1 files changed, 27 insertions, 20 deletions

diff --git a/arch/x86/kernel/cpu/mce/dev-mcelog.c b/arch/x86/kernel/cpu/mce/dev-mcelog.c
index 7c8958dee103..d089567a9ce8 100644
--- a/arch/x86/kernel/cpu/mce/dev-mcelog.c
+++ b/arch/x86/kernel/cpu/mce/dev-mcelog.c
@@ -29,11 +29,7 @@ static char *mce_helper_argv[2] = { mce_helper, NULL };
  * separate MCEs from kernel messages to avoid bogus bug reports.
  */
 
-static struct mce_log_buffer mcelog = {
-	.signature	= MCE_LOG_SIGNATURE,
-	.len		= MCE_LOG_LEN,
-	.recordlen	= sizeof(struct mce),
-};
+static struct mce_log_buffer *mcelog;
 
 static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
 
@@ -45,21 +41,21 @@ static int dev_mce_log(struct notifier_block *nb, unsigned long val,
 
 	mutex_lock(&mce_chrdev_read_mutex);
 
-	entry = mcelog.next;
+	entry = mcelog->next;
 
 	/*
 	 * When the buffer fills up discard new entries. Assume that the
 	 * earlier errors are the more interesting ones:
 	 */
-	if (entry >= MCE_LOG_LEN) {
-		set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog.flags);
+	if (entry >= mcelog->len) {
+		set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog->flags);
 		goto unlock;
 	}
 
-	mcelog.next = entry + 1;
+	mcelog->next = entry + 1;
 
-	memcpy(mcelog.entry + entry, mce, sizeof(struct mce));
-	mcelog.entry[entry].finished = 1;
+	memcpy(mcelog->entry + entry, mce, sizeof(struct mce));
+	mcelog->entry[entry].finished = 1;
 
 	/* wake processes polling /dev/mcelog */
 	wake_up_interruptible(&mce_chrdev_wait);
@@ -214,21 +210,21 @@ static ssize_t mce_chrdev_read(struct file *filp, char __user *ubuf,
 
 	/* Only supports full reads right now */
 	err = -EINVAL;
-	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce))
+	if (*off != 0 || usize < mcelog->len * sizeof(struct mce))
 		goto out;
 
-	next = mcelog.next;
+	next = mcelog->next;
 	err = 0;
 
 	for (i = 0; i < next; i++) {
-		struct mce *m = &mcelog.entry[i];
+		struct mce *m = &mcelog->entry[i];
 
 		err |= copy_to_user(buf, m, sizeof(*m));
 		buf += sizeof(*m);
 	}
 
-	memset(mcelog.entry, 0, next * sizeof(struct mce));
-	mcelog.next = 0;
+	memset(mcelog->entry, 0, next * sizeof(struct mce));
+	mcelog->next = 0;
 
 	if (err)
 		err = -EFAULT;
@@ -242,7 +238,7 @@ out:
 static __poll_t mce_chrdev_poll(struct file *file, poll_table *wait)
 {
 	poll_wait(file, &mce_chrdev_wait, wait);
-	if (READ_ONCE(mcelog.next))
+	if (READ_ONCE(mcelog->next))
 		return EPOLLIN | EPOLLRDNORM;
 	if (!mce_apei_read_done && apei_check_mce())
 		return EPOLLIN | EPOLLRDNORM;
@@ -261,13 +257,13 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd,
 	case MCE_GET_RECORD_LEN:
 		return put_user(sizeof(struct mce), p);
 	case MCE_GET_LOG_LEN:
-		return put_user(MCE_LOG_LEN, p);
+		return put_user(mcelog->len, p);
 	case MCE_GETCLEAR_FLAGS: {
 		unsigned flags;
 
 		do {
-			flags = mcelog.flags;
-		} while (cmpxchg(&mcelog.flags, flags, 0) != flags);
+			flags = mcelog->flags;
+		} while (cmpxchg(&mcelog->flags, flags, 0) != flags);
 
 		return put_user(flags, p);
 	}
@@ -339,8 +335,18 @@ static struct miscdevice mce_chrdev_device = {
 
 static __init int dev_mcelog_init_device(void)
 {
+	int mce_log_len;
 	int err;
 
+	mce_log_len = max(MCE_LOG_MIN_LEN, num_online_cpus());
+	mcelog = kzalloc(sizeof(*mcelog) + mce_log_len * sizeof(struct mce), GFP_KERNEL);
+	if (!mcelog)
+		return -ENOMEM;
+
+	strncpy(mcelog->signature, MCE_LOG_SIGNATURE, sizeof(mcelog->signature));
+	mcelog->len = mce_log_len;
+	mcelog->recordlen = sizeof(struct mce);
+
 	/* register character device /dev/mcelog */
 	err = misc_register(&mce_chrdev_device);
 	if (err) {
@@ -350,6 +356,7 @@ static __init int dev_mcelog_init_device(void)
 		else
 			pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
 
+		kfree(mcelog);
 		return err;
 	}