Re: [PATCH v2 3/4] x86, head_32/64.S: Enable SMEP

[Matthew Garrett]

On Mon, May 16, 2011 at 02:34:44PM -0700, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> 
> Enable newly documented SMEP (Supervisor Mode Execution Protection) CPU
> feature in kernel.
> 
> SMEP prevents the CPU in kernel-mode to jump to an executable page that does
> not have the kernel/system flag set in the pte. This prevents the kernel
> from executing user-space code accidentally or maliciously, so it for example
> prevents kernel exploits from jumping to specially prepared user-mode shell
> code. The violation will cause page fault #PF and will have error code
> identical to XD violation.

Are EFI runtime service pages currently set up appropriately?

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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