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Diffstat (limited to 'Documentation/ABI/testing/sysfs-edac-memory-repair')
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diff --git a/Documentation/ABI/testing/sysfs-edac-memory-repair b/Documentation/ABI/testing/sysfs-edac-memory-repair new file mode 100644 index 000000000000..0434a3b23ff3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-edac-memory-repair @@ -0,0 +1,206 @@ +What: /sys/bus/edac/devices/<dev-name>/mem_repairX +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + The sysfs EDAC bus devices /<dev-name>/mem_repairX subdirectory + pertains to the memory media repair features control, such as + PPR (Post Package Repair), memory sparing etc, where <dev-name> + directory corresponds to a device registered with the EDAC + device driver for the memory repair features. + + Post Package Repair is a maintenance operation requests the memory + device to perform a repair operation on its media. It is a memory + self-healing feature that fixes a failing memory location by + replacing it with a spare row in a DRAM device. For example, a + CXL memory device with DRAM components that support PPR features may + implement PPR maintenance operations. DRAM components may support + two types of PPR functions: hard PPR, for a permanent row repair, and + soft PPR, for a temporary row repair. Soft PPR may be much faster + than hard PPR, but the repair is lost with a power cycle. + + The sysfs attributes nodes for a repair feature are only + present if the parent driver has implemented the corresponding + attr callback function and provided the necessary operations + to the EDAC device driver during registration. + + In some states of system configuration (e.g. before address + decoders have been configured), memory devices (e.g. CXL) + may not have an active mapping in the main host address + physical address map. As such, the memory to repair must be + identified by a device specific physical addressing scheme + using a device physical address(DPA). The DPA and other control + attributes to use will be presented in related error records. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/repair_type +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RO) Memory repair type. For eg. post package repair, + memory sparing etc. Valid values are: + + - ppr - Post package repair. + + - cacheline-sparing + + - row-sparing + + - bank-sparing + + - rank-sparing + + - All other values are reserved. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/persist_mode +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) Get/Set the current persist repair mode set for a + repair function. Persist repair modes supported in the + device, based on a memory repair function, either is temporary, + which is lost with a power cycle or permanent. Valid values are: + + - 0 - Soft memory repair (temporary repair). + + - 1 - Hard memory repair (permanent repair). + + - All other values are reserved. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/repair_safe_when_in_use +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RO) True if memory media is accessible and data is retained + during the memory repair operation. + The data may not be retained and memory requests may not be + correctly processed during a repair operation. In such case + repair operation can not be executed at runtime. The memory + must be taken offline. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/hpa +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) Host Physical Address (HPA) of the memory to repair. + The HPA to use will be provided in related error records. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/dpa +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) Device Physical Address (DPA) of the memory to repair. + The specific DPA to use will be provided in related error + records. + + In some states of system configuration (e.g. before address + decoders have been configured), memory devices (e.g. CXL) + may not have an active mapping in the main host address + physical address map. As such, the memory to repair must be + identified by a device specific physical addressing scheme + using a DPA. The device physical address(DPA) to use will be + presented in related error records. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/nibble_mask +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) Read/Write Nibble mask of the memory to repair. + Nibble mask identifies one or more nibbles in error on the + memory bus that produced the error event. Nibble Mask bit 0 + shall be set if nibble 0 on the memory bus produced the + event, etc. For example, CXL PPR and sparing, a nibble mask + bit set to 1 indicates the request to perform repair + operation in the specific device. All nibble mask bits set + to 1 indicates the request to perform the operation in all + devices. Eg. for CXL memory repair, the specific value of + nibble mask to use will be provided in related error records. + For more details, See nibble mask field in CXL spec ver 3.1, + section 8.2.9.7.1.2 Table 8-103 soft PPR and section + 8.2.9.7.1.3 Table 8-104 hard PPR, section 8.2.9.7.1.4 + Table 8-105 memory sparing. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/min_hpa +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/max_hpa +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/min_dpa +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/max_dpa +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) The supported range of memory address that is to be + repaired. The memory device may give the supported range of + attributes to use and it will depend on the memory device + and the portion of memory to repair. + The userspace may receive the specific value of attributes + to use for a repair operation from the memory device via + related error records and trace events, for eg. CXL DRAM + and CXL general media error records in CXL memory devices. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/bank_group +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/bank +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/rank +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/row +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/column +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/channel +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/sub_channel +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (RW) The control attributes for the memory to be repaired. + The specific value of attributes to use depends on the + portion of memory to repair and will be reported to the host + in related error records and be available to userspace + in trace events, such as CXL DRAM and CXL general media + error records of CXL memory devices. + + When readng back these attributes, it returns the current + value of memory requested to be repaired. + + bank_group - The bank group of the memory to repair. + + bank - The bank number of the memory to repair. + + rank - The rank of the memory to repair. Rank is defined as a + set of memory devices on a channel that together execute a + transaction. + + row - The row number of the memory to repair. + + column - The column number of the memory to repair. + + channel - The channel of the memory to repair. Channel is + defined as an interface that can be independently accessed + for a transaction. + + sub_channel - The subchannel of the memory to repair. + + The requirement to set these attributes varies based on the + repair function. The attributes in sysfs are not present + unless required for a repair function. + + For example, CXL spec ver 3.1, Section 8.2.9.7.1.2 Table 8-103 + soft PPR and Section 8.2.9.7.1.3 Table 8-104 hard PPR operations, + these attributes are not required to set. CXL spec ver 3.1, + Section 8.2.9.7.1.4 Table 8-105 memory sparing, these attributes + are required to set based on memory sparing granularity. + +What: /sys/bus/edac/devices/<dev-name>/mem_repairX/repair +Date: March 2025 +KernelVersion: 6.15 +Contact: linux-edac@vger.kernel.org +Description: + (WO) Issue the memory repair operation for the specified + memory repair attributes. The operation may fail if resources + are insufficient based on the requirements of the memory + device and repair function. + + - 1 - Issue the repair operation. + + - All other values are reserved. |