Add CXL region debugfs attributes to inject and clear poison based
on an offset into the region. These new interfaces allow users to
operate on poison at the region level without needing to resolve
Device Physical Addresses (DPA) or target individual memdevs.
The implementation uses a new helper, region_offset_to_dpa_result()
that applies decoder interleave logic, including XOR-based address
decoding when applicable. Note that XOR decodes rely on driver
internal xormaps which are not exposed to userspace. So, this support
is not only a simplification of poison operations that could be done
using existing per memdev operations, but also it enables this
functionality for XOR interleaved regions for the first time.
New debugfs attributes are added in /sys/kernel/debug/cxl/regionX/:
inject_poison and clear_poison. These are only exposed if all memdevs
participating in the region support both inject and clear commands,
ensuring consistent and reliable behavior across multi-device regions.
If tracing is enabled, these operations are logged as cxl_poison
events in /sys/kernel/tracing/trace.
The ABI documentation warns users of the significant risks that
come with using these capabilities.
A CXL Maturity Map update shows this user flow is now supported.
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/f3fd8628ab57ea79704fb2d645902cd499c066af.1754290144.git.alison.schofield@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Stephen reported that an htmldocs build hit:
Documentation/ABI/testing/debugfs-cxl:38: ERROR: Unexpected indentation.
It turns out that line was fine but the tool was unhappy about some line
breaks in the table of values to error types.
It turns out that:
make V=1 SPHINXDIRS="admin-guide" htmldocs
...can not be used to get more info about what is behind a documentation
build error. It was only pure luck that reflowing the text resulted in
an error message that seemed a imply a problem later on with line breaks
around the table.
Fixes: 8039804cfa ("cxl/core: Add CXL EINJ debugfs files")
Cc: Jonathan Corbet <corbet@lwn.net>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: http://lore.kernel.org/r/20240314141313.7ba04aff@canb.auug.org.au
Cc: Ben Cheatham <Benjamin.Cheatham@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Export CXL helper functions in einj-cxl.c for getting/injecting
available CXL protocol error types to sysfs under kernel/debug/cxl.
The kernel/debug/cxl/einj_types file will print the available CXL
protocol errors in the same format as the available_error_types
file provided by the einj module. The
kernel/debug/cxl/$dport_dev/einj_inject file is functionally the same
as the error_type and error_inject files provided by the EINJ module,
i.e.: writing an error type into $dport_dev/einj_inject will inject
said error type into the CXL dport represented by $dport_dev.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
Link: https://lore.kernel.org/r/20240311142508.31717-4-Benjamin.Cheatham@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
