Re: PATCH: 3/6 [2nd try]: Add AVX support (i386 changes)

Mark Kettenis
2010-03-29T20:32:15Z

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> Date: Sun, 28 Mar 2010 07:24:53 -0700
> From: "H.J. Lu" <hjl.tools@gmail.com>
>
> > Anyway, how about setting the size of the .reg-xstate to
> > I386_XSTATE_SSE_SIZE unconditionally?  Tools will look at xcr0 value
> > encoded in there to determine what information in there is valid, so
> > dumping a little bit more than strictly necessary shouldn't be a
> > problem.
>
> That will make the code more complex since the generic gcore
> implementation will have to adjust section size based on XCR0.
> But if it is what is required, I will make the change.

Sorry, I think you're missing my point here. The idea is to make
gcore always write out a NT_XSTATE note that has the maximal size
(I386_XSTATE_MAX_SIZE, I now see I typed the wrong thing above). Then
when you write out the section, you fill the bits that aren't used
with zeroes and make sure the value of xcr0 stored in there is set
correctly.