Re: [PATCH v2 07/15] x86/lib/copy_user_64.S: Convert to ALTERNATIVE_2

[Ingo Molnar]

* Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Wed, Mar 04, 2015 at 08:13:24AM +0100, Ingo Molnar wrote:
> > Btw., the x86 memset() variants are using this today, and I think this 
> > is the most optimal jump-patching variant, even if it means a small 
> > amount of code duplication between the copy_user variants.
> 
> Yeah, the problem with that one was that we patch a huge amount of code,
> see the dump below.
> 
> The X86_FEATURE_REP_GOOD thing replaces a 172 bytes memset with the 
> 42 byte REP;STOSQ version and the X86_FEATURE_ERMS does the same 
> with REP;STOSB.

So I'd not patch in the large _orig variant, it's legacy mostly - but 
the two fast variants?

Thanks,

	Ingo
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