Messages in this thread | | | Date | Tue, 22 Jul 2008 15:46:01 +0200 | From | Ingo Molnar <> | Subject | Re: Bug on 2.6.26 - x86 VIA Nehemiah CentaurHauls processor cannot boot |
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* H. Peter Anvin <hpa@zytor.com> wrote:
> Ingo Molnar wrote: >>> >>> Not a bug. >> >> it would still be nice to get a nice printk and panic during bootup >> instead of some obscure crash, hm? >> > > Yes. The fundamental problem is that Centaur has a set of CPUs which > report family == 6 but don't have the long NOP instructions. We would > need an exact CPUID criterion for these CPUs in order to be able to > report it as an error. An alternative would be to attempt trapping in > the real-mode code (#UD is one of the *very* few CPU exceptions which > can be reliably captured in real mode on a BIOS system), but doing so > would probably mean breaking Loadlin at the very least. > > We can't "printk and panic" because we never get that far in the > kernel proper, for obvious reasons: the code is quite littered with > these buggers.
hm. How about to default to a safe NOP all the way up to where we can fix up alternatives and install a different NOP. (which we could also test first via intentionally jumping on it and catching any exception via a special exception handler)
Ingo
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