X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=arch%2Fx86%2Fkernel%2Fcpu%2Fmcheck%2Fmce.c;h=707165dbc20343310147dcd483605b7bfde456f0;hb=9a90e09854a3c7cc603ab8fc9163f77bb1f66cfa;hp=a8aacd4b513c4ac1c8eaeb712806b3fcc208eaee;hpb=5c0e9f28da84c68ce0ae68b7a75faaf862e156e2;p=safe%2Fjmp%2Flinux-2.6

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a8aacd4..707165d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -26,6 +26,7 @@
 #include <linux/sched.h>
 #include <linux/sysfs.h>
 #include <linux/types.h>
+#include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/poll.h>
@@ -46,6 +47,13 @@
 
 #include "mce-internal.h"
 
+static DEFINE_MUTEX(mce_read_mutex);
+
+#define rcu_dereference_check_mce(p) \
+	rcu_dereference_check((p), \
+			      rcu_read_lock_sched_held() || \
+			      lockdep_is_held(&mce_read_mutex))
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/mce.h>
 
@@ -158,7 +166,7 @@ void mce_log(struct mce *mce)
 	mce->finished = 0;
 	wmb();
 	for (;;) {
-		entry = rcu_dereference(mcelog.next);
+		entry = rcu_dereference_check_mce(mcelog.next);
 		for (;;) {
 			/*
 			 * When the buffer fills up discard new entries.
@@ -256,7 +264,7 @@ static void wait_for_panic(void)
 
 static void mce_panic(char *msg, struct mce *final, char *exp)
 {
-	int i;
+	int i, apei_err = 0;
 
 	if (!fake_panic) {
 		/*
@@ -279,8 +287,11 @@ static void mce_panic(char *msg, struct mce *final, char *exp)
 		struct mce *m = &mcelog.entry[i];
 		if (!(m->status & MCI_STATUS_VAL))
 			continue;
-		if (!(m->status & MCI_STATUS_UC))
+		if (!(m->status & MCI_STATUS_UC)) {
 			print_mce(m);
+			if (!apei_err)
+				apei_err = apei_write_mce(m);
+		}
 	}
 	/* Now print uncorrected but with the final one last */
 	for (i = 0; i < MCE_LOG_LEN; i++) {
@@ -289,11 +300,17 @@ static void mce_panic(char *msg, struct mce *final, char *exp)
 			continue;
 		if (!(m->status & MCI_STATUS_UC))
 			continue;
-		if (!final || memcmp(m, final, sizeof(struct mce)))
+		if (!final || memcmp(m, final, sizeof(struct mce))) {
 			print_mce(m);
+			if (!apei_err)
+				apei_err = apei_write_mce(m);
+		}
 	}
-	if (final)
+	if (final) {
 		print_mce(final);
+		if (!apei_err)
+			apei_err = apei_write_mce(final);
+	}
 	if (cpu_missing)
 		printk(KERN_EMERG "Some CPUs didn't answer in synchronization\n");
 	print_mce_tail();
@@ -531,7 +548,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 	struct mce m;
 	int i;
 
-	__get_cpu_var(mce_poll_count)++;
+	percpu_inc(mce_poll_count);
 
 	mce_setup(&m);
 
@@ -926,7 +943,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 
 	atomic_inc(&mce_entry);
 
-	__get_cpu_var(mce_exception_count)++;
+	percpu_inc(mce_exception_count);
 
 	if (notify_die(DIE_NMI, "machine check", regs, error_code,
 			   18, SIGKILL) == NOTIFY_STOP)
@@ -1485,7 +1502,42 @@ static void collect_tscs(void *data)
 	rdtscll(cpu_tsc[smp_processor_id()]);
 }
 
-static DEFINE_MUTEX(mce_read_mutex);
+static int mce_apei_read_done;
+
+/* Collect MCE record of previous boot in persistent storage via APEI ERST. */
+static int __mce_read_apei(char __user **ubuf, size_t usize)
+{
+	int rc;
+	u64 record_id;
+	struct mce m;
+
+	if (usize < sizeof(struct mce))
+		return -EINVAL;
+
+	rc = apei_read_mce(&m, &record_id);
+	/* Error or no more MCE record */
+	if (rc <= 0) {
+		mce_apei_read_done = 1;
+		return rc;
+	}
+	rc = -EFAULT;
+	if (copy_to_user(*ubuf, &m, sizeof(struct mce)))
+		return rc;
+	/*
+	 * In fact, we should have cleared the record after that has
+	 * been flushed to the disk or sent to network in
+	 * /sbin/mcelog, but we have no interface to support that now,
+	 * so just clear it to avoid duplication.
+	 */
+	rc = apei_clear_mce(record_id);
+	if (rc) {
+		mce_apei_read_done = 1;
+		return rc;
+	}
+	*ubuf += sizeof(struct mce);
+
+	return 0;
+}
 
 static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
 			loff_t *off)
@@ -1500,16 +1552,20 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
 		return -ENOMEM;
 
 	mutex_lock(&mce_read_mutex);
-	next = rcu_dereference(mcelog.next);
 
-	/* Only supports full reads right now */
-	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
-		mutex_unlock(&mce_read_mutex);
-		kfree(cpu_tsc);
-
-		return -EINVAL;
+	if (!mce_apei_read_done) {
+		err = __mce_read_apei(&buf, usize);
+		if (err || buf != ubuf)
+			goto out;
 	}
 
+	next = rcu_dereference_check_mce(mcelog.next);
+
+	/* Only supports full reads right now */
+	err = -EINVAL;
+	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce))
+		goto out;
+
 	err = 0;
 	prev = 0;
 	do {
@@ -1556,16 +1612,23 @@ timeout:
 			memset(&mcelog.entry[i], 0, sizeof(struct mce));
 		}
 	}
+
+	if (err)
+		err = -EFAULT;
+
+out:
 	mutex_unlock(&mce_read_mutex);
 	kfree(cpu_tsc);
 
-	return err ? -EFAULT : buf - ubuf;
+	return err ? err : buf - ubuf;
 }
 
 static unsigned int mce_poll(struct file *file, poll_table *wait)
 {
 	poll_wait(file, &mce_wait, wait);
-	if (rcu_dereference(mcelog.next))
+	if (rcu_dereference_check_mce(mcelog.next))
+		return POLLIN | POLLRDNORM;
+	if (!mce_apei_read_done && apei_check_mce())
 		return POLLIN | POLLRDNORM;
 	return 0;
 }
@@ -2044,6 +2107,7 @@ static __init void mce_init_banks(void)
 		struct mce_bank *b = &mce_banks[i];
 		struct sysdev_attribute *a = &b->attr;
 
+		sysfs_attr_init(&a->attr);
 		a->attr.name	= b->attrname;
 		snprintf(b->attrname, ATTR_LEN, "bank%d", i);