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authorAndy Lutomirski <luto@kernel.org>2015-07-15 10:29:41 -0700
committerIngo Molnar <mingo@kernel.org>2015-07-17 12:50:14 +0200
commita97439aa1aec10387797b4abae3cf117de1c90d7 (patch)
tree6350d830fed0e1a6908bc53eaa9aefff2425902b /arch/x86/Kconfig.debug
parent36f1a77b3aa57c5c2eb1ae2d67d07c4350a78345 (diff)
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x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code
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: Andy Lutomirski <luto@kernel.org> Reviewed-by: Steven 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: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/Kconfig.debug')
-rw-r--r--arch/x86/Kconfig.debug12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index a15893d..d8c0d32 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -297,6 +297,18 @@ config OPTIMIZE_INLINING
If unsure, say N.
+config DEBUG_ENTRY
+ bool "Debug low-level entry code"
+ depends on DEBUG_KERNEL
+ ---help---
+ This option enables sanity checks in x86's low-level entry code.
+ Some of these sanity checks may slow down kernel entries and
+ exits or otherwise impact performance.
+
+ This is currently used to help test NMI code.
+
+ If unsure, say N.
+
config DEBUG_NMI_SELFTEST
bool "NMI Selftest"
depends on DEBUG_KERNEL && X86_LOCAL_APIC
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