Messages in this thread | | | Date | Wed, 30 Jun 2004 15:38:50 +0100 | From | Jamie Lokier <> | Subject | Re: Do x86 NX and AMD prefetch check cause page fault infinite loop? |
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On x86 and x86-64 with NX, is a fault due to non-exec permission distinguishable from a fault due to lack of read/write permissions?
I.e. does the flags word have a different bit set?
If so, the solution is simple: don't just return if it's a non-exec fault.
(It's possible that won't work if the CPU is very speculative and generates data faults from prefetches despite them being in non-exec area -- i.e. if the buggy data fault gets precedence over the non-exec fault or segment. But I'd hope that's not the case).
-- Jamie
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