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From: Andi Kleen <andi@firstfloor.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andi Kleen <andi@firstfloor.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	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 20:37:48 +0200	[thread overview]
Message-ID: <20140712183748.GW18735@two.firstfloor.org> (raw)
In-Reply-To: <CALCETrUqeUJT7xGy0TERVjJUAZUCXJGdgaDWv-f5+vkkArP8ig@mail.gmail.com>

> 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

  reply	other threads:[~2014-07-12 18:37 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 [this message]
2014-07-12 18:40         ` H. Peter Anvin
2014-07-12 18:52           ` Andi Kleen
2014-07-12 21:17             ` Andy Lutomirski
2014-07-18  1:13               ` Andy Lutomirski

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