From: Andi Kleen <andi@firstfloor.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Glauber de Oliveira Costa <gcosta@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86: Create clflush() inline, remove hardcoded wbinvd
Date: Sun, 22 Jul 2007 21:55:32 +0200 [thread overview]
Message-ID: <20070722195532.GA1432@one.firstfloor.org> (raw)
In-Reply-To: <46A39C64.9070301@zytor.com>
On Sun, Jul 22, 2007 at 11:05:24AM -0700, H. Peter Anvin wrote:
> Andi Kleen wrote:
> >> The main reason is that everyone seems to invoke it either incorrectly
> > Where is it incorrect?
>
> Using "r" or "m" (as opposed as "+m") gives gcc the wrong dependency
> information, and it could, at least in theory, cause memory references
> to be moved around it -- especially when using "r".
That doesn't sound correct. Taking the address should be like an escaping
pointer and equivalent to read/write and effectively disable optimizations
on this memory.
-Andi
next prev parent reply other threads:[~2007-07-22 19:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-19 22:55 [PATCH] Use wbinvd() macro instead of raw inline assembly in .c files Glauber de Oliveira Costa
2007-07-20 11:43 ` Andi Kleen
2007-07-20 17:22 ` H. Peter Anvin
2007-07-21 7:32 ` Muli Ben-Yehuda
2007-07-20 21:19 ` [PATCH] x86: Create clflush() inline, remove hardcoded wbinvd H. Peter Anvin
2007-07-20 21:27 ` Andi Kleen
2007-07-20 21:33 ` H. Peter Anvin
2007-07-22 9:18 ` Andi Kleen
2007-07-22 18:05 ` H. Peter Anvin
2007-07-22 19:55 ` Andi Kleen [this message]
2007-07-22 20:02 ` H. Peter Anvin
2007-07-20 23:37 ` Glauber de Oliveira Costa
2007-07-20 23:43 ` H. Peter Anvin
2007-07-21 18:11 ` Muli Ben-Yehuda
2007-07-21 19:52 ` H. Peter Anvin
2007-07-21 20:16 ` Muli Ben-Yehuda
2007-07-21 20:18 ` H. Peter Anvin
2007-07-21 20:44 ` Muli Ben-Yehuda
2007-07-21 22:09 ` H. Peter Anvin
2007-07-21 22:24 ` H. Peter Anvin
2007-07-22 4:20 ` Muli Ben-Yehuda
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