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powerpc: use NMI IPI for smp_send_stop 

Use the NMI IPI rather than smp_call_function for smp_send_stop.
Have stopped CPUs hard disable interrupts rather than just soft
disable.

This function is used in crash/panic/shutdown paths to bring other
CPUs down as quickly and reliably as possible, and minimizing their
potential to cause trouble.

Avoiding the Linux smp_call_function infrastructure and (if supported)
using true NMI IPIs makes this more robust.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-04-01 20:36:13 +10:00 committed by Michael Ellerman
parent a2b5e056b7
commit 6bed323762
1 changed files with 8 additions and 0 deletions
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8
arch/powerpc/kernel/smp.c
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@ -565,7 +565,11 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
}
#endif
#ifdef CONFIG_NMI_IPI
static void stop_this_cpu(struct pt_regs *regs)
#else
static void stop_this_cpu(void *dummy)
#endif
{
/* Remove this CPU */
set_cpu_online(smp_processor_id(), false);
@ -577,7 +581,11 @@ static void stop_this_cpu(void *dummy)
void smp_send_stop(void)
{
#ifdef CONFIG_NMI_IPI
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, stop_this_cpu, 1000000);
#else
smp_call_function(stop_this_cpu, NULL, 0);
#endif
}
struct thread_info *current_set[NR_CPUS];