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2025-08-12cxl/region: Add inject and clear poison by region offsetAlison Schofield
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>
2025-07-25Documentation/ABI/testing/debugfs-cxl: Add 'cxl' to clear_poison pathAlison Schofield
'cxl' is missing from the path to the clear_poison attribute. Add it. Signed-off-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> Link: https://patch.msgid.link/20250724224308.2101255-1-alison.schofield@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-07-10cxl/memdev: Replace ENXIO with EBUSY for inject poison limit reachedAlison Schofield
The CXL driver provides a debugfs interface offering users the ability to inject and clear poison to a memdev. Once a user has injected up to the devices limit further injection requests fail with ENXIO until a clear poison is issued. Users may not have device specs in hand or may want to intentionally hit the limit and then clear. Replace the usual ENXIO return status with EBUSY so users can recognize this failure. Signed-off-by: Alison Schofield <alison.schofield@intel.com> Tested-by: Xingtao Yao <yaoxt.fnst@fujitsu.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Link: https://patch.msgid.link/825bd4c67fb55a4373c4182d999ad49d4e6b4fe7.1720316188.git.alison.schofield@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-03-14Documentation/ABI/testing/debugfs-cxl: Fix "Unexpected indentation"Dan Williams
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: 8039804cfa73 ("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>
2024-03-12cxl/core: Add CXL EINJ debugfs filesBen Cheatham
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>
2023-04-23cxl/mem: Add debugfs attributes for poison inject and clearAlison Schofield
Inject and Clear Poison commands are optionally supported by CXL memdev devices and are intended for use in debug environments only. Add debugfs attributes for user access. Documentation/ABI/testing/debugfs-cxl describes the usage. Signed-off-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/0c9ea8e671b8e58465d18722788b60d325c675c7.1681874357.git.alison.schofield@intel.com Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>