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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:  Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Don Zickus 2006-09-26 10:52:27 +02:00 committed by Andi Kleen
parent 2fbe7b25c8
commit 407984f1af
6 changed files with 114 additions and 0 deletions
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52
arch/i386/kernel/nmi.c
View File

@ -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);

48
arch/x86_64/kernel/nmi.c
View File

@ -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);

1
include/asm-i386/nmi.h
View File

@ -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);

1
include/asm-x86_64/nmi.h
View File

@ -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);

1
include/linux/sysctl.h
View File

@ -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 */
};

11
kernel/sysctl.c
View File

@ -76,6 +76,9 @@ extern int compat_log;
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
int nmi_watchdog_enabled;
extern int proc_nmi_enabled(struct ctl_table *, int , struct file *,
void __user *, size_t *, loff_t *);
#endif
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
@ -628,6 +631,14 @@ static ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = KERN_NMI_WATCHDOG,
.procname = "nmi_watchdog",
.data = &nmi_watchdog_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = &proc_nmi_enabled,
},
#endif
#if defined(CONFIG_X86)
{