Messages in this thread | | | Date | Fri, 26 Feb 2010 10:22:52 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: Enable NMI on all cpus on UV |
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* Russ Anderson <rja@sgi.com> wrote:
> On Mon, Feb 22, 2010 at 11:38:53AM +0100, Ingo Molnar wrote: > > > > * Russ Anderson <rja@sgi.com> wrote: > > > > > Enable NMI on all cpus in UV system and add an NMI handler > > > to dump_stack on each cpu. > > > > > > Signed-off-by: Russ Anderson <rja@sgi.com> > [...] > > > struct mm_struct *mm, > > > Index: linux/arch/x86/kernel/smpboot.c > > > =================================================================== > > > --- linux.orig/arch/x86/kernel/smpboot.c 2010-02-17 10:21:55.000000000 -0600 > > > +++ linux/arch/x86/kernel/smpboot.c 2010-02-17 10:32:20.000000000 -0600 > > > @@ -320,6 +320,8 @@ notrace static void __cpuinit start_seco > > > unlock_vector_lock(); > > > ipi_call_unlock(); > > > per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; > > > + if (is_uv_system()) > > > + uv_nmi_init(); > > > > Instead of cramming it into the init sequence open-coded, shouldnt this be > > done via the x86_platform driver mechanism? > > Attached is the updated patch with the x86_platform driver mechanism > used for uv_nmi_init.
ok, this looks far cleaner. A few nits:
> + * When NMI is received, print a stack trace. > + */ > +int uv_handle_nmi(struct notifier_block *self, > + unsigned long reason, void *data)
Please put prototypes on a single line if it's still below 100 cols or so.
> +{ > + unsigned long flags; > + static DEFINE_SPINLOCK(uv_nmi_lock);
Please dont hide locks amongst local variables. (even if they are only used by that function)
> + > + if (reason != DIE_NMI_IPI) > + return NOTIFY_OK; > + /* > + * Use a lock so only one cpu prints at a time > + * to prevent intermixed output. > + */ > + spin_lock_irqsave(&uv_nmi_lock, flags); > + printk(KERN_INFO "NMI stack dump cpu %u:\n", > + smp_processor_id());
Can be on a single line too.
Can use pr_info().
Should use a raw spinlock - this is NMI context.
> + dump_stack(); > + spin_unlock_irqrestore(&uv_nmi_lock, flags); > + > + return NOTIFY_STOP; > +} > + > +static struct notifier_block uv_dump_stack_nmi_nb = { > + .notifier_call = uv_handle_nmi, > + .next = NULL, > + .priority = 0 > +};
Please align structure initializations vertically.
Plus no need to open-code the setting of priority to 0 i guess.
> + > +void uv_register_nmi_notifier(void) > +{ > + if (register_die_notifier(&uv_dump_stack_nmi_nb)) > + printk(KERN_WARNING "UV NMI handler failed to register\n"); > +} > + > +void uv_nmi_init(void) > +{ > + unsigned int value; > + > + /* > + * Unmask NMI on all cpus > + */ > + value = apic_read(APIC_LVT1) | APIC_DM_NMI; > + value &= ~APIC_LVT_MASKED; > + apic_write(APIC_LVT1, value); > +} > > void __init uv_system_init(void) > { > @@ -690,5 +739,6 @@ void __init uv_system_init(void) > > uv_cpu_init(); > uv_scir_register_cpu_notifier(); > + uv_register_nmi_notifier(); > proc_mkdir("sgi_uv", NULL); > } > Index: linux/arch/x86/include/asm/uv/uv.h > =================================================================== > --- linux.orig/arch/x86/include/asm/uv/uv.h 2010-02-25 11:01:48.131694174 -0600 > +++ linux/arch/x86/include/asm/uv/uv.h 2010-02-25 11:02:17.622069711 -0600 > @@ -11,6 +11,7 @@ struct mm_struct; > extern enum uv_system_type get_uv_system_type(void); > extern int is_uv_system(void); > extern void uv_cpu_init(void); > +extern void uv_nmi_init(void); > extern void uv_system_init(void); > extern const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask, > struct mm_struct *mm, > Index: linux/arch/x86/kernel/smpboot.c > =================================================================== > --- linux.orig/arch/x86/kernel/smpboot.c 2010-02-25 11:01:50.929770347 -0600 > +++ linux/arch/x86/kernel/smpboot.c 2010-02-25 11:02:17.664720876 -0600 > @@ -263,6 +263,11 @@ static void __cpuinit smp_callin(void) > cpumask_set_cpu(cpuid, cpu_callin_mask); > } > > +void default_nmi_init(void) > +{ > + return; > +}
That return is not needed.
> + > /* > * Activate a secondary processor. > */ > @@ -320,6 +325,7 @@ notrace static void __cpuinit start_seco > unlock_vector_lock(); > ipi_call_unlock(); > per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; > + x86_platform.nmi_init(); > > /* enable local interrupts */ > local_irq_enable(); > Index: linux/arch/x86/include/asm/x86_init.h > =================================================================== > --- linux.orig/arch/x86/include/asm/x86_init.h 2010-02-25 11:01:48.131694174 -0600 > +++ linux/arch/x86/include/asm/x86_init.h 2010-02-25 11:02:17.696714616 -0600 > @@ -126,6 +126,7 @@ struct x86_cpuinit_ops { > * @get_wallclock: get time from HW clock like RTC etc. > * @set_wallclock: set time back to HW clock > * @is_untracked_pat_range exclude from PAT logic > + * @nmi_init enable NMI on cpus > */ > struct x86_platform_ops { > unsigned long (*calibrate_tsc)(void); > @@ -133,6 +134,7 @@ struct x86_platform_ops { > int (*set_wallclock)(unsigned long nowtime); > void (*iommu_shutdown)(void); > bool (*is_untracked_pat_range)(u64 start, u64 end); > + void (*nmi_init)(void); > }; > > extern struct x86_init_ops x86_init; > Index: linux/arch/x86/kernel/x86_init.c > =================================================================== > --- linux.orig/arch/x86/kernel/x86_init.c 2010-02-25 11:01:47.848760574 -0600 > +++ linux/arch/x86/kernel/x86_init.c 2010-02-25 11:02:17.732996103 -0600 > @@ -13,6 +13,7 @@ > #include <asm/e820.h> > #include <asm/time.h> > #include <asm/irq.h> > +#include <asm/nmi.h> > #include <asm/pat.h> > #include <asm/tsc.h> > #include <asm/iommu.h> > @@ -82,4 +83,5 @@ struct x86_platform_ops x86_platform = { > .set_wallclock = mach_set_rtc_mmss, > .iommu_shutdown = iommu_shutdown_noop, > .is_untracked_pat_range = is_ISA_range, > + .nmi_init = default_nmi_init > };
the default can be in this file too - then you can also make it 'static' and save some space and not touch smpboot.c.
> Index: linux/arch/x86/include/asm/nmi.h > =================================================================== > --- linux.orig/arch/x86/include/asm/nmi.h 2010-02-25 11:01:48.131694174 -0600 > +++ linux/arch/x86/include/asm/nmi.h 2010-02-25 11:02:17.756721420 -0600 > @@ -24,6 +24,7 @@ extern int reserve_perfctr_nmi(unsigned > extern void release_perfctr_nmi(unsigned int); > extern int reserve_evntsel_nmi(unsigned int); > extern void release_evntsel_nmi(unsigned int); > +extern void default_nmi_init(void); > > extern void setup_apic_nmi_watchdog(void *); > extern void stop_apic_nmi_watchdog(void *);
This will go away in that case as well.
Thanks,
Ingo
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