MIME-Version: 1.0
In-Reply-To: <55CD3382.5070506@list.ru>
References: <55CA90B4.2010205@list.ru>
	<CA+55aFw5DzEn+jYmY0KwbkytBzowo45o3Czh1cQZ_aaR1+WZYA@mail.gmail.com>
	<55CCD921.4040301@list.ru>
	<CA+55aFycGSrN27gP4kh6eLZdkSxFvVqS8cZn1YJairD3+z3Zpg@mail.gmail.com>
	<CALCETrUDYw3oobs27QNraCQo8z3eR-3xoBmQE-fQkGvh=Ax0sA@mail.gmail.com>
	<CA+55aFz_KF5p0LcxroCVJ5zPrUmthR6X0Q1YWKMepDYKn=J-sA@mail.gmail.com>
	<20150813200823.GS2059@uranus>
	<CA+55aFyYNgPoh0VxqcGUxB-_z7oK+zB18YhJQQrozdb_gLAp5g@mail.gmail.com>
	<55CD0F29.4070604@gmail.com>
	<CA+55aFyqb29r+1YP2iYStFOij9X0QDWqjgmee=JcTkB-q8iEdA@mail.gmail.com>
	<55CD13F3.1070904@list.ru>
	<CALCETrVX-Op1U-RED9bkb3R9v7jcu5O1ur1Yt08ppZ0VFyZx7A@mail.gmail.com>
	<55CD1968.7070002@list.ru>
	<CALCETrUJS9kgNgggbnYJrLr93ARtocZBAGDVuudWahM7JhQuwQ@mail.gmail.com>
	<55CD1F79.2010508@list.ru>
	<CALCETrWf=rRZLJ=RWS_s2NDN5GNZT87DKTgt7eS81ncrXxi5hA@mail.gmail.com>
	<55CD2F9A.9040300@list.ru>
	<CALCETrV4Xbcw9JtFgoR6BOz=TTnj7KEuzOJeLcELur6yJT7E9Q@mail.gmail.com>
	<55CD3382.5070506@list.ru>
Date: Thu, 13 Aug 2015 17:27:09 -0700
Message-ID: <CA+55aFxRbtQd372SKQYRKfkpZ+BSqj6EwdB96n+SqUaxJ-LXuA@mail.gmail.com>
Subject: Re: [regression] x86/signal/64: Fix SS handling for signals delivered
 to 64-bit programs breaks dosemu
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Stas Sergeev <stsp@list.ru>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Raymond Jennings <shentino@gmail.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Pavel Emelyanov <xemul@parallels.com>,
        Linux kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 735
Lines: 18

On Thu, Aug 13, 2015 at 5:17 PM, Stas Sergeev <stsp@list.ru> wrote:
>
> For example because you can as well do:
> prctl(ARCH_SET_SIGNAL_SS, 0)
> which will mean "restore ss in sighandler to its current value",

I really think a prctl() is the wrong thing to do.

If you want a signal handler to save/restore segments, I think it
should be a SA_xyz flag to sigaction() (the way we have SA_RESTART
etc).  And off by default because of the obvious compatibility issues.

                Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/