From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
To: "H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: BUG: early intel microcode update violating alignment rules
Date: Mon, 11 Aug 2014 15:18:32 -0300 [thread overview]
Message-ID: <1407781112.3399765.151527845.7EC32D9C@webmail.messagingengine.com> (raw)
In-Reply-To: <53E8D876.1060004@zytor.com>
On Mon, Aug 11, 2014, at 11:51, H. Peter Anvin wrote:
> We could put a buffer in the initdata region (we really could use an
> initbss region!) or in the brk.
That sounds much better than the hideous crap I came up with. The
buffer would need to be at least 64KiB in size to be on the safe side.
The largest public microcode update ATM is 23KiB.
I am not sure if we might need more than 64KiB: the Intel SDM mentions
that in real mode the update data must not cross a segment boundary, and
also must not exceed a segment limit. I am a bit rusty on real mode,
but doesn't that mean, in practice, that microcode update data size is
limited in size to 64KiB?
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
next prev parent reply other threads:[~2014-08-11 18:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-09 23:19 Henrique de Moraes Holschuh
2014-08-11 10:22 ` Borislav Petkov
2014-08-11 13:16 ` Henrique de Moraes Holschuh
2014-08-11 14:00 ` Borislav Petkov
2014-08-11 14:50 ` H. Peter Anvin
2014-08-11 18:52 ` Bill Davidsen
2014-08-11 19:15 ` Borislav Petkov
2014-08-14 13:12 ` Henrique de Moraes Holschuh
2014-08-11 14:51 ` H. Peter Anvin
2014-08-11 18:18 ` Henrique de Moraes Holschuh [this message]
2014-08-11 18:48 ` H. Peter Anvin
2014-08-31 19:45 ` early microcode: how to disable at runtime? Henrique de Moraes Holschuh
2014-08-31 19:48 ` H. Peter Anvin
2014-08-31 20:11 ` Henrique de Moraes Holschuh
2014-09-01 5:13 ` Borislav Petkov
2014-09-01 10:19 ` Henrique de Moraes Holschuh
2014-09-01 16:35 ` H. Peter Anvin
2014-09-01 17:43 ` Henrique de Moraes Holschuh
2014-09-01 18:48 ` H. Peter Anvin
2014-09-01 19:59 ` Henrique de Moraes Holschuh
2014-09-02 6:33 ` Borislav Petkov
2014-09-02 13:16 ` Henrique de Moraes Holschuh
2014-09-03 6:40 ` Borislav Petkov
2014-09-03 12:43 ` Henrique de Moraes Holschuh
2014-09-04 15:42 ` Borislav Petkov
2014-09-04 17:45 ` Henrique de Moraes Holschuh
2014-09-05 8:50 ` Borislav Petkov
2014-09-05 14:23 ` Henrique de Moraes Holschuh
2014-09-04 18:37 ` Yu, Fenghua
2014-09-05 8:52 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1407781112.3399765.151527845.7EC32D9C@webmail.messagingengine.com \
--to=hmh@hmh.eng.br \
--cc=bp@alien8.de \
--cc=fenghua.yu@intel.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®