Borislav,
How about skipping the misc_register() steps and keep silence if
you know it is running as Dom0 ? as it is easy to know.
Reviewed-by: Ethan Zhao <ethan.z...@oracle.com>
On Wed, Jun 21, 2017 at 5:16 AM, Borislav Petkov <b...@alien8.de> wrote:
> From: Juergen Gross <jgr...@suse.com>
>
> 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 <jgr...@suse.com>
> Cc: Tony Luck <tony.l...@intel.com>
> Cc: linux-edac <linux-e...@vger.kernel.org>
> Cc: x86-ml <x...@kernel.org>
> Cc: xen-de...@lists.xenproject.org
> Link: http://lkml.kernel.org/r/20170614084059.19294-1-jgr...@suse.com
> [ Massage a bit. ]
> Signed-off-by: Borislav Petkov <b...@suse.de>
> ---
> arch/x86/kernel/cpu/mcheck/dev-mcelog.c | 8 +++++++-
> drivers/xen/mcelog.c | 2 ++
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
> b/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
> index a80427c30c93..10cec43aac38 100644
> --- 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
> index a493c7315e94..6cc1c15bcd84 100644
> --- 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:
> --
> 2.13.0
>
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