linux-kernel - Re: [RFC] arm: use built-in byte swap function

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: <20130207181315.GM17833@n2100.arm.linux.org.uk>
Date:	Thu, 7 Feb 2013 18:13:15 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Kim Phillips <kim.phillips@...escale.com>
Cc:	"Woodhouse, David" <david.woodhouse@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Daniel Santos <daniel.santos@...ox.com>,
	David Rientjes <rientjes@...gle.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Rob Herring <robherring2@...il.com>
Subject: Re: [RFC] arm: use built-in byte swap function

On Wed, Feb 06, 2013 at 07:19:05PM -0600, Kim Phillips wrote:
> either that, or link with libgcc - why does arch/arm64 do this and
> arch/arm not?  It's not obvious from git log.

We want to be in control of what code the kernel runs, and that means
not using libgcc.  libgcc can do all sorts of stuff because it makes
assumptions about the environment which it is executing in (glibc).

For example, it assumes there may be a GOT, and that it can issue SWI
calls...

However, the biggest reason not to use libgcc is that we want to control
what gets used in the kernel - for example, no floating point, and no
use of 64 x 64bit division.

So all round, using libgcc in AArch32 would bring us a number of issues
that we don't get with the current approach.

AArch64 uses it because it's maintained entirely separately and the
decision has been made by other people - and some of these concerns do
not exist on a 64-bit architecture.
--
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/