[PATCH v3 0/5] Fix issues with ARM Processor CPER records

[PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Mauro Carvalho Chehab]

This is needed for both kernelspace and userspace properly handle
ARM processor CPER events.

Patch 1 of this series fix the UEFI 2.6+ implementation of the ARM
trace event, as the original implementation was incomplete.
Changeset e9279e83ad1f ("trace, ras: add ARM processor error trace event")
added such event, but it reports only some fields of the CPER record
defined on UEFI 2.6+ appendix N, table N.16.  Those are not enough
actually parse such events on userspace, as not even the event type
is exported.

Patch 2 fixes a compilation breakage when W=1;

Patch 3 adds a new helper function to be used by cper and ghes drivers to
display CPER bitmaps;

Patch 4 fixes CPER logic according with UEFI 2.9A errata. Before it, there
was no description about how processor type field was encoded. The errata
defines it as a bitmask, and provides the information about how it should
be encoded.

Patch 5 adds CPER functions to Kernel-doc.

This series was validated with the help of an ARM EINJ code for QEMU:
	https://gitlab.com/mchehab_kernel/qemu/-/tree/qemu_submission_v5.1?ref_type=heads

	$ ./scripts/ghes_inject.py -d arm -m 2 4 -t tlb-error bus-error,micro-arch
	GUID: e19e3d16-bc11-11e4-9caa-c2051d5d46b0
	CPER:
	      00000000  04 00 00 00 02 00 00 00 68 00 00 00 00 00 00 00   ........h.......
	      00000010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
	      00000020  00 00 00 00 00 00 00 00 00 20 05 00 04 02 00 03   ......... ......
	      00000030  7f 00 54 00 00 00 00 00 ef be ad de 00 00 00 00   ..T.............
	      00000040  ad 0b ba ab 00 00 00 00 00 20 00 00 18 01 00 03   ......... ......
	      00000050  00 00 00 00 00 00 00 00 ef be ad de 00 00 00 00   ................
	      00000060  ad 0b ba ab 00 00 00 00                           ........

	Error injected.

The CPER event is now properly handled:

[   83.807957] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1
[   83.808314] {1}[Hardware Error]: event severity: recoverable
[   83.808545] {1}[Hardware Error]:  Error 0, type: recoverable
[   83.808806] {1}[Hardware Error]:   section_type: ARM processor error
[   83.809045] {1}[Hardware Error]:   MIDR: 0x0000000000000000
[   83.809262] {1}[Hardware Error]:   running state: 0x0
[   83.809441] {1}[Hardware Error]:   Power State Coordination Interface state: 0
[   83.809691] {1}[Hardware Error]:   Error info structure 0:
[   83.809885] {1}[Hardware Error]:   num errors: 3
[   83.810128] {1}[Hardware Error]:    error_type: 0x04: TLB error
[   83.810364] {1}[Hardware Error]:    error_info: 0x000000000054007f
[   83.810595] {1}[Hardware Error]:     transaction type: Instruction
[   83.810821] {1}[Hardware Error]:     TLB error, operation type: Instruction fetch
[   83.811095] {1}[Hardware Error]:     TLB level: 1
[   83.811283] {1}[Hardware Error]:     processor context not corrupted
[   83.811501] {1}[Hardware Error]:     the error has not been corrected
[   83.811721] {1}[Hardware Error]:     PC is imprecise
[   83.811924] {1}[Hardware Error]:   Error info structure 1:
[   83.812105] {1}[Hardware Error]:   num errors: 2
[   83.812263] {1}[Hardware Error]:    error_type: 0x18: bus error|micro-architectural error
[   83.812956] [Firmware Warn]: GHES: Unhandled processor error type 0x04: TLB error
[   83.813212] [Firmware Warn]: GHES: Unhandled processor error type 0x18: bus error|micro-architectural error

- 

I also tested the ghes and cper reports both with and without this
change, using different versions of rasdaemon, with and without
support for the extended trace event. Those are a summary of the
test results:

- adding more fields to the trace events didn't break userspace API:
  both versions of rasdaemon handled it;

- the rasdaemon patches to handle the new trace report was missing
  a backward-compatibility logic. I fixed already. So, rasdaemon
  can now handle both old and new trace events.

Btw, rasdaemon has gained support for the extended trace since its
version 0.5.8 (released in 2021). I didn't saw any issues there
complain about troubles on it, so either distros used on ARM servers
are using an old version of rasdaemon, or they're carrying on the trace
event changes as well.

---

v3:
 - rebased on the top of 6.11-rc1;
 - test example updated to reflect latest error-inj patch series submitted
   to qemu-devel

v2:
  - removed an uneeded patch adding #ifdef for CONFIG_ARM/ARM64;
  - cper_bits_to_str() now returns the number of chars filled at the buffer;
  - did a cosmetic (blank lines) improvement at include/linux/ras.h;
  - arm_event trace dynamic arrays renamed to pei_buf/ctx_buf/oem_buf.
    

Daniel Ferguson (1):
  RAS: Report all ARM processor CPER information to userspace

Mauro Carvalho Chehab (4):
  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
  docs: efi: add CPER functions to driver-api

 .../driver-api/firmware/efi/index.rst         | 11 ++--
 drivers/acpi/apei/ghes.c                      | 26 +++++-----
 drivers/firmware/efi/cper-arm.c               | 52 +++++++++----------
 drivers/firmware/efi/cper.c                   | 45 +++++++++++++++-
 drivers/ras/ras.c                             | 45 +++++++++++++++-
 include/linux/cper.h                          | 12 +++--
 include/linux/ras.h                           | 16 ++++--
 include/ras/ras_event.h                       | 48 +++++++++++++++--
 8 files changed, 196 insertions(+), 59 deletions(-)

-- 
2.45.2

[PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Mauro Carvalho Chehab]

This is needed for both kernelspace and userspace properly handle
ARM processor CPER events.

Patch 1 of this series fix the UEFI 2.6+ implementation of the ARM
trace event, as the original implementation was incomplete.
Changeset e9279e83ad1f ("trace, ras: add ARM processor error trace event")
added such event, but it reports only some fields of the CPER record
defined on UEFI 2.6+ appendix N, table N.16.  Those are not enough
actually parse such events on userspace, as not even the event type
is exported.

Patch 2 fixes a compilation breakage when W=1;

Patch 3 adds a new helper function to be used by cper and ghes drivers to
display CPER bitmaps;

Patch 4 fixes CPER logic according with UEFI 2.9A errata. Before it, there
was no description about how processor type field was encoded. The errata
defines it as a bitmask, and provides the information about how it should
be encoded.

Patch 5 adds CPER functions to Kernel-doc.

This series was validated with the help of an ARM EINJ code for QEMU:

	https://gitlab.com/mchehab_kernel/qemu/-/tree/qemu_submission

$ scripts/ghes_inject.py -d arm -p 0xdeadbeef -t cache,bus,micro-arch

[   11.094205] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 0
[   11.095009] {1}[Hardware Error]: event severity: recoverable
[   11.095486] {1}[Hardware Error]:  Error 0, type: recoverable
[   11.096090] {1}[Hardware Error]:   section_type: ARM processor error
[   11.096399] {1}[Hardware Error]:   MIDR: 0x00000000000f0510
[   11.097135] {1}[Hardware Error]:   Multiprocessor Affinity Register (MPIDR): 0x0000000080000000
[   11.097811] {1}[Hardware Error]:   running state: 0x0
[   11.098193] {1}[Hardware Error]:   Power State Coordination Interface state: 0
[   11.098699] {1}[Hardware Error]:   Error info structure 0:
[   11.099174] {1}[Hardware Error]:   num errors: 2
[   11.099682] {1}[Hardware Error]:    error_type: 0x1a: cache error|bus error|micro-architectural error
[   11.100150] {1}[Hardware Error]:    physical fault address: 0x00000000deadbeef
[   11.111214] Memory failure: 0xdeadb: recovery action for free buddy page: Recovered

- 

I also tested the ghes and cper reports both with and without this
change, using different versions of rasdaemon, with and without
support for the extended trace event. Those are a summary of the
test results:

- adding more fields to the trace events didn't break userspace API:
  both versions of rasdaemon handled it;

- the rasdaemon patches to handle the new trace report was missing
  a backward-compatibility logic. I fixed already. So, rasdaemon
  can now handle both old and new trace events.

Btw, rasdaemon has gained support for the extended trace since its
version 0.5.8 (released in 2021). I didn't saw any issues there
complain about troubles on it, so either distros used on ARM servers
are using an old version of rasdaemon, or they're carrying on the trace
event changes as well.

---

v3:
 - history of patch 1 improved with a chain of co-developed-by;
 - add a better description and an example on patch 3;
 - use BIT_ULL() on patch 3;
 - add a missing include on patch 4.

v2:
  - removed an uneeded patch adding #ifdef for CONFIG_ARM/ARM64;
  - cper_bits_to_str() now returns the number of chars filled at the buffer;
  - did a cosmetic (blank lines) improvement at include/linux/ras.h;
  - arm_event trace dynamic arrays renamed to pei_buf/ctx_buf/oem_buf.
    


Jason Tian (1):
  RAS: Report all ARM processor CPER information to userspace

Mauro Carvalho Chehab (4):
  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
  docs: efi: add CPER functions to driver-api

 .../driver-api/firmware/efi/index.rst         | 11 +++-
 drivers/acpi/apei/ghes.c                      | 27 ++++----
 drivers/firmware/efi/cper-arm.c               | 52 ++++++++--------
 drivers/firmware/efi/cper.c                   | 62 ++++++++++++++++++-
 drivers/ras/ras.c                             | 41 +++++++++++-
 include/linux/cper.h                          | 12 ++--
 include/linux/ras.h                           | 16 ++++-
 include/ras/ras_event.h                       | 48 ++++++++++++--
 8 files changed, 210 insertions(+), 59 deletions(-)

-- 
2.46.0

[PATCH v3 5/5] docs: efi: add CPER functions to driver-api

[Mauro Carvalho Chehab]

There are two kernel-doc like descriptions at cper, which is used
by other parts of cper and on ghes driver. They both have kernel-doc
like descriptions.

Change the tags for them to be actual kernel-doc tags and add them
to the driver-api documentaion at the UEFI section.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 Documentation/driver-api/firmware/efi/index.rst | 11 ++++++++---
 drivers/firmware/efi/cper.c                     |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Documentation/driver-api/firmware/efi/index.rst b/Documentation/driver-api/firmware/efi/index.rst
index 4fe8abba9fc6..5a6b6229592c 100644
--- a/Documentation/driver-api/firmware/efi/index.rst
+++ b/Documentation/driver-api/firmware/efi/index.rst
@@ -1,11 +1,16 @@
 .. SPDX-License-Identifier: GPL-2.0
 
-============
-UEFI Support
-============
+====================================================
+Unified Extensible Firmware Interface (UEFI) Support
+====================================================
 
 UEFI stub library functions
 ===========================
 
 .. kernel-doc:: drivers/firmware/efi/libstub/mem.c
    :internal:
+
+UEFI Common Platform Error Record (CPER) functions
+==================================================
+
+.. kernel-doc:: drivers/firmware/efi/cper.c
diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index f60fe7367e3b..4d2dfcc746b6 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -70,7 +70,7 @@ const char *cper_severity_str(unsigned int severity)
 }
 EXPORT_SYMBOL_GPL(cper_severity_str);
 
-/*
+/**
  * cper_print_bits - print strings for set bits
  * @pfx: prefix for each line, including log level and prefix string
  * @bits: bit mask
-- 
2.46.0

Re: [PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Borislav Petkov]

On Wed, Sep 04, 2024 at 08:07:13AM +0200, Mauro Carvalho Chehab wrote:
> Jason Tian (1):
>   RAS: Report all ARM processor CPER information to userspace
> 
> Mauro Carvalho Chehab (4):
>   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
>   docs: efi: add CPER functions to driver-api
> 
>  .../driver-api/firmware/efi/index.rst         | 11 +++-
>  drivers/acpi/apei/ghes.c                      | 27 ++++----
>  drivers/firmware/efi/cper-arm.c               | 52 ++++++++--------
>  drivers/firmware/efi/cper.c                   | 62 ++++++++++++++++++-
>  drivers/ras/ras.c                             | 41 +++++++++++-
>  include/linux/cper.h                          | 12 ++--
>  include/linux/ras.h                           | 16 ++++-
>  include/ras/ras_event.h                       | 48 ++++++++++++--
>  8 files changed, 210 insertions(+), 59 deletions(-)

With the issues to patch 1 fixed:

Acked-by: Borislav Petkov (AMD) <bp@alien8.de>

I'm presuming this'll go through Ard's tree. Alternatively, I can pick it up
too with Ard's ack.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Ard Biesheuvel]

On Fri, 11 Oct 2024 at 13:57, Borislav Petkov <bp@alien8.de> wrote:
>
> On Wed, Sep 04, 2024 at 08:07:13AM +0200, Mauro Carvalho Chehab wrote:
> > Jason Tian (1):
> >   RAS: Report all ARM processor CPER information to userspace
> >
> > Mauro Carvalho Chehab (4):
> >   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
> >   docs: efi: add CPER functions to driver-api
> >
> >  .../driver-api/firmware/efi/index.rst         | 11 +++-
> >  drivers/acpi/apei/ghes.c                      | 27 ++++----
> >  drivers/firmware/efi/cper-arm.c               | 52 ++++++++--------
> >  drivers/firmware/efi/cper.c                   | 62 ++++++++++++++++++-
> >  drivers/ras/ras.c                             | 41 +++++++++++-
> >  include/linux/cper.h                          | 12 ++--
> >  include/linux/ras.h                           | 16 ++++-
> >  include/ras/ras_event.h                       | 48 ++++++++++++--
> >  8 files changed, 210 insertions(+), 59 deletions(-)
>
> With the issues to patch 1 fixed:
>
> Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
>
> I'm presuming this'll go through Ard's tree. Alternatively, I can pick it up
> too with Ard's ack.
>

Either works for me.

Mauro: please put all maintainers on cc of the code you are touching - thanks.

Re: [PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Daniel Ferguson]

On 10/14/2024 3:00 AM, Ard Biesheuvel wrote:
> On Fri, 11 Oct 2024 at 13:57, Borislav Petkov <bp@alien8.de> wrote:
>>
>> On Wed, Sep 04, 2024 at 08:07:13AM +0200, Mauro Carvalho Chehab wrote:
>>> Jason Tian (1):
>>>   RAS: Report all ARM processor CPER information to userspace
>>>
>>> Mauro Carvalho Chehab (4):
>>>   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
>>>   docs: efi: add CPER functions to driver-api
>>>
>>>  .../driver-api/firmware/efi/index.rst         | 11 +++-
>>>  drivers/acpi/apei/ghes.c                      | 27 ++++----
>>>  drivers/firmware/efi/cper-arm.c               | 52 ++++++++--------
>>>  drivers/firmware/efi/cper.c                   | 62 ++++++++++++++++++-
>>>  drivers/ras/ras.c                             | 41 +++++++++++-
>>>  include/linux/cper.h                          | 12 ++--
>>>  include/linux/ras.h                           | 16 ++++-
>>>  include/ras/ras_event.h                       | 48 ++++++++++++--
>>>  8 files changed, 210 insertions(+), 59 deletions(-)
>>
>> With the issues to patch 1 fixed:
>>
>> Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
>>
>> I'm presuming this'll go through Ard's tree. Alternatively, I can pick it up
>> too with Ard's ack.
>>
> 
> Either works for me.
> 
> Mauro: please put all maintainers on cc of the code you are touching - thanks.

What can I do to help this patch move forward?
I noticed it needs to be rebased as of kernel v6.15.

Would it be helpful if I were to rebase, add all the maintainers to the cc, and
resubmit ?

I did rebase to v6.15 and tested. Everything still seems good to go.

Re: [PATCH v3 0/5] Fix issues with ARM Processor CPER records

[Ard Biesheuvel]

On Fri, 6 Jun 2025 at 20:30, Daniel Ferguson
<danielf@os.amperecomputing.com> wrote:
>
>
>
> On 10/14/2024 3:00 AM, Ard Biesheuvel wrote:
> > On Fri, 11 Oct 2024 at 13:57, Borislav Petkov <bp@alien8.de> wrote:
> >>
> >> On Wed, Sep 04, 2024 at 08:07:13AM +0200, Mauro Carvalho Chehab wrote:
> >>> Jason Tian (1):
> >>>   RAS: Report all ARM processor CPER information to userspace
> >>>
> >>> Mauro Carvalho Chehab (4):
> >>>   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
> >>>   docs: efi: add CPER functions to driver-api
> >>>
> >>>  .../driver-api/firmware/efi/index.rst         | 11 +++-
> >>>  drivers/acpi/apei/ghes.c                      | 27 ++++----
> >>>  drivers/firmware/efi/cper-arm.c               | 52 ++++++++--------
> >>>  drivers/firmware/efi/cper.c                   | 62 ++++++++++++++++++-
> >>>  drivers/ras/ras.c                             | 41 +++++++++++-
> >>>  include/linux/cper.h                          | 12 ++--
> >>>  include/linux/ras.h                           | 16 ++++-
> >>>  include/ras/ras_event.h                       | 48 ++++++++++++--
> >>>  8 files changed, 210 insertions(+), 59 deletions(-)
> >>
> >> With the issues to patch 1 fixed:
> >>
> >> Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
> >>
> >> I'm presuming this'll go through Ard's tree. Alternatively, I can pick it up
> >> too with Ard's ack.
> >>
> >
> > Either works for me.
> >
> > Mauro: please put all maintainers on cc of the code you are touching - thanks.
>
> What can I do to help this patch move forward?
> I noticed it needs to be rebased as of kernel v6.15.
>
> Would it be helpful if I were to rebase, add all the maintainers to the cc, and
> resubmit ?
>

Yes, please. And make sure you incorporate Boris's feedback on patch
#1 and apply his conditional ack.

Thanks,