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  • Max Filippov's avatar
    xtensa: implement fake NMI · 38fef73c
    Max Filippov authored
    In case perf IRQ is the highest of the medium-level IRQs, and is alone
    on its level, it may be treated as NMI:
    - LOCKLEVEL is defined to be one level less than EXCM level,
    - IRQ masking never lowers current IRQ level,
    - new fake exception cause code, EXCCAUSE_MAPPED_NMI is assigned to that
      IRQ; new second level exception handler, do_nmi, assigned to it
      handles it as NMI,
    - atomic operations in configurations without s32c1i still need to mask
      all interrupts.
    Cc: Peter Zijlstra <>
    Acked-by: default avatarPeter Zijlstra (Intel) <>
    Signed-off-by: default avatarMax Filippov <>