* [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC
@ 2013-10-24 1:30 Fenghua Yu
2013-10-25 10:57 ` Ingo Molnar
2013-11-07 15:18 ` [tip:x86/apic] x86/apic: Disable I/ O APIC before shutdown of the " tip-bot for Fenghua Yu
0 siblings, 2 replies; 4+ messages in thread
From: Fenghua Yu @ 2013-10-24 1:30 UTC (permalink / raw)
To: H Peter Anvin, Ingo Molnar, Thomas Gleixner, linux-kernel; +Cc: Fenghua Yu
From: Fenghua Yu <fenghua.yu@intel.com>
In reboot and crash path, when shutdown local APIC, I/O APIC is still active.
This may cause issues because external interrupts can still come in and
disturb 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>
---
arch/x86/kernel/crash.c | 2 +-
arch/x86/kernel/reboot.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index e0e0841..18677a9 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -127,12 +127,12 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
cpu_emergency_vmxoff();
cpu_emergency_svm_disable();
- lapic_shutdown();
#ifdef CONFIG_X86_IO_APIC
/* Prevent crash_kexec() from deadlocking on ioapic_lock. */
ioapic_zap_locks();
disable_IO_APIC();
#endif
+ lapic_shutdown();
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 7e920bf..618ce26 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -550,6 +550,10 @@ static void native_machine_emergency_restart(void)
void native_machine_shutdown(void)
{
/* Stop the cpus and apics */
+#ifdef CONFIG_X86_IO_APIC
+ disable_IO_APIC();
+#endif
+
#ifdef CONFIG_SMP
/*
* Stop all of the others. Also disable the local irq to
@@ -562,10 +566,6 @@ void native_machine_shutdown(void)
lapic_shutdown();
-#ifdef CONFIG_X86_IO_APIC
- disable_IO_APIC();
-#endif
-
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif
--
1.6.0.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC
2013-10-24 1:30 [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC Fenghua Yu
@ 2013-10-25 10:57 ` Ingo Molnar
2013-11-06 22:32 ` Yu, Fenghua
2013-11-07 15:18 ` [tip:x86/apic] x86/apic: Disable I/ O APIC before shutdown of the " tip-bot for Fenghua Yu
1 sibling, 1 reply; 4+ messages in thread
From: Ingo Molnar @ 2013-10-25 10:57 UTC (permalink / raw)
To: Fenghua Yu; +Cc: H Peter Anvin, Ingo Molnar, Thomas Gleixner, linux-kernel
* Fenghua Yu <fenghua.yu@intel.com> wrote:
> From: Fenghua Yu <fenghua.yu@intel.com>
>
> In reboot and crash path, when shutdown local APIC, I/O APIC is still active.
> This may cause issues because external interrupts can still come in and
> disturb local APIC during shutdown process. To quiet external interrupts,
> disable I/O APIC before shutdown local APIC.
What specific 'issues' were observed, on what kind of systems?
Thanks,
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC
2013-10-25 10:57 ` Ingo Molnar
@ 2013-11-06 22:32 ` Yu, Fenghua
0 siblings, 0 replies; 4+ messages in thread
From: Yu, Fenghua @ 2013-11-06 22:32 UTC (permalink / raw)
To: Ingo Molnar; +Cc: H Peter Anvin, Ingo Molnar, Thomas Gleixner, linux-kernel
> Ingo Molnar [mailto:mingo.kernel.org@gmail.com] wrote:
> Friday, October 25, 2013 3:58 AM
>
> * Fenghua Yu <fenghua.yu@intel.com> wrote:
>
> > From: Fenghua Yu <fenghua.yu@intel.com>
> >
> > In reboot and crash path, when shutdown local APIC, I/O APIC is still
> active.
> > This may cause issues because external interrupts can still come in
> and
> > disturb local APIC during shutdown process. To quiet external
> interrupts,
> > disable I/O APIC before shutdown local APIC.
>
> What specific 'issues' were observed, on what kind of systems?
>
This patch is a workaround for a to-be-published erratum; the erratum
will be published in a few weeks.
Thanks.
-Fenghua
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip:x86/apic] x86/apic: Disable I/ O APIC before shutdown of the local APIC
2013-10-24 1:30 [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC Fenghua Yu
2013-10-25 10:57 ` Ingo Molnar
@ 2013-11-07 15:18 ` tip-bot for Fenghua Yu
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Fenghua Yu @ 2013-11-07 15:18 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, stable, fenghua.yu, tglx
Commit-ID: 522e66464467543c0d88d023336eec4df03ad40b
Gitweb: http://git.kernel.org/tip/522e66464467543c0d88d023336eec4df03ad40b
Author: Fenghua Yu <fenghua.yu@intel.com>
AuthorDate: Wed, 23 Oct 2013 18:30:12 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 7 Nov 2013 10:12:37 +0100
x86/apic: Disable I/O APIC before shutdown of the local APIC
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
Cc: <stable@kernel.org>
[ I suppose the 'issue' is a hang during shutdown. It's a fine change nevertheless. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/crash.c | 2 +-
arch/x86/kernel/reboot.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index e0e0841..18677a9 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -127,12 +127,12 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
cpu_emergency_vmxoff();
cpu_emergency_svm_disable();
- lapic_shutdown();
#ifdef CONFIG_X86_IO_APIC
/* Prevent crash_kexec() from deadlocking on ioapic_lock. */
ioapic_zap_locks();
disable_IO_APIC();
#endif
+ lapic_shutdown();
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 7e920bf..618ce26 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -550,6 +550,10 @@ static void native_machine_emergency_restart(void)
void native_machine_shutdown(void)
{
/* Stop the cpus and apics */
+#ifdef CONFIG_X86_IO_APIC
+ disable_IO_APIC();
+#endif
+
#ifdef CONFIG_SMP
/*
* Stop all of the others. Also disable the local irq to
@@ -562,10 +566,6 @@ void native_machine_shutdown(void)
lapic_shutdown();
-#ifdef CONFIG_X86_IO_APIC
- disable_IO_APIC();
-#endif
-
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2013-10-24 1:30 [PATCH] x86/apic: Disable I/O APIC before shutdown local APIC Fenghua Yu
2013-10-25 10:57 ` Ingo Molnar
2013-11-06 22:32 ` Yu, Fenghua
2013-11-07 15:18 ` [tip:x86/apic] x86/apic: Disable I/ O APIC before shutdown of the " tip-bot for Fenghua Yu
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