Messages in this thread |  | | | Date | Sat, 26 Jul 2008 14:35:39 -0400 | | From | "H. Peter Anvin" <> | | Subject | Re: Bug on 2.6.26 - x86 VIA Nehemiah CentaurHauls processor cannot boot |
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Andi Kleen wrote: > > This was originally supposed to be handled in the early real mode > head.S code. That is why I put the CPUID checking code in there > to error out early when you can still print to the console > using the BIOS functions. > > I suspect this regressed when that code was moved to C, because > now the C compiler generates CMOV early. > > How about always building the real mode C code with -march=i386? > It is not performance critical so that is ok. >
The real mode code *is* compiled with -march=i386, and in the CMOV case it will err out with a legible message.
The issue isn't CMOV at all, it's with long NOPs, which don't have a CPUID bit -- they're supposed to be supported if family >= 6, but some VIA chips violate that condition.
-hpa
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