From: "H. Peter Anvin" <hpa@zytor.com>
To: Chuck Ebbert <cebbert.lkml@gmail.com>,
Andy Lutomirski <luto@amacapital.net>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>
Subject: Re: x86, microcode: BUG: microcode update that changes x86_capability
Date: Thu, 18 Sep 2014 12:55:16 -0700 [thread overview]
Message-ID: <9c84cde6-3d70-4337-8738-0283d06d8cf0@email.android.com> (raw)
In-Reply-To: <20140918145328.0253f009@as>
We should, but this is also part of why we want the early ucode capability.
On September 18, 2014 12:53:28 PM PDT, Chuck Ebbert <cebbert.lkml@gmail.com> wrote:
>On Thu, 18 Sep 2014 12:14:59 -0700
>Andy Lutomirski <luto@amacapital.net> wrote:
>
>> On 09/18/2014 06:52 AM, Henrique de Moraes Holschuh wrote:
>> > The new Haswell microcode update[1] removes the "hle" (hardware
>lock
>> > elision) processor capability. And it is not cosmetic, either:
>Intel TSX
>> > opcodes will cause an illegal opcode trap after the microcode
>update[2].
>> >
>> > This means cpu_info()->x86_capability becomes stale after the
>microcode
>> > update.
>> >
>> > We could add logic to compute the new x86_capability after a
>microcode
>> > update run, and OOPS the kernel if something too important (i.e.
>anything
>> > the kernel uses) went away. Otherwise, refresh
>cpu_info()->x86_capability.
>> >
>> > Is that doable?
>> >
>> >
>> > [1] sig 0x000306f2, pf mask 0x6f, 2014-09-03, rev 0x0029, size
>28672
>> > sig 0x000306c3, pf mask 0x32, 2014-07-03, rev 0x001c, size
>21504
>> > sig 0x00040651, pf mask 0x72, 2014-07-03, rev 0x001c, size
>20480
>> > sig 0x00040661, pf mask 0x32, 2014-07-03, rev 0x0012, size
>23552
>>
>> This is HSD136, right? Do you have a link to where that ucode comes
>> from? Does it have release notes?
>>
>
>https://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=24290&lang=eng
>
>I can't find any release notes.
>
>Haswell-EP is also affected, it appears:
>
>http://techreport.com/news/26911/errata-prompts-intel-to-disable-tsx-in-haswell-early-broadwell-cpus
>
>> >
>> > [2] instantly segfaulting every running process using
>libpthread-2.19,
>> > as well as any other users of Intel TSX.
>> > https://bugs.launchpad.net/intel/+bug/1370352
>> >
>> > And yes, this means we will kill support for microcode updates
>> > outside of the initramfs/early-initramfs, at least in Debian,
>> > and likely in Ubuntu.
>> >
>>
>> Given that there is exactly one microcode update like this (at least
>of
>> the sort that blows up userspace), I think that we should seriously
>> consider blacklisting just this particular microcode update once
>> userspace is running.
>>
>
>All future updates for these CPUs will have this problem.
--
Sent from my mobile phone. Please pardon brevity and lack of formatting.
next prev parent reply other threads:[~2014-09-18 19:55 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-18 13:52 x86, microcode: BUG: microcode update that changes x86_capability Henrique de Moraes Holschuh
2014-09-18 19:14 ` Andy Lutomirski
2014-09-18 19:53 ` Chuck Ebbert
2014-09-18 19:55 ` H. Peter Anvin [this message]
2014-09-18 20:06 ` Henrique de Moraes Holschuh
2014-09-19 0:13 ` Henrique de Moraes Holschuh
2014-09-19 0:23 ` Andy Lutomirski
2014-09-19 0:28 ` H. Peter Anvin
2014-09-19 1:00 ` Andy Lutomirski
2014-09-19 8:03 ` Borislav Petkov
2014-09-19 11:00 ` Henrique de Moraes Holschuh
2014-09-19 11:29 ` Borislav Petkov
2014-09-19 12:54 ` Chuck Ebbert
2014-09-19 13:14 ` Josh Boyer
2014-09-19 13:37 ` Chuck Ebbert
2014-09-19 15:00 ` Borislav Petkov
2014-09-19 16:13 ` Andy Lutomirski
2014-09-19 16:54 ` Henrique de Moraes Holschuh
2014-09-19 16:42 ` Henrique de Moraes Holschuh
2014-09-23 20:00 ` Borislav Petkov
2014-09-24 14:56 ` Henrique de Moraes Holschuh
2014-09-24 15:00 ` Andy Lutomirski
2014-09-24 17:45 ` Henrique de Moraes Holschuh
2014-09-24 17:48 ` Andy Lutomirski
2014-09-24 18:59 ` Henrique de Moraes Holschuh
2014-09-24 19:34 ` Andy Lutomirski
2014-09-25 8:57 ` Borislav Petkov
2014-09-25 8:51 ` Borislav Petkov
2014-09-25 11:36 ` Henrique de Moraes Holschuh
2014-09-25 12:10 ` Borislav Petkov
2014-09-25 14:40 ` Henrique de Moraes Holschuh
2014-09-25 14:56 ` Borislav Petkov
2014-09-25 15:30 ` Henrique de Moraes Holschuh
2014-09-25 15:50 ` Borislav Petkov
2014-09-25 16:41 ` Henrique de Moraes Holschuh
2014-09-25 16:57 ` Borislav Petkov
2014-09-25 17:09 ` Henrique de Moraes Holschuh
2014-09-19 13:51 ` Henrique de Moraes Holschuh
2014-09-19 14:49 ` Borislav Petkov
2014-09-19 17:22 ` Henrique de Moraes Holschuh
2014-09-19 22:35 ` Henrique de Moraes Holschuh
2014-09-29 11:51 ` Henrique de Moraes Holschuh
2014-09-19 9:56 ` Henrique de Moraes Holschuh
2014-09-19 16:11 ` Henrique de Moraes Holschuh
2014-09-22 0:37 ` Andi Kleen
2014-09-22 0:51 ` H. Peter Anvin
2014-09-22 0:58 ` Andi Kleen
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