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Commit 4038f901 authored by Shaohua Li's avatar Shaohua Li Committed by Andi Kleen
Browse files

[PATCH] i386/x86-64: Fix NMI watchdog suspend/resume 



Making NMI suspend/resume work with SMP. We use CPU hotplug to offline
APs in SMP suspend/resume. Only BSP executes sysdev's .suspend/.resume
method. APs should follow CPU hotplug code path.

And:

+From: Don Zickus <dzickus@redhat.com>

Makes the start/stop paths of nmi watchdog more robust to handle the
suspend/resume cases more gracefully.

AK: I merged the two patches together

Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent c41c5cd3

arch/i386/kernel/nmi.c

+26 −7
Original line number Diff line number Diff line
@@ -63,7 +63,6 @@ struct nmi_watchdog_ctlblk { 
static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk);



/* local prototypes */

static void stop_apic_nmi_watchdog(void *unused);

static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);



extern void show_registers(struct pt_regs *regs);
@@ -341,15 +340,20 @@ static int nmi_pm_active; /* nmi_active before suspend */ 


static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)

{

	/* only CPU0 goes here, other CPUs should be offline */

	nmi_pm_active = atomic_read(&nmi_active);

	disable_lapic_nmi_watchdog();

	stop_apic_nmi_watchdog(NULL);

	BUG_ON(atomic_read(&nmi_active) != 0);

	return 0;

}



static int lapic_nmi_resume(struct sys_device *dev)

{

	if (nmi_pm_active > 0)

		enable_lapic_nmi_watchdog();

	/* only CPU0 goes here, other CPUs should be offline */

	if (nmi_pm_active > 0) {

		setup_apic_nmi_watchdog(NULL);

		touch_nmi_watchdog();

	}

	return 0;

}
@@ -626,11 +630,21 @@ static void stop_p4_watchdog(void) 


void setup_apic_nmi_watchdog (void *unused)

{

	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);



	/* only support LOCAL and IO APICs for now */

	if ((nmi_watchdog != NMI_LOCAL_APIC) &&

	    (nmi_watchdog != NMI_IO_APIC))

	    	return;



	if (wd->enabled == 1)

		return;



	/* cheap hack to support suspend/resume */

	/* if cpu0 is not active neither should the other cpus */

	if ((smp_processor_id() != 0) && (atomic_read(&nmi_active) <= 0))

		return;



	if (nmi_watchdog == NMI_LOCAL_APIC) {

		switch (boot_cpu_data.x86_vendor) {

		case X86_VENDOR_AMD:
@@ -663,17 +677,22 @@ void setup_apic_nmi_watchdog (void *unused) 
			return;

		}

	}

	__get_cpu_var(nmi_watchdog_ctlblk.enabled) = 1;

	wd->enabled = 1;

	atomic_inc(&nmi_active);

}



static void stop_apic_nmi_watchdog(void *unused)

void stop_apic_nmi_watchdog(void *unused)

{

	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);



	/* only support LOCAL and IO APICs for now */

	if ((nmi_watchdog != NMI_LOCAL_APIC) &&

	    (nmi_watchdog != NMI_IO_APIC))

	    	return;



	if (wd->enabled == 0)

		return;



	if (nmi_watchdog == NMI_LOCAL_APIC) {

		switch (boot_cpu_data.x86_vendor) {

		case X86_VENDOR_AMD:
@@ -697,7 +716,7 @@ static void stop_apic_nmi_watchdog(void *unused) 
			return;

		}

	}

	__get_cpu_var(nmi_watchdog_ctlblk.enabled) = 0;

	wd->enabled = 0;

	atomic_dec(&nmi_active);

}

arch/i386/kernel/smpboot.c

+2 −1
Original line number Diff line number Diff line
@@ -1376,7 +1376,8 @@ int __cpu_disable(void) 
	 */

	if (cpu == 0)

		return -EBUSY;



	if (nmi_watchdog == NMI_LOCAL_APIC)

		stop_apic_nmi_watchdog(NULL);

	clear_local_APIC();

	/* Allow any queued timer interrupts to get serviced */

	local_irq_enable();

arch/x86_64/kernel/nmi.c

+26 −7
Original line number Diff line number Diff line
@@ -63,7 +63,6 @@ struct nmi_watchdog_ctlblk { 
static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk);



/* local prototypes */

static void stop_apic_nmi_watchdog(void *unused);

static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);



/* converts an msr to an appropriate reservation bit */
@@ -337,15 +336,20 @@ static int nmi_pm_active; /* nmi_active before suspend */ 


static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)

{

	/* only CPU0 goes here, other CPUs should be offline */

	nmi_pm_active = atomic_read(&nmi_active);

	disable_lapic_nmi_watchdog();

	stop_apic_nmi_watchdog(NULL);

	BUG_ON(atomic_read(&nmi_active) != 0);

	return 0;

}



static int lapic_nmi_resume(struct sys_device *dev)

{

	if (nmi_pm_active > 0)

		enable_lapic_nmi_watchdog();

	/* only CPU0 goes here, other CPUs should be offline */

	if (nmi_pm_active > 0) {

		setup_apic_nmi_watchdog(NULL);

		touch_nmi_watchdog();

	}

	return 0;

}
@@ -561,11 +565,21 @@ static void stop_p4_watchdog(void) 


void setup_apic_nmi_watchdog(void *unused)

{

	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);



	/* only support LOCAL and IO APICs for now */

	if ((nmi_watchdog != NMI_LOCAL_APIC) &&

	    (nmi_watchdog != NMI_IO_APIC))

	    	return;



	if (wd->enabled == 1)

		return;



	/* cheap hack to support suspend/resume */

	/* if cpu0 is not active neither should the other cpus */

	if ((smp_processor_id() != 0) && (atomic_read(&nmi_active) <= 0))

		return;



	if (nmi_watchdog == NMI_LOCAL_APIC) {

		switch (boot_cpu_data.x86_vendor) {

		case X86_VENDOR_AMD:
@@ -582,17 +596,22 @@ void setup_apic_nmi_watchdog(void *unused) 
			return;

		}

	}

	__get_cpu_var(nmi_watchdog_ctlblk.enabled) = 1;

	wd->enabled = 1;

	atomic_inc(&nmi_active);

}



static void stop_apic_nmi_watchdog(void *unused)

void stop_apic_nmi_watchdog(void *unused)

{

	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);



	/* only support LOCAL and IO APICs for now */

	if ((nmi_watchdog != NMI_LOCAL_APIC) &&

	    (nmi_watchdog != NMI_IO_APIC))

	    	return;



	if (wd->enabled == 0)

		return;



	if (nmi_watchdog == NMI_LOCAL_APIC) {

		switch (boot_cpu_data.x86_vendor) {

		case X86_VENDOR_AMD:
@@ -607,7 +626,7 @@ static void stop_apic_nmi_watchdog(void *unused) 
			return;

		}

	}

	__get_cpu_var(nmi_watchdog_ctlblk.enabled) = 0;

	wd->enabled = 0;

	atomic_dec(&nmi_active);

}

arch/x86_64/kernel/smpboot.c

+2 −0
Original line number Diff line number Diff line
@@ -1233,6 +1233,8 @@ int __cpu_disable(void) 
	if (cpu == 0)

		return -EBUSY;



	if (nmi_watchdog == NMI_LOCAL_APIC)

		stop_apic_nmi_watchdog(NULL);

	clear_local_APIC();



	/*

include/asm-i386/nmi.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ extern int reserve_evntsel_nmi(unsigned int); 
extern void release_evntsel_nmi(unsigned int);



extern void setup_apic_nmi_watchdog (void *);

extern void stop_apic_nmi_watchdog (void *);

extern void disable_timer_nmi_watchdog(void);

extern void enable_timer_nmi_watchdog(void);

extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);