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ARM: SMP: ensure smp_send_stop() waits for CPUs to stop

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Wait for CPUs to indicate that they've stopped, after sending the
stop IPI, rather than blindly continuing on and hoping that they've
stopped in time.  Print a warning if we fail to stop the other CPUs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
2010-12-02 09:53:54 +00:00
parent 0eb0511d17
commit 28e18293cf
1 changed files with 15 additions and 3 deletions
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14
arch/arm/kernel/smp.c
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@@ -575,12 +575,24 @@ void smp_send_reschedule(int cpu)
void smp_send_stop(void)
{
unsigned long timeout;
if (num_online_cpus() > 1) {
cpumask_t mask = cpu_online_map;
cpu_clear(smp_processor_id(), mask);
if (!cpus_empty(mask))
smp_cross_call(&mask, IPI_CPU_STOP);
}
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
while (num_online_cpus() > 1 && timeout--)
udelay(1);
if (num_online_cpus() > 1)
pr_warning("SMP: failed to stop secondary CPUs\n");
}
/*
* not supported here
*/