[patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[Cyrill Gorcunov]

[-- Attachment #1: perfctr-watchdog-coding-style --]
[-- Type: text/plain, Size: 11757 bytes --]

Just some code beautification. Nothing else.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Index: linux-2.6.git/arch/x86/kernel/cpu/perfctr-watchdog.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/cpu/perfctr-watchdog.c	2008-06-21 13:21:54.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/cpu/perfctr-watchdog.c	2008-06-21 19:08:17.000000000 +0400
@@ -1,11 +1,15 @@
-/* local apic based NMI watchdog for various CPUs.
-   This file also handles reservation of performance counters for coordination
-   with other users (like oprofile).
-
-   Note that these events normally don't tick when the CPU idles. This means
-   the frequency varies with CPU load.
-
-   Original code for K7/P6 written by Keith Owens */
+/*
+ * local apic based NMI watchdog for various CPUs.
+ *
+ * This file also handles reservation of performance counters for coordination
+ * with other users (like oprofile).
+ *
+ * Note that these events normally don't tick when the CPU idles. This means
+ * the frequency varies with CPU load.
+ *
+ * Original code for K7/P6 written by Keith Owens
+ *
+ */
 
 #include <linux/percpu.h>
 #include <linux/module.h>
@@ -36,12 +40,16 @@ struct wd_ops {
 
 static const struct wd_ops *wd_ops;
 
-/* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
- * offset from MSR_P4_BSU_ESCR0.  It will be the max for all platforms (for now)
+/*
+ * this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
+ * offset from MSR_P4_BSU_ESCR0.
+ *
+ * It will be the max for all platforms (for now)
  */
 #define NMI_MAX_COUNTER_BITS 66
 
-/* perfctr_nmi_owner tracks the ownership of the perfctr registers:
+/*
+ * perfctr_nmi_owner tracks the ownership of the perfctr registers:
  * evtsel_nmi_owner tracks the ownership of the event selection
  * - different performance counters/ event selection may be reserved for
  *   different subsystems this reservation system just tries to coordinate
@@ -73,8 +81,10 @@ static inline unsigned int nmi_perfctr_m
 	return 0;
 }
 
-/* converts an msr to an appropriate reservation bit */
-/* returns the bit offset of the event selection register */
+/*
+ * converts an msr to an appropriate reservation bit
+ * returns the bit offset of the event selection register
+ */
 static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr)
 {
 	/* returns the bit offset of the event selection register */
@@ -114,6 +124,7 @@ int avail_to_resrv_perfctr_nmi(unsigned 
 
 	return (!test_bit(counter, perfctr_nmi_owner));
 }
+EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
 
 int reserve_perfctr_nmi(unsigned int msr)
 {
@@ -128,6 +139,7 @@ int reserve_perfctr_nmi(unsigned int msr
 		return 1;
 	return 0;
 }
+EXPORT_SYMBOL(reserve_perfctr_nmi);
 
 void release_perfctr_nmi(unsigned int msr)
 {
@@ -140,6 +152,7 @@ void release_perfctr_nmi(unsigned int ms
 
 	clear_bit(counter, perfctr_nmi_owner);
 }
+EXPORT_SYMBOL(release_perfctr_nmi);
 
 int reserve_evntsel_nmi(unsigned int msr)
 {
@@ -154,6 +167,7 @@ int reserve_evntsel_nmi(unsigned int msr
 		return 1;
 	return 0;
 }
+EXPORT_SYMBOL(reserve_evntsel_nmi);
 
 void release_evntsel_nmi(unsigned int msr)
 {
@@ -166,11 +180,6 @@ void release_evntsel_nmi(unsigned int ms
 
 	clear_bit(counter, evntsel_nmi_owner);
 }
-
-EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
-EXPORT_SYMBOL(reserve_perfctr_nmi);
-EXPORT_SYMBOL(release_perfctr_nmi);
-EXPORT_SYMBOL(reserve_evntsel_nmi);
 EXPORT_SYMBOL(release_evntsel_nmi);
 
 void disable_lapic_nmi_watchdog(void)
@@ -234,8 +243,8 @@ static unsigned int adjust_for_32bit_ctr
 	return retval;
 }
 
-static void
-write_watchdog_counter(unsigned int perfctr_msr, const char *descr, unsigned nmi_hz)
+static void write_watchdog_counter(unsigned int perfctr_msr,
+				const char *descr, unsigned nmi_hz)
 {
 	u64 count = (u64)cpu_khz * 1000;
 
@@ -246,7 +255,7 @@ write_watchdog_counter(unsigned int perf
 }
 
 static void write_watchdog_counter32(unsigned int perfctr_msr,
-		const char *descr, unsigned nmi_hz)
+				const char *descr, unsigned nmi_hz)
 {
 	u64 count = (u64)cpu_khz * 1000;
 
@@ -256,9 +265,10 @@ static void write_watchdog_counter32(uns
 	wrmsr(perfctr_msr, (u32)(-count), 0);
 }
 
-/* AMD K7/K8/Family10h/Family11h support. AMD keeps this interface
-   nicely stable so there is not much variety */
-
+/*
+ * AMD K7/K8/Family10h/Family11h support.
+ * AMD keeps this interface nicely stable so there is not much variety
+ */
 #define K7_EVNTSEL_ENABLE	(1 << 22)
 #define K7_EVNTSEL_INT		(1 << 20)
 #define K7_EVNTSEL_OS		(1 << 17)
@@ -291,7 +301,7 @@ static int setup_k7_watchdog(unsigned nm
 
 	wd->perfctr_msr = perfctr_msr;
 	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  //unused
+	wd->cccr_msr = 0;  /* unused */
 	return 1;
 }
 
@@ -327,18 +337,19 @@ static void single_msr_rearm(struct nmi_
 }
 
 static const struct wd_ops k7_wd_ops = {
-	.reserve = single_msr_reserve,
-	.unreserve = single_msr_unreserve,
-	.setup = setup_k7_watchdog,
-	.rearm = single_msr_rearm,
-	.stop = single_msr_stop_watchdog,
-	.perfctr = MSR_K7_PERFCTR0,
-	.evntsel = MSR_K7_EVNTSEL0,
-	.checkbit = 1ULL<<47,
+	.reserve	= single_msr_reserve,
+	.unreserve	= single_msr_unreserve,
+	.setup		= setup_k7_watchdog,
+	.rearm		= single_msr_rearm,
+	.stop		= single_msr_stop_watchdog,
+	.perfctr	= MSR_K7_PERFCTR0,
+	.evntsel	= MSR_K7_EVNTSEL0,
+	.checkbit	= 1ULL << 47,
 };
 
-/* Intel Model 6 (PPro+,P2,P3,P-M,Core1) */
-
+/*
+ * Intel Model 6 (PPro+,P2,P3,P-M,Core1)
+ */
 #define P6_EVNTSEL0_ENABLE	(1 << 22)
 #define P6_EVNTSEL_INT		(1 << 20)
 #define P6_EVNTSEL_OS		(1 << 17)
@@ -374,52 +385,58 @@ static int setup_p6_watchdog(unsigned nm
 
 	wd->perfctr_msr = perfctr_msr;
 	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  //unused
+	wd->cccr_msr = 0;  /* unused */
 	return 1;
 }
 
 static void p6_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 {
-	/* P6 based Pentium M need to re-unmask
+	/*
+	 * P6 based Pentium M need to re-unmask
 	 * the apic vector but it doesn't hurt
 	 * other P6 variant.
-	 * ArchPerfom/Core Duo also needs this */
+	 * ArchPerfom/Core Duo also needs this
+	 */
 	apic_write(APIC_LVTPC, APIC_DM_NMI);
+
 	/* P6/ARCH_PERFMON has 32 bit counter write */
 	write_watchdog_counter32(wd->perfctr_msr, NULL,nmi_hz);
 }
 
 static const struct wd_ops p6_wd_ops = {
-	.reserve = single_msr_reserve,
-	.unreserve = single_msr_unreserve,
-	.setup = setup_p6_watchdog,
-	.rearm = p6_rearm,
-	.stop = single_msr_stop_watchdog,
-	.perfctr = MSR_P6_PERFCTR0,
-	.evntsel = MSR_P6_EVNTSEL0,
-	.checkbit = 1ULL<<39,
+	.reserve	= single_msr_reserve,
+	.unreserve	= single_msr_unreserve,
+	.setup		= setup_p6_watchdog,
+	.rearm		= p6_rearm,
+	.stop		= single_msr_stop_watchdog,
+	.perfctr	= MSR_P6_PERFCTR0,
+	.evntsel	= MSR_P6_EVNTSEL0,
+	.checkbit	= 1ULL << 39,
 };
 
-/* Intel P4 performance counters. By far the most complicated of all. */
-
-#define MSR_P4_MISC_ENABLE_PERF_AVAIL	(1<<7)
-#define P4_ESCR_EVENT_SELECT(N)	((N)<<25)
-#define P4_ESCR_OS		(1<<3)
-#define P4_ESCR_USR		(1<<2)
-#define P4_CCCR_OVF_PMI0	(1<<26)
-#define P4_CCCR_OVF_PMI1	(1<<27)
-#define P4_CCCR_THRESHOLD(N)	((N)<<20)
-#define P4_CCCR_COMPLEMENT	(1<<19)
-#define P4_CCCR_COMPARE		(1<<18)
-#define P4_CCCR_REQUIRED	(3<<16)
-#define P4_CCCR_ESCR_SELECT(N)	((N)<<13)
-#define P4_CCCR_ENABLE		(1<<12)
-#define P4_CCCR_OVF 		(1<<31)
-
-/* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
-   CRU_ESCR0 (with any non-null event selector) through a complemented
-   max threshold. [IA32-Vol3, Section 14.9.9] */
+/*
+ * Intel P4 performance counters.
+ * By far the most complicated of all.
+ */
+#define MSR_P4_MISC_ENABLE_PERF_AVAIL	(1 << 7)
+#define P4_ESCR_EVENT_SELECT(N)	((N) << 25)
+#define P4_ESCR_OS		(1 << 3)
+#define P4_ESCR_USR		(1 << 2)
+#define P4_CCCR_OVF_PMI0	(1 << 26)
+#define P4_CCCR_OVF_PMI1	(1 << 27)
+#define P4_CCCR_THRESHOLD(N)	((N) << 20)
+#define P4_CCCR_COMPLEMENT	(1 << 19)
+#define P4_CCCR_COMPARE		(1 << 18)
+#define P4_CCCR_REQUIRED	(3 << 16)
+#define P4_CCCR_ESCR_SELECT(N)	((N) << 13)
+#define P4_CCCR_ENABLE		(1 << 12)
+#define P4_CCCR_OVF 		(1 << 31)
 
+/*
+ * Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
+ * CRU_ESCR0 (with any non-null event selector) through a complemented
+ * max threshold. [IA32-Vol3, Section 14.9.9]
+ */
 static int setup_p4_watchdog(unsigned nmi_hz)
 {
 	unsigned int perfctr_msr, evntsel_msr, cccr_msr;
@@ -444,7 +461,8 @@ static int setup_p4_watchdog(unsigned nm
 #endif
 		ht_num = 0;
 
-	/* performance counters are shared resources
+	/*
+	 * performance counters are shared resources
 	 * assign each hyperthread its own set
 	 * (re-use the ESCR0 register, seems safe
 	 * and keeps the cccr_val the same)
@@ -542,20 +560,21 @@ static void p4_rearm(struct nmi_watchdog
 }
 
 static const struct wd_ops p4_wd_ops = {
-	.reserve = p4_reserve,
-	.unreserve = p4_unreserve,
-	.setup = setup_p4_watchdog,
-	.rearm = p4_rearm,
-	.stop = stop_p4_watchdog,
+	.reserve	= p4_reserve,
+	.unreserve	= p4_unreserve,
+	.setup		= setup_p4_watchdog,
+	.rearm		= p4_rearm,
+	.stop		= stop_p4_watchdog,
 	/* RED-PEN this is wrong for the other sibling */
-	.perfctr = MSR_P4_BPU_PERFCTR0,
-	.evntsel = MSR_P4_BSU_ESCR0,
-	.checkbit = 1ULL<<39,
+	.perfctr	= MSR_P4_BPU_PERFCTR0,
+	.evntsel	= MSR_P4_BSU_ESCR0,
+	.checkbit	= 1ULL << 39,
 };
 
-/* Watchdog using the Intel architected PerfMon. Used for Core2 and hopefully
-   all future Intel CPUs. */
-
+/*
+ * Watchdog using the Intel architected PerfMon.
+ * Used for Core2 and hopefully all future Intel CPUs.
+ */
 #define ARCH_PERFMON_NMI_EVENT_SEL	ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL
 #define ARCH_PERFMON_NMI_EVENT_UMASK	ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK
 
@@ -601,19 +620,19 @@ static int setup_intel_arch_watchdog(uns
 
 	wd->perfctr_msr = perfctr_msr;
 	wd->evntsel_msr = evntsel_msr;
-	wd->cccr_msr = 0;  //unused
+	wd->cccr_msr = 0;  /* unused */
 	intel_arch_wd_ops.checkbit = 1ULL << (eax.split.bit_width - 1);
 	return 1;
 }
 
 static struct wd_ops intel_arch_wd_ops __read_mostly = {
-	.reserve = single_msr_reserve,
-	.unreserve = single_msr_unreserve,
-	.setup = setup_intel_arch_watchdog,
-	.rearm = p6_rearm,
-	.stop = single_msr_stop_watchdog,
-	.perfctr = MSR_ARCH_PERFMON_PERFCTR1,
-	.evntsel = MSR_ARCH_PERFMON_EVENTSEL1,
+	.reserve	= single_msr_reserve,
+	.unreserve	= single_msr_unreserve,
+	.setup		= setup_intel_arch_watchdog,
+	.rearm		= p6_rearm,
+	.stop		= single_msr_stop_watchdog,
+	.perfctr	= MSR_ARCH_PERFMON_PERFCTR1,
+	.evntsel	= MSR_ARCH_PERFMON_EVENTSEL1,
 };
 
 static void probe_nmi_watchdog(void)
@@ -626,8 +645,10 @@ static void probe_nmi_watchdog(void)
 		wd_ops = &k7_wd_ops;
 		break;
 	case X86_VENDOR_INTEL:
-		/* Work around Core Duo (Yonah) errata AE49 where perfctr1
-		   doesn't have a working enable bit. */
+		/*
+		 * Work around Core Duo (Yonah) errata AE49 where perfctr1
+		 * doesn't have a working enable bit.
+		 */
 		if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 14) {
 			intel_arch_wd_ops.perfctr = MSR_ARCH_PERFMON_PERFCTR0;
 			intel_arch_wd_ops.evntsel = MSR_ARCH_PERFMON_EVENTSEL0;
@@ -638,7 +659,7 @@ static void probe_nmi_watchdog(void)
 		}
 		switch (boot_cpu_data.x86) {
 		case 6:
-			if (boot_cpu_data.x86_model > 0xd)
+			if (boot_cpu_data.x86_model > 13)
 				return;
 
 			wd_ops = &p6_wd_ops;
@@ -699,10 +720,11 @@ int lapic_wd_event(unsigned nmi_hz)
 {
 	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
 	u64 ctr;
+
 	rdmsrl(wd->perfctr_msr, ctr);
-	if (ctr & wd_ops->checkbit) { /* perfctr still running? */
+	if (ctr & wd_ops->checkbit) /* perfctr still running? */
 		return 0;
-	}
+
 	wd_ops->rearm(wd, nmi_hz);
 	return 1;
 }

-- 

Re: [patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[Ingo Molnar]

* Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> Just some code beautification. Nothing else.

applied, thanks Cyrill.

note, your mailer sets the wrong timestamps:

| Date: Thu, 01 Jan 1970 03:00:01 +0300
| From: Cyrill Gorcunov <gorcunov@gmail.com>

i'll edit them out of your patches so that Git doesnt get bogus dates.

	Ingo

Re: [patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[Cyrill Gorcunov]

[Ingo Molnar - Tue, Jun 24, 2008 at 06:36:22PM +0200]
| 
| * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
| 
| > Just some code beautification. Nothing else.
| 
| applied, thanks Cyrill.
| 
| note, your mailer sets the wrong timestamps:
| 
| | Date: Thu, 01 Jan 1970 03:00:01 +0300
| | From: Cyrill Gorcunov <gorcunov@gmail.com>
| 
| i'll edit them out of your patches so that Git doesnt get bogus dates.
| 
| 	Ingo
| 

Thanks Ingo, I've mentoined in 'reply' mail for first message
in series that somehow happened that date was screwed up.
I can resent the series if needed.

		- Cyrill -

Re: [patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[Ingo Molnar]

* Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> [Ingo Molnar - Tue, Jun 24, 2008 at 06:36:22PM +0200]
> | 
> | * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
> | 
> | > Just some code beautification. Nothing else.
> | 
> | applied, thanks Cyrill.
> | 
> | note, your mailer sets the wrong timestamps:
> | 
> | | Date: Thu, 01 Jan 1970 03:00:01 +0300
> | | From: Cyrill Gorcunov <gorcunov@gmail.com>
> | 
> | i'll edit them out of your patches so that Git doesnt get bogus dates.
> | 
> | 	Ingo
> 
> Thanks Ingo, I've mentoined in 'reply' mail for first message in 
> series that somehow happened that date was screwed up. I can resent 
> the series if needed.

no need to resend, fixed it all up :-)

	Ingo

Re: [patch 1/5] x86: perfctr-watchdog.c - coding style cleanup

[Cyrill Gorcunov]

Thanks a lot, Ingo

On 6/25/08, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
>
>> [Ingo Molnar - Tue, Jun 24, 2008 at 06:36:22PM +0200]
>> |
>> | * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
>> |
>> | > Just some code beautification. Nothing else.
>> |
>> | applied, thanks Cyrill.
>> |
>> | note, your mailer sets the wrong timestamps:
>> |
>> | | Date: Thu, 01 Jan 1970 03:00:01 +0300
>> | | From: Cyrill Gorcunov <gorcunov@gmail.com>
>> |
>> | i'll edit them out of your patches so that Git doesnt get bogus dates.
>> |
>> | 	Ingo
>>
>> Thanks Ingo, I've mentoined in 'reply' mail for first message in
>> series that somehow happened that date was screwed up. I can resent
>> the series if needed.
>
> no need to resend, fixed it all up :-)
>
> 	Ingo
>

[patch 2/5] x86: nmi_watchdog - use nmi_watchdog variable for printing

[Cyrill Gorcunov]

[-- Attachment #1: nmi-apic-use-nmi_watchdog --]
[-- Type: text/plain, Size: 1382 bytes --]

Since it is possible NMI_ definitions could be changed
one day we better print out real nmi_watchdog value instead
of constant string

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Index: linux-2.6.git/arch/x86/kernel/apic_32.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic_32.c	2008-06-22 23:02:50.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/apic_32.c	2008-06-23 18:38:49.000000000 +0400
@@ -550,7 +550,7 @@ void __init setup_boot_APIC_clock(void)
 			lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
 		else
 			printk(KERN_WARNING "APIC timer registered as dummy,"
-			       " due to nmi_watchdog=1!\n");
+				" due to nmi_watchdog=%d!\n", nmi_watchdog);
 	}
 
 	/* Setup the lapic or request the broadcast */
Index: linux-2.6.git/arch/x86/kernel/apic_64.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic_64.c	2008-06-22 23:02:50.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/apic_64.c	2008-06-23 18:44:41.000000000 +0400
@@ -417,7 +417,7 @@ void __init setup_boot_APIC_clock(void)
 		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
 	else
 		printk(KERN_WARNING "APIC timer registered as dummy,"
-		       " due to nmi_watchdog=1!\n");
+			" due to nmi_watchdog=%d!\n", nmi_watchdog);
 
 	setup_APIC_timer();
 }

-- 

[patch 3/5] x86: nmi_watchdog - remove useless check

[Cyrill Gorcunov]

[-- Attachment #1: nmi-reduce-check --]
[-- Type: text/plain, Size: 794 bytes --]

Since nmi_watchdog is unsigned variable we may
safely remove the check for negative value

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Index: linux-2.6.git/arch/x86/kernel/nmi.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/nmi.c	2008-06-22 23:02:50.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/nmi.c	2008-06-23 20:02:47.000000000 +0400
@@ -186,7 +186,7 @@ error:
 
 static int __init setup_nmi_watchdog(char *str)
 {
-	int nmi;
+	unsigned int nmi;
 
 	if (!strncmp(str, "panic", 5)) {
 		panic_on_timeout = 1;
@@ -198,7 +198,7 @@ static int __init setup_nmi_watchdog(cha
 
 	get_option(&str, &nmi);
 
-	if (nmi >= NMI_INVALID || nmi < NMI_NONE)
+	if (nmi >= NMI_INVALID)
 		return 0;
 
 	nmi_watchdog = nmi;

-- 

[patch 4/5] x86: nmi_watchdog - use NMI_NONE by default

[Cyrill Gorcunov]

[-- Attachment #1: nmi-watchdog-use-none --]
[-- Type: text/plain, Size: 5155 bytes --]

There is no need to keep NMI_DISABLED definition and use it
for nmi_watchdog by default. Here is the point why:

- IO-APIC and APIC chips are programmed for nmi_watchdog support at very
  early stage of kernel booting and not having nmi_watchdog specified as
  boot option lead only to nmi_watchdog becomes to NMI_NONE anyway
- enable nmi_watchdog thru /proc/sys/kernel/nmi if it was not specified at
  boot is not possible too (even having this sysfs entry)

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Index: linux-2.6.git/include/asm-x86/nmi.h
====================================================================
--- linux-2.6.git.orig/include/asm-x86/nmi.h	2008-06-24 19:30:34.000000000 +0400
+++ linux-2.6.git/include/asm-x86/nmi.h	2008-06-24 19:32:44.000000000 +0400
@@ -20,7 +20,6 @@ extern void default_do_nmi(struct pt_reg
 #endif
 
 extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
-extern void nmi_watchdog_default(void);
 extern int check_nmi_watchdog(void);
 extern int nmi_watchdog_enabled;
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
@@ -38,12 +37,10 @@ extern int nmi_watchdog_tick(struct pt_r
 
 extern atomic_t nmi_active;
 extern unsigned int nmi_watchdog;
-#define NMI_DISABLED    -1
 #define NMI_NONE	0
 #define NMI_IO_APIC	1
 #define NMI_LOCAL_APIC	2
 #define NMI_INVALID	3
-#define NMI_DEFAULT	NMI_DISABLED
 
 struct ctl_table;
 struct file;
Index: linux-2.6.git/arch/x86/kernel/apic_64.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic_64.c	2008-06-24 19:30:59.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/apic_64.c	2008-06-24 19:31:03.000000000 +0400
@@ -826,7 +826,6 @@ static void __cpuinit lapic_setup_esr(vo
 void __cpuinit end_local_APIC_setup(void)
 {
 	lapic_setup_esr();
-	nmi_watchdog_default();
 	setup_apic_nmi_watchdog(NULL);
 	apic_pm_activate();
 }
Index: linux-2.6.git/arch/x86/kernel/io_apic_64.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/io_apic_64.c	2008-06-24 19:30:34.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/io_apic_64.c	2008-06-24 19:31:03.000000000 +0400
@@ -1729,7 +1729,6 @@ static inline void __init check_timer(vo
 		}
 		unmask_IO_APIC_irq(0);
 		if (!no_timer_check && timer_irq_works()) {
-			nmi_watchdog_default();
 			if (nmi_watchdog == NMI_IO_APIC) {
 				setup_nmi();
 				enable_8259A_irq(0);
@@ -1758,7 +1757,6 @@ static inline void __init check_timer(vo
 		if (timer_irq_works()) {
 			apic_printk(APIC_VERBOSE," works.\n");
 			timer_through_8259 = 1;
-			nmi_watchdog_default();
 			if (nmi_watchdog == NMI_IO_APIC) {
 				disable_8259A_irq(0);
 				setup_nmi();
Index: linux-2.6.git/arch/x86/kernel/smpboot.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/smpboot.c	2008-06-24 19:30:34.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/smpboot.c	2008-06-24 19:31:03.000000000 +0400
@@ -1140,7 +1140,6 @@ static void __init smp_cpu_index_default
 void __init native_smp_prepare_cpus(unsigned int max_cpus)
 {
 	preempt_disable();
-	nmi_watchdog_default();
 	smp_cpu_index_default();
 	current_cpu_data = boot_cpu_data;
 	cpu_callin_map = cpumask_of_cpu(0);
Index: linux-2.6.git/arch/x86/kernel/nmi.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/nmi.c	2008-06-24 19:31:01.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/nmi.c	2008-06-24 19:32:09.000000000 +0400
@@ -49,7 +49,7 @@ static cpumask_t backtrace_mask = CPU_MA
 atomic_t nmi_active = ATOMIC_INIT(0);		/* oprofile uses this */
 EXPORT_SYMBOL(nmi_active);
 
-unsigned int nmi_watchdog = NMI_DEFAULT;
+unsigned int nmi_watchdog = NMI_NONE;
 EXPORT_SYMBOL(nmi_watchdog);
 
 static int panic_on_timeout;
@@ -89,14 +89,6 @@ static inline unsigned int get_timer_irq
 #endif
 }
 
-/* Run after command line and cpu_init init, but before all other checks */
-void nmi_watchdog_default(void)
-{
-	if (nmi_watchdog != NMI_DEFAULT)
-		return;
-	nmi_watchdog = NMI_NONE;
-}
-
 #ifdef CONFIG_SMP
 /*
  * The performance counters used by NMI_LOCAL_APIC don't trigger when
@@ -124,7 +116,7 @@ int __init check_nmi_watchdog(void)
 	unsigned int *prev_nmi_count;
 	int cpu;
 
-	if (nmi_watchdog == NMI_NONE || nmi_watchdog == NMI_DISABLED)
+	if (nmi_watchdog == NMI_NONE)
 		return 0;
 
 	if (!atomic_read(&nmi_active))
@@ -481,24 +473,12 @@ int proc_nmi_enabled(struct ctl_table *t
 	if (!!old_state == !!nmi_watchdog_enabled)
 		return 0;
 
-	if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_DISABLED) {
+	if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_NONE) {
 		printk(KERN_WARNING
 			"NMI watchdog is permanently disabled\n");
 		return -EIO;
 	}
 
-	/* if nmi_watchdog is not set yet, then set it */
-	nmi_watchdog_default();
-
-#ifdef CONFIG_X86_32
-	if (nmi_watchdog == NMI_NONE) {
-		if (lapic_watchdog_ok())
-			nmi_watchdog = NMI_LOCAL_APIC;
-		else
-			nmi_watchdog = NMI_IO_APIC;
-	}
-#endif
-
 	if (nmi_watchdog == NMI_LOCAL_APIC) {
 		if (nmi_watchdog_enabled)
 			enable_lapic_nmi_watchdog();

-- 

[patch 5/5] x86: nmi_watchdog - introduce nmi_watchdog_active() helper

[Cyrill Gorcunov]

[-- Attachment #1: nmi-watchdog-active --]
[-- Type: text/plain, Size: 2325 bytes --]

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Index: linux-2.6.git/include/asm-x86/nmi.h
====================================================================
--- linux-2.6.git.orig/include/asm-x86/nmi.h	2008-06-24 19:32:44.000000000 +0400
+++ linux-2.6.git/include/asm-x86/nmi.h	2008-06-24 19:45:13.000000000 +0400
@@ -56,6 +56,19 @@ static inline void localise_nmi_watchdog
 	if (nmi_watchdog == NMI_IO_APIC)
 		nmi_watchdog = NMI_LOCAL_APIC;
 }
+
+/* check if nmi_watchdog is active (ie was specified at boot) */
+static inline int nmi_watchdog_active(void)
+{
+	/*
+	 * actually it should be:
+	 * 	return (nmi_watchdog == NMI_LOCAL_APIC ||
+	 * 		nmi_watchdog == NMI_IO_APIC)
+	 * but since they are power of two we could use a
+	 * cheaper way --cvg
+	 */
+	return nmi_watchdog & 0x3;
+}
 #endif
 
 void lapic_watchdog_stop(void);
Index: linux-2.6.git/arch/x86/kernel/nmi.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/nmi.c	2008-06-24 19:32:09.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/nmi.c	2008-06-24 19:34:16.000000000 +0400
@@ -116,10 +116,7 @@ int __init check_nmi_watchdog(void)
 	unsigned int *prev_nmi_count;
 	int cpu;
 
-	if (nmi_watchdog == NMI_NONE)
-		return 0;
-
-	if (!atomic_read(&nmi_active))
+	if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
 		return 0;
 
 	prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
@@ -316,8 +313,7 @@ void setup_apic_nmi_watchdog(void *unuse
 void stop_apic_nmi_watchdog(void *unused)
 {
 	/* only support LOCAL and IO APICs for now */
-	if (nmi_watchdog != NMI_LOCAL_APIC &&
-	    nmi_watchdog != NMI_IO_APIC)
+	if (!nmi_watchdog_active())
 		return;
 	if (__get_cpu_var(wd_enabled) == 0)
 		return;
@@ -347,8 +343,7 @@ static DEFINE_PER_CPU(int, nmi_touch);
 
 void touch_nmi_watchdog(void)
 {
-	if (nmi_watchdog == NMI_LOCAL_APIC ||
-		nmi_watchdog == NMI_IO_APIC) {
+	if (nmi_watchdog_active()) {
 		unsigned cpu;
 
 		/*
@@ -473,7 +468,7 @@ int proc_nmi_enabled(struct ctl_table *t
 	if (!!old_state == !!nmi_watchdog_enabled)
 		return 0;
 
-	if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_NONE) {
+	if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
 		printk(KERN_WARNING
 			"NMI watchdog is permanently disabled\n");
 		return -EIO;

--