Re: [PATCH 3/4] x86/mce: Clarify comments regarding deferred error

From: Borislav Petkov
Date: Wed Feb 24 2016 - 06:37:51 EST


On Tue, Feb 23, 2016 at 05:02:40PM -0600, Aravind Gopalakrishnan wrote:
> On 2/23/16 6:11 AM, Borislav Petkov wrote:
> >On Tue, Feb 16, 2016 at 03:45:10PM -0600, Aravind Gopalakrishnan wrote:
> >> /* AMD-specific bits */
> >>-#define MCI_STATUS_DEFERRED (1ULL<<44) /* declare an uncorrected error */
> >>+#define MCI_STATUS_DEFERRED (1ULL<<44) /* declare a deferred error */
> >/* uncorrected error, deferred exception */
> >
> >sounds better to me.
>
> Hmm. Well, Deferred error is a separate class of error by itself.
> It's neither Corrected in HW nor is it Uncorrected like a MCE.

Let's consult the BKDG:

"Deferred: deferred error.

Read-write; Updated-by-hardware. Cold reset:0.
1=A deferred error was created. A deferred error is the result of an
uncorrectable data error which did not immediately cause a processor
exception; the data is poisoned and an exception is deferred until
the data is loaded by a core. See 2.16.1.10 [Deferred Errors and Data
Poisoning]."

So it is an uncorrected error for which the raising of the error
exception was deferred until consumption.

> If you feel "Uncorrected error, deferred error exception" won;t be
> confusing, that's OK with me.

Why would it be confusing? It is describing exactly what a deferred
error is, albeit a bit too laconic but people can find the longer
description.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.