x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise

When running under Xen as dom0, /dev/mcelog is being provided by Xen instead of the normal mcelog character device of the MCE core. Convert an error message being issued by the MCE core in this case to an informative message that Xen has registered the device. Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: Tony Luck <[email protected]> Cc: linux-edac <[email protected]> Link: http://lkml.kernel.org/r/[email protected]
jimmycarry · Jun 20, 2017 · b867059 · b867059
1 parent 6057077
commit b867059
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/arch/x86/kernel/cpu/mcheck/dev-mcelog.c b/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
@@ -415,9 +415,15 @@ static __init int dev_mcelog_init_device(void)
 	/* register character device /dev/mcelog */
 	err = misc_register(&mce_chrdev_device);
 	if (err) {
-		pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+		if (err == -EBUSY)
+			/* Xen dom0 might have registered the device already. */
+			pr_info("Unable to init device /dev/mcelog, already registered");
+		else
+			pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+
 		return err;
 	}
+
 	mce_register_decode_chain(&dev_mcelog_nb);
 	return 0;
 }

diff --git a/drivers/xen/mcelog.c b/drivers/xen/mcelog.c
@@ -408,6 +408,8 @@ static int __init xen_late_init_mcelog(void)
 	if (ret)
 		goto deregister;
 
+	pr_info("/dev/mcelog registered by Xen\n");
+
 	return 0;
 
 deregister: