Re: [PATCH 1/4] x86: entry.S: tidy up several suboptimal insns

[H. Peter Anvin]

On 02/24/2015 12:36 PM, Borislav Petkov wrote:
> On Tue, Feb 24, 2015 at 09:13:03PM +0100, Denys Vlasenko wrote:
>> They aren't equal.  $1 and $2 in two lowest bits will also
>> be interpreted as "userspace" here. "Equal to $3" sends
>> a wrong message here to a human reading the code,
>> the code doesn't test for CPL=3, it tests for any nonzero CPL.
> 
> Doh, of course.
> 
> I was going to propose to make it even more explicit:
> 
> 	andb $3, CS(%rsp)...
> 
> but that's destructive.
> 
> So yours makes it less misleading, actually. To me at least and
> obviously.
> 

Yes, please use JZ/JNZ with TEST.

	-hpa


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