Re: [PATCH] x86: Disable 4MB page tables for Atom, work around errataAAE44

From: Jeremy Fitzhardinge
Date: Wed Mar 31 2010 - 18:35:58 EST


On 03/22/2010 08:20 AM, Colin King wrote:
"If software clears the PS (page size) bit in a present PDE (page directory
entry), that will cause linear addresses mapped through this PDE to use
4-KByte pages instead of using a large page after old TLB entries are
invalidated. Due to this erratum, if a code fetch uses this PDE before the
TLB entry for the large page is invalidated then it may fetch from a different
physical address than specified by either the old large page translation or
the new 4-KByte page translation. This erratum may also cause speculative code
fetches from incorrect addresses."

Does this only affect non-PAE 32-bit? Or does it also affect 3 and 4 level pagetables with 2MB large pages?

J
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