lkml.org 
[lkml]   [2022]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path
    From
    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

    \
     
     \ /
      Last update: 2022-04-29 23:39    [W:2.142 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site