Re: [PATCH] x86/asm/entry/64: better check for canonical address

[Andy Lutomirski]

On Tue, Apr 21, 2015 at 9:27 AM, Denys Vlasenko <dvlasenk@xxxxxxxxxx> wrote:
> This change makes the check exact (no more false positives
> on "negative" addresses).

Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>

I'll take a full implementation of what Intel says over probably
unmeasurable performance.  If anyone in the AMD camp really cared, we
could add X86_BUG_SYSRET_NEEDS_CANONICAL_RCX and use alternatives to
patch this out on AMD.  I doubt this would buy us much.

--Andy
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