Messages in this thread Patch in this message | | | From | Don Zickus <> | Subject | [PATCH 4/4] [RFC][powerpc] nmi_watchdog: support for powerpc | Date | Fri, 12 Feb 2010 17:19:21 -0500 |
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In order to make sure other arches compiled properly, I used powerpc as a test bed. It was just basic sanity checking code to see if the infrastructure bits worked ok. The lock up detection logic is non-existant and the sample_period is some large made up number.
The interesting piece of the patch is the change to ppc970-pmc.c. I had to move the initcall from arch_init to early_init to allow the nmi_watchdog to register with the perf_event subsystem as cpus were coming online. Otherwise it failed with ENXIO.
This patch is just a conversation starter. I am not sure if powerpc has a true NMI and if this is really needed. But since I spent some time making it work, I thought I would throw it out there.
Signed-off-by: Don Zickus <dzickus@redhat.com> --- arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/Makefile | 1 + arch/powerpc/kernel/hw_nmi.c | 45 ++++++++++++++++++++++++++++++++++++++ arch/powerpc/kernel/ppc970-pmu.c | 2 +- 4 files changed, 48 insertions(+), 1 deletions(-) create mode 100644 arch/powerpc/kernel/hw_nmi.c
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index ba3948c..146b0b5 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -140,6 +140,7 @@ config PPC select HAVE_SYSCALL_WRAPPERS if PPC64 select GENERIC_ATOMIC64 if PPC32 select HAVE_PERF_EVENTS + select PERF_EVENTS_NMI config EARLY_PRINTK bool diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index c002b04..08e3d2d 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -86,6 +86,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o +obj-$(CONFIG_NMI_WATCHDOG) += hw_nmi.o pci64-$(CONFIG_PPC64) += pci_dn.o isa-bridge.o obj-$(CONFIG_PCI) += pci_$(CONFIG_WORD_SIZE).o $(pci64-y) \ diff --git a/arch/powerpc/kernel/hw_nmi.c b/arch/powerpc/kernel/hw_nmi.c new file mode 100644 index 0000000..2313724 --- /dev/null +++ b/arch/powerpc/kernel/hw_nmi.c @@ -0,0 +1,45 @@ +/* + * HW NMI watchdog support + * + * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. + * + * Arch specific calls to support NMI watchdog + * + * Bits copied from original nmi.c file + * + */ + +#include <linux/smp.h> +//#include <linux/cpumask.h> +//#include <linux/sched.h> +#include <linux/percpu.h> +#include <linux/kernel_stat.h> + +//#include <linux/nmi.h> + +static DEFINE_PER_CPU(unsigned, last_irq_sum); + +int hw_nmi_is_cpu_stuck(struct pt_regs *regs) +{ + unsigned int sum; + int cpu = smp_processor_id(); + + /* We determine if the cpu is stuck by checking whether any + * interrupts have happened since we last checked. Of course + * an nmi storm could create false positives, but the higher + * level logic should account for that + */ + return 0; + sum = kstat_irqs_cpu(0, cpu); + if (__get_cpu_var(last_irq_sum) == sum) { + return 1; + } else { + __get_cpu_var(last_irq_sum) = sum; + return 0; + } +} + +u64 hw_nmi_get_sample_period(void) +{ + return 10000 * 1000; +} diff --git a/arch/powerpc/kernel/ppc970-pmu.c b/arch/powerpc/kernel/ppc970-pmu.c index 8eff48e..d91aaf1 100644 --- a/arch/powerpc/kernel/ppc970-pmu.c +++ b/arch/powerpc/kernel/ppc970-pmu.c @@ -492,4 +492,4 @@ static int init_ppc970_pmu(void) return register_power_pmu(&ppc970_pmu); } -arch_initcall(init_ppc970_pmu); +early_initcall(init_ppc970_pmu); -- 1.6.6.83.gc9a2
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