linux-kernel - Re: [PATCH v4 9/9] ACPI: APEI: EINJ: Update the documentation for EINJv2 support

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Message-ID: <20250313095915.00000847@huawei.com>
Date: Thu, 13 Mar 2025 09:59:15 +0000
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Zaid Alali <zaidal@...amperecomputing.com>
CC: <rafael@...nel.org>, <lenb@...nel.org>, <james.morse@....com>,
	<tony.luck@...el.com>, <bp@...en8.de>, <robert.moore@...el.com>,
	<dan.j.williams@...el.com>, <Benjamin.Cheatham@....com>,
	<Avadhut.Naik@....com>, <viro@...iv.linux.org.uk>, <arnd@...db.de>,
	<ira.weiny@...el.com>, <dave.jiang@...el.com>,
	<sthanneeru.opensrc@...ron.com>, <linux-acpi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <acpica-devel@...ts.linux.dev>
Subject: Re: [PATCH v4 9/9] ACPI: APEI: EINJ: Update the documentation for
 EINJv2 support

On Thu,  6 Mar 2025 15:48:10 -0800
Zaid Alali <zaidal@...amperecomputing.com> wrote:

> Add documentation for the updated ACPI specs for EINJv2(1)(2)
> 
> (1)https://bugzilla.tianocore.org/show_bug.cgi?id=4615
> (2)https://bugzilla.tianocore.org/attachment.cgi?id=1446
> 
> Signed-off-by: Zaid Alali <zaidal@...amperecomputing.com>
> ---
>  .../firmware-guide/acpi/apei/einj.rst         | 41 ++++++++++++++++++-
>  1 file changed, 39 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/firmware-guide/acpi/apei/einj.rst b/Documentation/firmware-guide/acpi/apei/einj.rst
> index c52b9da08fa9..31c848183af0 100644
> --- a/Documentation/firmware-guide/acpi/apei/einj.rst
> +++ b/Documentation/firmware-guide/acpi/apei/einj.rst
> @@ -59,6 +59,9 @@ The following files belong to it:
>    0x00000200        Platform Correctable
>    0x00000400        Platform Uncorrectable non-fatal
>    0x00000800        Platform Uncorrectable fatal
> +  V2_0x00000001     EINJV2 Processor Error
> +  V2_0x00000002     EINJV2 Memory Error
> +  V2_0x00000004     EINJV2 PCI Express Error
>    ================  ===================================
>  
>    The format of the file contents are as above, except present are only
> @@ -85,9 +88,11 @@ The following files belong to it:
>      Bit 0
>        Processor APIC field valid (see param3 below).
>      Bit 1
> -      Memory address and mask valid (param1 and param2).
> +      Memory address and range valid (param1 and param2).

So was this a bug technically before?  If it was maybe separate
patch.


>      Bit 2
>        PCIe (seg,bus,dev,fn) valid (see param4 below).
> +    Bit 3
> +      EINJv2 extension structure is valid
>  
>    If set to zero, legacy behavior is mimicked where the type of
>    injection specifies just one bit set, and param1 is multiplexed.
> @@ -110,6 +115,7 @@ The following files belong to it:
>    Used when the 0x1 bit is set in "flags" to specify the APIC id
>  
>  - param4
> +
This also shouldn't really be in a patch adding new stuff.
We should treat docs in similar fashion to code - if it is just whitespace
separate patch.

>    Used when the 0x4 bit is set in "flags" to specify target PCIe device
>  
>  - notrigger
> @@ -122,6 +128,18 @@ The following files belong to it:
>    this actually works depends on what operations the BIOS actually
>    includes in the trigger phase.
>  
> +- einjv2_component_count
> +
> +  The value from this file is used to set the "Component Array Count"
> +  field of EINJv2 Extension Structure.

Can we not parse this from the provided component array?  Why is separate
parameter useful?  You don't seem to write it below in the example.


> +
> +- einjv2_component_array
> +
> +  The contents of this file are used to set the "Component Array" field
> +  of the EINJv2 Extension Structure. The expected format is hex values
> +  for component id and syndrome separated by space, and multiple
> +  components are separated by new line.
> +
>  CXL error types are supported from ACPI 6.5 onwards (given a CXL port
>  is present). The EINJ user interface for CXL error types is at
>  <debugfs mount point>/cxl. The following files belong to it:
> @@ -139,7 +157,6 @@ is present). The EINJ user interface for CXL error types is at
>    under <debugfs mount point>/apei/einj, while CXL 1.1/1.0 port injections
>    must use this file.
>  
> -

Another white space change that shouldn't be in this patch in my view.

>  BIOS versions based on the ACPI 4.0 specification have limited options
>  in controlling where the errors are injected. Your BIOS may support an
>  extension (enabled with the param_extension=1 module parameter, or boot
> @@ -194,6 +211,26 @@ An error injection example::
>    # echo 0x8 > error_type			# Choose correctable memory error
>    # echo 1 > error_inject			# Inject now
>  
> +An EINJv2 error injection example::
> +
> +  # cd /sys/kernel/debug/apei/einj
> +  # cat available_error_type			# See which errors can be injected
> +  0x00000002	Processor Uncorrectable non-fatal
> +  0x00000008	Memory Correctable
> +  0x00000010	Memory Uncorrectable non-fatal
> +  0x00000001	EINJV2 Processor Error
> +  0x00000002	EINJV2 Memory Error
> +
> +  # echo 0x12345000 > param1			# Set memory address for injection
> +  # echo 0xfffffffffffff000 > param2		# Range - anywhere in this page
> +  # comp_arr="0x1 0x2				# Fill in the component array
> +    >0x1 0x4
> +    >0x2 0x4"
> +  # echo "$comp_arr" > einjv2_component_array
> +  # echo V2_0x2 > error_type			# Choose EINJv2 memory error
> +  # echo 0xa > flags				# set flags to indicate EINJv2
> +  # echo 1 > error_inject			# Inject now
> +
>  You should see something like this in dmesg::
>  
>    [22715.830801] EDAC sbridge MC3: HANDLING MCE MEMORY ERROR