linux-kernel - Re: MMIO and gcc re-ordering issue

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: <20080527092430.6380d962@core>
Date:	Tue, 27 May 2008 09:24:30 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	David Miller <davem@...emloft.net>
Cc:	benh@...nel.crashing.org, linux-arch@...r.kernel.org,
	scottwood@...escale.com, linuxppc-dev@...abs.org,
	linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
	tpiepho@...escale.com
Subject: Re: MMIO and gcc re-ordering issue

> It's just another complicated thing for driver authors to get wrong.
> The other side of the coin is of course the cost.
> 
> The only thing I am absolutely sure of is that we should make a
> decision fast, document it, and just stick to it.

It's unfortunate that the __read/___write versions have other different
semantics. The default should definitely be ordered but having un-ordered
ones as an option would be good for zapping the hot paths that matter.

Most I/O paths aren't even worth the thinking time for non-ordered I/O.

Alan
--
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/