so use the cpus_state_saved cpumask for that and make it local to
crash_ipi_callback.

For controlling progress now use atomic_t cpus_in_crash to count how
many CPUs have made it into the kdump code, and time_to_dump to tell
everyone it's time to dump.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2011-11-30 00:23:17 +00:00 committed by Benjamin Herrenschmidt
parent 549e88a134
commit 2440c01e10
1 changed files with 21 additions and 12 deletions
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33
arch/powerpc/kernel/crash.c
View File

@ -46,7 +46,8 @@
/* This keeps a track of which one is the crashing cpu. */
int crashing_cpu = -1;
static cpumask_t cpus_in_crash = CPU_MASK_NONE;
static atomic_t cpus_in_crash;
static int time_to_dump;
#define CRASH_HANDLER_MAX 3
/* NULL terminated list of shutdown handles */
@ -67,21 +68,27 @@ static int handle_fault(struct pt_regs *regs)
void crash_ipi_callback(struct pt_regs *regs)
{
static cpumask_t cpus_state_saved = CPU_MASK_NONE;
int cpu = smp_processor_id();
if (!cpu_online(cpu))
return;
hard_irq_disable();
if (!cpumask_test_cpu(cpu, &cpus_in_crash))
if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
crash_save_cpu(regs, cpu);
cpumask_set_cpu(cpu, &cpus_in_crash);
cpumask_set_cpu(cpu, &cpus_state_saved);
}
atomic_inc(&cpus_in_crash);
smp_mb__after_atomic_inc();
/*
* Starting the kdump boot.
* This barrier is needed to make sure that all CPUs are stopped.
*/
while (!cpumask_test_cpu(crashing_cpu, &cpus_in_crash))
while (!time_to_dump)
cpu_relax();
if (ppc_md.kexec_cpu_down)
@ -115,19 +122,18 @@ again:
* respond.
*/
msecs = IPI_TIMEOUT;
while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0))
mdelay(1);
}
/* Would it be better to replace the trap vector here? */
if (cpumask_weight(&cpus_in_crash) >= ncpus) {
if (atomic_read(&cpus_in_crash) >= ncpus) {
printk(KERN_EMERG "IPI complete\n");
return;
}
printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
ncpus - cpumask_weight(&cpus_in_crash));
ncpus - atomic_read(&cpus_in_crash));
/*
* If we have a panic timeout set then we can't wait indefinitely
@ -155,10 +161,10 @@ again:
* crash code again. We need to reset cpus_in_crash so we
* wait for everyone to do this.
*/
cpus_in_crash = CPU_MASK_NONE;
atomic_set(&cpus_in_crash, 0);
smp_mb();
while (cpumask_weight(&cpus_in_crash) < ncpus)
while (atomic_read(&cpus_in_crash) < ncpus)
cpu_relax();
}
@ -316,7 +322,6 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
* such that another IPI will not be sent.
*/
crashing_cpu = smp_processor_id();
crash_save_cpu(regs, crashing_cpu);
/*
* If we came in via system reset, wait a while for the secondary
@ -326,7 +331,11 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
mdelay(PRIMARY_TIMEOUT);
crash_kexec_prepare_cpus(crashing_cpu);
cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
crash_save_cpu(regs, crashing_cpu);
time_to_dump = 1;
crash_kexec_wait_realmode(crashing_cpu);
machine_kexec_mask_interrupts();