diff options
Diffstat (limited to 'arch/x86_64/kernel/mce.c')
| -rw-r--r-- | arch/x86_64/kernel/mce.c | 105 |
1 files changed, 68 insertions, 37 deletions
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c index 77fee481be4..968613572b9 100644 --- a/arch/x86_64/kernel/mce.c +++ b/arch/x86_64/kernel/mce.c @@ -18,6 +18,8 @@ #include <linux/capability.h> #include <linux/cpu.h> #include <linux/percpu.h> +#include <linux/poll.h> +#include <linux/thread_info.h> #include <linux/ctype.h> #include <linux/kmod.h> #include <linux/kdebug.h> @@ -26,6 +28,7 @@ #include <asm/mce.h> #include <asm/uaccess.h> #include <asm/smp.h> +#include <asm/idle.h> #define MISC_MCELOG_MINOR 227 #define NR_BANKS 6 @@ -39,8 +42,7 @@ static int mce_dont_init; static int tolerant = 1; static int banks; static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL }; -static unsigned long console_logged; -static int notify_user; +static unsigned long notify_user; static int rip_msr; static int mce_bootlog = 1; static atomic_t mce_events; @@ -48,6 +50,8 @@ static atomic_t mce_events; static char trigger[128]; static char *trigger_argv[2] = { trigger, NULL }; +static DECLARE_WAIT_QUEUE_HEAD(mce_wait); + /* * Lockless MCE logging infrastructure. * This avoids deadlocks on printk locks without having to break locks. Also @@ -94,8 +98,7 @@ void mce_log(struct mce *mce) mcelog.entry[entry].finished = 1; wmb(); - if (!test_and_set_bit(0, &console_logged)) - notify_user = 1; + set_bit(0, ¬ify_user); } static void print_mce(struct mce *m) @@ -128,6 +131,10 @@ static void print_mce(struct mce *m) static void mce_panic(char *msg, struct mce *backup, unsigned long start) { int i; + + if (tolerant >= 3) + return; + oops_begin(); for (i = 0; i < MCE_LOG_LEN; i++) { unsigned long tsc = mcelog.entry[i].tsc; @@ -139,10 +146,7 @@ static void mce_panic(char *msg, struct mce *backup, unsigned long start) } if (backup) print_mce(backup); - if (tolerant >= 3) - printk("Fake panic: %s\n", msg); - else - panic(msg); + panic(msg); } static int mce_available(struct cpuinfo_x86 *c) @@ -167,17 +171,6 @@ static inline void mce_get_rip(struct mce *m, struct pt_regs *regs) } } -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, UMH_NO_WAIT); - } -} - /* * The actual machine check handler */ @@ -251,12 +244,8 @@ void do_machine_check(struct pt_regs * regs, long error_code) } /* Never do anything final in the polling timer */ - if (!regs) { - /* Normal interrupt context here. Call trigger for any new - events. */ - do_mce_trigger(); + if (!regs) goto out; - } /* If we didn't find an uncorrectable error, pick the last one (shouldn't happen, just being safe). */ @@ -288,6 +277,9 @@ void do_machine_check(struct pt_regs * regs, long error_code) do_exit(SIGBUS); } + /* notify userspace ASAP */ + set_thread_flag(TIF_MCE_NOTIFY); + out: /* Last thing done in the machine check exception to clear state. */ wrmsrl(MSR_IA32_MCG_STATUS, 0); @@ -344,37 +336,67 @@ static void mcheck_timer(struct work_struct *work) on_each_cpu(mcheck_check_cpu, NULL, 1, 1); /* - * It's ok to read stale data here for notify_user and - * console_logged as we'll simply get the updated versions - * on the next mcheck_timer execution and atomic operations - * on console_logged act as synchronization for notify_user - * writes. + * Alert userspace if needed. If we logged an MCE, reduce the + * polling interval, otherwise increase the polling interval. */ - if (notify_user && console_logged) { + if (mce_notify_user()) { + next_interval = max(next_interval/2, HZ/100); + } else { + next_interval = min(next_interval*2, check_interval*HZ); + } + + schedule_delayed_work(&mcheck_work, next_interval); +} + +/* + * This is only called from process context. This is where we do + * anything we need to alert userspace about new MCEs. This is called + * directly from the poller and also from entry.S and idle, thanks to + * TIF_MCE_NOTIFY. + */ +int mce_notify_user(void) +{ + clear_thread_flag(TIF_MCE_NOTIFY); + if (test_and_clear_bit(0, ¬ify_user)) { static unsigned long last_print; unsigned long now = jiffies; - /* if we logged an MCE, reduce the polling interval */ - next_interval = max(next_interval/2, HZ/100); - notify_user = 0; - clear_bit(0, &console_logged); + wake_up_interruptible(&mce_wait); + if (trigger[0]) + call_usermodehelper(trigger, trigger_argv, NULL, + UMH_NO_WAIT); + if (time_after_eq(now, last_print + (check_interval*HZ))) { last_print = now; printk(KERN_INFO "Machine check events logged\n"); } - } else { - next_interval = min(next_interval*2, check_interval*HZ); + + return 1; } + return 0; +} - schedule_delayed_work(&mcheck_work, next_interval); +/* see if the idle task needs to notify userspace */ +static int +mce_idle_callback(struct notifier_block *nfb, unsigned long action, void *junk) +{ + /* IDLE_END should be safe - interrupts are back on */ + if (action == IDLE_END && test_thread_flag(TIF_MCE_NOTIFY)) + mce_notify_user(); + + return NOTIFY_OK; } +static struct notifier_block mce_idle_notifier = { + .notifier_call = mce_idle_callback, +}; static __init int periodic_mcheck_init(void) { next_interval = check_interval * HZ; if (next_interval) schedule_delayed_work(&mcheck_work, next_interval); + idle_notifier_register(&mce_idle_notifier); return 0; } __initcall(periodic_mcheck_init); @@ -566,6 +588,14 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff return err ? -EFAULT : buf - ubuf; } +static unsigned int mce_poll(struct file *file, poll_table *wait) +{ + poll_wait(file, &mce_wait, wait); + if (rcu_dereference(mcelog.next)) + return POLLIN | POLLRDNORM; + return 0; +} + static int mce_ioctl(struct inode *i, struct file *f,unsigned int cmd, unsigned long arg) { int __user *p = (int __user *)arg; @@ -592,6 +622,7 @@ static const struct file_operations mce_chrdev_ops = { .open = mce_open, .release = mce_release, .read = mce_read, + .poll = mce_poll, .ioctl = mce_ioctl, }; |