linux-kernel - Re: [PATCH v4 0/3] Fix CPER issues related to UEFI 2.9A Errata

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Message-ID: <20240621172645.21082af3@coco.lan>
Date: Fri, 21 Jun 2024 17:26:45 +0200
From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To: Ard Biesheuvel <ardb@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>, Tony Luck <tony.luck@...el.com>, James
 Morse <james.morse@....com>, Jonathan Cameron
 <Jonathan.Cameron@...wei.com>, Shiju Jose <shiju.jose@...wei.com>,
 linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-edac@...r.kernel.org, Len Brown <lenb@...nel.org>,
 linux-acpi@...r.kernel.org
Subject: Re: [PATCH v4 0/3] Fix CPER issues related to UEFI 2.9A Errata

Hi Ard,

Em Fri, 21 Jun 2024 09:45:16 +0200
Ard Biesheuvel <ardb@...nel.org> escreveu:

> On Thu, 20 Jun 2024 at 20:01, Mauro Carvalho Chehab
> <mchehab+huawei@...nel.org> wrote:
> >
> > The UEFI 2.9A errata makes clear how ARM processor type encoding should
> > be done: it is meant to be equal to Generic processor, using a bitmask.
> >
> > The current code assumes, for both generic and ARM processor types
> > that this is an integer, which is an incorrect assumption.
> >
> > Fix it. While here, also fix a compilation issue when using W=1.
> >
> > After the change, Kernel will properly decode receiving two errors at the same
> > message, as defined at UEFI spec:
> >
> > [   75.282430] Memory failure: 0x5cdfd: recovery action for free buddy page: Recovered
> > [   94.973081] {2}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1
> > [   94.973770] {2}[Hardware Error]: event severity: recoverable
> > [   94.974334] {2}[Hardware Error]:  Error 0, type: recoverable
> > [   94.974962] {2}[Hardware Error]:   section_type: ARM processor error
> > [   94.975586] {2}[Hardware Error]:   MIDR: 0x000000000000cd24
> > [   94.976202] {2}[Hardware Error]:   Multiprocessor Affinity Register (MPIDR): 0x000000000000ab12
> > [   94.977011] {2}[Hardware Error]:   error affinity level: 2
> > [   94.977593] {2}[Hardware Error]:   running state: 0x1
> > [   94.978135] {2}[Hardware Error]:   Power State Coordination Interface state: 4660
> > [   94.978884] {2}[Hardware Error]:   Error info structure 0:
> > [   94.979463] {2}[Hardware Error]:   num errors: 3
> > [   94.979971] {2}[Hardware Error]:    first error captured
> > [   94.980523] {2}[Hardware Error]:    propagated error captured
> > [   94.981110] {2}[Hardware Error]:    overflow occurred, error info is incomplete
> > [   94.981893] {2}[Hardware Error]:    error_type: 0x0006: cache error|TLB error
> > [   94.982606] {2}[Hardware Error]:    error_info: 0x000000000091000f
> > [   94.983249] {2}[Hardware Error]:     transaction type: Data Access
> > [   94.983891] {2}[Hardware Error]:     cache error, operation type: Data write
> > [   94.984559] {2}[Hardware Error]:     TLB error, operation type: Data write
> > [   94.985215] {2}[Hardware Error]:     cache level: 2
> > [   94.985749] {2}[Hardware Error]:     TLB level: 2
> > [   94.986277] {2}[Hardware Error]:     processor context not corrupted
> >
> > And the error code is properly decoded according with table N.17 from UEFI 2.10
> > spec:
> >
> >         [   94.981893] {2}[Hardware Error]:    error_type: 0x0006: cache error|TLB error
> >
> > Mauro Carvalho Chehab (3):
> >   efi/cper: Adjust infopfx size to accept an extra space
> >   efi/cper: Add a new helper function to print bitmasks
> >   efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs
> >  
> 
> Hello Mauro,
> 
> How this is v4 different from the preceding 3 revisions that you sent
> over the past 2 days?
> 
> I would expect an experienced maintainer like yourself to be familiar
> with the common practice here: please leave some time between sending
> revisions so people can take a look. And if there is a pressing need
> to deviate from this rule, at least put an explanation in the commit
> log of how the series differs from the preceding one.

Sorry, I'll add a version review on that. Basically I was missing a
test environment to do error injection. When I got it enabled, and fixed
to cope with UEFI 2.9A/2.10 expected behavior, I was able to discover 
some issues and to do some code improvements.

v1: 
- (tagged as RFC) was mostly to give a heads up that the current 
  implementation is not following the spec. It also touches
  only cper code.

v2:
- It fixes the way printks are handled on both cper_arm and ghes
  drivers;

v3:
- It adds a helper function to produce a buffer describing the
  error bits at cper's printk and ghes pr_warn_bitrated. It also
  fixes a W=1 error while building cper;

v4:
- The print function had some bugs on it, which was discovered with
  the help of an error injection tool I'm now using.

I have already another version ready to send. It does some code
cleanup and address the issues pointed by Tony and Jonathan. If you
prefer, I can hold it until Monday to give you some time to look
at it.

Thanks,
Mauro