• Andy Lutomirski's avatar
    x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code · a97439aa
    Andy Lutomirski authored
    It turns out to be rather tedious to test the NMI nesting code.
    Make it easier: add a new CONFIG_DEBUG_ENTRY option that causes
    the NMI handler to pre-emptively unmask NMIs.
    
    With this option set, errors in the repeat_nmi logic or failures
    to detect that we're in a nested NMI will result in quick panics
    under perf (especially if multiple counters are running at high
    frequency) instead of requiring an unusual workload that
    generates page faults or breakpoints inside NMIs.
    
    I called it CONFIG_DEBUG_ENTRY instead of CONFIG_DEBUG_NMI_ENTRY
    because I want to add new non-NMI checks elsewhere in the entry
    code in the future, and I'd rather not add too many new config
    options or add this option and then immediately rename it.
    Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
    Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    a97439aa
Kconfig.debug 11.2 KB