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From: "H. Peter Anvin" <hpa@zytor.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Joe Perches <joe@perches.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86_64 : support atomic ops with 64 bits integer values
Date: Sat, 16 Aug 2008 08:04:23 -0700	[thread overview]
Message-ID: <48A6EC77.8080904@zytor.com> (raw)
In-Reply-To: <20080816073926.GA19546@Krystal>

Mathieu Desnoyers wrote:
> x86_64 add/sub atomic ops does not seems to accept integer values bigger
> than 32 bits as immediates. Intel's add/sub documentation specifies they
> have to be passed as registers.

This is correct; this is in fact true for all instructions except "mov".

Whether it's sign- or zero-extending is sometimes subtle, but not in 
these cases.

Do you happen to know if this is a manifest bug in the current kernel 
(i.e. if there is anywhere we're using more than ±2 GB as a constant to 
these functions?)

Either way, I'll queue this up to tip:x86/urgent if Ingo hasn't already 
since this is a pure bug fix.

	-hpa

  reply	other threads:[~2008-08-16 15:08 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-16  7:39 [PATCH] x86_64 : support atomic ops with 64 bits integer values Mathieu Desnoyers
2008-08-16 15:04 ` H. Peter Anvin [this message]
2008-08-16 15:43   ` Mathieu Desnoyers
2008-08-16 17:30     ` Linus Torvalds
2008-08-16 21:19       ` [RFC PATCH] Fair rwlock Mathieu Desnoyers
2008-08-16 21:33         ` Linus Torvalds
2008-08-17  7:53           ` [RFC PATCH] Fair low-latency rwlock v3 Mathieu Desnoyers
2008-08-17 16:17             ` Linus Torvalds
2008-08-17 19:10               ` [RFC PATCH] Fair low-latency rwlock v5 Mathieu Desnoyers
2008-08-17 21:30                 ` [RFC PATCH] Fair low-latency rwlock v5 (updated benchmarks) Mathieu Desnoyers
2008-08-18 18:59                 ` [RFC PATCH] Fair low-latency rwlock v5 Linus Torvalds
2008-08-18 23:25                 ` Paul E. McKenney
2008-08-19  6:04                   ` Mathieu Desnoyers
2008-08-19  7:33                     ` Mathieu Desnoyers
2008-08-19  9:06                       ` Mathieu Desnoyers
2008-08-19 16:48                       ` Linus Torvalds
2008-08-21 20:50                         ` [RFC PATCH] Writer-biased low-latency rwlock v8 Mathieu Desnoyers
2008-08-21 21:00                           ` Linus Torvalds
2008-08-21 21:15                             ` Linus Torvalds
2008-08-21 22:22                               ` Linus Torvalds
2008-08-23  5:09                               ` Mathieu Desnoyers
2008-08-23 18:02                                 ` Linus Torvalds
2008-08-23 20:30                                   ` Mathieu Desnoyers
2008-08-23 21:40                                     ` Linus Torvalds
2008-08-21 21:26                             ` H. Peter Anvin
2008-08-21 21:41                               ` Linus Torvalds
2008-08-25 19:20                 ` [RFC PATCH] Fair low-latency rwlock v5 Peter Zijlstra

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