On Fri, Jan 20, 2023 at 09:03:55AM -0800, Song Liu wrote:

quoted

quoted

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Shouldn't there also be a fix for this powerpc issue?

There was a working version, but it was not very clean. We couldn't agree
on the path forward for powerpc, so we are hoping to ship the fix to x86 (and
s390?) first [1].

Sorry for coming in late, I was on leave so I missed a lot of the
discussions on previous versions.  The decision to leave powerpc broken
wasn't clear from reading the commit message.  The bug is mentioned, and
the fix is implied, but surprisingly there's no fix.

I agree that the powerpc fix should be in a separate patch, but I still
don't feel comfortable merging the x86 fix without the corresponding
powerpc fix.

powerpc is a major arch and not a second-class citizen.  If we don't fix
it now then it'll probably never get fixed until it blows up in the real
world.

For powerpc, instead of clearing, how about just "fixing" the warning
site, something like so (untested)?

This version looks reasonable to me.

Ok, I'll run it through testing and work up a proper patch.  I just
noticed the one I posted has a major bug thanks to restore_r2()'s
surprising return semantics.

-- 
Josh