x86/apic: Disable I/O APIC before shutdown of the local APIC
commit 522e66464467543c0d88d023336eec4df03ad40b upstream.
In reboot and crash path, when we shut down the local APIC, the I/O APIC is
still active. This may cause issues because external interrupts
can still come in and disturb the local APIC during shutdown process.
To quiet external interrupts, disable I/O APIC before shutdown local APIC.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1382578212-4677-1-git-send-email-fenghua.yu@intel.com
[ I suppose the 'issue' is a hang during shutdown. It's a fine change nevertheless. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index bd70df6..d398f31 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -668,6 +668,13 @@
/* The boot cpu is always logical cpu 0 */
int reboot_cpu_id = 0;
+#endif
+
+#ifdef CONFIG_X86_IO_APIC
+ disable_IO_APIC();
+#endif
+
+#ifdef CONFIG_SMP
#ifdef CONFIG_X86_32
/* See if there has been given a command line override */
@@ -691,10 +698,6 @@
lapic_shutdown();
-#ifdef CONFIG_X86_IO_APIC
- disable_IO_APIC();
-#endif
-
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif