Subject: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400

Signed-off-by: Boris Ostrovsky <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Reported-by: Joerg-Volker Peetz <[email protected]>
Tested-by: Joerg-Volker Peetz <[email protected]>

Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC timer
interrupts don't occur in C states greater than C1). This, for example, means that
X86_FEATURE_ARAT flag should not be set for these parts.

This addresses regression introduced by commit b87cf80af3ba4b4c008b4face3c68d604e1715c6
(x86, AMD: Set ARAT feature on AMD processors") so it is somewhat high priority.
---
arch/x86/kernel/cpu/amd.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 3532d3b..71499b4 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -698,7 +698,7 @@ cpu_dev_register(amd_cpu_dev);
*/

const int amd_erratum_400[] =
- AMD_OSVW_ERRATUM(1, AMD_MODEL_RANGE(0xf, 0x41, 0x2, 0xff, 0xf),
+ AMD_OSVW_ERRATUM(1, AMD_MODEL_RANGE(0xf, 0x4, 0x2, 0xff, 0xf),
AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0xff, 0xf));
EXPORT_SYMBOL_GPL(amd_erratum_400);

--
1.7.3.4


2011-04-29 19:55:58

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400


* Boris Ostrovsky <[email protected]> wrote:

> Signed-off-by: Boris Ostrovsky <[email protected]>
> Acked-by: Borislav Petkov <[email protected]>
> Reported-by: Joerg-Volker Peetz <[email protected]>
> Tested-by: Joerg-Volker Peetz <[email protected]>
>
> Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC
> timer interrupts don't occur in C states greater than C1). This, for example,
> means that X86_FEATURE_ARAT flag should not be set for these parts.
>
> This addresses regression introduced by commit
> b87cf80af3ba4b4c008b4face3c68d604e1715c6 (x86, AMD: Set ARAT feature on AMD
> processors") so it is somewhat high priority.

Hm, what is the regression, how do users see it? Hangs? Delays? Crashes?
Something more benign? The changelog should really contain such information.

Thanks,

Ingo

Subject: Re: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400

On 04/29/2011 03:55 PM, Ingo Molnar wrote:
>
> * Boris Ostrovsky<[email protected]> wrote:
>
>> Signed-off-by: Boris Ostrovsky<[email protected]>
>> Acked-by: Borislav Petkov<[email protected]>
>> Reported-by: Joerg-Volker Peetz<[email protected]>
>> Tested-by: Joerg-Volker Peetz<[email protected]>
>>
>> Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC
>> timer interrupts don't occur in C states greater than C1). This, for example,
>> means that X86_FEATURE_ARAT flag should not be set for these parts.
>>
>> This addresses regression introduced by commit
>> b87cf80af3ba4b4c008b4face3c68d604e1715c6 (x86, AMD: Set ARAT feature on AMD
>> processors") so it is somewhat high priority.
>
> Hm, what is the regression, how do users see it? Hangs? Delays? Crashes?
> Something more benign? The changelog should really contain such information.


The system becomes unresponsive until an external interrupt (e.g.
keyboard input) happens. The most obvious effect is that time is not
reported correctly. We haven't seen anything worse but that's probably
bad enough.

Do you want me to resubmit the patch with updated comments?

Thanks.
-boris

2011-04-29 20:24:07

by Borislav Petkov

[permalink] [raw]
Subject: Re: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400

On Fri, Apr 29, 2011 at 04:11:26PM -0400, Boris Ostrovsky wrote:
> On 04/29/2011 03:55 PM, Ingo Molnar wrote:
> >
> > * Boris Ostrovsky<[email protected]> wrote:
> >
> >> Signed-off-by: Boris Ostrovsky<[email protected]>
> >> Acked-by: Borislav Petkov<[email protected]>
> >> Reported-by: Joerg-Volker Peetz<[email protected]>
> >> Tested-by: Joerg-Volker Peetz<[email protected]>
> >>
> >> Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC
> >> timer interrupts don't occur in C states greater than C1). This, for example,
> >> means that X86_FEATURE_ARAT flag should not be set for these parts.
> >>
> >> This addresses regression introduced by commit
> >> b87cf80af3ba4b4c008b4face3c68d604e1715c6 (x86, AMD: Set ARAT feature on AMD
> >> processors") so it is somewhat high priority.
> >
> > Hm, what is the regression, how do users see it? Hangs? Delays? Crashes?
> > Something more benign? The changelog should really contain such information.
>
>
> The system becomes unresponsive until an external interrupt (e.g.
> keyboard input) happens. The most obvious effect is that time is not
> reported correctly. We haven't seen anything worse but that's probably
> bad enough.
>
> Do you want me to resubmit the patch with updated comments?

Yes please. Being too verbose is much better than being laconic with the
commit message.

Also, please put those lines

Signed-off-by: Boris Ostrovsky <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Reported-by: Joerg-Volker Peetz <[email protected]>
Tested-by: Joerg-Volker Peetz <[email protected]>

_after_ the commit message.

Thanks.

--
Regards/Gruss,
Boris.

Operating Systems Research Center
Advanced Micro Devices, Inc.

2011-04-29 20:35:33

by Jiri Slaby

[permalink] [raw]
Subject: Re: [PATCH] Subject: [PATCH] x86, AMD: K8 Rev.A-E processors are subject to erratum 400

On 04/29/2011 10:23 PM, Borislav Petkov wrote:
> On Fri, Apr 29, 2011 at 04:11:26PM -0400, Boris Ostrovsky wrote:
>> On 04/29/2011 03:55 PM, Ingo Molnar wrote:
>>>
>>> * Boris Ostrovsky<[email protected]> wrote:
>>>
>>>> Signed-off-by: Boris Ostrovsky<[email protected]>
>>>> Acked-by: Borislav Petkov<[email protected]>
>>>> Reported-by: Joerg-Volker Peetz<[email protected]>
>>>> Tested-by: Joerg-Volker Peetz<[email protected]>
>>>>
>>>> Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC
>>>> timer interrupts don't occur in C states greater than C1). This, for example,
>>>> means that X86_FEATURE_ARAT flag should not be set for these parts.
>>>>
>>>> This addresses regression introduced by commit
>>>> b87cf80af3ba4b4c008b4face3c68d604e1715c6 (x86, AMD: Set ARAT feature on AMD
>>>> processors") so it is somewhat high priority.
>>>
>>> Hm, what is the regression, how do users see it? Hangs? Delays? Crashes?
>>> Something more benign? The changelog should really contain such information.
>>
>>
>> The system becomes unresponsive until an external interrupt (e.g.
>> keyboard input) happens. The most obvious effect is that time is not
>> reported correctly. We haven't seen anything worse but that's probably
>> bad enough.
>>
>> Do you want me to resubmit the patch with updated comments?
>
> Yes please. Being too verbose is much better than being laconic with the
> commit message.
>
> Also, please put those lines
>
> Signed-off-by: Boris Ostrovsky <[email protected]>
> Acked-by: Borislav Petkov <[email protected]>
> Reported-by: Joerg-Volker Peetz <[email protected]>
> Tested-by: Joerg-Volker Peetz <[email protected]>
>
> _after_ the commit message.

And also please add
Cc: [email protected]
as the original commit (b87cf80a) was merged into stable trees.

thanks,
--
js