cxl/edac: Support for finding memory operation attributes from the current boot

JIRA: https://issues.redhat.com/browse/RHEL-107284

commit 0b5ccb0
Author: Shiju Jose <shiju.jose@huawei.com>
Date:   Wed May 21 13:47:44 2025 +0100

    cxl/edac: Support for finding memory operation attributes from the current boot

    Certain operations on memory, such as memory repair, are permitted
    only when the address and other attributes for the operation are
    from the current boot. This is determined by checking whether the
    memory attributes for the operation match those in the CXL gen_media
    or CXL DRAM memory event records reported during the current boot.

    The CXL event records must be backed up because they are cleared
    in the hardware after being processed by the kernel.

    Support is added for storing CXL gen_media or CXL DRAM memory event
    records in xarrays. Old records are deleted when they expire or when
    there is an overflow and which depends on platform correctly report
    Event Record Timestamp field of CXL spec Table 8-55 Common Event
    Record Format.

    Additionally, helper functions are implemented to find a matching
    record in the xarray storage based on the memory attributes and
    repair type.

    Add validity check, when matching attributes for sparing, using
    the validity flag in the DRAM event record, to ensure that all
    required attributes for a requested repair operation are valid and
    set.

    Reviewed-by: Dave Jiang <dave.jiang@intel.com>
    Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
    Reviewed-by: Alison Schofield <alison.schofield@intel.com>
    Acked-by: Dan Williams <dan.j.williams@intel.com>
    Link: https://patch.msgid.link/20250521124749.817-7-shiju.jose@huawei.com
    Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Signed-off-by: John W. Linville <linville@redhat.com>

Author: John W. Linville

drivers/cxl/Kconfig

@@ -164,6 +164,27 @@ config CXL_EDAC_ECS
 	  of a memory ECS feature established by the platform/device.
 	  Otherwise say 'n'.
 
+config CXL_EDAC_MEM_REPAIR
+	bool "Enable CXL Memory Repair"
+	depends on CXL_EDAC_MEM_FEATURES
+	depends on EDAC_MEM_REPAIR
+	help
+	  The CXL EDAC memory repair control is optional and allows host
+	  to control the memory repair features (e.g. sparing, PPR)
+	  configurations of CXL memory expander devices.
+
+	  When enabled, the memory repair feature requires an additional
+	  memory of approximately 43KB to store CXL DRAM and CXL general
+	  media event records.
+
+	  When enabled 'cxl_mem' EDAC devices are published with memory
+	  repair control attributes as described by
+	  Documentation/ABI/testing/sysfs-edac-memory-repair.
+
+	  Say 'y' if you have an expert need to change default settings
+	  of a memory repair feature established by the platform/device.
+	  Otherwise say 'n'.
+
 config CXL_PORT
 	default CXL_BUS
 	tristate

drivers/cxl/core/edac.c

@@ -14,10 +14,12 @@
 #include <linux/cleanup.h>
 #include <linux/edac.h>
 #include <linux/limits.h>
+#include <linux/xarray.h>
 #include <cxl/features.h>
 #include <cxl.h>
 #include <cxlmem.h>
 #include "core.h"
+#include "trace.h"
 
 #define CXL_NR_EDAC_DEV_FEATURES 2
 
@@ -862,10 +864,285 @@ static int cxl_perform_maintenance(struct cxl_mailbox *cxl_mbox, u8 class,
 	return cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
 }
 
+/*
+ * Support for finding a memory operation attributes
+ * are from the current boot or not.
+ */
+
+struct cxl_mem_err_rec {
+	struct xarray rec_gen_media;
+	struct xarray rec_dram;
+};
+
+enum cxl_mem_repair_type {
+	CXL_PPR,
+	CXL_CACHELINE_SPARING,
+	CXL_ROW_SPARING,
+	CXL_BANK_SPARING,
+	CXL_RANK_SPARING,
+	CXL_REPAIR_MAX,
+};
+
+/**
+ * struct cxl_mem_repair_attrbs - CXL memory repair attributes
+ * @dpa: DPA of memory to repair
+ * @nibble_mask: nibble mask, identifies one or more nibbles on the memory bus
+ * @row: row of memory to repair
+ * @column: column of memory to repair
+ * @channel: channel of memory to repair
+ * @sub_channel: sub channel of memory to repair
+ * @rank: rank of memory to repair
+ * @bank_group: bank group of memory to repair
+ * @bank: bank of memory to repair
+ * @repair_type: repair type. For eg. PPR, memory sparing etc.
+ */
+struct cxl_mem_repair_attrbs {
+	u64 dpa;
+	u32 nibble_mask;
+	u32 row;
+	u16 column;
+	u8 channel;
+	u8 sub_channel;
+	u8 rank;
+	u8 bank_group;
+	u8 bank;
+	enum cxl_mem_repair_type repair_type;
+};
+
+static struct cxl_event_gen_media *
+cxl_find_rec_gen_media(struct cxl_memdev *cxlmd,
+		       struct cxl_mem_repair_attrbs *attrbs)
+{
+	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
+	struct cxl_event_gen_media *rec;
+
+	if (!array_rec)
+		return NULL;
+
+	rec = xa_load(&array_rec->rec_gen_media, attrbs->dpa);
+	if (!rec)
+		return NULL;
+
+	if (attrbs->repair_type == CXL_PPR)
+		return rec;
+
+	return NULL;
+}
+
+static struct cxl_event_dram *
+cxl_find_rec_dram(struct cxl_memdev *cxlmd,
+		  struct cxl_mem_repair_attrbs *attrbs)
+{
+	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
+	struct cxl_event_dram *rec;
+	u16 validity_flags;
+
+	if (!array_rec)
+		return NULL;
+
+	rec = xa_load(&array_rec->rec_dram, attrbs->dpa);
+	if (!rec)
+		return NULL;
+
+	validity_flags = get_unaligned_le16(rec->media_hdr.validity_flags);
+	if (!(validity_flags & CXL_DER_VALID_CHANNEL) ||
+	    !(validity_flags & CXL_DER_VALID_RANK))
+		return NULL;
+
+	switch (attrbs->repair_type) {
+	case CXL_PPR:
+		if (!(validity_flags & CXL_DER_VALID_NIBBLE) ||
+		    get_unaligned_le24(rec->nibble_mask) == attrbs->nibble_mask)
+			return rec;
+		break;
+	case CXL_CACHELINE_SPARING:
+		if (!(validity_flags & CXL_DER_VALID_BANK_GROUP) ||
+		    !(validity_flags & CXL_DER_VALID_BANK) ||
+		    !(validity_flags & CXL_DER_VALID_ROW) ||
+		    !(validity_flags & CXL_DER_VALID_COLUMN))
+			return NULL;
+
+		if (rec->media_hdr.channel == attrbs->channel &&
+		    rec->media_hdr.rank == attrbs->rank &&
+		    rec->bank_group == attrbs->bank_group &&
+		    rec->bank == attrbs->bank &&
+		    get_unaligned_le24(rec->row) == attrbs->row &&
+		    get_unaligned_le16(rec->column) == attrbs->column &&
+		    (!(validity_flags & CXL_DER_VALID_NIBBLE) ||
+		     get_unaligned_le24(rec->nibble_mask) ==
+			     attrbs->nibble_mask) &&
+		    (!(validity_flags & CXL_DER_VALID_SUB_CHANNEL) ||
+		     rec->sub_channel == attrbs->sub_channel))
+			return rec;
+		break;
+	case CXL_ROW_SPARING:
+		if (!(validity_flags & CXL_DER_VALID_BANK_GROUP) ||
+		    !(validity_flags & CXL_DER_VALID_BANK) ||
+		    !(validity_flags & CXL_DER_VALID_ROW))
+			return NULL;
+
+		if (rec->media_hdr.channel == attrbs->channel &&
+		    rec->media_hdr.rank == attrbs->rank &&
+		    rec->bank_group == attrbs->bank_group &&
+		    rec->bank == attrbs->bank &&
+		    get_unaligned_le24(rec->row) == attrbs->row &&
+		    (!(validity_flags & CXL_DER_VALID_NIBBLE) ||
+		     get_unaligned_le24(rec->nibble_mask) ==
+			     attrbs->nibble_mask))
+			return rec;
+		break;
+	case CXL_BANK_SPARING:
+		if (!(validity_flags & CXL_DER_VALID_BANK_GROUP) ||
+		    !(validity_flags & CXL_DER_VALID_BANK))
+			return NULL;
+
+		if (rec->media_hdr.channel == attrbs->channel &&
+		    rec->media_hdr.rank == attrbs->rank &&
+		    rec->bank_group == attrbs->bank_group &&
+		    rec->bank == attrbs->bank &&
+		    (!(validity_flags & CXL_DER_VALID_NIBBLE) ||
+		     get_unaligned_le24(rec->nibble_mask) ==
+			     attrbs->nibble_mask))
+			return rec;
+		break;
+	case CXL_RANK_SPARING:
+		if (rec->media_hdr.channel == attrbs->channel &&
+		    rec->media_hdr.rank == attrbs->rank &&
+		    (!(validity_flags & CXL_DER_VALID_NIBBLE) ||
+		     get_unaligned_le24(rec->nibble_mask) ==
+			     attrbs->nibble_mask))
+			return rec;
+		break;
+	default:
+		return NULL;
+	}
+
+	return NULL;
+}
+
+#define CXL_MAX_STORAGE_DAYS 10
+#define CXL_MAX_STORAGE_TIME_SECS (CXL_MAX_STORAGE_DAYS * 24 * 60 * 60)
+
+static void cxl_del_expired_gmedia_recs(struct xarray *rec_xarray,
+					struct cxl_event_gen_media *cur_rec)
+{
+	u64 cur_ts = le64_to_cpu(cur_rec->media_hdr.hdr.timestamp);
+	struct cxl_event_gen_media *rec;
+	unsigned long index;
+	u64 delta_ts_secs;
+
+	xa_for_each(rec_xarray, index, rec) {
+		delta_ts_secs = (cur_ts -
+			le64_to_cpu(rec->media_hdr.hdr.timestamp)) / 1000000000ULL;
+		if (delta_ts_secs >= CXL_MAX_STORAGE_TIME_SECS) {
+			xa_erase(rec_xarray, index);
+			kfree(rec);
+		}
+	}
+}
+
+static void cxl_del_expired_dram_recs(struct xarray *rec_xarray,
+				      struct cxl_event_dram *cur_rec)
+{
+	u64 cur_ts = le64_to_cpu(cur_rec->media_hdr.hdr.timestamp);
+	struct cxl_event_dram *rec;
+	unsigned long index;
+	u64 delta_secs;
+
+	xa_for_each(rec_xarray, index, rec) {
+		delta_secs = (cur_ts -
+			le64_to_cpu(rec->media_hdr.hdr.timestamp)) / 1000000000ULL;
+		if (delta_secs >= CXL_MAX_STORAGE_TIME_SECS) {
+			xa_erase(rec_xarray, index);
+			kfree(rec);
+		}
+	}
+}
+
+#define CXL_MAX_REC_STORAGE_COUNT 200
+
+static void cxl_del_overflow_old_recs(struct xarray *rec_xarray)
+{
+	void *err_rec;
+	unsigned long index, count = 0;
+
+	xa_for_each(rec_xarray, index, err_rec)
+		count++;
+
+	if (count <= CXL_MAX_REC_STORAGE_COUNT)
+		return;
+
+	count -= CXL_MAX_REC_STORAGE_COUNT;
+	xa_for_each(rec_xarray, index, err_rec) {
+		xa_erase(rec_xarray, index);
+		kfree(err_rec);
+		count--;
+		if (!count)
+			break;
+	}
+}
+
+int cxl_store_rec_gen_media(struct cxl_memdev *cxlmd, union cxl_event *evt)
+{
+	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
+	struct cxl_event_gen_media *rec;
+	void *old_rec;
+
+	if (!IS_ENABLED(CONFIG_CXL_EDAC_MEM_REPAIR) || !array_rec)
+		return 0;
+
+	rec = kmemdup(&evt->gen_media, sizeof(*rec), GFP_KERNEL);
+	if (!rec)
+		return -ENOMEM;
+
+	old_rec = xa_store(&array_rec->rec_gen_media,
+			   le64_to_cpu(rec->media_hdr.phys_addr), rec,
+			   GFP_KERNEL);
+	if (xa_is_err(old_rec))
+		return xa_err(old_rec);
+
+	kfree(old_rec);
+
+	cxl_del_expired_gmedia_recs(&array_rec->rec_gen_media, rec);
+	cxl_del_overflow_old_recs(&array_rec->rec_gen_media);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_store_rec_gen_media, "CXL");
+
+int cxl_store_rec_dram(struct cxl_memdev *cxlmd, union cxl_event *evt)
+{
+	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
+	struct cxl_event_dram *rec;
+	void *old_rec;
+
+	if (!IS_ENABLED(CONFIG_CXL_EDAC_MEM_REPAIR) || !array_rec)
+		return 0;
+
+	rec = kmemdup(&evt->dram, sizeof(*rec), GFP_KERNEL);
+	if (!rec)
+		return -ENOMEM;
+
+	old_rec = xa_store(&array_rec->rec_dram,
+			   le64_to_cpu(rec->media_hdr.phys_addr), rec,
+			   GFP_KERNEL);
+	if (xa_is_err(old_rec))
+		return xa_err(old_rec);
+
+	kfree(old_rec);
+
+	cxl_del_expired_dram_recs(&array_rec->rec_dram, rec);
+	cxl_del_overflow_old_recs(&array_rec->rec_dram);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_store_rec_dram, "CXL");
+
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 {
 	struct edac_dev_feature ras_features[CXL_NR_EDAC_DEV_FEATURES];
 	int num_ras_features = 0;
+	u8 repair_inst = 0;
 	int rc;
 
 	if (IS_ENABLED(CONFIG_CXL_EDAC_SCRUB)) {
@@ -886,6 +1163,20 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 			num_ras_features++;
 	}
 
+	if (IS_ENABLED(CONFIG_CXL_EDAC_MEM_REPAIR)) {
+		if (repair_inst) {
+			struct cxl_mem_err_rec *array_rec =
+				devm_kzalloc(&cxlmd->dev, sizeof(*array_rec),
+					     GFP_KERNEL);
+			if (!array_rec)
+				return -ENOMEM;
+
+			xa_init(&array_rec->rec_gen_media);
+			xa_init(&array_rec->rec_dram);
+			cxlmd->err_rec_array = array_rec;
+		}
+	}
+
 	if (!num_ras_features)
 		return -EINVAL;
 
@@ -923,3 +1214,23 @@ int devm_cxl_region_edac_register(struct cxl_region *cxlr)
 				 num_ras_features, ras_features);
 }
 EXPORT_SYMBOL_NS_GPL(devm_cxl_region_edac_register, "CXL");
+
+void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
+{
+	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
+	struct cxl_event_gen_media *rec_gen_media;
+	struct cxl_event_dram *rec_dram;
+	unsigned long index;
+
+	if (!IS_ENABLED(CONFIG_CXL_EDAC_MEM_REPAIR) || !array_rec)
+		return;
+
+	xa_for_each(&array_rec->rec_dram, index, rec_dram)
+		kfree(rec_dram);
+	xa_destroy(&array_rec->rec_dram);
+
+	xa_for_each(&array_rec->rec_gen_media, index, rec_gen_media)
+		kfree(rec_gen_media);
+	xa_destroy(&array_rec->rec_gen_media);
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_memdev_edac_release, "CXL");

drivers/cxl/core/mbox.c

@@ -922,12 +922,19 @@ void cxl_event_trace_record(const struct cxl_memdev *cxlmd,
 				hpa_alias = hpa - cache_size;
 		}
 
-		if (event_type == CXL_CPER_EVENT_GEN_MEDIA)
+		if (event_type == CXL_CPER_EVENT_GEN_MEDIA) {
+			if (cxl_store_rec_gen_media((struct cxl_memdev *)cxlmd, evt))
+				dev_dbg(&cxlmd->dev, "CXL store rec_gen_media failed\n");
+
 			trace_cxl_general_media(cxlmd, type, cxlr, hpa,
 						hpa_alias, &evt->gen_media);
-		else if (event_type == CXL_CPER_EVENT_DRAM)
+		} else if (event_type == CXL_CPER_EVENT_DRAM) {
+			if (cxl_store_rec_dram((struct cxl_memdev *)cxlmd, evt))
+				dev_dbg(&cxlmd->dev, "CXL store rec_dram failed\n");
+
 			trace_cxl_dram(cxlmd, type, cxlr, hpa, hpa_alias,
 				       &evt->dram);
+		}
 	}
 }
 EXPORT_SYMBOL_NS_GPL(cxl_event_trace_record, "CXL");