Messages in this thread Patch in this message | | | From | Don Zickus <> | Subject | [PATCH 4/9] x86, NMI: Remove DIE_NMI_IPI and add priorties to handlers | Date | Tue, 30 Nov 2010 17:27:25 -0500 |
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When re-ordering how the NMI handles its callbacks, a conversation started asking what DIE_NMI_IPI meant. No one could answer it.
Noticing that is was wasteful to call the die_chain a second time with just another argument, DIE_NMI_IPI, it was decided to nuke it and add priorities to the die_chain handlers to maintain existing behaviour.
This patch replaces DIE_NMI_IPI with the appropriate option, mostly DIE_NMI. Then it adds priorities to those handlers, using a globally defined set of priorities for NMI.
The thought is eventually we will just switch the nmi handlers from the die_chain to something more nmi specific.
Signed-off-by: Don Zickus <dzickus@redhat.com> --- arch/x86/include/asm/kdebug.h | 1 - arch/x86/include/asm/nmi.h | 20 ++++++++++++++++++++ arch/x86/kernel/apic/hw_nmi.c | 3 +-- arch/x86/kernel/apic/x2apic_uv_x.c | 2 +- arch/x86/kernel/cpu/mcheck/mce-inject.c | 5 +++-- arch/x86/kernel/cpu/perf_event.c | 4 ++-- arch/x86/kernel/kgdb.c | 6 +----- arch/x86/kernel/reboot.c | 5 ++++- arch/x86/kernel/traps.c | 8 +------- arch/x86/oprofile/nmi_int.c | 4 ++-- arch/x86/oprofile/nmi_timer_int.c | 4 ++-- 11 files changed, 37 insertions(+), 25 deletions(-)
diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h index f23eb25..ca242d3 100644 --- a/arch/x86/include/asm/kdebug.h +++ b/arch/x86/include/asm/kdebug.h @@ -18,7 +18,6 @@ enum die_val { DIE_TRAP, DIE_GPF, DIE_CALL, - DIE_NMI_IPI, DIE_PAGE_FAULT, DIE_NMIUNKNOWN, }; diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h index 3545838..9c4ff0b 100644 --- a/arch/x86/include/asm/nmi.h +++ b/arch/x86/include/asm/nmi.h @@ -23,6 +23,26 @@ void arch_trigger_all_cpu_backtrace(void); #define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace #endif +/* + * Define some priorities for the nmi notifier call chain. + * + * Create a local nmi bit that has a higher priority than + * external nmis, because the local ones are more frequent. + * + * Also setup some default high/normal/low settings for + * subsystems to registers with. Using 4 bits to seperate + * the priorities. This can go alot higher if needed be. + */ + +#define NMI_LOCAL_SHIFT 16 /* randomly picked */ +#define NMI_LOCAL_BIT (1ULL << NMI_LOCAL_SHIFT) +#define NMI_HIGH_PRIOR (1ULL << 8) +#define NMI_NORMAL_PRIOR (1ULL << 4) +#define NMI_LOW_PRIOR (1ULL << 0) +#define NMI_LOCAL_HIGH_PRIOR (NMI_LOCAL_BIT | NMI_HIGH_PRIOR) +#define NMI_LOCAL_NORMAL_PRIOR (NMI_LOCAL_BIT | NMI_NORMAL_PRIOR) +#define NMI_LOCAL_LOW_PRIOR (NMI_LOCAL_BIT | NMI_LOW_PRIOR) + void stop_nmi(void); void restart_nmi(void); diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c index a86840c..82bff25 100644 --- a/arch/x86/kernel/apic/hw_nmi.c +++ b/arch/x86/kernel/apic/hw_nmi.c @@ -63,7 +63,6 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self, switch (cmd) { case DIE_NMI: - case DIE_NMI_IPI: break; default: @@ -90,7 +89,7 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self, static __read_mostly struct notifier_block backtrace_notifier = { .notifier_call = arch_trigger_all_cpu_backtrace_handler, .next = NULL, - .priority = 1 + .priority = NMI_LOCAL_LOW_PRIOR, }; static int __init register_trigger_all_cpu_backtrace(void) diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c index c1c52c3..927902d 100644 --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -639,7 +639,7 @@ void __cpuinit uv_cpu_init(void) */ int uv_handle_nmi(struct notifier_block *self, unsigned long reason, void *data) { - if (reason != DIE_NMI_IPI) + if (reason != DIE_NMIUNKNOWN) return NOTIFY_OK; if (in_crash_kexec) diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c index e7dbde7..a779719 100644 --- a/arch/x86/kernel/cpu/mcheck/mce-inject.c +++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c @@ -25,6 +25,7 @@ #include <linux/gfp.h> #include <asm/mce.h> #include <asm/apic.h> +#include <asm/nmi.h> /* Update fake mce registers on current CPU. */ static void inject_mce(struct mce *m) @@ -83,7 +84,7 @@ static int mce_raise_notify(struct notifier_block *self, struct die_args *args = (struct die_args *)data; int cpu = smp_processor_id(); struct mce *m = &__get_cpu_var(injectm); - if (val != DIE_NMI_IPI || !cpumask_test_cpu(cpu, mce_inject_cpumask)) + if (val != DIE_NMI || !cpumask_test_cpu(cpu, mce_inject_cpumask)) return NOTIFY_DONE; cpumask_clear_cpu(cpu, mce_inject_cpumask); if (m->inject_flags & MCJ_EXCEPTION) @@ -95,7 +96,7 @@ static int mce_raise_notify(struct notifier_block *self, static struct notifier_block mce_raise_nb = { .notifier_call = mce_raise_notify, - .priority = 1000, + .priority = NMI_LOCAL_NORMAL_PRIOR, }; /* Inject mce on current CPU */ diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 48aa91f..7b91396 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1229,7 +1229,7 @@ perf_event_nmi_handler(struct notifier_block *self, return NOTIFY_DONE; switch (cmd) { - case DIE_NMI_IPI: + case DIE_NMI: break; case DIE_NMIUNKNOWN: this_nmi = percpu_read(irq_stat.__nmi_count); @@ -1279,7 +1279,7 @@ perf_event_nmi_handler(struct notifier_block *self, static __read_mostly struct notifier_block perf_event_nmi_notifier = { .notifier_call = perf_event_nmi_handler, .next = NULL, - .priority = 1 + .priority = NMI_LOCAL_LOW_PRIOR, }; static struct event_constraint unconstrained; diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index cd21b65..1e8b583 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -525,10 +525,6 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) } return NOTIFY_DONE; - case DIE_NMI_IPI: - /* Just ignore, we will handle the roundup on DIE_NMI. */ - return NOTIFY_DONE; - case DIE_NMIUNKNOWN: if (was_in_debug_nmi[raw_smp_processor_id()]) { was_in_debug_nmi[raw_smp_processor_id()] = 0; @@ -606,7 +602,7 @@ static struct notifier_block kgdb_notifier = { /* * Lowest-prio notifier priority, we want to be notified last: */ - .priority = -INT_MAX, + .priority = NMI_LOCAL_LOW_PRIOR, }; /** diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index c495aa8..fc7aae1 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -18,6 +18,7 @@ #include <asm/pci_x86.h> #include <asm/virtext.h> #include <asm/cpu.h> +#include <asm/nmi.h> #ifdef CONFIG_X86_32 # include <linux/ctype.h> @@ -747,7 +748,7 @@ static int crash_nmi_callback(struct notifier_block *self, { int cpu; - if (val != DIE_NMI_IPI) + if (val != DIE_NMI) return NOTIFY_OK; cpu = raw_smp_processor_id(); @@ -778,6 +779,8 @@ static void smp_send_nmi_allbutself(void) static struct notifier_block crash_nmi_nb = { .notifier_call = crash_nmi_callback, + /* we want to be the first one called */ + .priority = NMI_LOCAL_HIGH_PRIOR+1, }; /* Halt all other CPUs, calling the specified function on each of them diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 5184b21..0668b51 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -404,8 +404,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) * CPU-specific NMI: send to specific CPU or NMI sources must * be processed on specific CPU */ - if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, 0, 2, SIGINT) - == NOTIFY_STOP) + if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) return; /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */ @@ -414,9 +413,6 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) if (!cpu) { reason = get_nmi_reason(); if (reason & NMI_REASON_MASK) { - if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) - == NOTIFY_STOP) - return; if (reason & NMI_REASON_SERR) pci_serr_error(reason, regs); else if (reason & NMI_REASON_IOCHK) @@ -431,8 +427,6 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) return; } } - if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) - return; unknown_nmi_error(reason, regs); } diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c index ee7ff0e..e476044 100644 --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -64,7 +64,7 @@ static int profile_exceptions_notify(struct notifier_block *self, int ret = NOTIFY_DONE; switch (val) { - case DIE_NMI_IPI: + case DIE_NMI: if (ctr_running) model->check_ctrs(args->regs, &__get_cpu_var(cpu_msrs)); else if (!nmi_enabled) @@ -360,7 +360,7 @@ static void nmi_cpu_setup(void *dummy) static struct notifier_block profile_exceptions_nb = { .notifier_call = profile_exceptions_notify, .next = NULL, - .priority = 2 + .priority = NMI_LOCAL_LOW_PRIOR, }; static void nmi_cpu_restore_registers(struct op_msrs *msrs) diff --git a/arch/x86/oprofile/nmi_timer_int.c b/arch/x86/oprofile/nmi_timer_int.c index fb40645..720bf5a 100644 --- a/arch/x86/oprofile/nmi_timer_int.c +++ b/arch/x86/oprofile/nmi_timer_int.c @@ -25,7 +25,7 @@ static int profile_timer_exceptions_notify(struct notifier_block *self, int ret = NOTIFY_DONE; switch (val) { - case DIE_NMI_IPI: + case DIE_NMI: oprofile_add_sample(args->regs, 0); ret = NOTIFY_STOP; break; @@ -38,7 +38,7 @@ static int profile_timer_exceptions_notify(struct notifier_block *self, static struct notifier_block profile_timer_exceptions_nb = { .notifier_call = profile_timer_exceptions_notify, .next = NULL, - .priority = 0 + .priority = NMI_LOW_PRIOR, }; static int timer_start(void) -- 1.7.3.2
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