• Maciej W. Rozycki's avatar
    [PATCH] x86, x86_64: Only handle system NMIs on the BSP · 67e8e04a
    Maciej W. Rozycki authored
     While discussing races in the NMI handler's trailer fiddling with RTC
    registers, I've discovered we incorrectly attempt to handle NMIs coming
    from the system (memory errors, IOCHK# assertions, etc.) with all
    processors even though the interrupts are only routed to the bootstrap
    processor.  If one of these events coincides with a NMI watchdog tick it
    may even be handled multiple times in parallel.
    
    Here is a fix that makes application processors ignore these events.  They
    no longer access the NMI status bits at I/O port 0x61 which has also the
    advantage of removing the contention on the port when the I/O APIC NMI
    watchdog makes all processors arrive at the handler at the same time.
    Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    67e8e04a
traps.c 23.6 KB