xtensa: make fake NMI configurable
Do not always use fake NMI when safe, provide Kconfig option instead.
Print a warning if fake NMI is chosen in unsafe configuration, but allow
it, because it may work if the user knows that interrupts with
priorities at or above PMM IRQ are not used. Add a check to NMI handler
that BUGs if any of these IRQs fire.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 82044f7..128e63d 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -139,6 +139,22 @@
If unsure, say N.
+config XTENSA_FAKE_NMI
+ bool "Treat PMM IRQ as NMI"
+ depends on XTENSA_VARIANT_HAVE_PERF_EVENTS
+ default n
+ help
+ If PMM IRQ is the only IRQ at EXCM level it is safe to
+ treat it as NMI, which improves accuracy of profiling.
+
+ If there are other interrupts at or above PMM IRQ priority level
+ but not above the EXCM level, PMM IRQ still may be treated as NMI,
+ but only if these IRQs are not used. There will be a build warning
+ saying that this is not safe, and a bugcheck if one of these IRQs
+ actually fire.
+
+ If unsure, say N.
+
config XTENSA_UNALIGNED_USER
bool "Unaligned memory access in use space"
help