powerpc: Add NMI IPI infrastructure
Add a simple NMI IPI system that handles concurrency and reentrancy.
The platform does not have to implement a true non-maskable interrupt,
the default is to simply use the debugger break IPI message. This has
now been co-opted for a general IPI message, and users (debugger and
crash) have been reimplemented on top of the NMI system.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Incorporate incremental fixes from Nick]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 7401e92..48cc3d8 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -80,6 +80,11 @@
/proc/interrupts. If you configure your system to have too few,
drivers will fail to load or worse - handle with care.
+config NMI_IPI
+ bool
+ depends on SMP && (DEBUGGER || KEXEC_CORE)
+ default y
+
config STACKTRACE_SUPPORT
bool
default y