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mycjjjhhh



Joined: 21 Sep 2010
Posts: 2
mycjjjhhh
In X86 paged mode,
when CPU fetch instruction, whether the A bit of page directory item and page table item about code page are set or not?

I think not ,because it's not data access? I'm right or wrong?
Post 21 Sep 2010, 12:11
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
mycjjjhhh,

Why do you think there's some mistery in this bit behavior?
Intel SDM, vol. 3, rev. 034, p. 4-39 wrote:
Whenever the processor uses a paging-structure entry as part of linear-address translation, it sets the accessed flag in that entry (if it is not already set).
This subchapter (4.8 ACCESSED AND DIRTY FLAGS) even addresses issues with executing code from the same page where its PTE resides.
Post 21 Sep 2010, 13:20
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