Messages in this thread | | | Date | Fri, 29 Apr 2022 18:38:19 -0300 | Subject | Re: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path | From | "Guilherme G. Piccoli" <> |
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Thanks Marc and Michael for the review/discussion.
On 29/04/2022 15:20, Marc Zyngier wrote: > [...]
> My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. >
Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me.
You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code.
Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from.
But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it.
Appreciate your clarifications about that, thanks again. Cheers,
Guilherme
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