qubes-linux-kernel/0003-mce-hide-EBUSY-initialization-error-on-Xen.patch
2018-11-11 18:40:18 +01:00

71 lines
2.2 KiB
Diff

From 2d71f4d315dfcaaa9e4c1e3693e391f9d2b0a8b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
<marmarek@invisiblethingslab.com>
Date: Tue, 5 Jan 2016 02:44:04 +0100
Subject: [PATCH] mce: hide EBUSY initialization error on Xen
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In case of Xen, the device is already registered by xen mcelog (in
xen_late_init_mcelog), so fail here is expected. Note that
mcheck_init_device call is still expected to initialize mce_device. Comment
from threshold_init_device explaining the situation:
/*
* there are 3 funcs which need to be _initcalled in a logic sequence:
* 1. xen_late_init_mcelog
* 2. mcheck_init_device
* 3. threshold_init_device
*
* xen_late_init_mcelog must register xen_mce_chrdev_device before
* native mce_chrdev_device registration if running under xen platform;
*
* mcheck_init_device should be inited before threshold_init_device to
* initialize mce_device, otherwise a NULL ptr dereference will cause panic.
*
* so we use following _initcalls
* 1. device_initcall(xen_late_init_mcelog);
* 2. device_initcall_sync(mcheck_init_device);
* 3. late_initcall(threshold_init_device);
*
* when running under xen, the initcall order is 1,2,3;
* on baremetal, we skip 1 and we do only 2 and 3.
*/
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
arch/x86/kernel/cpu/mcheck/mce.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 953b3ce92dcc..e0bb9b52d8d1 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -52,6 +52,10 @@
#include <asm/msr.h>
#include <asm/reboot.h>
+#ifdef CONFIG_XEN_MCE_LOG
+#include <xen/xen.h>
+#endif
+
#include "mce-internal.h"
static DEFINE_MUTEX(mce_log_mutex);
@@ -2395,6 +2399,11 @@ static __init int mcheck_init_device(void)
free_cpumask_var(mce_device_initialized);
err_out:
+#ifdef CONFIG_XEN_MCE_LOG
+ /* in case of Xen, the character device was already registered, so do not
+ * treat this as an error */
+ if (!xen_initial_domain() || err != -EBUSY)
+#endif
pr_err("Unable to init MCE device (rc: %d)\n", err);
return err;
--
2.17.1