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-rw-r--r--arch/x86_64/kernel/entry.S6
-rw-r--r--arch/x86_64/kernel/mce.c105
-rw-r--r--arch/x86_64/kernel/signal.c7
-rw-r--r--include/asm-x86_64/mce.h2
-rw-r--r--include/asm-x86_64/thread_info.h2
5 files changed, 82 insertions, 40 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index a67f87bf401..830cfc6ee8c 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -282,7 +282,7 @@ sysret_careful:
sysret_signal:
TRACE_IRQS_ON
sti
- testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
+ testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
jz 1f
/* Really a signal */
@@ -375,7 +375,7 @@ int_very_careful:
jmp int_restore_rest
int_signal:
- testl $(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_SINGLESTEP),%edx
+ testl $(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
jz 1f
movq %rsp,%rdi # &ptregs -> arg1
xorl %esi,%esi # oldset -> arg2
@@ -599,7 +599,7 @@ retint_careful:
jmp retint_check
retint_signal:
- testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
+ testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
jz retint_swapgs
TRACE_IRQS_ON
sti
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, &notify_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, &notify_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,
};
diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 290f5d8037c..4886afcd628 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -26,6 +26,7 @@
#include <asm/i387.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
+#include <asm/mce.h>
/* #define DEBUG_SIG 1 */
@@ -472,6 +473,12 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
clear_thread_flag(TIF_SINGLESTEP);
}
+#ifdef CONFIG_X86_MCE
+ /* notify userspace of pending MCEs */
+ if (thread_info_flags & _TIF_MCE_NOTIFY)
+ mce_notify_user();
+#endif /* CONFIG_X86_MCE */
+
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
do_signal(regs);
diff --git a/include/asm-x86_64/mce.h b/include/asm-x86_64/mce.h
index 177e92b4019..556be5563e3 100644
--- a/include/asm-x86_64/mce.h
+++ b/include/asm-x86_64/mce.h
@@ -105,6 +105,8 @@ extern atomic_t mce_entry;
extern void do_machine_check(struct pt_regs *, long);
+extern int mce_notify_user(void);
+
#endif
#endif
diff --git a/include/asm-x86_64/thread_info.h b/include/asm-x86_64/thread_info.h
index 10bb5a8ed68..33c72ef15a0 100644
--- a/include/asm-x86_64/thread_info.h
+++ b/include/asm-x86_64/thread_info.h
@@ -115,6 +115,7 @@ static inline struct thread_info *stack_thread_info(void)
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal */
+#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
/* 16 free */
#define TIF_IA32 17 /* 32bit process */
#define TIF_FORK 18 /* ret_from_fork */
@@ -133,6 +134,7 @@ static inline struct thread_info *stack_thread_info(void)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
+#define _TIF_MCE_NOTIFY (1<<TIF_MCE_NOTIFY)
#define _TIF_IA32 (1<<TIF_IA32)
#define _TIF_FORK (1<<TIF_FORK)
#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-22 08:23:12 +0000