Re: [PATCH -v3 3/6] x86, NMI, Rewrite NMI handler

Don Zickus
2010-11-02T20:47:36Z

On Wed, Nov 03, 2010 at 02:16:03AM +0800, Huang Ying wrote:
> > 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_EXT_LOW_PRIOR,
>
> Do not find definition of NMI_EXT_LOW_PRIOR, forget to add it?

I attached an updated patch with that change.

Cheers,
Don

---
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 | 9 +--------
arch/x86/oprofile/nmi_int.c | 4 ++--
arch/x86/oprofile/nmi_timer_int.c | 4 ++--
11 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
index 5bdfca8..e28ec43 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 932f0f8..cfb6156 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -68,6 +68,26 @@ static inline int nmi_watchdog_active(void)
}
#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 lapic_watchdog_stop(void);
int lapic_watchdog_init(unsigned nmi_hz);
int lapic_wd_event(unsigned nmi_hz);
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 07a837d..44ff8c9 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -67,7 +67,6 @@ arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,

switch (cmd) {
case DIE_NMI:
- case DIE_NMI_IPI:
break;

default:
@@ -95,7 +94,7 @@ 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 be6f9c4..e6c6294 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -605,7 +605,7 @@ 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 da98b6d..55a3797 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1226,7 +1226,7 @@ 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);
@@ -1276,7 +1276,7 @@ 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 852b819..020d052 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -523,10 +523,6 @@ 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;
@@ -604,7 +600,7 @@ 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 e3af342..eabbde6 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>
@@ -753,7 +754,7 @@ 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();
@@ -784,6 +785,8 @@ 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 d8acab3..9e56e3d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -395,8 +395,7 @@ 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_ipi", regs, 0, 2, SIGINT) == NOTIFY_STOP)
return;

/* Non-CPU-specific NMI: NMI sources can be processed on any CPU */
@@ -405,9 +404,6 @@ 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)
@@ -423,9 +419,6 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
}
}

- if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP)
- return;
-
#if defined(CONFIG_X86_LOCAL_APIC) && !defined(CONFIG_LOCKUP_DETECTOR)
if (nmi_watchdog_tick(regs, reason))
return;
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 57f01bb..43b4f35 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 ab72a21..5f14fcb 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)
--
1.7.2.3