[PATCH] x86-64: Allow to run a program when a machine check event is detected
When a machine check event is detected (including a AMD RevF threshold
overflow event) allow to run a "trigger" program. This allows user space
to react to such events sooner.
The trigger is configured using a new trigger entry in the
machinecheck sysfs interface. It is currently shared between
all CPUs.
I also fixed the AMD threshold handler to run the machine
check polling code immediately to actually log any events
that might have caused the threshold interrupt.
Also added some documentation for the mce sysfs interface.
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index bdb54a2..8011a8e 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -19,6 +19,7 @@
#include <linux/cpu.h>
#include <linux/percpu.h>
#include <linux/ctype.h>
+#include <linux/kmod.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/mce.h>
@@ -42,6 +43,10 @@
static int notify_user;
static int rip_msr;
static int mce_bootlog = 1;
+static atomic_t mce_events;
+
+static char trigger[128];
+static char *trigger_argv[2] = { trigger, NULL };
/*
* Lockless MCE logging infrastructure.
@@ -57,6 +62,7 @@
void mce_log(struct mce *mce)
{
unsigned next, entry;
+ atomic_inc(&mce_events);
mce->finished = 0;
wmb();
for (;;) {
@@ -161,6 +167,17 @@
}
}
+static void do_mce_trigger(void)
+{
+ static atomic_t mce_logged;
+ int events = atomic_read(&mce_events);
+ if (events != atomic_read(&mce_logged) && trigger[0]) {
+ /* Small race window, but should be harmless. */
+ atomic_set(&mce_logged, events);
+ call_usermodehelper(trigger, trigger_argv, NULL, -1);
+ }
+}
+
/*
* The actual machine check handler
*/
@@ -234,8 +251,12 @@
}
/* Never do anything final in the polling timer */
- if (!regs)
+ if (!regs) {
+ /* Normal interrupt context here. Call trigger for any new
+ events. */
+ do_mce_trigger();
goto out;
+ }
/* If we didn't find an uncorrectable error, pick
the last one (shouldn't happen, just being safe). */
@@ -606,17 +627,42 @@
} \
static SYSDEV_ATTR(name, 0644, show_ ## name, set_ ## name);
+/* TBD should generate these dynamically based on number of available banks */
ACCESSOR(bank0ctl,bank[0],mce_restart())
ACCESSOR(bank1ctl,bank[1],mce_restart())
ACCESSOR(bank2ctl,bank[2],mce_restart())
ACCESSOR(bank3ctl,bank[3],mce_restart())
ACCESSOR(bank4ctl,bank[4],mce_restart())
ACCESSOR(bank5ctl,bank[5],mce_restart())
-static struct sysdev_attribute * bank_attributes[NR_BANKS] = {
- &attr_bank0ctl, &attr_bank1ctl, &attr_bank2ctl,
- &attr_bank3ctl, &attr_bank4ctl, &attr_bank5ctl};
+
+static ssize_t show_trigger(struct sys_device *s, char *buf)
+{
+ strcpy(buf, trigger);
+ strcat(buf, "\n");
+ return strlen(trigger) + 1;
+}
+
+static ssize_t set_trigger(struct sys_device *s,const char *buf,size_t siz)
+{
+ char *p;
+ int len;
+ strncpy(trigger, buf, sizeof(trigger));
+ trigger[sizeof(trigger)-1] = 0;
+ len = strlen(trigger);
+ p = strchr(trigger, '\n');
+ if (*p) *p = 0;
+ return len;
+}
+
+static SYSDEV_ATTR(trigger, 0644, show_trigger, set_trigger);
ACCESSOR(tolerant,tolerant,)
ACCESSOR(check_interval,check_interval,mce_restart())
+static struct sysdev_attribute *mce_attributes[] = {
+ &attr_bank0ctl, &attr_bank1ctl, &attr_bank2ctl,
+ &attr_bank3ctl, &attr_bank4ctl, &attr_bank5ctl,
+ &attr_tolerant, &attr_check_interval, &attr_trigger,
+ NULL
+};
/* Per cpu sysdev init. All of the cpus still share the same ctl bank */
static __cpuinit int mce_create_device(unsigned int cpu)
@@ -632,11 +678,9 @@
err = sysdev_register(&per_cpu(device_mce,cpu));
if (!err) {
- for (i = 0; i < banks; i++)
+ for (i = 0; mce_attributes[i]; i++)
sysdev_create_file(&per_cpu(device_mce,cpu),
- bank_attributes[i]);
- sysdev_create_file(&per_cpu(device_mce,cpu), &attr_tolerant);
- sysdev_create_file(&per_cpu(device_mce,cpu), &attr_check_interval);
+ mce_attributes[i]);
}
return err;
}
@@ -645,11 +689,9 @@
{
int i;
- for (i = 0; i < banks; i++)
+ for (i = 0; mce_attributes[i]; i++)
sysdev_remove_file(&per_cpu(device_mce,cpu),
- bank_attributes[i]);
- sysdev_remove_file(&per_cpu(device_mce,cpu), &attr_tolerant);
- sysdev_remove_file(&per_cpu(device_mce,cpu), &attr_check_interval);
+ mce_attributes[i]);
sysdev_unregister(&per_cpu(device_mce,cpu));
memset(&per_cpu(device_mce, cpu).kobj, 0, sizeof(struct kobject));
}
