On Sat, 2015-02-28 at 13:49 -0800, Linus Torvalds wrote:

 .../...

 - we handle write faults separately (see the first part of access_error()

 - so now we know it was a read or an instruction fetch

 - if PF_PROT is set, that means that the present bit was set in the
page tables, so it must have been an exec access to a NX page

 - otherwise, we just say "PROTNONE means no access, otherwise
populate the page tables"

.. and if it turns out that it was a PF_INSTR to a NX page, we'll end
up taking the page fault *again* after it's been populated, and now
since the page table was populated, the access_error() will catch it
with the PF_PROT case.

Or something like that. I might have screwed up some detail, but it
should all work.

I see, it should work yes, I'll still add that FAULT_FLAG_EXEC for
those who can tell reliably but it shouldn't hurt for x86 to not set it.

Cheers,
Ben.

                     Linus
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