EDAC: Add a memory repair control feature

Add a generic EDAC memory repair control driver to manage memory repairs in
the system, such as CXL Post Package Repair (PPR) and other soft and hard PPR
features.

For example, a CXL device with DRAM components that support PPR features may
implement PPR maintenance operations. DRAM components may support two types of
PPR:

 - hard PPR, for a permanent row repair, and
 - soft PPR,  for a temporary row repair.

Soft PPR is much faster than hard PPR, but the repair is lost with a power
cycle.

When a CXL device detects an error in a memory, it may report the need for
a repair maintenance operation by using an event record where the "maintenance
needed" flag is set. The event records contain the device physical
address (DPA) and other optional attributes of the memory to repair.

The kernel will report the corresponding CXL general media or DRAM trace event
to userspace, and userspace tools (e.g. rasdaemon) will initiate a repair
operation in response to the device request via the sysfs repair control.

Device with memory repair features registers with EDAC device driver, which
retrieves a memory repair descriptor from EDAC memory repair driver and exposes
the sysfs repair control attributes to userspace in

  /sys/bus/edac/devices/<dev-name>/mem_repairX/.

The common memory repair control interface abstracts the control of arbitrary
memory repair functionality into a standardized set of functions.  The sysfs
memory repair attribute nodes are only available if the client driver has
implemented the corresponding attribute callback function and provided
operations to the EDAC device driver during registration.

  [ bp: Massage, fixup edac_dev_register() retvals, merge
    write_overflow fix to mem_repair_create_desc() ]

Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250212143654.1893-5-shiju.jose@huawei.com

4 files changed, 319 insertions, 0 deletions

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 9dfc2ea02df1..703522d5d6c3 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -93,6 +93,16 @@ config EDAC_ECS
 	  into a unified set of functions.
 	  Say 'y/n' to enable/disable EDAC ECS feature.
 
+config EDAC_MEM_REPAIR
+	bool "EDAC memory repair feature"
+	help
+	  The EDAC memory repair feature is optional and is designed to control
+	  the memory devices with repair features, such as Post Package Repair
+	  (PPR), memory sparing etc. The common sysfs memory repair interface
+	  abstracts the control of various memory repair functionalities into
+	  a unified set of functions.
+	  Say 'y/n' to enable/disable EDAC memory repair feature.
+
 config EDAC_AMD64
 	tristate "AMD64 (Opteron, Athlon64)"
 	depends on AMD_NB && EDAC_DECODE_MCE
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index c3c8b15b1490..a8f2d8f6c894 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -14,6 +14,7 @@ edac_core-y	+= edac_module.o edac_device_sysfs.o wq.o
 edac_core-$(CONFIG_EDAC_DEBUG)		+= debugfs.o
 edac_core-$(CONFIG_EDAC_SCRUB)		+= scrub.o
 edac_core-$(CONFIG_EDAC_ECS)		+= ecs.o
+edac_core-$(CONFIG_EDAC_MEM_REPAIR)	+= mem_repair.o
 
 ifdef CONFIG_PCI
 edac_core-y	+= edac_pci.o edac_pci_sysfs.o
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index b914ca3fc5e5..16611515ab34 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -575,6 +575,7 @@ static void edac_dev_release(struct device *dev)
 {
 	struct edac_dev_feat_ctx *ctx = container_of(dev, struct edac_dev_feat_ctx, dev);
 
+	kfree(ctx->mem_repair);
 	kfree(ctx->scrub);
 	kfree(ctx->dev.groups);
 	kfree(ctx);
@@ -613,6 +614,7 @@ int edac_dev_register(struct device *parent, char *name,
 	const struct attribute_group **ras_attr_groups;
 	struct edac_dev_data *dev_data;
 	struct edac_dev_feat_ctx *ctx;
+	int mem_repair_cnt = 0;
 	int attr_gcnt = 0;
 	int ret = -ENOMEM;
 	int scrub_cnt = 0;
@@ -631,6 +633,10 @@ int edac_dev_register(struct device *parent, char *name,
 		case RAS_FEAT_ECS:
 			attr_gcnt += ras_features[feat].ecs_info.num_media_frus;
 			break;
+		case RAS_FEAT_MEM_REPAIR:
+			attr_gcnt++;
+			mem_repair_cnt++;
+			break;
 		default:
 			return -EINVAL;
 		}
@@ -650,8 +656,15 @@ int edac_dev_register(struct device *parent, char *name,
 			goto groups_free;
 	}
 
+	if (mem_repair_cnt) {
+		ctx->mem_repair = kcalloc(mem_repair_cnt, sizeof(*ctx->mem_repair), GFP_KERNEL);
+		if (!ctx->mem_repair)
+			goto data_mem_free;
+	}
+
 	attr_gcnt = 0;
 	scrub_cnt = 0;
+	mem_repair_cnt = 0;
 	for (feat = 0; feat < num_features; feat++, ras_features++) {
 		switch (ras_features->ft_type) {
 		case RAS_FEAT_SCRUB:
@@ -688,6 +701,25 @@ int edac_dev_register(struct device *parent, char *name,
 
 			attr_gcnt += ras_features->ecs_info.num_media_frus;
 			break;
+		case RAS_FEAT_MEM_REPAIR:
+			if (!ras_features->mem_repair_ops ||
+			    mem_repair_cnt != ras_features->instance) {
+				ret = -EINVAL;
+				goto data_mem_free;
+			}
+
+			dev_data = &ctx->mem_repair[mem_repair_cnt];
+			dev_data->instance = mem_repair_cnt;
+			dev_data->mem_repair_ops = ras_features->mem_repair_ops;
+			dev_data->private = ras_features->ctx;
+			ret = edac_mem_repair_get_desc(parent, &ras_attr_groups[attr_gcnt],
+						       ras_features->instance);
+			if (ret)
+				goto data_mem_free;
+
+			mem_repair_cnt++;
+			attr_gcnt++;
+			break;
 		default:
 			ret = -EINVAL;
 			goto data_mem_free;
@@ -714,6 +746,7 @@ int edac_dev_register(struct device *parent, char *name,
 	return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
 
 data_mem_free:
+	kfree(ctx->mem_repair);
 	kfree(ctx->scrub);
 groups_free:
 	kfree(ras_attr_groups);
diff --git a/drivers/edac/mem_repair.c b/drivers/edac/mem_repair.c
new file mode 100755
index 000000000000..5c94ac1027db
--- /dev/null
+++ b/drivers/edac/mem_repair.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * The generic EDAC memory repair driver is designed to control the memory
+ * devices with memory repair features, such as Post Package Repair (PPR),
+ * memory sparing etc. The common sysfs memory repair interface abstracts
+ * the control of various arbitrary memory repair functionalities into a
+ * unified set of functions.
+ *
+ * Copyright (c) 2024-2025 HiSilicon Limited.
+ */
+
+#include <linux/edac.h>
+
+enum edac_mem_repair_attributes {
+	MR_TYPE,
+	MR_PERSIST_MODE,
+	MR_SAFE_IN_USE,
+	MR_HPA,
+	MR_MIN_HPA,
+	MR_MAX_HPA,
+	MR_DPA,
+	MR_MIN_DPA,
+	MR_MAX_DPA,
+	MR_NIBBLE_MASK,
+	MEM_DO_REPAIR,
+	MR_MAX_ATTRS
+};
+
+struct edac_mem_repair_dev_attr {
+	struct device_attribute dev_attr;
+	u8 instance;
+};
+
+struct edac_mem_repair_context {
+	char name[EDAC_FEAT_NAME_LEN];
+	struct edac_mem_repair_dev_attr mem_repair_dev_attr[MR_MAX_ATTRS];
+	struct attribute *mem_repair_attrs[MR_MAX_ATTRS + 1];
+	struct attribute_group group;
+};
+
+#define TO_MR_DEV_ATTR(_dev_attr)      \
+	container_of(_dev_attr, struct edac_mem_repair_dev_attr, dev_attr)
+
+#define MR_ATTR_SHOW(attrib, cb, type, format)			\
+static ssize_t attrib##_show(struct device *ras_feat_dev,			\
+			     struct device_attribute *attr, char *buf)		\
+{										\
+	u8 inst = TO_MR_DEV_ATTR(attr)->instance;			\
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);		\
+	const struct edac_mem_repair_ops *ops =					\
+		ctx->mem_repair[inst].mem_repair_ops;				\
+	type data;								\
+	int ret;								\
+										\
+	ret = ops->cb(ras_feat_dev->parent, ctx->mem_repair[inst].private,	\
+		      &data);							\
+	if (ret)								\
+		return ret;							\
+										\
+	return sysfs_emit(buf, format, data);					\
+}
+
+MR_ATTR_SHOW(repair_type, get_repair_type, const char *, "%s\n")
+MR_ATTR_SHOW(persist_mode, get_persist_mode, bool, "%u\n")
+MR_ATTR_SHOW(repair_safe_when_in_use, get_repair_safe_when_in_use, bool, "%u\n")
+MR_ATTR_SHOW(hpa, get_hpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(min_hpa, get_min_hpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(max_hpa, get_max_hpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(dpa, get_dpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(min_dpa, get_min_dpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(max_dpa, get_max_dpa, u64, "0x%llx\n")
+MR_ATTR_SHOW(nibble_mask, get_nibble_mask, u32, "0x%x\n")
+
+#define MR_ATTR_STORE(attrib, cb, type, conv_func)			\
+static ssize_t attrib##_store(struct device *ras_feat_dev,			\
+			      struct device_attribute *attr,			\
+			      const char *buf, size_t len)			\
+{										\
+	u8 inst = TO_MR_DEV_ATTR(attr)->instance;			\
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);		\
+	const struct edac_mem_repair_ops *ops =					\
+		ctx->mem_repair[inst].mem_repair_ops;				\
+	type data;								\
+	int ret;								\
+										\
+	ret = conv_func(buf, 0, &data);						\
+	if (ret < 0)								\
+		return ret;							\
+										\
+	ret = ops->cb(ras_feat_dev->parent, ctx->mem_repair[inst].private,	\
+		      data);							\
+	if (ret)								\
+		return ret;							\
+										\
+	return len;								\
+}
+
+MR_ATTR_STORE(persist_mode, set_persist_mode, unsigned long, kstrtoul)
+MR_ATTR_STORE(hpa, set_hpa, u64, kstrtou64)
+MR_ATTR_STORE(dpa, set_dpa, u64, kstrtou64)
+MR_ATTR_STORE(nibble_mask, set_nibble_mask, unsigned long, kstrtoul)
+
+#define MR_DO_OP(attrib, cb)						\
+static ssize_t attrib##_store(struct device *ras_feat_dev,				\
+			      struct device_attribute *attr,				\
+			      const char *buf, size_t len)				\
+{											\
+	u8 inst = TO_MR_DEV_ATTR(attr)->instance;				\
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);			\
+	const struct edac_mem_repair_ops *ops = ctx->mem_repair[inst].mem_repair_ops;	\
+	unsigned long data;								\
+	int ret;									\
+											\
+	ret = kstrtoul(buf, 0, &data);							\
+	if (ret < 0)									\
+		return ret;								\
+											\
+	ret = ops->cb(ras_feat_dev->parent, ctx->mem_repair[inst].private, data);	\
+	if (ret)									\
+		return ret;								\
+											\
+	return len;									\
+}
+
+MR_DO_OP(repair, do_repair)
+
+static umode_t mem_repair_attr_visible(struct kobject *kobj, struct attribute *a, int attr_id)
+{
+	struct device *ras_feat_dev = kobj_to_dev(kobj);
+	struct device_attribute *dev_attr = container_of(a, struct device_attribute, attr);
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);
+	u8 inst = TO_MR_DEV_ATTR(dev_attr)->instance;
+	const struct edac_mem_repair_ops *ops = ctx->mem_repair[inst].mem_repair_ops;
+
+	switch (attr_id) {
+	case MR_TYPE:
+		if (ops->get_repair_type)
+			return a->mode;
+		break;
+	case MR_PERSIST_MODE:
+		if (ops->get_persist_mode) {
+			if (ops->set_persist_mode)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case MR_SAFE_IN_USE:
+		if (ops->get_repair_safe_when_in_use)
+			return a->mode;
+		break;
+	case MR_HPA:
+		if (ops->get_hpa) {
+			if (ops->set_hpa)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case MR_MIN_HPA:
+		if (ops->get_min_hpa)
+			return a->mode;
+		break;
+	case MR_MAX_HPA:
+		if (ops->get_max_hpa)
+			return a->mode;
+		break;
+	case MR_DPA:
+		if (ops->get_dpa) {
+			if (ops->set_dpa)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case MR_MIN_DPA:
+		if (ops->get_min_dpa)
+			return a->mode;
+		break;
+	case MR_MAX_DPA:
+		if (ops->get_max_dpa)
+			return a->mode;
+		break;
+	case MR_NIBBLE_MASK:
+		if (ops->get_nibble_mask) {
+			if (ops->set_nibble_mask)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case MEM_DO_REPAIR:
+		if (ops->do_repair)
+			return a->mode;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+#define MR_ATTR_RO(_name, _instance)       \
+	((struct edac_mem_repair_dev_attr) { .dev_attr = __ATTR_RO(_name), \
+					     .instance = _instance })
+
+#define MR_ATTR_WO(_name, _instance)       \
+	((struct edac_mem_repair_dev_attr) { .dev_attr = __ATTR_WO(_name), \
+					     .instance = _instance })
+
+#define MR_ATTR_RW(_name, _instance)       \
+	((struct edac_mem_repair_dev_attr) { .dev_attr = __ATTR_RW(_name), \
+					     .instance = _instance })
+
+static int mem_repair_create_desc(struct device *dev,
+				  const struct attribute_group **attr_groups,
+				  u8 instance)
+{
+	struct edac_mem_repair_context *ctx;
+	struct attribute_group *group;
+	int i;
+	struct edac_mem_repair_dev_attr dev_attr[] = {
+		[MR_TYPE]	  = MR_ATTR_RO(repair_type, instance),
+		[MR_PERSIST_MODE] = MR_ATTR_RW(persist_mode, instance),
+		[MR_SAFE_IN_USE]  = MR_ATTR_RO(repair_safe_when_in_use, instance),
+		[MR_HPA]	  = MR_ATTR_RW(hpa, instance),
+		[MR_MIN_HPA]	  = MR_ATTR_RO(min_hpa, instance),
+		[MR_MAX_HPA]	  = MR_ATTR_RO(max_hpa, instance),
+		[MR_DPA]	  = MR_ATTR_RW(dpa, instance),
+		[MR_MIN_DPA]	  = MR_ATTR_RO(min_dpa, instance),
+		[MR_MAX_DPA]	  = MR_ATTR_RO(max_dpa, instance),
+		[MR_NIBBLE_MASK]  = MR_ATTR_RW(nibble_mask, instance),
+		[MEM_DO_REPAIR]	  = MR_ATTR_WO(repair, instance)
+	};
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	for (i = 0; i < MR_MAX_ATTRS; i++) {
+		memcpy(&ctx->mem_repair_dev_attr[i],
+		       &dev_attr[i], sizeof(dev_attr[i]));
+		ctx->mem_repair_attrs[i] =
+			&ctx->mem_repair_dev_attr[i].dev_attr.attr;
+	}
+
+	sprintf(ctx->name, "%s%d", "mem_repair", instance);
+	group = &ctx->group;
+	group->name = ctx->name;
+	group->attrs = ctx->mem_repair_attrs;
+	group->is_visible  = mem_repair_attr_visible;
+	attr_groups[0] = group;
+
+	return 0;
+}
+
+/**
+ * edac_mem_repair_get_desc - get EDAC memory repair descriptors
+ * @dev: client device with memory repair feature
+ * @attr_groups: pointer to attribute group container
+ * @instance: device's memory repair instance number.
+ *
+ * Return:
+ *  * %0	- Success.
+ *  * %-EINVAL	- Invalid parameters passed.
+ *  * %-ENOMEM	- Dynamic memory allocation failed.
+ */
+int edac_mem_repair_get_desc(struct device *dev,
+			     const struct attribute_group **attr_groups, u8 instance)
+{
+	if (!dev || !attr_groups)
+		return -EINVAL;
+
+	return mem_repair_create_desc(dev, attr_groups, instance);
+}