Messages in this thread | | | Date | Tue, 9 Dec 2008 12:15:08 +0100 | From | Andi Kleen <> | Subject | Re: x86-64: __pa_symbol() vs. __pa() |
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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
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