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Date: Thu, 26 Feb 2026 23:00:38 +0100
From: hch <hch@lst.de>
To: Richard Weinberger <richard@nod.at>
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Subject: Re: [PATCH 03/25] um/xor: don't override XOR_SELECT_TEMPLATE
Message-ID: <20260226220038.GA15172@lst.de>
References: <20260226151106.144735-1-hch@lst.de> <20260226151106.144735-4-hch@lst.de> <445921547.2198.1772142326749.JavaMail.zimbra@nod.at>
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On Thu, Feb 26, 2026 at 10:45:26PM +0100, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
> > Von: "hch" <hch@lst.de>
> > XOR_SELECT_TEMPLATE is only ever called with a NULL argument, so all the
> > ifdef'ery doesn't do anything.  With our without this, the time travel
> > mode should work fine on CPUs that support AVX2, as the AVX2
> > implementation is forced in this case, and won't work otherwise.
> 
> IIRC Johannes added XOR_SELECT_TEMPLATE() here to skip
> the template selection logic because it didn't work with time travel mode.
> 
> Johannes, can you please test whether this change does not break
> time travel mode?

I'm pretty sure that was the intent, but as I wrote above it worked
and still works on AVX-supporting CPUs by chance, and already doesn't
on older CPUs, and unless my git blaming went wrong someewhere already
didn't when this was originally added.