linux-kernel - Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it

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]

Date:	Fri, 8 Dec 2006 09:06:00 -0800 (PST)
From:	Christoph Lameter <clameter@....com>
To:	David Howells <dhowells@...hat.com>
cc:	Russell King <rmk+lkml@....linux.org.uk>,
	Nick Piggin <nickpiggin@...oo.com.au>, torvalds@...l.org,
	akpm@...l.org, linux-arm-kernel@...ts.arm.linux.org.uk,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch
 doesn't support it 

On Fri, 8 Dec 2006, David Howells wrote:

> > It is the most universal atomic instruction that I know of.
> 
> I think TAS-type things and XCHG-type things are more common.

Huh? The most popular architectures are i386 x86_64 sparc ia64 etc which 
all have one or the other form of cmpxchg (some issues with early sparc 
and i386).

And yes the xchg was the first multiprocessor instruction and therefore 
is also available on very old processors.

> In fact I think more things have LL/SC than have CMPXCHG.

LL/SC can be easily used to come up with a cmpxchg equivalent.
-
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/