Messages in this thread | | | Date | Tue, 10 Nov 2009 08:47:23 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v4] [x86] detect and report lack of NX protections |
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On 11/10/2009 07:49 AM, Kees Cook wrote: >> >> The second clause can only get executed if CONFIG_X86_PAE is unset, >> which in turn means _PAGE_NX == 0... so that piece of code is meaningless. > > CONFIG_X86_PAE is unset for x86_64, where _PAGE_NX is valid. (This was > the main situation I was trying to address.) So that chunk runs for > non-pae 32bit, and all 64bit: >
In reality, X86_PAE really should have been defined for 64 bits, since 64 bits really is PAE in most aspects.
Anyway, for the 64-bit case it looks like the proper place for any of this is in check_efer() just below, not in this null routine.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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