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ARM: 7405/1: kexec: call platform_cpu_kill on the killer rather than the victim 

When performing a kexec on an SMP system, the secondary cores are stopped
by calling machine_shutdown(), which in turn issues IPIs to offline the
other CPUs. Unfortunately, this isn't enough to reboot the cores into
a new kernel (since they are just executing a cpu_relax loop somewhere
in memory) so we make use of platform_cpu_kill, part of the CPU hotplug
implementation, to place the cores somewhere safe. This function expects
to be called on the killing CPU for each core that it takes out.

This patch moves the platform_cpu_kill callback out of the IPI handler
and into smp_send_stop, therefore ensuring that it executes on the
killing CPU rather than on the victim, matching what the hotplug code
requires.

Cc: stable@vger.kernel.org
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2012-04-27 12:51:43 +01:00 committed by Russell King
parent 6a1c53124a
commit 6fa99b7f80
1 changed files with 17 additions and 11 deletions
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28
arch/arm/kernel/smp.c
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@ -510,10 +510,6 @@ static void ipi_cpu_stop(unsigned int cpu)
local_fiq_disable();
local_irq_disable();
#ifdef CONFIG_HOTPLUG_CPU
platform_cpu_kill(cpu);
#endif
while (1)
cpu_relax();
}
@ -576,17 +572,25 @@ void smp_send_reschedule(int cpu)
smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
}
#ifdef CONFIG_HOTPLUG_CPU
static void smp_kill_cpus(cpumask_t *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask)
platform_cpu_kill(cpu);
}
#else
static void smp_kill_cpus(cpumask_t *mask) { }
#endif
void smp_send_stop(void)
{
unsigned long timeout;
struct cpumask mask;
if (num_online_cpus() > 1) {
struct cpumask mask;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
smp_cross_call(&mask, IPI_CPU_STOP);
}
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
smp_cross_call(&mask, IPI_CPU_STOP);
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
@ -595,6 +599,8 @@ void smp_send_stop(void)
if (num_online_cpus() > 1)
pr_warning("SMP: failed to stop secondary CPUs\n");
smp_kill_cpus(&mask);
}
/*