From 2104180a53698df5aec35aed5f840a26ade0551d Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 12 Jul 2017 14:35:52 -0700 Subject: 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 Reviewed-by: Don Zickus Tested-by: Babu Moger [sparc] Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/include/asm/smp.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/powerpc/include/asm/smp.h') diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index ebddb2111d87..8ea98504f900 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -55,6 +55,8 @@ struct smp_ops_t { int (*cpu_bootable)(unsigned int nr); }; +extern void smp_flush_nmi_ipi(u64 delay_us); +extern int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us); extern void smp_send_debugger_break(void); extern void start_secondary_resume(void); extern void smp_generic_give_timebase(void); -- cgit v1.2.3