Re: [PATCH] x86/asm/entry/64: Use shorter MOVs from segmers registers

[Linus Torvalds]

On Thu, May 14, 2015 at 10:05 AM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> I don't object to the patch, but did we actually confirm that it
> always overwrites all of %ecx?

Just to clarify: I don't object to the patch because the code doesn't
actually end up *depending* on the high bits anyway, and does
word-sized compares etc. And the instruction size and speed things I
don't doubt. So it's just the commit message I wanted to check wrt
that whole "always overwrites all of %ecx". Because older CPU's didn't
necessarily (things like partial register writes are much less of an
issue when you're in-order and stupid ;)

                        Linus
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