powerpc/64s: implement arch-specific hardlockup watchdog
Implement an arch-speicfic watchdog rather than use the perf-based
hardlockup detector.
The new watchdog takes the soft-NMI directly, rather than going through
perf. Perf interrupts are to be made maskable in future, so that would
prevent the perf detector from working in those regions.
Additionally, implement a SMP based detector where all CPUs watch one
another by pinging a shared cpumask. This is because powerpc Book3S
does not have a true periodic local NMI, but some platforms do implement
a true NMI IPI.
If a CPU is stuck with interrupts hard disabled, the soft-NMI watchdog
does not work, but the SMP watchdog will. Even on platforms without a
true NMI IPI to get a good trace from the stuck CPU, other CPUs will
notice the lockup sufficiently to report it and panic.
[npiggin@gmail.com: honor watchdog disable at boot/hotplug]
Link: http://lkml.kernel.org/r/20170621001346.5bb337c9@roar.ozlabs.ibm.com
[npiggin@gmail.com: fix false positive warning at CPU unplug]
Link: http://lkml.kernel.org/r/20170630080740.20766-1-npiggin@gmail.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170616065715.18390-6-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 63ed758..fce2f4f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -82,7 +82,7 @@
config NMI_IPI
bool
- depends on SMP && (DEBUGGER || KEXEC_CORE)
+ depends on SMP && (DEBUGGER || KEXEC_CORE || HARDLOCKUP_DETECTOR)
default y
config STACKTRACE_SUPPORT
@@ -192,12 +192,13 @@
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MOD_ARCH_SPECIFIC
- select HAVE_NMI if PERF_EVENTS
+ select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
+ select HAVE_HARDLOCKUP_DETECTOR_ARCH if (PPC64 && PPC_BOOK3S)
select HAVE_OPROFILE
select HAVE_OPTPROBES if PPC64
select HAVE_PERF_EVENTS
select HAVE_PERF_EVENTS_NMI if PPC64
- select HAVE_HARDLOCKUP_DETECTOR_PERF if HAVE_PERF_EVENTS_NMI
+ select HAVE_HARDLOCKUP_DETECTOR_PERF if HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_RCU_TABLE_FREE if SMP