[PATCH v2 2/3] powerpc: Call chained reset handlers during reset
andrew.smirnov at gmail.com
Wed Aug 10 04:27:58 AEST 2016
On Sun, Jul 31, 2016 at 8:47 PM, Nicholas Piggin <npiggin at gmail.com> wrote:
> On Thu, 28 Jul 2016 16:07:17 -0700
> Andrey Smirnov <andrew.smirnov at gmail.com> wrote:
>> Call out to all restart handlers that were added via
>> register_restart_handler() API when restarting the machine.
>> Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
>> No changes compared to v1
>> arch/powerpc/kernel/setup-common.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>> diff --git a/arch/powerpc/kernel/setup-common.c
>> b/arch/powerpc/kernel/setup-common.c index 5cd3283..205d073 100644
>> --- a/arch/powerpc/kernel/setup-common.c
>> +++ b/arch/powerpc/kernel/setup-common.c
>> @@ -145,6 +145,10 @@ void machine_restart(char *cmd)
>> + do_kernel_restart(cmd);
>> + mdelay(1000);
> Ah, I see why you don't move smp_send_stop(). 3 other architectures
> call do_kernel_restart(). arm and arm64 call it with
I am not very familiar with low-level SPM code, so take all below with
a grain of salt.
>From my understanding of the code ARM's implementation of
smp_send_stop() is different from MIPS/PowerPC ones in that it just
raises an IPI with a special "stop" flag set, which can and probably
should be done with IRQs disabled. Both MIPS and PowerPC call
smp_call_fuction() in their smp_send_stop() implementation, which if I
read the documentation correctly should not be called with interrupts
disabled, so it looks like the call to local_irq_disabled() could only
be placed after the call to smp_send_stop() on those platforms.
> arm and mips insert the 1s delay. All call it
> after smp_send_stop(). I don't see the harm in the delay. Should we
> call it with local interrupts disabled?
With all above being said I don't see any harm in disabling interrupts.
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