linux-kernel - Re: gcc feature request / RFC: extra clobbered regs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150701174333.GA10247@tucnak.redhat.com>
Date:	Wed, 1 Jul 2015 19:43:33 +0200
From:	Jakub Jelinek <jakub@...hat.com>
To:	Vladimir Makarov <vmakarov@...hat.com>
Cc:	Andy Lutomirski <luto@...nel.org>, gcc@....gnu.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: gcc feature request / RFC: extra clobbered regs

On Wed, Jul 01, 2015 at 01:35:16PM -0400, Vladimir Makarov wrote:
> Actually it raise a question for me.  If we describe that a function
> clobbers more than calling convention and then use it as a value (assigning
> a variable or passing as an argument) and loosing a track of it and than
> call it.  How can RA know what the call clobbers actually.  So for the
> function with the attributes we should prohibit use it as a value or make
> the attributes as a part of the function type, or at least say it is unsafe.
> So now I see this as a *bigger problem* with this extension.  Although I
> guess it already exists as we have description of different ABI as an
> extension.

Unfortunately target attribute is function decl attribute rather than
function type.  And having more attributes affect switchable targets will be
non-fun.

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