| Message ID | 20170620211637.2590-1-bp@alien8.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.zhao@oracle.com>
On Wed, Jun 21, 2017 at 5:16 AM, Borislav Petkov <bp@alien8.de> wrote:
> From: Juergen Gross <jgross@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 <jgross@suse.com>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: linux-edac <linux-edac@vger.kernel.org>
> Cc: x86-ml <x86@kernel.org>
> Cc: xen-devel@lists.xenproject.org
> Link: http://lkml.kernel.org/r/20170614084059.19294-1-jgross@suse.com
> [ Massage a bit. ]
> Signed-off-by: Borislav Petkov <bp@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
>
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: