Re: [boot crash] Re: [tip:x86/mce3] x86, mce: use 64bit machinecheck code on 32bit

From: Ingo Molnar
Date: Mon Aug 17 2009 - 07:01:25 EST



* Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:

> Hidetoshi Seto wrote:
>
>> One possibility is: if the BIOS doesn't clear status in banks,
>> new mce codes will try to log such junks.
>>
>> If the junk is totally junk but can be decoded as a valid log
>> with MISCV or ADDRV bit, and if the cpu try to access register
>> which is not implemented (e.g. IA32_MCi_MISC/ADDR), then such
>> access might cause a general protection exception. (ref. ASDM 3A
>> 15.3.2.3)
>
> The MCA declares if it comes with ADDR or MISC in a status bit and
> the MCA code only accesses these MSRs if these status bits are
> set. Also I believe P3 implemented ADDR at least, likely even
> MISC.
>
> The old 32bit MCA code did that too

That's true, but did you also want to make a specific point?

Ingo
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