diff options
Diffstat (limited to 'Documentation/ABI/testing/debugfs-cxl')
| -rw-r--r-- | Documentation/ABI/testing/debugfs-cxl | 96 |
1 files changed, 92 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/debugfs-cxl b/Documentation/ABI/testing/debugfs-cxl index c61f9b813973..2989d4da96c1 100644 --- a/Documentation/ABI/testing/debugfs-cxl +++ b/Documentation/ABI/testing/debugfs-cxl @@ -14,12 +14,27 @@ Description: event to its internal Informational Event log, updates the Event Status register, and if configured, interrupts the host. It is not an error to inject poison into an address that - already has poison present and no error is returned. The - inject_poison attribute is only visible for devices supporting - the capability. + already has poison present and no error is returned. If the + device returns 'Inject Poison Limit Reached' an -EBUSY error + is returned to the user. The inject_poison attribute is only + visible for devices supporting the capability. + TEST-ONLY INTERFACE: This interface is intended for testing + and validation purposes only. It is not a data repair mechanism + and should never be used on production systems or live data. -What: /sys/kernel/debug/memX/clear_poison + DATA LOSS RISK: For CXL persistent memory (PMEM) devices, + poison injection can result in permanent data loss. Injected + poison may render data permanently inaccessible even after + clearing, as the clear operation writes zeros and does not + recover original data. + + SYSTEM STABILITY RISK: For volatile memory, poison injection + can cause kernel crashes, system instability, or unpredictable + behavior if the poisoned addresses are accessed by running code + or critical kernel structures. + +What: /sys/kernel/debug/cxl/memX/clear_poison Date: April, 2023 KernelVersion: v6.4 Contact: linux-cxl@vger.kernel.org @@ -34,6 +49,79 @@ Description: The clear_poison attribute is only visible for devices supporting the capability. + TEST-ONLY INTERFACE: This interface is intended for testing + and validation purposes only. It is not a data repair mechanism + and should never be used on production systems or live data. + + CLEAR IS NOT DATA RECOVERY: This operation writes zeros to the + specified address range and removes the address from the poison + list. It does NOT recover or restore original data that may have + been present before poison injection. Any original data at the + cleared address is permanently lost and replaced with zeros. + + CLEAR IS NOT A REPAIR MECHANISM: This interface is for testing + purposes only and should not be used as a data repair tool. + Clearing poison is fundamentally different from data recovery + or error correction. + +What: /sys/kernel/debug/cxl/regionX/inject_poison +Date: August, 2025 +Contact: linux-cxl@vger.kernel.org +Description: + (WO) When a Host Physical Address (HPA) is written to this + attribute, the region driver translates it to a Device + Physical Address (DPA) and identifies the corresponding + memdev. It then sends an inject poison command to that memdev + at the translated DPA. Refer to the memdev ABI entry at: + /sys/kernel/debug/cxl/memX/inject_poison for the detailed + behavior. This attribute is only visible if all memdevs + participating in the region support both inject and clear + poison commands. + + TEST-ONLY INTERFACE: This interface is intended for testing + and validation purposes only. It is not a data repair mechanism + and should never be used on production systems or live data. + + DATA LOSS RISK: For CXL persistent memory (PMEM) devices, + poison injection can result in permanent data loss. Injected + poison may render data permanently inaccessible even after + clearing, as the clear operation writes zeros and does not + recover original data. + + SYSTEM STABILITY RISK: For volatile memory, poison injection + can cause kernel crashes, system instability, or unpredictable + behavior if the poisoned addresses are accessed by running code + or critical kernel structures. + +What: /sys/kernel/debug/cxl/regionX/clear_poison +Date: August, 2025 +Contact: linux-cxl@vger.kernel.org +Description: + (WO) When a Host Physical Address (HPA) is written to this + attribute, the region driver translates it to a Device + Physical Address (DPA) and identifies the corresponding + memdev. It then sends a clear poison command to that memdev + at the translated DPA. Refer to the memdev ABI entry at: + /sys/kernel/debug/cxl/memX/clear_poison for the detailed + behavior. This attribute is only visible if all memdevs + participating in the region support both inject and clear + poison commands. + + TEST-ONLY INTERFACE: This interface is intended for testing + and validation purposes only. It is not a data repair mechanism + and should never be used on production systems or live data. + + CLEAR IS NOT DATA RECOVERY: This operation writes zeros to the + specified address range and removes the address from the poison + list. It does NOT recover or restore original data that may have + been present before poison injection. Any original data at the + cleared address is permanently lost and replaced with zeros. + + CLEAR IS NOT A REPAIR MECHANISM: This interface is for testing + purposes only and should not be used as a data repair tool. + Clearing poison is fundamentally different from data recovery + or error correction. + What: /sys/kernel/debug/cxl/einj_types Date: January, 2024 KernelVersion: v6.9 |