Messages in this thread | | | Date | Tue, 20 May 2014 21:27:55 +0100 | From | Matt Fleming <> | Subject | Re: [GIT PULL] EFI changes for v3.16 |
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On Mon, 19 May, at 03:47:31PM, H. Peter Anvin wrote: > > How on earth does this solve anything? The only thing we add here is a > WARN_ON_ONCE()... but the above text already tells us we have a problem. > > It seems, rather, that we need to figure out how to deal with a pstore > in this case. There are a few possibilities: > > 1. We could keep an XSAVE buffer area around for this particular use. > I am *assuming* we don't let more than one CPU into EFI, because I > cannot for my life imagine that this is safe in typical CPUs.
Correct. This is actually prohibited by the spec, so we have a lock to enforce it.
> 2. Drop the pstore on the floor if !irq_fpu_usable(). > > 3. Allow the pstore, then die (on the assumption that we're dead > anyway.)
Personally, I'd prefer 2, but I'm open to suggestions.
-- Matt Fleming, Intel Open Source Technology Center
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