Re: [PATCH 8/8] ACPI: APEI: EINJ: Update the documentation for EINJv2 support

[Tony Luck <tony.luck@intel.com>]

On Tue, Oct 22, 2024 at 02:34:29PM -0700, Zaid Alali 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@os.amperecomputing.com>
> ---
>  .../firmware-guide/acpi/apei/einj.rst         | 46 ++++++++++++++++++-
>  1 file changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/firmware-guide/acpi/apei/einj.rst b/Documentation/firmware-guide/acpi/apei/einj.rst
> index c52b9da08fa9..3ad092111035 100644
> --- a/Documentation/firmware-guide/acpi/apei/einj.rst
> +++ b/Documentation/firmware-guide/acpi/apei/einj.rst
> @@ -61,6 +61,14 @@ The following files belong to it:
>    0x00000800        Platform Uncorrectable fatal
>    ================  ===================================
>  
> +  ================  ===================================
> +  Error Type Value      Error Description
> +  ================  ===================================

This shows up in the html output as a separate table with the
same headers. Why not concatenate this to the existing table?

The example of EINJv2 shows these extra lines just appearing
right after the v1 lines.

> +  0x00000001        EINJV2 Processor Error
> +  0x00000002        EINJV2 Memory Error
> +  0x00000004        EINJV2 PCI Express Error
> +  ================  ===================================
> +
>    The format of the file contents are as above, except present are only
>    the available error types.
>  
> @@ -85,9 +93,11 @@ 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).
>      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 +120,7 @@ The following files belong to it:
>    Used when the 0x1 bit is set in "flags" to specify the APIC id
>  
>  - param4
> +
>    Used when the 0x4 bit is set in "flags" to specify target PCIe device
>  
>  - notrigger
> @@ -122,6 +133,18 @@ 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.
> +
> +- 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 +162,6 @@ 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.
>  
> -
>  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 +216,26 @@ 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

This seems confusing to me. Is 0x00000002 the code for a V1 processor
uncorrectable, or a V2 memory error? It seems that the "error_type" file
is interpreted differently depending on what is written to the "flags"
file.

> +
> +  # 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"

Default $PS2 prompt in bash doesn't have leading spaces before the ">".
So this example looks unnatural to me.

> +  # echo "$comp_arr" > einjv2_component_array
> +  # echo 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
> -- 
> 2.34.1

-Tony