Re: i686 quirk for AMD Geode

From: Matt Thrailkill
Date: Wed Nov 11 2009 - 21:23:42 EST


On Wed, Nov 11, 2009 at 1:32 AM, Willy Tarreau <w@xxxxxx> wrote:
> All I can say is that executing a NOP results in no state change in
> the processor except the instruction pointer which points to the
> next instruction after execution. Since a NOP changes nothing, it
> cannot be used alone to provide any privilege, access to data or
> any such thing. Since it does not perform any jump, it cannot either
> be used to take back control of the execution flow. And it is certain
> that the next instruction after it will be executed, so if the NOP
> crosses a page boundary and completes on a non-executable one, the
> next instruction will trigger the PF.
>
> So I can't see how a NOP can be used to circumvent any protection.

So a nop(l) sled won't be a problem, right?
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