[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>
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index acd3fde..28065d0 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -846,6 +846,58 @@
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);
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 9d175dc..3a17411 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -750,6 +750,54 @@
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);
diff --git a/include/asm-i386/nmi.h b/include/asm-i386/nmi.h
index 34d6bf0..13b5d83 100644
--- a/include/asm-i386/nmi.h
+++ b/include/asm-i386/nmi.h
@@ -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);
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index 8818c39..2c23b0d 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -43,6 +43,7 @@
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);
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 736ed91..ecb79ba 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -150,6 +150,7 @@
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 */
};
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 83f1683..040de6b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -76,6 +76,9 @@
#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 @@
.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)
{
