From: Matt Fleming <matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
To: Bart Kuivenhoven <bemk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org,
tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org,
mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
jcm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH] x86 efi: bugfix interrupt disabling sequence
Date: Fri, 20 Sep 2013 16:28:59 +0100 [thread overview]
Message-ID: <20130920152859.GC21381@console-pimps.org> (raw)
In-Reply-To: <1379525333-4373-1-git-send-email-bemk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On Wed, 18 Sep, at 07:28:53PM, Bart Kuivenhoven wrote:
> The problem in efi_main was that the idt was cleared before the
> interrupts were disabled.
>
> The UEFI spec states that interrupts aren't used so this shouldn't be
> too much of a problem. Peripherals however don't necessarily know about
> this and thus might cause interrupts to happen anyway. Even if
> ExitBootServices() has been called.
>
> This means there is a risk of an interrupt being triggered while the IDT
> register is nullified and the interrupt bit hasn't been cleared,
> allowing for a triple fault.
Just to be clear, you haven't witnessed a triple fault, correct?
> This patch fixes this by clearing the interrupt bit before the lidt
> instruction.
I think we can go even further than this and get rid of all of the IDT
code in the EFI boot stub. The kernel maintains its own IDT anyway.
--
Matt Fleming, Intel Open Source Technology Center
next prev parent reply other threads:[~2013-09-20 15:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-18 17:28 [PATCH] x86 efi: bugfix interrupt disabling sequence Bart Kuivenhoven
[not found] ` <1379525333-4373-1-git-send-email-bemk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-09-20 15:28 ` Matt Fleming [this message]
2013-09-20 20:21 ` Bart Kuivenhoven
[not found] ` <1379708486.12705.131.camel-0VdLhd/A9PkhetGgFr3ssPXAX3CI6PSWQQ4Iyu8u01E@public.gmane.org>
2013-09-21 7:50 ` Ingo Molnar
2013-09-21 15:41 ` Matt Fleming
[not found] ` <20130921154127.GD21381-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2013-09-23 9:27 ` Bart Kuivenhoven
-- strict thread matches above, loose matches on Subject: below --
2013-09-23 9:45 Bart Kuivenhoven
[not found] ` <1379929528-7534-1-git-send-email-bemk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-09-25 13:12 ` Matt Fleming
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=20130920152859.GC21381@console-pimps.org \
--to=matt-hnk1s37rvnbexh+ff434mdi2o/jbrioy@public.gmane.org \
--cc=bemk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org \
--cc=jcm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org \
--cc=x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.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;
as well as URLs for NNTP newsgroup(s).