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Commit 407984f1 authored by Don Zickus's avatar Don Zickus Committed by Andi Kleen
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[PATCH] x86: Add abilty to enable/disable nmi watchdog with sysctl 



Adds a new /proc/sys/kernel/nmi call that will enable/disable the nmi
watchdog.

Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent 2fbe7b25

arch/i386/kernel/nmi.c

+52 −0
Original line number Diff line number Diff line
@@ -846,6 +846,58 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) 
	return 0;

}



/*

 * proc handler for /proc/sys/kernel/nmi_watchdog

 */

int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,

			void __user *buffer, size_t *length, loff_t *ppos)

{

	int old_state;



	nmi_watchdog_enabled = (atomic_read(&nmi_active) > 0) ? 1 : 0;

	old_state = nmi_watchdog_enabled;

	proc_dointvec(table, write, file, buffer, length, ppos);

	if (!!old_state == !!nmi_watchdog_enabled)

		return 0;



	if (atomic_read(&nmi_active) < 0) {

		printk(KERN_WARNING "NMI watchdog is permanently disabled\n");

		return -EINVAL;

	}



	if (nmi_watchdog == NMI_DEFAULT) {

		if (nmi_known_cpu() > 0)

			nmi_watchdog = NMI_LOCAL_APIC;

		else

			nmi_watchdog = NMI_IO_APIC;

	}



	if (nmi_watchdog == NMI_LOCAL_APIC)

	{

		if (nmi_watchdog_enabled)

			enable_lapic_nmi_watchdog();

		else

			disable_lapic_nmi_watchdog();

	} else if (nmi_watchdog == NMI_IO_APIC) {

		/* FIXME

		 * for some reason these functions don't work

		 */

		printk("Can not enable/disable NMI on IO APIC\n");

		return -EINVAL;

#if 0

		if (nmi_watchdog_enabled)

			enable_timer_nmi_watchdog();

		else

			disable_timer_nmi_watchdog();

#endif

	} else {

		printk( KERN_WARNING

			"NMI watchdog doesn't know what hardware to touch\n");

		return -EIO;

	}

	return 0;

}



#endif



EXPORT_SYMBOL(nmi_active);

arch/x86_64/kernel/nmi.c

+48 −0
Original line number Diff line number Diff line
@@ -750,6 +750,54 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) 
	return 0;

}



/*

 * proc handler for /proc/sys/kernel/nmi

 */

int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,

			void __user *buffer, size_t *length, loff_t *ppos)

{

	int old_state;



	nmi_watchdog_enabled = (atomic_read(&nmi_active) > 0) ? 1 : 0;

	old_state = nmi_watchdog_enabled;

	proc_dointvec(table, write, file, buffer, length, ppos);

	if (!!old_state == !!nmi_watchdog_enabled)

		return 0;



	if (atomic_read(&nmi_active) < 0) {

		printk( KERN_WARNING "NMI watchdog is permanently disabled\n");

		return -EINVAL;

	}



	/* if nmi_watchdog is not set yet, then set it */

	nmi_watchdog_default();



	if (nmi_watchdog == NMI_LOCAL_APIC)

	{

		if (nmi_watchdog_enabled)

			enable_lapic_nmi_watchdog();

		else

			disable_lapic_nmi_watchdog();

	} else if (nmi_watchdog == NMI_IO_APIC) {

		/* FIXME

		 * for some reason these functions don't work

		 */

		printk("Can not enable/disable NMI on IO APIC\n");

		return -EIO;

#if 0

		if (nmi_watchdog_enabled)

			enable_timer_nmi_watchdog();

		else

			disable_timer_nmi_watchdog();

#endif

	} else {

		printk(KERN_WARNING

			"NMI watchdog doesn't know what hardware to touch\n");

		return -EIO;

	}

	return 0;

}



#endif



EXPORT_SYMBOL(nmi_active);

include/asm-i386/nmi.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 */

int do_nmi_callback(struct pt_regs *regs, int cpu);



extern int nmi_watchdog_enabled;

extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);

extern int avail_to_resrv_perfctr_nmi(unsigned int);

extern int reserve_perfctr_nmi(unsigned int);

include/asm-x86_64/nmi.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ extern void die_nmi(char *str, struct pt_regs *regs); 


extern int panic_on_timeout;

extern int unknown_nmi_panic;

extern int nmi_watchdog_enabled;



extern int check_nmi_watchdog(void);

extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);

include/linux/sysctl.h

+1 −0
Original line number Diff line number Diff line
@@ -150,6 +150,7 @@ enum 
	KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */

	KERN_COMPAT_LOG=73,	/* int: print compat layer  messages */

	KERN_MAX_LOCK_DEPTH=74,

	KERN_NMI_WATCHDOG=75, /* int: enable/disable nmi watchdog */

};