Xen mcelog device initialization path _expect to fail_ baremetal flavor during initialization. So hide this error message to not scare users. Fixes QubesOS/qubes-issues#1164
Marek Marczykowski-Górecki
8 years ago
parent
3d4f4bcf16
commit
1c910bcf9c
@ -0,0 +1,72 @@
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From 26df8496fdb73e9ae2bdf9d1684484196260a8f3 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
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<marmarek@invisiblethingslab.com>
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Date: Tue, 5 Jan 2016 02:44:04 +0100
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Subject: [PATCH] mce: hide EBUSY initialization error on Xen
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Organization: Invisible Things Lab
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Cc: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
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In case of Xen, the device is already registered by xen mcelog (in
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xen_late_init_mcelog), so fail here is expected. Note that
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mcheck_init_device call is still expected to initialize mce_device. Comment
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from threshold_init_device explaining the situation:
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/*
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* there are 3 funcs which need to be _initcalled in a logic sequence:
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* 1. xen_late_init_mcelog
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* 2. mcheck_init_device
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* 3. threshold_init_device
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*
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* xen_late_init_mcelog must register xen_mce_chrdev_device before
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* native mce_chrdev_device registration if running under xen platform;
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*
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* mcheck_init_device should be inited before threshold_init_device to
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* initialize mce_device, otherwise a NULL ptr dereference will cause panic.
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*
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* so we use following _initcalls
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* 1. device_initcall(xen_late_init_mcelog);
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* 2. device_initcall_sync(mcheck_init_device);
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* 3. late_initcall(threshold_init_device);
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*
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* when running under xen, the initcall order is 1,2,3;
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* on baremetal, we skip 1 and we do only 2 and 3.
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*/
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Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
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---
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arch/x86/kernel/cpu/mcheck/mce.c | 9 +++++++++
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1 file changed, 9 insertions(+)
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diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
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index c5b0d56..69b0b4b 100644
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--- a/arch/x86/kernel/cpu/mcheck/mce.c
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+++ b/arch/x86/kernel/cpu/mcheck/mce.c
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@@ -48,6 +48,10 @@
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#include <asm/mce.h>
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#include <asm/msr.h>
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+#ifdef CONFIG_XEN_MCE_LOG
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+#include <xen/xen.h>
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+#endif
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+
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#include "mce-internal.h"
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static DEFINE_MUTEX(mce_chrdev_read_mutex);
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@@ -2512,6 +2516,11 @@ err_out_mem:
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free_cpumask_var(mce_device_initialized);
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err_out:
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+#ifdef CONFIG_XEN_MCE_LOG
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+ /* in case of Xen, the character device was already registered, so do not
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+ * treat this as an error */
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+ if (!xen_initial_domain() || err != -EBUSY)
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+#endif
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pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
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return err;
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--
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2.1.0
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