Messages in this thread | | | Date | Sun, 30 May 2010 11:36:16 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86, hweight: Fix UML boot crash |
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On 05/30/2010 10:03 AM, Borislav Petkov wrote: > Obviously UML cannot stomach callee reg-saving trickery > introduced with d61931d89be506372d01a90d1755f6d0a9fafe2d (x86: > Add optimized popcnt variants) and oopses during boot: > http://marc.info/?l=linux-kernel&m=127522065202435&w=2 > > Go ahead and fall back to the software hweight* routines on UML.
I actually don't understand why UML can't stomach that... it would work exactly the same in userspace as in kernel space. The only thing that I can think of is if UML overrides the CFLAGS including the per-file CFLAGS, but that would seem to cause all kinds of other issues.
I would also be a lot happier if this was handled in <asm/arch_hweight.h> than in <asm/bitops.h>. Finally, if UML really can't handle this, then ARCH_HWEIGHT_CFLAGS should be disabled on UML.
This bothers me, because it really feels like something is fundamentally broken in UML tryingto track the upstream architecture, and this is just a bandage.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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