From: Andi Kleen <andi@firstfloor.org>
To: Jan Beulich <jbeulich@novell.com>
Cc: mingo@elte.hu, Andi Kleen <andi@firstfloor.org>,
tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org
Subject: Re: x86-64: __pa_symbol() vs. __pa()
Date: Tue, 9 Dec 2008 12:15:08 +0100 [thread overview]
Message-ID: <20081209111508.GB23556@one.firstfloor.org> (raw)
In-Reply-To: <493E50DE.76E4.0078.0@novell.com>
On Tue, Dec 09, 2008 at 10:05:02AM +0000, Jan Beulich wrote:
> Can any of you recall the reason for the comment accompanying the
> __pa_symbol() definition:
>
> /* __pa_symbol should be used for C visible symbols.
> This seems to be the official gcc blessed way to do such arithmetic. */
gcc assumes that such symbol arithmetic doesn't wrap. iirc there was a
miscompilation on PPC64 because of that and then it was fixed
everywhere. On x86-64 there are normally no wraps, but there might
be in some cases.
-Andi
prev parent reply other threads:[~2008-12-09 11:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-09 10:05 Jan Beulich
2008-12-09 11:15 ` Andi Kleen [this message]
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