Re: [PATCH 4/7] x86, mce: create helper function to save addr/miscwhen needed

From: Borislav Petkov
Date: Wed Dec 14 2011 - 11:09:40 EST


On Tue, Dec 13, 2011 at 09:44:07AM -0800, Luck, Tony wrote:
> > Am I reading this correctly in that you need to cut off the same amount
> > of bits on both sides of MCi_ADDR and the address magnitude coincides
> > with the left shift amount? I.e. and for example, if MCi_ADDR[44:3]
> > and you need to cut off 3 bits of both sides to get a 48-bit physical
> > address?
>
> No - just masking bits at the low end (shift right and the bits we don't
> want fall into the bit bucket, shift left by the same amount and we fill
> those spots with zeroes). Upper bits are unchanged.

Doh, of course, I must be drunk. Please disregard this comment.

>
> I could write it as:
> m->addr &= ~((1ull << shift) - 1);

>
> But I think the shift-right, shift-left is used elsewhere in the kernel too.

No, yours is fine.

ACK.

--
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/