LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>, Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [PATCH 2/2] x86_64,signal: Remove 'fs' and 'gs' from sigcontext
Date: Sat, 12 Jul 2014 11:40:03 -0700	[thread overview]
Message-ID: <0795204d-575c-40b9-b5b0-75ab14eee330@email.android.com> (raw)
In-Reply-To: <20140712183748.GW18735@two.firstfloor.org>

Because you are doing something weird (like Pin, for example) and take an asynchronous fault?

On July 12, 2014 11:37:48 AM PDT, Andi Kleen <andi@firstfloor.org> wrote:
>> This seems like it's asking for trouble.  I think wxe'd have to
>> separately save the selectors and the base registers to avoid
>breaking
>> something, especially once wrgsbase, etc are enabled.
>
>I agree, it would likely break existing code.
>
>> Linus, for context, the other patch in this series saves and restores
>> SS. 
>
>> Without that, 64-bit sigreturn to a nondefault stack segment is
>> basically impossible.  
>
>Why would you ever want to do that?
>
>-Andi

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

  reply	other threads:[~2014-07-12 18:40 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-11 16:29 [PATCH 0/2] x86_64,signal: Fix the set of saved segment registers Andy Lutomirski
2014-07-11 16:29 ` [PATCH 1/2] x86_64,signal: Save and restore SS in signal frames Andy Lutomirski
2015-03-09 20:15   ` Andy Lutomirski
2014-07-11 16:29 ` [PATCH 2/2] x86_64,signal: Remove 'fs' and 'gs' from sigcontext Andy Lutomirski
2014-07-11 18:12   ` Andi Kleen
2014-07-11 18:39     ` Andy Lutomirski
2014-07-12  2:09       ` H. Peter Anvin
2014-07-12  2:04   ` H. Peter Anvin
2014-07-12  2:21   ` Linus Torvalds
2014-07-12  2:26     ` H. Peter Anvin
2014-07-12  8:39     ` Andy Lutomirski
2014-07-12 18:37       ` Andi Kleen
2014-07-12 18:40         ` H. Peter Anvin [this message]
2014-07-12 18:52           ` Andi Kleen
2014-07-12 21:17             ` Andy Lutomirski
2014-07-18  1:13               ` Andy Lutomirski

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=0795204d-575c-40b9-b5b0-75ab14eee330@email.android.com \
    --to=hpa@zytor.com \
    --cc=andi@firstfloor.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@amacapital.net \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH 2/2] x86_64,signal: Remove '\''fs'\'' and '\''gs'\'' from sigcontext' \
    /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

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).