[PATCH v5 0/8] cxl: support CXL memory RAS features

[PATCH v5 0/8] cxl: support CXL memory RAS features

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Support for CXL memory EDAC features: patrol scrub, ECS, soft-PPR and
memory sparing.

Detailed history of the complete EDAC series with CXL EDAC patches[1].

The code is based on [2] v6.15-rc4.

1. https://lore.kernel.org/linux-cxl/20250212143654.1893-1-shiju.jose@huawei.com/
2. https://github.com/torvalds/linux.git

Userspace code for CXL memory repair features [3] and
sample boot-script for CXL memory repair [4].

[3]: https://lore.kernel.org/lkml/20250207143028.1865-1-shiju.jose@huawei.com/
[4]: https://lore.kernel.org/lkml/20250207143028.1865-5-shiju.jose@huawei.com/

Changes
=======
v4 -> v5:
1. Fixed a compilation warning introduced by v3->v4, reported by Dave Jiang on v4. 
   drivers/cxl/core/edac.c: In function ‘cxl_mem_perform_sparing’:
   drivers/cxl/core/edac.c:1335:29: warning: the comparison will always evaluate as ‘true’ for the address of ‘validity_flags’ will never be NULL [-Waddress]
 1335 |                         if (!rec->media_hdr.validity_flags)
      |                             ^
   In file included from ./drivers/cxl/cxlmem.h:10,
                 from drivers/cxl/core/edac.c:21:
   ./include/cxl/event.h:35:12: note: ‘validity_flags’ declared here
   35 |         u8 validity_flags[2];
      |            ^~~~~~~~~~~~~~
2. Updated patches for tags given.

v3 -> v4:
1. Feedback from Dave Jiang on v3,
1.1. Changes for comments in EDAC scrub documentation for CXL use cases.
     https://lore.kernel.org/all/2df68c68-f1a8-4327-abc9-d265326c133d@intel.com/
1.2. Changes for comments in CXL memory sparing control feature.
     https://lore.kernel.org/all/4ee3323c-fb27-4fbe-b032-78fd54bc21a0@intel.com/
      
v2 -> v3:
1. Feedback from Dan Williams on v2,
   https://lore.kernel.org/linux-mm/20250320180450.539-1-shiju.jose@huawei.com/
  - Modified get_support_feature_info() in fwctl series generic to use in
    cxl/fxctl and cxl/edac and replace cxl_get_feature_entry() in the CXL edac
    series.
  - Add usecase note for CXL ECS in Documentation/edac/scrub.rst.
  - Add info message when device scrub rate set by a region overwritten with a
    local device scrub rate or another region's scrub rate.
  - Replace 'ps' with patrol_scrub in the patrol scrub feature.
  - Replaced usage of intermediate objects struct cxl_memdev_ps_params and
    enum cxl_scrub_param etc for patrol scrub and did same for ECS.
  - Rename CXL_MEMDEV_PS_* macros.
  - Rename scrub_cycle_hrs-> scrub_cycle_hours
  - Add if (!cxl_dev_name)
	return -ENOMEM;  to devm_cxl_memdev_edac_register()
  - Add  devm_cxl_region_edac_register(cxlr) for CXL_PARTMODE_PMEM case.
  - Add separate configurations for CXL scrub, ECS and memory repair
    CXL_EDAC_SCRUB, CXL_EDAC_ECS and CXL_EDAC_MEM_REPAIR.
  - Add 
       if (!capable(CAP_SYS_RAWIO))
             return -EPERM; for set attributes callbacks for CXL scrub, ECS and
    memory repair.  	       
  - In patch "cxl/mbox: Add support for PERFORM_MAINTENANCE mailbox command"
    * cxl_do_maintenance() -> cxl_perform_maintenance() and moved to cxl/core/edac.c 
    * kmalloc() -> kvzalloc()
  - In patch, "cxl: Support for finding memory operation attributes from the current boot"  
    * Moved code from drivers/cxl/core/ras.c to drivers/cxl/core/edac.c
    * Add few logics to releasing the cache to give safety with respect to error storms and burning
    * unlimited memory. 
    * Add estimated memory overhead expense of this feature documented in the Kconfig.
    * Unified various names such as attr, param, attrbs throughout the patches.
    * Moved > struct xarray rec_gen_media and struct xarray rec_dram; out of struct cxl_memdev
      to CXL edac object, but there is required a pointer to this object in struct cxl_memdev
      because the error records are reported and thus stored in the cxl_memdev context not
      in the CXL EDAC context.
      
2. Feedback from Borislav on v2,
  - In include/linux/edac.h 
    Replace EDAC_PPR -> EDAC_REPAIR_PPR
            EDAC_CACHELINE_SPARING -> EDAC_REPAIR_CACHELINE_SPARING etc.

v1 -> v2:
1. Feedback from Dan Williams on v1,
   https://lore.kernel.org/linux-mm/20250307091137.00006a0a@huawei.com/T/
  - Fixed lock issues in region scrubbing, added local cxl_acquire()
    and cxl_unlock.
  - Replaced CXL examples using cat and echo from EDAC .rst docs
    with short description and ref to ABI docs. Also corrections
    in existing descriptions as suggested by Dan.
  - Add policy description for the scrub control feature.
    However this may require inputs from CXL experts.
  - Replaced CONFIG_CXL_RAS_FEATURES with CONFIG_CXL_EDAC_MEM_FEATURES.
  - Few changes to depends part of CONFIG_CXL_EDAC_MEM_FEATURES.
  - Rename drivers/cxl/core/memfeatures.c as drivers/cxl/core/edac.c
  - snprintf() -> kasprintf() in few places.

2. Feedback from Alison on v1,
  - In cxl_get_feature_entry()(patch 1), return NULL on failures and
    reintroduced checks in cxl_get_feature_entry().
  - Changed logic in for loop in region based scrubbing code.
  - Replace cxl_are_decoders_committed() to cxl_is_memdev_memory_online()
    and add as a local function to drivers/cxl/core/edac.c
  - Changed few multiline comments to single line comments.
  - Removed unnecessary comments from the code.
  - Reduced line length of few macros in ECS and memory repair code.
  - In new files, changed "GPL-2.0-or-later" -> "GPL-2.0-only".
  - Ran clang-format for new files and updated.                                                                                                                                          
3. Changes for feedbacks from Jonathan on v1.
  - Changed few multiline comments to single line comments.


Shiju Jose (8):
  EDAC: Update documentation for the CXL memory patrol scrub control
    feature
  cxl: Update prototype of function get_support_feature_info()
  cxl/edac: Add CXL memory device patrol scrub control feature
  cxl/edac: Add CXL memory device ECS control feature
  cxl/edac: Add support for PERFORM_MAINTENANCE command
  cxl/edac: Support for finding memory operation attributes from the
    current boot
  cxl/edac: Add CXL memory device memory sparing control feature
  cxl/edac: Add CXL memory device soft PPR control feature

 Documentation/edac/memory_repair.rst |   31 +
 Documentation/edac/scrub.rst         |   76 +
 drivers/cxl/Kconfig                  |   71 +
 drivers/cxl/core/Makefile            |    1 +
 drivers/cxl/core/core.h              |    2 +
 drivers/cxl/core/edac.c              | 2082 ++++++++++++++++++++++++++
 drivers/cxl/core/features.c          |   17 +-
 drivers/cxl/core/mbox.c              |   11 +-
 drivers/cxl/core/memdev.c            |    1 +
 drivers/cxl/core/region.c            |   10 +
 drivers/cxl/cxl.h                    |   10 +
 drivers/cxl/cxlmem.h                 |   36 +
 drivers/cxl/mem.c                    |    4 +
 drivers/edac/mem_repair.c            |    9 +
 include/linux/edac.h                 |    7 +
 15 files changed, 2356 insertions(+), 12 deletions(-)
 create mode 100644 drivers/cxl/core/edac.c

-- 
2.43.0

[PATCH v5 1/8] EDAC: Update documentation for the CXL memory patrol scrub control feature

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Update the Documentation/edac/scrub.rst to include use cases and
policies for CXL memory device-based, CXL region-based patrol scrub
control and CXL Error Check Scrub (ECS).

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 Documentation/edac/scrub.rst | 76 ++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/Documentation/edac/scrub.rst b/Documentation/edac/scrub.rst
index daab929cdba1..5c99f42eae0a 100644
--- a/Documentation/edac/scrub.rst
+++ b/Documentation/edac/scrub.rst
@@ -264,3 +264,79 @@ Sysfs files are documented in
 `Documentation/ABI/testing/sysfs-edac-scrub`
 
 `Documentation/ABI/testing/sysfs-edac-ecs`
+
+Examples
+--------
+
+The usage takes the form shown in these examples:
+
+1. CXL memory Patrol Scrub
+
+The following are the use cases identified why we might increase the scrub rate.
+
+- Scrubbing is needed at device granularity because a device is showing
+  unexpectedly high errors.
+
+- Scrubbing may apply to memory that isn't online at all yet. Likely this
+  is a system wide default setting on boot.
+
+- Scrubbing at a higher rate because the monitor software has determined that
+  more reliability is necessary for a particular data set. This is called
+  Differentiated Reliability.
+
+1.1. Device based scrubbing
+
+CXL memory is exposed to memory management subsystem and ultimately userspace
+via CXL devices. Device-based scrubbing is used for the first use case
+described in "Section 1 CXL Memory Patrol Scrub".
+
+When combining control via the device interfaces and region interfaces,
+"see Section 1.2 Region based scrubbing".
+
+Sysfs files for scrubbing are documented in
+`Documentation/ABI/testing/sysfs-edac-scrub`
+
+1.2. Region based scrubbing
+
+CXL memory is exposed to memory management subsystem and ultimately userspace
+via CXL regions. CXL Regions represent mapped memory capacity in system
+physical address space. These can incorporate one or more parts of multiple CXL
+memory devices with traffic interleaved across them. The user may want to control
+the scrub rate via this more abstract region instead of having to figure out the
+constituent devices and program them separately. The scrub rate for each device
+covers the whole device. Thus if multiple regions use parts of that device then
+requests for scrubbing of other regions may result in a higher scrub rate than
+requested for this specific region.
+
+Region-based scrubbing is used for the third use case described in
+"Section 1 CXL Memory Patrol Scrub".
+
+Userspace must follow below set of rules on how to set the scrub rates for any
+mixture of requirements.
+
+1. Taking each region in turn from lowest desired scrub rate to highest and set
+   their scrub rates. Later regions may override the scrub rate on individual
+   devices (and hence potentially whole regions).
+
+2. Take each device for which enhanced scrubbing is required (higher rate) and
+   set those scrub rates. This will override the scrub rates of individual devices,
+   setting them to the maximum rate required for any of the regions they help back,
+   unless a specific rate is already defined.
+
+Sysfs files for scrubbing are documented in
+`Documentation/ABI/testing/sysfs-edac-scrub`
+
+2. CXL memory Error Check Scrub (ECS)
+
+The Error Check Scrub (ECS) feature enables a memory device to perform error
+checking and correction (ECC) and count single-bit errors. The associated
+memory controller sets the ECS mode with a trigger sent to the memory
+device. CXL ECS control, allows the host, thus the userspace, to change the
+attributes for error count mode, threshold number of errors per segment
+(indicating how many segments have at least that number of errors) for
+reporting errors, and reset the ECS counter. Thus, the responsibility for
+initiating Error Check Scrub on a memory device may lie with the memory
+controller or platform when unexpectedly high error rates are detected.
+
+Sysfs files for scrubbing are documented in
+`Documentation/ABI/testing/sysfs-edac-ecs`
-- 
2.43.0

[PATCH v5 2/8] cxl: Update prototype of function get_support_feature_info()

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Add following changes to function get_support_feature_info()
1. Make generic to share between cxl-fwctl and cxl-edac paths.
2. Rename get_support_feature_info() to cxl_feature_info()
3. Change parameter const struct fwctl_rpc_cxl *rpc_in to
   const uuid_t *uuid.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 drivers/cxl/core/core.h     |  2 ++
 drivers/cxl/core/features.c | 17 +++++++----------
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 17b692eb3257..613cce5c4f7b 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -124,6 +124,8 @@ int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
 					    int nid, resource_size_t *size);
 
 #ifdef CONFIG_CXL_FEATURES
+struct cxl_feat_entry *
+cxl_feature_info(struct cxl_features_state *cxlfs, const uuid_t *uuid);
 size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
 		       enum cxl_get_feat_selection selection,
 		       void *feat_out, size_t feat_out_size, u16 offset,
diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 1498e2369c37..a83a2214a136 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -355,17 +355,11 @@ static void cxlctl_close_uctx(struct fwctl_uctx *uctx)
 {
 }
 
-static struct cxl_feat_entry *
-get_support_feature_info(struct cxl_features_state *cxlfs,
-			 const struct fwctl_rpc_cxl *rpc_in)
+struct cxl_feat_entry *
+cxl_feature_info(struct cxl_features_state *cxlfs,
+		 const uuid_t *uuid)
 {
 	struct cxl_feat_entry *feat;
-	const uuid_t *uuid;
-
-	if (rpc_in->op_size < sizeof(uuid))
-		return ERR_PTR(-EINVAL);
-
-	uuid = &rpc_in->set_feat_in.uuid;
 
 	for (int i = 0; i < cxlfs->entries->num_features; i++) {
 		feat = &cxlfs->entries->ent[i];
@@ -547,7 +541,10 @@ static bool cxlctl_validate_set_features(struct cxl_features_state *cxlfs,
 	struct cxl_feat_entry *feat;
 	u32 flags;
 
-	feat = get_support_feature_info(cxlfs, rpc_in);
+	if (rpc_in->op_size < sizeof(uuid_t))
+		return ERR_PTR(-EINVAL);
+
+	feat = cxl_feature_info(cxlfs, &rpc_in->set_feat_in.uuid);
 	if (IS_ERR(feat))
 		return false;
 
-- 
2.43.0

[PATCH v5 3/8] cxl/edac: Add CXL memory device patrol scrub control feature

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

CXL spec 3.2 section 8.2.10.9.11.1 describes the device patrol scrub
control feature. The device patrol scrub proactively locates and makes
corrections to errors in regular cycle.

Allow specifying the number of hours within which the patrol scrub must be
completed, subject to minimum and maximum limits reported by the device.
Also allow disabling scrub allowing trade-off error rates against
performance.

Add support for patrol scrub control on CXL memory devices.
Register with the EDAC device driver, which retrieves the scrub attribute
descriptors from EDAC scrub and exposes the sysfs scrub control attributes
to userspace. For example, scrub control for the CXL memory device
"cxl_mem0" is exposed in /sys/bus/edac/devices/cxl_mem0/scrubX/.

Additionally, add support for region-based CXL memory patrol scrub control.
CXL memory regions may be interleaved across one or more CXL memory
devices. For example, region-based scrub control for "cxl_region1" is
exposed in /sys/bus/edac/devices/cxl_region1/scrubX/.

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>
---
 drivers/cxl/Kconfig       |  33 +++
 drivers/cxl/core/Makefile |   1 +
 drivers/cxl/core/edac.c   | 495 ++++++++++++++++++++++++++++++++++++++
 drivers/cxl/core/region.c |  10 +
 drivers/cxl/cxl.h         |  10 +
 drivers/cxl/cxlmem.h      |  16 ++
 drivers/cxl/mem.c         |   4 +
 7 files changed, 569 insertions(+)
 create mode 100644 drivers/cxl/core/edac.c

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index cf1ba673b8c2..af72416edcd4 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -114,6 +114,39 @@ config CXL_FEATURES
 
 	  If unsure say 'n'
 
+config CXL_EDAC_MEM_FEATURES
+	bool "CXL: EDAC Memory Features"
+	depends on EXPERT
+	depends on CXL_MEM
+	depends on CXL_FEATURES
+	depends on EDAC >= CXL_BUS
+	help
+	  The CXL EDAC memory feature is optional and allows host to
+	  control the EDAC memory features configurations of CXL memory
+	  expander devices.
+
+	  Say 'y' if you have an expert need to change default settings
+	  of a memory RAS feature established by the platform/device.
+	  Otherwise say 'n'.
+
+config CXL_EDAC_SCRUB
+	bool "Enable CXL Patrol Scrub Control (Patrol Read)"
+	depends on CXL_EDAC_MEM_FEATURES
+	depends on EDAC_SCRUB
+	help
+	  The CXL EDAC scrub control is optional and allows host to
+	  control the scrub feature configurations of CXL memory expander
+	  devices.
+
+	  When enabled 'cxl_mem' and 'cxl_region' EDAC devices are
+	  published with memory scrub control attributes as described by
+	  Documentation/ABI/testing/sysfs-edac-scrub.
+
+	  Say 'y' if you have an expert need to change default settings
+	  of a memory scrub feature established by the platform/device
+	  (e.g. scrub rates for the patrol scrub feature).
+	  Otherwise say 'n'.
+
 config CXL_PORT
 	default CXL_BUS
 	tristate
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index 086df97a0fcf..79e2ef81fde8 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -20,3 +20,4 @@ cxl_core-$(CONFIG_TRACING) += trace.o
 cxl_core-$(CONFIG_CXL_REGION) += region.o
 cxl_core-$(CONFIG_CXL_MCE) += mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += features.o
+cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
new file mode 100644
index 000000000000..7d7eb1e8a47a
--- /dev/null
+++ b/drivers/cxl/core/edac.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CXL EDAC memory feature driver.
+ *
+ * Copyright (c) 2024-2025 HiSilicon Limited.
+ *
+ *  - Supports functions to configure EDAC features of the
+ *    CXL memory devices.
+ *  - Registers with the EDAC device subsystem driver to expose
+ *    the features sysfs attributes to the user for configuring
+ *    CXL memory RAS feature.
+ */
+
+#include <linux/cleanup.h>
+#include <linux/edac.h>
+#include <linux/limits.h>
+#include <cxl/features.h>
+#include <cxl.h>
+#include <cxlmem.h>
+#include "core.h"
+
+#define CXL_NR_EDAC_DEV_FEATURES 1
+
+#ifdef CONFIG_CXL_EDAC_SCRUB
+struct cxl_patrol_scrub_context {
+	u8 instance;
+	u16 get_feat_size;
+	u16 set_feat_size;
+	u8 get_version;
+	u8 set_version;
+	u16 effects;
+	struct cxl_memdev *cxlmd;
+	struct cxl_region *cxlr;
+};
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.9.11.1 Table 8-222 Device Patrol Scrub Control
+ * Feature Readable Attributes.
+ */
+struct cxl_scrub_rd_attrbs {
+	u8 scrub_cycle_cap;
+	__le16 scrub_cycle_hours;
+	u8 scrub_flags;
+} __packed;
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.9.11.1 Table 8-223 Device Patrol Scrub Control
+ * Feature Writable Attributes.
+ */
+struct cxl_scrub_wr_attrbs {
+	u8 scrub_cycle_hours;
+	u8 scrub_flags;
+} __packed;
+
+#define CXL_SCRUB_CONTROL_CHANGEABLE BIT(0)
+#define CXL_SCRUB_CONTROL_REALTIME BIT(1)
+#define CXL_SCRUB_CONTROL_CYCLE_MASK GENMASK(7, 0)
+#define CXL_SCRUB_CONTROL_MIN_CYCLE_MASK GENMASK(15, 8)
+#define CXL_SCRUB_CONTROL_ENABLE BIT(0)
+
+#define CXL_GET_SCRUB_CYCLE_CHANGEABLE(cap) \
+	FIELD_GET(CXL_SCRUB_CONTROL_CHANGEABLE, cap)
+#define CXL_GET_SCRUB_CYCLE(cycle) \
+	FIELD_GET(CXL_SCRUB_CONTROL_CYCLE_MASK, cycle)
+#define CXL_GET_SCRUB_MIN_CYCLE(cycle) \
+	FIELD_GET(CXL_SCRUB_CONTROL_MIN_CYCLE_MASK, cycle)
+#define CXL_GET_SCRUB_EN_STS(flags) FIELD_GET(CXL_SCRUB_CONTROL_ENABLE, flags)
+
+#define CXL_SET_SCRUB_CYCLE(cycle) \
+	FIELD_PREP(CXL_SCRUB_CONTROL_CYCLE_MASK, cycle)
+#define CXL_SET_SCRUB_EN(en) FIELD_PREP(CXL_SCRUB_CONTROL_ENABLE, en)
+
+static int cxl_mem_scrub_get_attrbs(struct cxl_mailbox *cxl_mbox, u8 *cap,
+				    u16 *cycle, u8 *flags, u8 *min_cycle)
+{
+	size_t rd_data_size = sizeof(struct cxl_scrub_rd_attrbs);
+	size_t data_size;
+	struct cxl_scrub_rd_attrbs *rd_attrbs __free(kfree) =
+		kzalloc(rd_data_size, GFP_KERNEL);
+	if (!rd_attrbs)
+		return -ENOMEM;
+
+	data_size = cxl_get_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
+				    CXL_GET_FEAT_SEL_CURRENT_VALUE, rd_attrbs,
+				    rd_data_size, 0, NULL);
+	if (!data_size)
+		return -EIO;
+
+	*cap = rd_attrbs->scrub_cycle_cap;
+	*cycle = le16_to_cpu(rd_attrbs->scrub_cycle_hours);
+	*flags = rd_attrbs->scrub_flags;
+	if (min_cycle)
+		*min_cycle = CXL_GET_SCRUB_MIN_CYCLE(*cycle);
+
+	return 0;
+}
+
+static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx,
+				u8 *cap, u16 *cycle, u8 *flags, u8 *min_cycle)
+{
+	struct cxl_mailbox *cxl_mbox;
+	u8 min_scrub_cycle = U8_MAX;
+	struct cxl_memdev *cxlmd;
+	int i, ret;
+
+	if (cxl_ps_ctx->cxlr) {
+		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
+		struct cxl_region_params *p = &cxlr->params;
+
+		struct rw_semaphore *region_lock __free(rwsem_read_release) =
+			rwsem_read_intr_acquire(&cxl_region_rwsem);
+		if (!region_lock)
+			return -EINTR;
+
+		for (i = 0; i < p->nr_targets; i++) {
+			struct cxl_endpoint_decoder *cxled = p->targets[i];
+
+			cxlmd = cxled_to_memdev(cxled);
+			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+			ret = cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle,
+						       flags, min_cycle);
+			if (ret)
+				return ret;
+
+			if (min_cycle)
+				min_scrub_cycle =
+					min(*min_cycle, min_scrub_cycle);
+		}
+
+		if (min_cycle)
+			*min_cycle = min_scrub_cycle;
+
+		return 0;
+	}
+	cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
+
+	return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags, min_cycle);
+}
+
+static int cxl_scrub_set_attrbs(struct device *dev,
+				struct cxl_patrol_scrub_context *cxl_ps_ctx,
+				u8 cycle, u8 flags)
+{
+	struct cxl_scrub_wr_attrbs wr_attrbs;
+	struct cxl_mailbox *cxl_mbox;
+	struct cxl_memdev *cxlmd;
+	int ret, i;
+
+	wr_attrbs.scrub_cycle_hours = cycle;
+	wr_attrbs.scrub_flags = flags;
+
+	if (cxl_ps_ctx->cxlr) {
+		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
+		struct cxl_region_params *p = &cxlr->params;
+
+		struct rw_semaphore *region_lock __free(rwsem_read_release) =
+			rwsem_read_intr_acquire(&cxl_region_rwsem);
+		if (!region_lock)
+			return -EINTR;
+
+		for (i = 0; i < p->nr_targets; i++) {
+			struct cxl_endpoint_decoder *cxled = p->targets[i];
+
+			cxlmd = cxled_to_memdev(cxled);
+			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+			ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
+					      cxl_ps_ctx->set_version, &wr_attrbs,
+					      sizeof(wr_attrbs),
+					      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
+					      0, NULL);
+			if (ret)
+				return ret;
+
+			if (cycle != cxlmd->cur_scrub_cycle) {
+				if (cxlmd->cur_region_id != -1)
+					dev_info(dev,
+						 "Device scrub rate(%d hours) set by region%d rate overwritten by region%d scrub rate(%d hours)\n",
+						 cxlmd->cur_scrub_cycle,
+						 cxlmd->cur_region_id, cxlr->id,
+						 cycle);
+
+				cxlmd->cur_scrub_cycle = cycle;
+				cxlmd->cur_region_id = cxlr->id;
+			}
+		}
+
+		return 0;
+	}
+
+	cxlmd = cxl_ps_ctx->cxlmd;
+	cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+	ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
+			      cxl_ps_ctx->set_version, &wr_attrbs,
+			      sizeof(wr_attrbs),
+			      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET, 0,
+			      NULL);
+	if (ret)
+		return ret;
+
+	if (cycle != cxlmd->cur_scrub_cycle) {
+		if (cxlmd->cur_region_id != -1)
+			dev_info(dev,
+				 "Device scrub rate(%d hours) set by region%d rate overwritten with device local scrub rate(%d hours)\n",
+				 cxlmd->cur_scrub_cycle, cxlmd->cur_region_id,
+				 cycle);
+
+		cxlmd->cur_scrub_cycle = cycle;
+		cxlmd->cur_region_id = -1;
+	}
+
+	return 0;
+}
+
+static int cxl_patrol_scrub_get_enabled_bg(struct device *dev, void *drv_data,
+					   bool *enabled)
+{
+	struct cxl_patrol_scrub_context *ctx = drv_data;
+	u8 cap, flags;
+	u16 cycle;
+	int ret;
+
+	ret = cxl_scrub_get_attrbs(ctx, &cap, &cycle, &flags, NULL);
+	if (ret)
+		return ret;
+
+	*enabled = CXL_GET_SCRUB_EN_STS(flags);
+
+	return 0;
+}
+
+static int cxl_patrol_scrub_set_enabled_bg(struct device *dev, void *drv_data,
+					   bool enable)
+{
+	struct cxl_patrol_scrub_context *ctx = drv_data;
+	u8 cap, flags, wr_cycle;
+	u16 rd_cycle;
+	int ret;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	ret = cxl_scrub_get_attrbs(ctx, &cap, &rd_cycle, &flags, NULL);
+	if (ret)
+		return ret;
+
+	wr_cycle = CXL_GET_SCRUB_CYCLE(rd_cycle);
+	flags = CXL_SET_SCRUB_EN(enable);
+
+	return cxl_scrub_set_attrbs(dev, ctx, wr_cycle, flags);
+}
+
+static int cxl_patrol_scrub_get_min_scrub_cycle(struct device *dev,
+						void *drv_data, u32 *min)
+{
+	struct cxl_patrol_scrub_context *ctx = drv_data;
+	u8 cap, flags, min_cycle;
+	u16 cycle;
+	int ret;
+
+	ret = cxl_scrub_get_attrbs(ctx, &cap, &cycle, &flags, &min_cycle);
+	if (ret)
+		return ret;
+
+	*min = min_cycle * 3600;
+
+	return 0;
+}
+
+static int cxl_patrol_scrub_get_max_scrub_cycle(struct device *dev,
+						void *drv_data, u32 *max)
+{
+	*max = U8_MAX * 3600; /* Max set by register size */
+
+	return 0;
+}
+
+static int cxl_patrol_scrub_get_scrub_cycle(struct device *dev, void *drv_data,
+					    u32 *scrub_cycle_secs)
+{
+	struct cxl_patrol_scrub_context *ctx = drv_data;
+	u8 cap, flags;
+	u16 cycle;
+	int ret;
+
+	ret = cxl_scrub_get_attrbs(ctx, &cap, &cycle, &flags, NULL);
+	if (ret)
+		return ret;
+
+	*scrub_cycle_secs = CXL_GET_SCRUB_CYCLE(cycle) * 3600;
+
+	return 0;
+}
+
+static int cxl_patrol_scrub_set_scrub_cycle(struct device *dev, void *drv_data,
+					    u32 scrub_cycle_secs)
+{
+	struct cxl_patrol_scrub_context *ctx = drv_data;
+	u8 scrub_cycle_hours = scrub_cycle_secs / 3600;
+	u8 cap, wr_cycle, flags, min_cycle;
+	u16 rd_cycle;
+	int ret;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	ret = cxl_scrub_get_attrbs(ctx, &cap, &rd_cycle, &flags, &min_cycle);
+	if (ret)
+		return ret;
+
+	if (!CXL_GET_SCRUB_CYCLE_CHANGEABLE(cap))
+		return -EOPNOTSUPP;
+
+	if (scrub_cycle_hours < min_cycle) {
+		dev_dbg(dev, "Invalid CXL patrol scrub cycle(%d) to set\n",
+			scrub_cycle_hours);
+		dev_dbg(dev,
+			"Minimum supported CXL patrol scrub cycle in hour %d\n",
+			min_cycle);
+		return -EINVAL;
+	}
+	wr_cycle = CXL_SET_SCRUB_CYCLE(scrub_cycle_hours);
+
+	return cxl_scrub_set_attrbs(dev, ctx, wr_cycle, flags);
+}
+
+static const struct edac_scrub_ops cxl_ps_scrub_ops = {
+	.get_enabled_bg = cxl_patrol_scrub_get_enabled_bg,
+	.set_enabled_bg = cxl_patrol_scrub_set_enabled_bg,
+	.get_min_cycle = cxl_patrol_scrub_get_min_scrub_cycle,
+	.get_max_cycle = cxl_patrol_scrub_get_max_scrub_cycle,
+	.get_cycle_duration = cxl_patrol_scrub_get_scrub_cycle,
+	.set_cycle_duration = cxl_patrol_scrub_set_scrub_cycle,
+};
+
+static int cxl_memdev_scrub_init(struct cxl_memdev *cxlmd,
+				 struct edac_dev_feature *ras_feature,
+				 u8 scrub_inst)
+{
+	struct cxl_patrol_scrub_context *cxl_ps_ctx;
+	struct cxl_feat_entry *feat_entry;
+	u8 cap, flags;
+	u16 cycle;
+	int rc;
+
+	feat_entry = cxl_feature_info(to_cxlfs(cxlmd->cxlds),
+				      &CXL_FEAT_PATROL_SCRUB_UUID);
+	if (!feat_entry)
+		return -EOPNOTSUPP;
+
+	if (!(le32_to_cpu(feat_entry->flags) & CXL_FEATURE_F_CHANGEABLE))
+		return -EOPNOTSUPP;
+
+	cxl_ps_ctx = devm_kzalloc(&cxlmd->dev, sizeof(*cxl_ps_ctx), GFP_KERNEL);
+	if (!cxl_ps_ctx)
+		return -ENOMEM;
+
+	*cxl_ps_ctx = (struct cxl_patrol_scrub_context){
+		.get_feat_size = le16_to_cpu(feat_entry->get_feat_size),
+		.set_feat_size = le16_to_cpu(feat_entry->set_feat_size),
+		.get_version = feat_entry->get_feat_ver,
+		.set_version = feat_entry->set_feat_ver,
+		.effects = le16_to_cpu(feat_entry->effects),
+		.instance = scrub_inst,
+		.cxlmd = cxlmd,
+	};
+
+	rc = cxl_mem_scrub_get_attrbs(&cxlmd->cxlds->cxl_mbox, &cap, &cycle,
+				      &flags, NULL);
+	if (rc)
+		return rc;
+
+	cxlmd->cur_scrub_cycle = CXL_GET_SCRUB_CYCLE(cycle);
+	cxlmd->cur_region_id = -1;
+
+	ras_feature->ft_type = RAS_FEAT_SCRUB;
+	ras_feature->instance = cxl_ps_ctx->instance;
+	ras_feature->scrub_ops = &cxl_ps_scrub_ops;
+	ras_feature->ctx = cxl_ps_ctx;
+
+	return 0;
+}
+
+static int cxl_region_scrub_init(struct cxl_region *cxlr,
+				 struct edac_dev_feature *ras_feature,
+				 u8 scrub_inst)
+{
+	struct cxl_patrol_scrub_context *cxl_ps_ctx;
+	struct cxl_region_params *p = &cxlr->params;
+	struct cxl_feat_entry *feat_entry = NULL;
+	struct cxl_memdev *cxlmd;
+	u8 cap, flags;
+	u16 cycle;
+	int i, rc;
+
+	/*
+	 * The cxl_region_rwsem must be held if the code below is used in a context
+	 * other than when the region is in the probe state, as shown here.
+	 */
+	for (i = 0; i < p->nr_targets; i++) {
+		struct cxl_endpoint_decoder *cxled = p->targets[i];
+
+		cxlmd = cxled_to_memdev(cxled);
+		feat_entry = cxl_feature_info(to_cxlfs(cxlmd->cxlds),
+					      &CXL_FEAT_PATROL_SCRUB_UUID);
+		if (!feat_entry)
+			return -EOPNOTSUPP;
+
+		if (!(le32_to_cpu(feat_entry->flags) &
+		      CXL_FEATURE_F_CHANGEABLE))
+			return -EOPNOTSUPP;
+
+		rc = cxl_mem_scrub_get_attrbs(&cxlmd->cxlds->cxl_mbox, &cap,
+					      &cycle, &flags, NULL);
+		if (rc)
+			return rc;
+
+		cxlmd->cur_scrub_cycle = CXL_GET_SCRUB_CYCLE(cycle);
+		cxlmd->cur_region_id = -1;
+	}
+
+	cxl_ps_ctx = devm_kzalloc(&cxlr->dev, sizeof(*cxl_ps_ctx), GFP_KERNEL);
+	if (!cxl_ps_ctx)
+		return -ENOMEM;
+
+	*cxl_ps_ctx = (struct cxl_patrol_scrub_context){
+		.get_feat_size = le16_to_cpu(feat_entry->get_feat_size),
+		.set_feat_size = le16_to_cpu(feat_entry->set_feat_size),
+		.get_version = feat_entry->get_feat_ver,
+		.set_version = feat_entry->set_feat_ver,
+		.effects = le16_to_cpu(feat_entry->effects),
+		.instance = scrub_inst,
+		.cxlr = cxlr,
+	};
+
+	ras_feature->ft_type = RAS_FEAT_SCRUB;
+	ras_feature->instance = cxl_ps_ctx->instance;
+	ras_feature->scrub_ops = &cxl_ps_scrub_ops;
+	ras_feature->ctx = cxl_ps_ctx;
+
+	return 0;
+}
+#endif /* CONFIG_CXL_EDAC_SCRUB */
+
+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;
+#if defined(CONFIG_CXL_EDAC_SCRUB)
+	int rc;
+#endif
+
+#ifdef CONFIG_CXL_EDAC_SCRUB
+	rc = cxl_memdev_scrub_init(cxlmd, &ras_features[num_ras_features], 0);
+	if (rc < 0 && rc != -EOPNOTSUPP)
+		return rc;
+
+	if (rc != -EOPNOTSUPP)
+		num_ras_features++;
+#endif
+
+	char *cxl_dev_name __free(kfree) =
+		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));
+	if (!cxl_dev_name)
+		return -ENOMEM;
+
+	return edac_dev_register(&cxlmd->dev, cxl_dev_name, NULL,
+				 num_ras_features, ras_features);
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_memdev_edac_register, "CXL");
+
+int devm_cxl_region_edac_register(struct cxl_region *cxlr)
+{
+#ifdef CONFIG_CXL_EDAC_SCRUB
+	struct edac_dev_feature ras_features[CXL_NR_EDAC_DEV_FEATURES];
+	int num_ras_features = 0;
+	int rc;
+
+	rc = cxl_region_scrub_init(cxlr, &ras_features[num_ras_features], 0);
+	if (rc < 0)
+		return rc;
+
+	num_ras_features++;
+
+	char *cxl_dev_name __free(kfree) =
+		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlr->dev));
+	if (!cxl_dev_name)
+		return -ENOMEM;
+
+	return edac_dev_register(&cxlr->dev, cxl_dev_name, NULL,
+				 num_ras_features, ras_features);
+#else
+	return 0;
+#endif
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_region_edac_register, "CXL");
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index c3f4dc244df7..d5b8108c4a6d 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3537,8 +3537,18 @@ static int cxl_region_probe(struct device *dev)
 
 	switch (cxlr->mode) {
 	case CXL_PARTMODE_PMEM:
+		rc = devm_cxl_region_edac_register(cxlr);
+		if (rc)
+			dev_dbg(&cxlr->dev, "CXL EDAC registration for region_id=%d failed\n",
+				cxlr->id);
+
 		return devm_cxl_add_pmem_region(cxlr);
 	case CXL_PARTMODE_RAM:
+		rc = devm_cxl_region_edac_register(cxlr);
+		if (rc)
+			dev_dbg(&cxlr->dev, "CXL EDAC registration for region_id=%d failed\n",
+				cxlr->id);
+
 		/*
 		 * The region can not be manged by CXL if any portion of
 		 * it is already online as 'System RAM'
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index a9ab46eb0610..8a252f8483f7 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -912,4 +912,14 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);
 
 u16 cxl_gpf_get_dvsec(struct device *dev);
 
+static inline struct rw_semaphore *rwsem_read_intr_acquire(struct rw_semaphore *rwsem)
+{
+	if (down_read_interruptible(rwsem))
+		return NULL;
+
+	return rwsem;
+}
+
+DEFINE_FREE(rwsem_read_release, struct rw_semaphore *, if (_T) up_read(_T))
+
 #endif /* __CXL_H__ */
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 3ec6b906371b..685957b312ea 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -45,6 +45,8 @@
  * @endpoint: connection to the CXL port topology for this memory device
  * @id: id number of this memdev instance.
  * @depth: endpoint port depth
+ * @cur_scrub_cycle: current scrub cycle set for this device
+ * @cur_region_id: id number of a backed region (if any) for which current scrub cycle set
  */
 struct cxl_memdev {
 	struct device dev;
@@ -56,6 +58,10 @@ struct cxl_memdev {
 	struct cxl_port *endpoint;
 	int id;
 	int depth;
+#ifdef CONFIG_CXL_EDAC_SCRUB
+	u8 cur_scrub_cycle;
+	int cur_region_id;
+#endif
 };
 
 static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
@@ -853,6 +859,16 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd);
 int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
 int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
 
+#if IS_ENABLED(CONFIG_CXL_EDAC_MEM_FEATURES)
+int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd);
+int devm_cxl_region_edac_register(struct cxl_region *cxlr);
+#else
+static inline int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
+{ return 0; }
+static inline int devm_cxl_region_edac_register(struct cxl_region *cxlr)
+{ return 0; }
+#endif
+
 #ifdef CONFIG_CXL_SUSPEND
 void cxl_mem_active_inc(void);
 void cxl_mem_active_dec(void);
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 9675243bd05b..6e6777b7bafb 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -180,6 +180,10 @@ static int cxl_mem_probe(struct device *dev)
 			return rc;
 	}
 
+	rc = devm_cxl_memdev_edac_register(cxlmd);
+	if (rc)
+		dev_dbg(dev, "CXL memdev EDAC registration failed rc=%d\n", rc);
+
 	/*
 	 * The kernel may be operating out of CXL memory on this device,
 	 * there is no spec defined way to determine whether this device
-- 
2.43.0

[PATCH v5 4/8] cxl/edac: Add CXL memory device ECS control feature

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

CXL spec 3.2 section 8.2.10.9.11.2 describes the DDR5 ECS (Error Check
Scrub) control feature.
The Error Check Scrub (ECS) is a feature defined in JEDEC DDR5 SDRAM
Specification (JESD79-5) and allows the DRAM to internally read, correct
single-bit errors, and write back corrected data bits to the DRAM array
while providing transparency to error counts.

The ECS control allows the requester to change the log entry type, the ECS
threshold count (provided the request falls within the limits specified in
DDR5 mode registers), switch between codeword mode and row count mode, and
reset the ECS counter.

Register with EDAC device driver, which retrieves the ECS attribute
descriptors from the EDAC ECS and exposes the ECS control attributes to
userspace via sysfs. For example, the ECS control for the memory media FRU0
in CXL mem0 device is located at /sys/bus/edac/devices/cxl_mem0/ecs_fru0/

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 drivers/cxl/Kconfig     |  17 ++
 drivers/cxl/core/edac.c | 363 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 378 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index af72416edcd4..51987f2a2548 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -147,6 +147,23 @@ config CXL_EDAC_SCRUB
 	  (e.g. scrub rates for the patrol scrub feature).
 	  Otherwise say 'n'.
 
+config CXL_EDAC_ECS
+	bool "Enable CXL Error Check Scrub (Repair)"
+	depends on CXL_EDAC_MEM_FEATURES
+	depends on EDAC_ECS
+	help
+	  The CXL EDAC ECS control is optional and allows host to
+	  control the ECS feature configurations of CXL memory expander
+	  devices.
+
+	  When enabled 'cxl_mem' EDAC devices are published with memory
+	  ECS control attributes as described by
+	  Documentation/ABI/testing/sysfs-edac-ecs.
+
+	  Say 'y' if you have an expert need to change default settings
+	  of a memory ECS feature established by the platform/device.
+	  Otherwise say 'n'.
+
 config CXL_PORT
 	default CXL_BUS
 	tristate
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index 7d7eb1e8a47a..a6898876ce7f 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -19,7 +19,7 @@
 #include <cxlmem.h>
 #include "core.h"
 
-#define CXL_NR_EDAC_DEV_FEATURES 1
+#define CXL_NR_EDAC_DEV_FEATURES 2
 
 #ifdef CONFIG_CXL_EDAC_SCRUB
 struct cxl_patrol_scrub_context {
@@ -441,11 +441,361 @@ static int cxl_region_scrub_init(struct cxl_region *cxlr,
 }
 #endif /* CONFIG_CXL_EDAC_SCRUB */
 
+#ifdef CONFIG_CXL_EDAC_ECS
+struct cxl_ecs_context {
+	u16 num_media_frus;
+	u16 get_feat_size;
+	u16 set_feat_size;
+	u8 get_version;
+	u8 set_version;
+	u16 effects;
+	struct cxl_memdev *cxlmd;
+};
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.9.11.2 Table 8-225 DDR5 ECS Control Feature
+ * Readable Attributes.
+ */
+struct cxl_ecs_fru_rd_attrbs {
+	u8 ecs_cap;
+	__le16 ecs_config;
+	u8 ecs_flags;
+} __packed;
+
+struct cxl_ecs_rd_attrbs {
+	u8 ecs_log_cap;
+	struct cxl_ecs_fru_rd_attrbs fru_attrbs[];
+} __packed;
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.9.11.2 Table 8-226 DDR5 ECS Control Feature
+ * Writable Attributes.
+ */
+struct cxl_ecs_fru_wr_attrbs {
+	__le16 ecs_config;
+} __packed;
+
+struct cxl_ecs_wr_attrbs {
+	u8 ecs_log_cap;
+	struct cxl_ecs_fru_wr_attrbs fru_attrbs[];
+} __packed;
+
+#define CXL_ECS_LOG_ENTRY_TYPE_MASK GENMASK(1, 0)
+#define CXL_ECS_REALTIME_REPORT_CAP_MASK BIT(0)
+#define CXL_ECS_THRESHOLD_COUNT_MASK GENMASK(2, 0)
+#define CXL_ECS_COUNT_MODE_MASK BIT(3)
+#define CXL_ECS_RESET_COUNTER_MASK BIT(4)
+#define CXL_ECS_RESET_COUNTER 1
+
+enum {
+	ECS_THRESHOLD_256 = 256,
+	ECS_THRESHOLD_1024 = 1024,
+	ECS_THRESHOLD_4096 = 4096,
+};
+
+enum {
+	ECS_THRESHOLD_IDX_256 = 3,
+	ECS_THRESHOLD_IDX_1024 = 4,
+	ECS_THRESHOLD_IDX_4096 = 5,
+};
+
+static const u16 ecs_supp_threshold[] = {
+	[ECS_THRESHOLD_IDX_256] = 256,
+	[ECS_THRESHOLD_IDX_1024] = 1024,
+	[ECS_THRESHOLD_IDX_4096] = 4096,
+};
+
+enum {
+	ECS_LOG_ENTRY_TYPE_DRAM = 0x0,
+	ECS_LOG_ENTRY_TYPE_MEM_MEDIA_FRU = 0x1,
+};
+
+enum cxl_ecs_count_mode {
+	ECS_MODE_COUNTS_ROWS = 0,
+	ECS_MODE_COUNTS_CODEWORDS = 1,
+};
+
+static int cxl_mem_ecs_get_attrbs(struct device *dev,
+				  struct cxl_ecs_context *cxl_ecs_ctx,
+				  int fru_id, u8 *log_cap, u16 *config)
+{
+	struct cxl_memdev *cxlmd = cxl_ecs_ctx->cxlmd;
+	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+	struct cxl_ecs_fru_rd_attrbs *fru_rd_attrbs;
+	size_t rd_data_size;
+	size_t data_size;
+
+	rd_data_size = cxl_ecs_ctx->get_feat_size;
+
+	struct cxl_ecs_rd_attrbs *rd_attrbs __free(kvfree) =
+		kvzalloc(rd_data_size, GFP_KERNEL);
+	if (!rd_attrbs)
+		return -ENOMEM;
+
+	data_size = cxl_get_feature(cxl_mbox, &CXL_FEAT_ECS_UUID,
+				    CXL_GET_FEAT_SEL_CURRENT_VALUE, rd_attrbs,
+				    rd_data_size, 0, NULL);
+	if (!data_size)
+		return -EIO;
+
+	fru_rd_attrbs = rd_attrbs->fru_attrbs;
+	*log_cap = rd_attrbs->ecs_log_cap;
+	*config = le16_to_cpu(fru_rd_attrbs[fru_id].ecs_config);
+
+	return 0;
+}
+
+static int cxl_mem_ecs_set_attrbs(struct device *dev,
+				  struct cxl_ecs_context *cxl_ecs_ctx,
+				  int fru_id, u8 log_cap, u16 config)
+{
+	struct cxl_memdev *cxlmd = cxl_ecs_ctx->cxlmd;
+	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+	struct cxl_ecs_fru_rd_attrbs *fru_rd_attrbs;
+	struct cxl_ecs_fru_wr_attrbs *fru_wr_attrbs;
+	size_t rd_data_size, wr_data_size;
+	u16 num_media_frus, count;
+	size_t data_size;
+
+	num_media_frus = cxl_ecs_ctx->num_media_frus;
+	rd_data_size = cxl_ecs_ctx->get_feat_size;
+	wr_data_size = cxl_ecs_ctx->set_feat_size;
+	struct cxl_ecs_rd_attrbs *rd_attrbs __free(kvfree) =
+		kvzalloc(rd_data_size, GFP_KERNEL);
+	if (!rd_attrbs)
+		return -ENOMEM;
+
+	data_size = cxl_get_feature(cxl_mbox, &CXL_FEAT_ECS_UUID,
+				    CXL_GET_FEAT_SEL_CURRENT_VALUE, rd_attrbs,
+				    rd_data_size, 0, NULL);
+	if (!data_size)
+		return -EIO;
+
+	struct cxl_ecs_wr_attrbs *wr_attrbs __free(kvfree) =
+		kvzalloc(wr_data_size, GFP_KERNEL);
+	if (!wr_attrbs)
+		return -ENOMEM;
+
+	/*
+	 * Fill writable attributes from the current attributes read
+	 * for all the media FRUs.
+	 */
+	fru_rd_attrbs = rd_attrbs->fru_attrbs;
+	fru_wr_attrbs = wr_attrbs->fru_attrbs;
+	wr_attrbs->ecs_log_cap = log_cap;
+	for (count = 0; count < num_media_frus; count++)
+		fru_wr_attrbs[count].ecs_config =
+			fru_rd_attrbs[count].ecs_config;
+
+	fru_wr_attrbs[fru_id].ecs_config = cpu_to_le16(config);
+
+	return cxl_set_feature(cxl_mbox, &CXL_FEAT_ECS_UUID,
+			       cxl_ecs_ctx->set_version, wr_attrbs,
+			       wr_data_size,
+			       CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
+			       0, NULL);
+}
+
+static u8 cxl_get_ecs_log_entry_type(u8 log_cap, u16 config)
+{
+	return FIELD_GET(CXL_ECS_LOG_ENTRY_TYPE_MASK, log_cap);
+}
+
+static u16 cxl_get_ecs_threshold(u8 log_cap, u16 config)
+{
+	u8 index = FIELD_GET(CXL_ECS_THRESHOLD_COUNT_MASK, config);
+
+	return ecs_supp_threshold[index];
+}
+
+static u8 cxl_get_ecs_count_mode(u8 log_cap, u16 config)
+{
+	return FIELD_GET(CXL_ECS_COUNT_MODE_MASK, config);
+}
+
+#define CXL_ECS_GET_ATTR(attrb)						    \
+	static int cxl_ecs_get_##attrb(struct device *dev, void *drv_data,  \
+				       int fru_id, u32 *val)		    \
+	{								    \
+		struct cxl_ecs_context *ctx = drv_data;			    \
+		u8 log_cap;						    \
+		u16 config;						    \
+		int ret;						    \
+									    \
+		ret = cxl_mem_ecs_get_attrbs(dev, ctx, fru_id, &log_cap,    \
+					     &config);			    \
+		if (ret)						    \
+			return ret;					    \
+									    \
+		*val = cxl_get_ecs_##attrb(log_cap, config);		    \
+									    \
+		return 0;						    \
+	}
+
+CXL_ECS_GET_ATTR(log_entry_type)
+CXL_ECS_GET_ATTR(count_mode)
+CXL_ECS_GET_ATTR(threshold)
+
+static int cxl_set_ecs_log_entry_type(struct device *dev, u8 *log_cap,
+				      u16 *config, u32 val)
+{
+	if (val != ECS_LOG_ENTRY_TYPE_DRAM &&
+	    val != ECS_LOG_ENTRY_TYPE_MEM_MEDIA_FRU)
+		return -EINVAL;
+
+	*log_cap = FIELD_PREP(CXL_ECS_LOG_ENTRY_TYPE_MASK, val);
+
+	return 0;
+}
+
+static int cxl_set_ecs_threshold(struct device *dev, u8 *log_cap, u16 *config,
+				 u32 val)
+{
+	*config &= ~CXL_ECS_THRESHOLD_COUNT_MASK;
+
+	switch (val) {
+	case ECS_THRESHOLD_256:
+		*config |= FIELD_PREP(CXL_ECS_THRESHOLD_COUNT_MASK,
+				      ECS_THRESHOLD_IDX_256);
+		break;
+	case ECS_THRESHOLD_1024:
+		*config |= FIELD_PREP(CXL_ECS_THRESHOLD_COUNT_MASK,
+				      ECS_THRESHOLD_IDX_1024);
+		break;
+	case ECS_THRESHOLD_4096:
+		*config |= FIELD_PREP(CXL_ECS_THRESHOLD_COUNT_MASK,
+				      ECS_THRESHOLD_IDX_4096);
+		break;
+	default:
+		dev_dbg(dev, "Invalid CXL ECS threshold count(%d) to set\n",
+			val);
+		dev_dbg(dev, "Supported ECS threshold counts: %u, %u, %u\n",
+			ECS_THRESHOLD_256, ECS_THRESHOLD_1024,
+			ECS_THRESHOLD_4096);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cxl_set_ecs_count_mode(struct device *dev, u8 *log_cap, u16 *config,
+				  u32 val)
+{
+	if (val != ECS_MODE_COUNTS_ROWS && val != ECS_MODE_COUNTS_CODEWORDS) {
+		dev_dbg(dev, "Invalid CXL ECS scrub mode(%d) to set\n", val);
+		dev_dbg(dev,
+			"Supported ECS Modes: 0: ECS counts rows with errors,"
+			" 1: ECS counts codewords with errors\n");
+		return -EINVAL;
+	}
+
+	*config &= ~CXL_ECS_COUNT_MODE_MASK;
+	*config |= FIELD_PREP(CXL_ECS_COUNT_MODE_MASK, val);
+
+	return 0;
+}
+
+static int cxl_set_ecs_reset_counter(struct device *dev, u8 *log_cap,
+				     u16 *config, u32 val)
+{
+	if (val != CXL_ECS_RESET_COUNTER)
+		return -EINVAL;
+
+	*config &= ~CXL_ECS_RESET_COUNTER_MASK;
+	*config |= FIELD_PREP(CXL_ECS_RESET_COUNTER_MASK, val);
+
+	return 0;
+}
+
+#define CXL_ECS_SET_ATTR(attrb)						    \
+	static int cxl_ecs_set_##attrb(struct device *dev, void *drv_data,  \
+					int fru_id, u32 val)		    \
+	{								    \
+		struct cxl_ecs_context *ctx = drv_data;			    \
+		u8 log_cap;						    \
+		u16 config;						    \
+		int ret;						    \
+									    \
+		if (!capable(CAP_SYS_RAWIO))				    \
+			return -EPERM;					    \
+									    \
+		ret = cxl_mem_ecs_get_attrbs(dev, ctx, fru_id, &log_cap,    \
+					     &config);			    \
+		if (ret)						    \
+			return ret;					    \
+									    \
+		ret = cxl_set_ecs_##attrb(dev, &log_cap, &config, val);     \
+		if (ret)						    \
+			return ret;					    \
+									    \
+		return cxl_mem_ecs_set_attrbs(dev, ctx, fru_id, log_cap,    \
+					      config);			    \
+	}
+CXL_ECS_SET_ATTR(log_entry_type)
+CXL_ECS_SET_ATTR(count_mode)
+CXL_ECS_SET_ATTR(reset_counter)
+CXL_ECS_SET_ATTR(threshold)
+
+static const struct edac_ecs_ops cxl_ecs_ops = {
+	.get_log_entry_type = cxl_ecs_get_log_entry_type,
+	.set_log_entry_type = cxl_ecs_set_log_entry_type,
+	.get_mode = cxl_ecs_get_count_mode,
+	.set_mode = cxl_ecs_set_count_mode,
+	.reset = cxl_ecs_set_reset_counter,
+	.get_threshold = cxl_ecs_get_threshold,
+	.set_threshold = cxl_ecs_set_threshold,
+};
+
+static int cxl_memdev_ecs_init(struct cxl_memdev *cxlmd,
+			       struct edac_dev_feature *ras_feature)
+{
+	struct cxl_ecs_context *cxl_ecs_ctx;
+	struct cxl_feat_entry *feat_entry;
+	int num_media_frus;
+
+	feat_entry =
+		cxl_feature_info(to_cxlfs(cxlmd->cxlds), &CXL_FEAT_ECS_UUID);
+	if (!feat_entry)
+		return -EOPNOTSUPP;
+
+	if (!(le32_to_cpu(feat_entry->flags) & CXL_FEATURE_F_CHANGEABLE))
+		return -EOPNOTSUPP;
+
+	num_media_frus = (le16_to_cpu(feat_entry->get_feat_size) -
+			  sizeof(struct cxl_ecs_rd_attrbs)) /
+			 sizeof(struct cxl_ecs_fru_rd_attrbs);
+	if (!num_media_frus)
+		return -EOPNOTSUPP;
+
+	cxl_ecs_ctx =
+		devm_kzalloc(&cxlmd->dev, sizeof(*cxl_ecs_ctx), GFP_KERNEL);
+	if (!cxl_ecs_ctx)
+		return -ENOMEM;
+
+	*cxl_ecs_ctx = (struct cxl_ecs_context){
+		.get_feat_size = le16_to_cpu(feat_entry->get_feat_size),
+		.set_feat_size = le16_to_cpu(feat_entry->set_feat_size),
+		.get_version = feat_entry->get_feat_ver,
+		.set_version = feat_entry->set_feat_ver,
+		.effects = le16_to_cpu(feat_entry->effects),
+		.num_media_frus = num_media_frus,
+		.cxlmd = cxlmd,
+	};
+
+	ras_feature->ft_type = RAS_FEAT_ECS;
+	ras_feature->ecs_ops = &cxl_ecs_ops;
+	ras_feature->ctx = cxl_ecs_ctx;
+	ras_feature->ecs_info.num_media_frus = num_media_frus;
+
+	return 0;
+}
+#endif /* CONFIG_CXL_EDAC_ECS */
+
 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;
-#if defined(CONFIG_CXL_EDAC_SCRUB)
+#if defined(CONFIG_CXL_EDAC_SCRUB) || defined(CONFIG_CXL_EDAC_ECS)
 	int rc;
 #endif
 
@@ -458,6 +808,15 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 		num_ras_features++;
 #endif
 
+#ifdef CONFIG_CXL_EDAC_ECS
+	rc = cxl_memdev_ecs_init(cxlmd, &ras_features[num_ras_features]);
+	if (rc < 0 && rc != -EOPNOTSUPP)
+		return rc;
+
+	if (rc != -EOPNOTSUPP)
+		num_ras_features++;
+#endif
+
 	char *cxl_dev_name __free(kfree) =
 		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));
 	if (!cxl_dev_name)
-- 
2.43.0

[PATCH v5 5/8] cxl/edac: Add support for PERFORM_MAINTENANCE command

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Add support for PERFORM_MAINTENANCE command.

CXL spec 3.2 section 8.2.10.7.1 describes the Perform Maintenance command.
This command requests the device to execute the maintenance operation
specified by the maintenance operation class and the maintenance operation
subclass.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 drivers/cxl/Kconfig     | 17 ++++++++++++++
 drivers/cxl/core/edac.c | 51 +++++++++++++++++++++++++++++++++++++++++
 drivers/cxl/cxlmem.h    |  1 +
 3 files changed, 69 insertions(+)

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 51987f2a2548..2333f7c0b6db 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -164,6 +164,23 @@ 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 '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
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index a6898876ce7f..5a4b67b43dc5 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -791,6 +791,57 @@ static int cxl_memdev_ecs_init(struct cxl_memdev *cxlmd,
 }
 #endif /* CONFIG_CXL_EDAC_ECS */
 
+#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
+/*
+ * Perform Maintenance CXL 3.2 Spec 8.2.10.7.1
+ */
+
+/*
+ * Perform Maintenance input payload
+ * CXL rev 3.2 section 8.2.10.7.1 Table 8-117
+ */
+struct cxl_mbox_maintenance_hdr {
+	u8 op_class;
+	u8 op_subclass;
+} __packed;
+
+static int cxl_perform_maintenance(struct cxl_mailbox *cxl_mbox, u8 class,
+				   u8 subclass, void *data_in,
+				   size_t data_in_size)
+{
+	struct cxl_memdev_maintenance_pi {
+		struct cxl_mbox_maintenance_hdr hdr;
+		u8 data[];
+	} __packed;
+	struct cxl_mbox_cmd mbox_cmd;
+	size_t hdr_size;
+
+	struct cxl_memdev_maintenance_pi *pi __free(kvfree) =
+		kvzalloc(cxl_mbox->payload_size, GFP_KERNEL);
+	if (!pi)
+		return -ENOMEM;
+
+	pi->hdr.op_class = class;
+	pi->hdr.op_subclass = subclass;
+	hdr_size = sizeof(pi->hdr);
+	/*
+	 * Check minimum mbox payload size is available for
+	 * the maintenance data transfer.
+	 */
+	if (hdr_size + data_in_size > cxl_mbox->payload_size)
+		return -ENOMEM;
+
+	memcpy(pi->data, data_in, data_in_size);
+	mbox_cmd = (struct cxl_mbox_cmd){
+		.opcode = CXL_MBOX_OP_DO_MAINTENANCE,
+		.size_in = hdr_size + data_in_size,
+		.payload_in = pi,
+	};
+
+	return cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
+}
+#endif /* CONFIG_CXL_EDAC_MEM_REPAIR */
+
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 {
 	struct edac_dev_feature ras_features[CXL_NR_EDAC_DEV_FEATURES];
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 685957b312ea..1b9bf6b42521 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -533,6 +533,7 @@ enum cxl_opcode {
 	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	= 0x0500,
 	CXL_MBOX_OP_GET_FEATURE		= 0x0501,
 	CXL_MBOX_OP_SET_FEATURE		= 0x0502,
+	CXL_MBOX_OP_DO_MAINTENANCE	= 0x0600,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
 	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
 	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
-- 
2.43.0

[PATCH v5 6/8] cxl/edac: Support for finding memory operation attributes from the current boot

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

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>
---
 drivers/cxl/Kconfig       |   4 +
 drivers/cxl/core/edac.c   | 307 ++++++++++++++++++++++++++++++++++++++
 drivers/cxl/core/mbox.c   |  11 +-
 drivers/cxl/core/memdev.c |   1 +
 drivers/cxl/cxlmem.h      |  19 +++
 5 files changed, 340 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 2333f7c0b6db..48b7314afdb8 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -173,6 +173,10 @@ config CXL_EDAC_MEM_REPAIR
 	  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.
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index 5a4b67b43dc5..489c9996bfbc 100644
--- a/drivers/cxl/core/edac.c
+++ b/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
 
@@ -840,6 +842,280 @@ 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->array_err_rec;
+	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->array_err_rec;
+	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->array_err_rec;
+	struct cxl_event_gen_media *rec;
+	void *old_rec;
+
+	if (!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->array_err_rec;
+	struct cxl_event_dram *rec;
+	void *old_rec;
+
+	if (!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");
 #endif /* CONFIG_CXL_EDAC_MEM_REPAIR */
 
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
@@ -868,6 +1144,16 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 		num_ras_features++;
 #endif
 
+#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
+	struct cxl_mem_err_rec *array_rec =
+		devm_kzalloc(&cxlmd->dev, sizeof(*array_rec), GFP_KERNEL);
+	if (!array_rec)
+		return -ENOMEM;
+
+	cxlmd->array_err_rec = array_rec;
+	xa_init(&array_rec->rec_gen_media);
+	xa_init(&array_rec->rec_dram);
+#endif
 	char *cxl_dev_name __free(kfree) =
 		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));
 	if (!cxl_dev_name)
@@ -903,3 +1189,24 @@ int devm_cxl_region_edac_register(struct cxl_region *cxlr)
 #endif
 }
 EXPORT_SYMBOL_NS_GPL(devm_cxl_region_edac_register, "CXL");
+
+void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
+{
+#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
+	struct cxl_mem_err_rec *array_rec = cxlmd->array_err_rec;
+	struct cxl_event_gen_media *rec_gen_media;
+	struct cxl_event_dram *rec_dram;
+	unsigned long index;
+
+	if (!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);
+#endif
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_memdev_edac_release, "CXL");
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index d72764056ce6..2689e6453c5a 100644
--- a/drivers/cxl/core/mbox.c
+++ b/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");
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index a16a5886d40a..953d8407d0dd 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -27,6 +27,7 @@ static void cxl_memdev_release(struct device *dev)
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 
 	ida_free(&cxl_memdev_ida, cxlmd->id);
+	devm_cxl_memdev_edac_release(cxlmd);
 	kfree(cxlmd);
 }
 
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 1b9bf6b42521..6f808809f7c0 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -47,6 +47,9 @@
  * @depth: endpoint port depth
  * @cur_scrub_cycle: current scrub cycle set for this device
  * @cur_region_id: id number of a backed region (if any) for which current scrub cycle set
+ * @array_err_rec: List of xarrarys to store the memdev error records to
+ *		   check attributes for a memory repair operation are from
+ *		   current boot.
  */
 struct cxl_memdev {
 	struct device dev;
@@ -62,6 +65,7 @@ struct cxl_memdev {
 	u8 cur_scrub_cycle;
 	int cur_region_id;
 #endif
+	void *array_err_rec;
 };
 
 static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
@@ -863,11 +867,26 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
 #if IS_ENABLED(CONFIG_CXL_EDAC_MEM_FEATURES)
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd);
 int devm_cxl_region_edac_register(struct cxl_region *cxlr);
+void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd);
 #else
 static inline int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 { return 0; }
 static inline int devm_cxl_region_edac_register(struct cxl_region *cxlr)
 { return 0; }
+static inline void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
+{ return; }
+#endif
+
+#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
+int cxl_store_rec_gen_media(struct cxl_memdev *cxlmd, union cxl_event *evt);
+int cxl_store_rec_dram(struct cxl_memdev *cxlmd, union cxl_event *evt);
+#else
+static inline int cxl_store_rec_gen_media(struct cxl_memdev *cxlmd,
+					  union cxl_event *evt)
+{ return 0; }
+static inline int cxl_store_rec_dram(struct cxl_memdev *cxlmd,
+				     union cxl_event *evt)
+{ return 0; }
 #endif
 
 #ifdef CONFIG_CXL_SUSPEND
-- 
2.43.0

[PATCH v5 7/8] cxl/edac: Add CXL memory device memory sparing control feature

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Memory sparing is defined as a repair function that replaces a portion of
memory with a portion of functional memory at that same DPA. The subclasses
for this operation vary in terms of the scope of the sparing being
performed. The cacheline sparing subclass refers to a sparing action that
can replace a full cacheline. Row sparing is provided as an alternative to
PPR sparing functions and its scope is that of a single DDR row.
As per CXL r3.2 Table 8-125 foot note 1. Memory sparing is preferred over
PPR when possible.
Bank sparing allows an entire bank to be replaced. Rank sparing is defined
as an operation in which an entire DDR rank is replaced.

Memory sparing maintenance operations may be supported by CXL devices
that implement CXL.mem protocol. A sparing maintenance operation requests
the CXL device to perform a repair operation on its media.
For example, a CXL device with DRAM components that support memory sparing
features may implement sparing maintenance operations.

The host may issue a query command by setting query resources flag in the
input payload (CXL spec 3.2 Table 8-120) to determine availability of
sparing resources for a given address. In response to a query request,
the device shall report the resource availability by producing the memory
sparing event record (CXL spec 3.2 Table 8-60) in which the Channel, Rank,
Nibble Mask, Bank Group, Bank, Row, Column, Sub-Channel fields are a copy
of the values specified in the request.

During the execution of a sparing maintenance operation, a CXL memory
device:
- may not retain data
- may not be able to process CXL.mem requests correctly.
These CXL memory device capabilities are specified by restriction flags
in the memory sparing feature readable attributes.

When a CXL device identifies error on a memory component, the device
may inform the host about the need for a memory sparing maintenance
operation by using DRAM event record, where the 'maintenance needed' flag
may set. The event record contains some of the DPA, Channel, Rank,
Nibble Mask, Bank Group, Bank, Row, Column, Sub-Channel fields that
should be repaired. The userspace tool requests for maintenance operation
if the 'maintenance needed' flag set in the CXL DRAM error record.

CXL spec 3.2 section 8.2.10.7.1.4 describes the device's memory sparing
maintenance operation feature.

CXL spec 3.2 section 8.2.10.7.2.3 describes the memory sparing feature
discovery and configuration.

Add support for controlling CXL memory device memory sparing feature.
Register with EDAC driver, which gets the memory repair attr descriptors
from the EDAC memory repair driver and exposes sysfs repair control
attributes for memory sparing to the userspace. For example CXL memory
sparing control for the CXL mem0 device is exposed in
/sys/bus/edac/devices/cxl_mem0/mem_repairX/

Use case
========
1. CXL device identifies a failure in a memory component, report to
   userspace in a CXL DRAM trace event with DPA and other attributes of
   memory to repair such as channel, rank, nibble mask, bank Group,
   bank, row, column, sub-channel.

2. Rasdaemon process the trace event and may issue query request in sysfs
check resources available for memory sparing if either of the following
conditions met.
 - 'maintenance needed' flag set in the event record.
 - 'threshold event' flag set for CVME threshold feature.
 - When the number of corrected error reported on a CXL.mem media to the
   userspace exceeds the threshold value for corrected error count defined
   by the userspace policy.

3. Rasdaemon process the memory sparing trace event and issue repair
   request for memory sparing.

Kernel CXL driver shall report memory sparing event record to the userspace
with the resource availability in order rasdaemon to process the event
record and issue a repair request in sysfs for the memory sparing operation
in the CXL device.

Note: Based on the feedbacks from the community 'query' sysfs attribute is
removed and reporting memory sparing error record to the userspace are not
supported. Instead userspace issues sparing operation and kernel does the
same to the CXL memory device, when 'maintenance needed' flag set in the
DRAM event record.

Add checks to ensure the memory to be repaired is offline and if online,
then originates from a CXL DRAM error record reported in the current boot
before requesting a memory sparing operation on the device.

Note: Tested memory sparing feature control with QEMU patch
      "hw/cxl: Add emulation for memory sparing control feature"
      https://lore.kernel.org/linux-cxl/20250509172229.726-1-shiju.jose@huawei.com/T/#m5f38512a95670d75739f9dad3ee91b95c7f5c8d6

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 Documentation/edac/memory_repair.rst |  21 +
 drivers/cxl/core/edac.c              | 548 ++++++++++++++++++++++++++-
 drivers/edac/mem_repair.c            |   9 +
 include/linux/edac.h                 |   7 +
 4 files changed, 583 insertions(+), 2 deletions(-)

diff --git a/Documentation/edac/memory_repair.rst b/Documentation/edac/memory_repair.rst
index 52162a422864..5b1cd8297442 100644
--- a/Documentation/edac/memory_repair.rst
+++ b/Documentation/edac/memory_repair.rst
@@ -119,3 +119,24 @@ sysfs
 
 Sysfs files are documented in
 `Documentation/ABI/testing/sysfs-edac-memory-repair`.
+
+Examples
+--------
+
+The memory repair usage takes the form shown in this example:
+
+1. CXL memory sparing
+
+Memory sparing is defined as a repair function that replaces a portion of
+memory with a portion of functional memory at that same DPA. The subclass
+for this operation, cacheline/row/bank/rank sparing, vary in terms of the
+scope of the sparing being performed.
+
+Memory sparing maintenance operations may be supported by CXL devices that
+implement CXL.mem protocol. A sparing maintenance operation requests the
+CXL device to perform a repair operation on its media. For example, a CXL
+device with DRAM components that support memory sparing features may
+implement sparing maintenance operations.
+
+Sysfs files for memory repair are documented in
+`Documentation/ABI/testing/sysfs-edac-memory-repair`
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index 489c9996bfbc..395d56457931 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -21,7 +21,17 @@
 #include "core.h"
 #include "trace.h"
 
-#define CXL_NR_EDAC_DEV_FEATURES 2
+#define CXL_NR_EDAC_DEV_FEATURES 6
+
+static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)
+{
+	struct cxl_port *port = cxlmd->endpoint;
+
+	if (port && cxl_num_decoders_committed(port))
+		return true;
+
+	return false;
+}
 
 #ifdef CONFIG_CXL_EDAC_SCRUB
 struct cxl_patrol_scrub_context {
@@ -1116,13 +1126,534 @@ int cxl_store_rec_dram(struct cxl_memdev *cxlmd, union cxl_event *evt)
 	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_store_rec_dram, "CXL");
+
+/*
+ * CXL memory sparing control
+ */
+enum cxl_mem_sparing_granularity {
+	CXL_MEM_SPARING_CACHELINE,
+	CXL_MEM_SPARING_ROW,
+	CXL_MEM_SPARING_BANK,
+	CXL_MEM_SPARING_RANK,
+	CXL_MEM_SPARING_MAX
+};
+
+struct cxl_mem_sparing_context {
+	struct cxl_memdev *cxlmd;
+	uuid_t repair_uuid;
+	u16 get_feat_size;
+	u16 set_feat_size;
+	u16 effects;
+	u8 instance;
+	u8 get_version;
+	u8 set_version;
+	u8 op_class;
+	u8 op_subclass;
+	bool cap_safe_when_in_use;
+	bool cap_hard_sparing;
+	bool cap_soft_sparing;
+	u8 channel;
+	u8 rank;
+	u8 bank_group;
+	u32 nibble_mask;
+	u64 dpa;
+	u32 row;
+	u16 column;
+	u8 bank;
+	u8 sub_channel;
+	enum edac_mem_repair_type repair_type;
+	bool persist_mode;
+};
+
+#define CXL_SPARING_RD_CAP_SAFE_IN_USE_MASK BIT(0)
+#define CXL_SPARING_RD_CAP_HARD_SPARING_MASK BIT(1)
+#define CXL_SPARING_RD_CAP_SOFT_SPARING_MASK BIT(2)
+
+#define CXL_SPARING_WR_DEVICE_INITIATED_MASK BIT(0)
+
+#define CXL_SPARING_QUERY_RESOURCE_FLAG BIT(0)
+#define CXL_SET_HARD_SPARING_FLAG BIT(1)
+#define CXL_SPARING_SUB_CHNL_VALID_FLAG BIT(2)
+#define CXL_SPARING_NIB_MASK_VALID_FLAG BIT(3)
+
+#define CXL_GET_SPARING_SAFE_IN_USE(flags) \
+	(FIELD_GET(CXL_SPARING_RD_CAP_SAFE_IN_USE_MASK, \
+		  flags) ^ 1)
+#define CXL_GET_CAP_HARD_SPARING(flags) \
+	FIELD_GET(CXL_SPARING_RD_CAP_HARD_SPARING_MASK, \
+		  flags)
+#define CXL_GET_CAP_SOFT_SPARING(flags) \
+	FIELD_GET(CXL_SPARING_RD_CAP_SOFT_SPARING_MASK, \
+		  flags)
+
+#define CXL_SET_SPARING_QUERY_RESOURCE(val) \
+	FIELD_PREP(CXL_SPARING_QUERY_RESOURCE_FLAG, val)
+#define CXL_SET_HARD_SPARING(val) \
+	FIELD_PREP(CXL_SET_HARD_SPARING_FLAG, val)
+#define CXL_SET_SPARING_SUB_CHNL_VALID(val) \
+	FIELD_PREP(CXL_SPARING_SUB_CHNL_VALID_FLAG, val)
+#define CXL_SET_SPARING_NIB_MASK_VALID(val) \
+	FIELD_PREP(CXL_SPARING_NIB_MASK_VALID_FLAG, val)
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.7.2.3 Table 8-134 Memory Sparing Feature
+ * Readable Attributes.
+ */
+struct cxl_memdev_repair_rd_attrbs_hdr {
+	u8 max_op_latency;
+	__le16 op_cap;
+	__le16 op_mode;
+	u8 op_class;
+	u8 op_subclass;
+	u8 rsvd[9];
+} __packed;
+
+struct cxl_memdev_sparing_rd_attrbs {
+	struct cxl_memdev_repair_rd_attrbs_hdr hdr;
+	u8 rsvd;
+	__le16 restriction_flags;
+} __packed;
+
+/*
+ * See CXL spec rev 3.2 @8.2.10.7.1.4 Table 8-120 Memory Sparing Input Payload.
+ */
+struct cxl_memdev_sparing_in_payload {
+	u8 flags;
+	u8 channel;
+	u8 rank;
+	u8 nibble_mask[3];
+	u8 bank_group;
+	u8 bank;
+	u8 row[3];
+	__le16 column;
+	u8 sub_channel;
+} __packed;
+
+static int
+cxl_mem_sparing_get_attrbs(struct cxl_mem_sparing_context *cxl_sparing_ctx)
+{
+	size_t rd_data_size = sizeof(struct cxl_memdev_sparing_rd_attrbs);
+	struct cxl_memdev *cxlmd = cxl_sparing_ctx->cxlmd;
+	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+	u16 restriction_flags;
+	size_t data_size;
+	u16 return_code;
+	struct cxl_memdev_sparing_rd_attrbs *rd_attrbs __free(kfree) =
+		kzalloc(rd_data_size, GFP_KERNEL);
+	if (!rd_attrbs)
+		return -ENOMEM;
+
+	data_size = cxl_get_feature(cxl_mbox, &cxl_sparing_ctx->repair_uuid,
+				    CXL_GET_FEAT_SEL_CURRENT_VALUE, rd_attrbs,
+				    rd_data_size, 0, &return_code);
+	if (!data_size)
+		return -EIO;
+
+	cxl_sparing_ctx->op_class = rd_attrbs->hdr.op_class;
+	cxl_sparing_ctx->op_subclass = rd_attrbs->hdr.op_subclass;
+	restriction_flags = le16_to_cpu(rd_attrbs->restriction_flags);
+	cxl_sparing_ctx->cap_safe_when_in_use =
+		CXL_GET_SPARING_SAFE_IN_USE(restriction_flags);
+	cxl_sparing_ctx->cap_hard_sparing =
+		CXL_GET_CAP_HARD_SPARING(restriction_flags);
+	cxl_sparing_ctx->cap_soft_sparing =
+		CXL_GET_CAP_SOFT_SPARING(restriction_flags);
+
+	return 0;
+}
+
+static struct cxl_event_dram *
+cxl_mem_get_rec_dram(struct cxl_memdev *cxlmd,
+		     struct cxl_mem_sparing_context *ctx)
+{
+	struct cxl_mem_repair_attrbs attrbs = { 0 };
+
+	attrbs.dpa = ctx->dpa;
+	attrbs.channel = ctx->channel;
+	attrbs.rank = ctx->rank;
+	attrbs.nibble_mask = ctx->nibble_mask;
+	switch (ctx->repair_type) {
+	case EDAC_REPAIR_CACHELINE_SPARING:
+		attrbs.repair_type = CXL_CACHELINE_SPARING;
+		attrbs.bank_group = ctx->bank_group;
+		attrbs.bank = ctx->bank;
+		attrbs.row = ctx->row;
+		attrbs.column = ctx->column;
+		attrbs.sub_channel = ctx->sub_channel;
+		break;
+	case EDAC_REPAIR_ROW_SPARING:
+		attrbs.repair_type = CXL_ROW_SPARING;
+		attrbs.bank_group = ctx->bank_group;
+		attrbs.bank = ctx->bank;
+		attrbs.row = ctx->row;
+		break;
+	case EDAC_REPAIR_BANK_SPARING:
+		attrbs.repair_type = CXL_BANK_SPARING;
+		attrbs.bank_group = ctx->bank_group;
+		attrbs.bank = ctx->bank;
+	break;
+	case EDAC_REPAIR_RANK_SPARING:
+		attrbs.repair_type = CXL_BANK_SPARING;
+		break;
+	default:
+		return NULL;
+	}
+
+	return cxl_find_rec_dram(cxlmd, &attrbs);
+}
+
+static int
+cxl_mem_perform_sparing(struct device *dev,
+			struct cxl_mem_sparing_context *cxl_sparing_ctx)
+{
+	struct cxl_memdev *cxlmd = cxl_sparing_ctx->cxlmd;
+	struct cxl_memdev_sparing_in_payload sparing_pi;
+	struct cxl_event_dram *rec = NULL;
+	u16 validity_flags = 0;
+
+	struct rw_semaphore *region_lock __free(rwsem_read_release) =
+		rwsem_read_intr_acquire(&cxl_region_rwsem);
+	if (!region_lock)
+		return -EINTR;
+
+	struct rw_semaphore *dpa_lock __free(rwsem_read_release) =
+		rwsem_read_intr_acquire(&cxl_dpa_rwsem);
+	if (!dpa_lock)
+		return -EINTR;
+
+	if (!cxl_sparing_ctx->cap_safe_when_in_use) {
+		/* Memory to repair must be offline */
+		if (cxl_is_memdev_memory_online(cxlmd))
+			return -EBUSY;
+	} else {
+		if (cxl_is_memdev_memory_online(cxlmd)) {
+			rec = cxl_mem_get_rec_dram(cxlmd, cxl_sparing_ctx);
+			if (!rec)
+				return -EINVAL;
+
+			if (!get_unaligned_le16(rec->media_hdr.validity_flags))
+				return -EINVAL;
+		}
+	}
+
+	memset(&sparing_pi, 0, sizeof(sparing_pi));
+	sparing_pi.flags = CXL_SET_SPARING_QUERY_RESOURCE(0);
+	if (cxl_sparing_ctx->persist_mode)
+		sparing_pi.flags |= CXL_SET_HARD_SPARING(1);
+
+	if (rec)
+		validity_flags = get_unaligned_le16(rec->media_hdr.validity_flags);
+
+	switch (cxl_sparing_ctx->repair_type) {
+	case EDAC_REPAIR_CACHELINE_SPARING:
+		sparing_pi.column = cpu_to_le16(cxl_sparing_ctx->column);
+		if (!rec || (validity_flags & CXL_DER_VALID_SUB_CHANNEL)) {
+			sparing_pi.flags |= CXL_SET_SPARING_SUB_CHNL_VALID(1);
+			sparing_pi.sub_channel = cxl_sparing_ctx->sub_channel;
+		}
+		fallthrough;
+	case EDAC_REPAIR_ROW_SPARING:
+		put_unaligned_le24(cxl_sparing_ctx->row, sparing_pi.row);
+		fallthrough;
+	case EDAC_REPAIR_BANK_SPARING:
+		sparing_pi.bank_group = cxl_sparing_ctx->bank_group;
+		sparing_pi.bank = cxl_sparing_ctx->bank;
+		fallthrough;
+	case EDAC_REPAIR_RANK_SPARING:
+		sparing_pi.rank = cxl_sparing_ctx->rank;
+		fallthrough;
+	default:
+		sparing_pi.channel = cxl_sparing_ctx->channel;
+		if ((rec && (validity_flags & CXL_DER_VALID_NIBBLE)) ||
+		    (!rec && (!cxl_sparing_ctx->nibble_mask ||
+			     (cxl_sparing_ctx->nibble_mask & 0xFFFFFF)))) {
+			sparing_pi.flags |= CXL_SET_SPARING_NIB_MASK_VALID(1);
+			put_unaligned_le24(cxl_sparing_ctx->nibble_mask,
+					   sparing_pi.nibble_mask);
+		}
+		break;
+	}
+
+	return cxl_perform_maintenance(&cxlmd->cxlds->cxl_mbox,
+				       cxl_sparing_ctx->op_class,
+				       cxl_sparing_ctx->op_subclass,
+				       &sparing_pi, sizeof(sparing_pi));
+}
+
+static int cxl_mem_sparing_get_repair_type(struct device *dev, void *drv_data,
+					   const char **repair_type)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+
+	switch (ctx->repair_type) {
+	case EDAC_REPAIR_CACHELINE_SPARING:
+	case EDAC_REPAIR_ROW_SPARING:
+	case EDAC_REPAIR_BANK_SPARING:
+	case EDAC_REPAIR_RANK_SPARING:
+		*repair_type = edac_repair_type[ctx->repair_type];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#define CXL_SPARING_GET_ATTR(attrb, data_type)			    \
+	static int cxl_mem_sparing_get_##attrb(			    \
+		struct device *dev, void *drv_data, data_type *val) \
+	{							    \
+		struct cxl_mem_sparing_context *ctx = drv_data;	    \
+								    \
+		*val = ctx->attrb;				    \
+								    \
+		return 0;					    \
+	}
+CXL_SPARING_GET_ATTR(persist_mode, bool)
+CXL_SPARING_GET_ATTR(dpa, u64)
+CXL_SPARING_GET_ATTR(nibble_mask, u32)
+CXL_SPARING_GET_ATTR(bank_group, u32)
+CXL_SPARING_GET_ATTR(bank, u32)
+CXL_SPARING_GET_ATTR(rank, u32)
+CXL_SPARING_GET_ATTR(row, u32)
+CXL_SPARING_GET_ATTR(column, u32)
+CXL_SPARING_GET_ATTR(channel, u32)
+CXL_SPARING_GET_ATTR(sub_channel, u32)
+
+#define CXL_SPARING_SET_ATTR(attrb, data_type)					\
+	static int cxl_mem_sparing_set_##attrb(struct device *dev,		\
+						void *drv_data, data_type val)	\
+	{									\
+		struct cxl_mem_sparing_context *ctx = drv_data;			\
+										\
+		ctx->attrb = val;						\
+										\
+		return 0;							\
+	}
+CXL_SPARING_SET_ATTR(nibble_mask, u32)
+CXL_SPARING_SET_ATTR(bank_group, u32)
+CXL_SPARING_SET_ATTR(bank, u32)
+CXL_SPARING_SET_ATTR(rank, u32)
+CXL_SPARING_SET_ATTR(row, u32)
+CXL_SPARING_SET_ATTR(column, u32)
+CXL_SPARING_SET_ATTR(channel, u32)
+CXL_SPARING_SET_ATTR(sub_channel, u32)
+
+static int cxl_mem_sparing_set_persist_mode(struct device *dev, void *drv_data,
+					    bool persist_mode)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+
+	if ((persist_mode && ctx->cap_hard_sparing) ||
+	    (!persist_mode && ctx->cap_soft_sparing))
+		ctx->persist_mode = persist_mode;
+	else
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int cxl_get_mem_sparing_safe_when_in_use(struct device *dev,
+						void *drv_data, bool *safe)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+
+	*safe = ctx->cap_safe_when_in_use;
+
+	return 0;
+}
+
+static int cxl_mem_sparing_get_min_dpa(struct device *dev, void *drv_data,
+				       u64 *min_dpa)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+	struct cxl_memdev *cxlmd = ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	*min_dpa = cxlds->dpa_res.start;
+
+	return 0;
+}
+
+static int cxl_mem_sparing_get_max_dpa(struct device *dev, void *drv_data,
+				       u64 *max_dpa)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+	struct cxl_memdev *cxlmd = ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	*max_dpa = cxlds->dpa_res.end;
+
+	return 0;
+}
+
+static int cxl_mem_sparing_set_dpa(struct device *dev, void *drv_data, u64 dpa)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+	struct cxl_memdev *cxlmd = ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	if (dpa < cxlds->dpa_res.start || dpa > cxlds->dpa_res.end)
+		return -EINVAL;
+
+	ctx->dpa = dpa;
+
+	return 0;
+}
+
+static int cxl_do_mem_sparing(struct device *dev, void *drv_data, u32 val)
+{
+	struct cxl_mem_sparing_context *ctx = drv_data;
+
+	if (val != EDAC_DO_MEM_REPAIR)
+		return -EINVAL;
+
+	return cxl_mem_perform_sparing(dev, ctx);
+}
+
+#define RANK_OPS                                                             \
+	.get_repair_type = cxl_mem_sparing_get_repair_type,                  \
+	.get_persist_mode = cxl_mem_sparing_get_persist_mode,                \
+	.set_persist_mode = cxl_mem_sparing_set_persist_mode,                \
+	.get_repair_safe_when_in_use = cxl_get_mem_sparing_safe_when_in_use, \
+	.get_min_dpa = cxl_mem_sparing_get_min_dpa,                          \
+	.get_max_dpa = cxl_mem_sparing_get_max_dpa,                          \
+	.get_dpa = cxl_mem_sparing_get_dpa,                                  \
+	.set_dpa = cxl_mem_sparing_set_dpa,                                  \
+	.get_nibble_mask = cxl_mem_sparing_get_nibble_mask,                  \
+	.set_nibble_mask = cxl_mem_sparing_set_nibble_mask,                  \
+	.get_rank = cxl_mem_sparing_get_rank,                                \
+	.set_rank = cxl_mem_sparing_set_rank,                                \
+	.get_channel = cxl_mem_sparing_get_channel,                          \
+	.set_channel = cxl_mem_sparing_set_channel,                          \
+	.do_repair = cxl_do_mem_sparing
+
+#define BANK_OPS                                                    \
+	RANK_OPS, .get_bank_group = cxl_mem_sparing_get_bank_group, \
+		.set_bank_group = cxl_mem_sparing_set_bank_group,   \
+		.get_bank = cxl_mem_sparing_get_bank,               \
+		.set_bank = cxl_mem_sparing_set_bank
+
+#define ROW_OPS                                       \
+	BANK_OPS, .get_row = cxl_mem_sparing_get_row, \
+		.set_row = cxl_mem_sparing_set_row
+
+#define CACHELINE_OPS                                               \
+	ROW_OPS, .get_column = cxl_mem_sparing_get_column,          \
+		.set_column = cxl_mem_sparing_set_column,           \
+		.get_sub_channel = cxl_mem_sparing_get_sub_channel, \
+		.set_sub_channel = cxl_mem_sparing_set_sub_channel
+
+static const struct edac_mem_repair_ops cxl_rank_sparing_ops = {
+	RANK_OPS,
+};
+
+static const struct edac_mem_repair_ops cxl_bank_sparing_ops = {
+	BANK_OPS,
+};
+
+static const struct edac_mem_repair_ops cxl_row_sparing_ops = {
+	ROW_OPS,
+};
+
+static const struct edac_mem_repair_ops cxl_cacheline_sparing_ops = {
+	CACHELINE_OPS,
+};
+
+struct cxl_mem_sparing_desc {
+	const uuid_t repair_uuid;
+	enum edac_mem_repair_type repair_type;
+	const struct edac_mem_repair_ops *repair_ops;
+};
+
+static const struct cxl_mem_sparing_desc mem_sparing_desc[] = {
+	{
+		.repair_uuid = CXL_FEAT_CACHELINE_SPARING_UUID,
+		.repair_type = EDAC_REPAIR_CACHELINE_SPARING,
+		.repair_ops = &cxl_cacheline_sparing_ops,
+	},
+	{
+		.repair_uuid = CXL_FEAT_ROW_SPARING_UUID,
+		.repair_type = EDAC_REPAIR_ROW_SPARING,
+		.repair_ops = &cxl_row_sparing_ops,
+	},
+	{
+		.repair_uuid = CXL_FEAT_BANK_SPARING_UUID,
+		.repair_type = EDAC_REPAIR_BANK_SPARING,
+		.repair_ops = &cxl_bank_sparing_ops,
+	},
+	{
+		.repair_uuid = CXL_FEAT_RANK_SPARING_UUID,
+		.repair_type = EDAC_REPAIR_RANK_SPARING,
+		.repair_ops = &cxl_rank_sparing_ops,
+	},
+};
+
+static int cxl_memdev_sparing_init(struct cxl_memdev *cxlmd,
+				   struct edac_dev_feature *ras_feature,
+				   const struct cxl_mem_sparing_desc *desc,
+				   u8 repair_inst)
+{
+	struct cxl_mem_sparing_context *cxl_sparing_ctx;
+	struct cxl_feat_entry *feat_entry;
+	int ret;
+
+	feat_entry = cxl_feature_info(to_cxlfs(cxlmd->cxlds),
+				      &desc->repair_uuid);
+	if (!feat_entry)
+		return -EOPNOTSUPP;
+
+	if (!(le32_to_cpu(feat_entry->flags) & CXL_FEATURE_F_CHANGEABLE))
+		return -EOPNOTSUPP;
+
+	cxl_sparing_ctx = devm_kzalloc(&cxlmd->dev, sizeof(*cxl_sparing_ctx),
+				       GFP_KERNEL);
+	if (!cxl_sparing_ctx)
+		return -ENOMEM;
+
+	*cxl_sparing_ctx = (struct cxl_mem_sparing_context){
+		.get_feat_size = le16_to_cpu(feat_entry->get_feat_size),
+		.set_feat_size = le16_to_cpu(feat_entry->set_feat_size),
+		.get_version = feat_entry->get_feat_ver,
+		.set_version = feat_entry->set_feat_ver,
+		.effects = le16_to_cpu(feat_entry->effects),
+		.cxlmd = cxlmd,
+		.repair_type = desc->repair_type,
+		.instance = repair_inst++,
+	};
+	uuid_copy(&cxl_sparing_ctx->repair_uuid, &desc->repair_uuid);
+
+	ret = cxl_mem_sparing_get_attrbs(cxl_sparing_ctx);
+	if (ret)
+		return ret;
+
+	if ((cxl_sparing_ctx->cap_soft_sparing &&
+	     cxl_sparing_ctx->cap_hard_sparing) ||
+	    cxl_sparing_ctx->cap_soft_sparing)
+		cxl_sparing_ctx->persist_mode = 0;
+	else if (cxl_sparing_ctx->cap_hard_sparing)
+		cxl_sparing_ctx->persist_mode = 1;
+	else
+		return -EOPNOTSUPP;
+
+	ras_feature->ft_type = RAS_FEAT_MEM_REPAIR;
+	ras_feature->instance = cxl_sparing_ctx->instance;
+	ras_feature->mem_repair_ops = desc->repair_ops;
+	ras_feature->ctx = cxl_sparing_ctx;
+
+	return 0;
+}
 #endif /* CONFIG_CXL_EDAC_MEM_REPAIR */
 
 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;
-#if defined(CONFIG_CXL_EDAC_SCRUB) || defined(CONFIG_CXL_EDAC_ECS)
+#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
+	u8 repair_inst = 0;
+#endif
+#if defined(CONFIG_CXL_EDAC_SCRUB) || defined(CONFIG_CXL_EDAC_ECS) || \
+	defined(CXL_EDAC_MEM_REPAIR)
 	int rc;
 #endif
 
@@ -1153,6 +1684,19 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 	cxlmd->array_err_rec = array_rec;
 	xa_init(&array_rec->rec_gen_media);
 	xa_init(&array_rec->rec_dram);
+
+	for (int i = 0; i < CXL_MEM_SPARING_MAX; i++) {
+		rc = cxl_memdev_sparing_init(cxlmd,
+					     &ras_features[num_ras_features],
+					     &mem_sparing_desc[i], repair_inst);
+		if (rc == -EOPNOTSUPP)
+			continue;
+		if (rc < 0)
+			return rc;
+
+		repair_inst++;
+		num_ras_features++;
+	}
 #endif
 	char *cxl_dev_name __free(kfree) =
 		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));
diff --git a/drivers/edac/mem_repair.c b/drivers/edac/mem_repair.c
index 3b1a845457b0..d1a8caa85369 100755
--- a/drivers/edac/mem_repair.c
+++ b/drivers/edac/mem_repair.c
@@ -45,6 +45,15 @@ struct edac_mem_repair_context {
 	struct attribute_group group;
 };
 
+const char * const edac_repair_type[] = {
+	[EDAC_REPAIR_PPR] = "ppr",
+	[EDAC_REPAIR_CACHELINE_SPARING] = "cacheline-sparing",
+	[EDAC_REPAIR_ROW_SPARING] = "row-sparing",
+	[EDAC_REPAIR_BANK_SPARING] = "bank-sparing",
+	[EDAC_REPAIR_RANK_SPARING] = "rank-sparing",
+};
+EXPORT_SYMBOL_GPL(edac_repair_type);
+
 #define TO_MR_DEV_ATTR(_dev_attr)      \
 	container_of(_dev_attr, struct edac_mem_repair_dev_attr, dev_attr)
 
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 451f9c152c99..fa32f2aca22f 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -745,9 +745,16 @@ static inline int edac_ecs_get_desc(struct device *ecs_dev,
 #endif /* CONFIG_EDAC_ECS */
 
 enum edac_mem_repair_type {
+	EDAC_REPAIR_PPR,
+	EDAC_REPAIR_CACHELINE_SPARING,
+	EDAC_REPAIR_ROW_SPARING,
+	EDAC_REPAIR_BANK_SPARING,
+	EDAC_REPAIR_RANK_SPARING,
 	EDAC_REPAIR_MAX
 };
 
+extern const char * const edac_repair_type[];
+
 enum edac_mem_repair_cmd {
 	EDAC_DO_MEM_REPAIR = 1,
 };
-- 
2.43.0

[PATCH v5 8/8] cxl/edac: Add CXL memory device soft PPR control feature

[shiju.jose]

From: Shiju Jose <shiju.jose@huawei.com>

Post Package Repair (PPR) maintenance operations may be supported by CXL
devices that implement CXL.mem protocol. A PPR maintenance operation
requests the CXL device to perform a repair operation on its media.
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 (hPPR), for a permanent row repair, and Soft PPR
(sPPR), for a temporary row repair. Soft PPR is much faster than hPPR,
but the repair is lost with a power cycle.

During the execution of a PPR Maintenance operation, a CXL memory device:
- May or may not retain data
- May or may not be able to process CXL.mem requests correctly, including
the ones that target the DPA involved in the repair.
These CXL Memory Device capabilities are specified by Restriction Flags
in the sPPR Feature and hPPR Feature.

Soft PPR maintenance operation may be executed at runtime, if data is
retained and CXL.mem requests are correctly processed. For CXL devices with
DRAM components, hPPR maintenance operation may be executed only at boot
because typically data may not be retained with hPPR maintenance operation.

When a CXL device identifies error on a memory component, the device
may inform the host about the need for a PPR maintenance operation by using
an Event Record, where the Maintenance Needed flag is set. The Event Record
specifies the DPA that should be repaired. A CXL device may not keep track
of the requests that have already been sent and the information on which
DPA should be repaired may be lost upon power cycle.
The userspace tool requests for maintenance operation if the number of
corrected error reported on a CXL.mem media exceeds error threshold.

CXL spec 3.2 section 8.2.10.7.1.2 describes the device's sPPR (soft PPR)
maintenance operation and section 8.2.10.7.1.3 describes the device's
hPPR (hard PPR) maintenance operation feature.

CXL spec 3.2 section 8.2.10.7.2.1 describes the sPPR feature discovery and
configuration.

CXL spec 3.2 section 8.2.10.7.2.2 describes the hPPR feature discovery and
configuration.

Add support for controlling CXL memory device soft PPR (sPPR) feature.
Register with EDAC driver, which gets the memory repair attr descriptors
from the EDAC memory repair driver and exposes sysfs repair control
attributes for PRR to the userspace. For example CXL PPR control for the
CXL mem0 device is exposed in /sys/bus/edac/devices/cxl_mem0/mem_repairX/

Add checks to ensure the memory to be repaired is offline and originates
from a CXL DRAM or CXL gen_media error record reported in the current boot,
before requesting a PPR operation on the device.

Note: Tested with QEMU patch for CXL PPR feature.
https://lore.kernel.org/linux-cxl/20250509172229.726-1-shiju.jose@huawei.com/T/#m70b2b010f43f7f4a6f9acee5ec9008498bf292c3

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 Documentation/edac/memory_repair.rst |  10 +
 drivers/cxl/core/edac.c              | 328 ++++++++++++++++++++++++++-
 2 files changed, 337 insertions(+), 1 deletion(-)

diff --git a/Documentation/edac/memory_repair.rst b/Documentation/edac/memory_repair.rst
index 5b1cd8297442..3a3fc11b8fea 100644
--- a/Documentation/edac/memory_repair.rst
+++ b/Documentation/edac/memory_repair.rst
@@ -138,5 +138,15 @@ CXL device to perform a repair operation on its media. For example, a CXL
 device with DRAM components that support memory sparing features may
 implement sparing maintenance operations.
 
+2. CXL memory Soft Post Package Repair (sPPR)
+
+Post Package Repair (PPR) maintenance operations may be supported by CXL
+devices that implement CXL.mem protocol. A PPR maintenance operation
+requests the CXL device to perform a repair operation on its media.
+For example, a CXL device with DRAM components that support PPR features
+may implement PPR Maintenance operations. Soft PPR (sPPR), is a temporary
+row repair. Soft PPR may be faster, but the repair is lost with a power
+cycle.
+
 Sysfs files for memory repair are documented in
 `Documentation/ABI/testing/sysfs-edac-memory-repair`
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index 395d56457931..87b347c232b2 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -14,6 +14,7 @@
 #include <linux/cleanup.h>
 #include <linux/edac.h>
 #include <linux/limits.h>
+#include <linux/unaligned.h>
 #include <linux/xarray.h>
 #include <cxl/features.h>
 #include <cxl.h>
@@ -21,7 +22,7 @@
 #include "core.h"
 #include "trace.h"
 
-#define CXL_NR_EDAC_DEV_FEATURES 6
+#define CXL_NR_EDAC_DEV_FEATURES 7
 
 static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)
 {
@@ -1643,6 +1644,321 @@ static int cxl_memdev_sparing_init(struct cxl_memdev *cxlmd,
 
 	return 0;
 }
+
+/*
+ * CXL memory soft PPR & hard PPR control definitions
+ */
+struct cxl_ppr_context {
+	uuid_t repair_uuid;
+	u8 instance;
+	u16 get_feat_size;
+	u16 set_feat_size;
+	u8 get_version;
+	u8 set_version;
+	u16 effects;
+	u8 op_class;
+	u8 op_subclass;
+	bool cap_dpa;
+	bool cap_nib_mask;
+	bool media_accessible;
+	bool data_retained;
+	struct cxl_memdev *cxlmd;
+	enum edac_mem_repair_type repair_type;
+	bool persist_mode;
+	u64 dpa;
+	u32 nibble_mask;
+};
+
+/*
+ * See CXL rev 3.2 @8.2.10.7.2.1 Table 8-128 sPPR Feature Readable Attributes
+ *
+ * See CXL rev 3.2 @8.2.10.7.2.2 Table 8-131 hPPR Feature Readable Attributes
+ */
+
+#define CXL_PPR_OP_CAP_DEVICE_INITIATED BIT(0)
+#define CXL_PPR_OP_MODE_DEV_INITIATED BIT(0)
+
+#define CXL_PPR_FLAG_DPA_SUPPORT_MASK BIT(0)
+#define CXL_PPR_FLAG_NIB_SUPPORT_MASK BIT(1)
+#define CXL_PPR_FLAG_MEM_SPARING_EV_REC_SUPPORT_MASK BIT(2)
+#define CXL_PPR_FLAG_DEV_INITED_PPR_AT_BOOT_CAP_MASK BIT(3)
+
+#define CXL_PPR_RESTRICTION_FLAG_MEDIA_ACCESSIBLE_MASK BIT(0)
+#define CXL_PPR_RESTRICTION_FLAG_DATA_RETAINED_MASK BIT(2)
+
+#define CXL_PPR_SPARING_EV_REC_EN_MASK BIT(0)
+#define CXL_PPR_DEV_INITED_PPR_AT_BOOT_EN_MASK BIT(1)
+
+#define CXL_PPR_GET_CAP_DPA(flags) \
+	FIELD_GET(CXL_PPR_FLAG_DPA_SUPPORT_MASK, flags)
+#define CXL_PPR_GET_CAP_NIB_MASK(flags) \
+	FIELD_GET(CXL_PPR_FLAG_NIB_SUPPORT_MASK, flags)
+#define CXL_PPR_GET_MEDIA_ACCESSIBLE(restriction_flags) \
+	(FIELD_GET(CXL_PPR_RESTRICTION_FLAG_MEDIA_ACCESSIBLE_MASK, \
+		   restriction_flags) ^ 1)
+#define CXL_PPR_GET_DATA_RETAINED(restriction_flags) \
+	(FIELD_GET(CXL_PPR_RESTRICTION_FLAG_DATA_RETAINED_MASK, \
+		   restriction_flags) ^ 1)
+
+struct cxl_memdev_ppr_rd_attrbs {
+	struct cxl_memdev_repair_rd_attrbs_hdr hdr;
+	u8 ppr_flags;
+	__le16 restriction_flags;
+	u8 ppr_op_mode;
+} __packed;
+
+/*
+ * See CXL rev 3.2 @8.2.10.7.1.2 Table 8-118 sPPR Maintenance Input Payload
+ *
+ * See CXL rev 3.2 @8.2.10.7.1.3 Table 8-119 hPPR Maintenance Input Payload
+ */
+struct cxl_memdev_ppr_maintenance_attrbs {
+	u8 flags;
+	__le64 dpa;
+	u8 nibble_mask[3];
+} __packed;
+
+static int cxl_mem_ppr_get_attrbs(struct cxl_ppr_context *cxl_ppr_ctx)
+{
+	size_t rd_data_size = sizeof(struct cxl_memdev_ppr_rd_attrbs);
+	struct cxl_memdev *cxlmd = cxl_ppr_ctx->cxlmd;
+	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
+	u16 restriction_flags;
+	size_t data_size;
+	u16 return_code;
+
+	struct cxl_memdev_ppr_rd_attrbs *rd_attrbs __free(kfree) =
+		kmalloc(rd_data_size, GFP_KERNEL);
+	if (!rd_attrbs)
+		return -ENOMEM;
+
+	data_size = cxl_get_feature(cxl_mbox, &cxl_ppr_ctx->repair_uuid,
+				    CXL_GET_FEAT_SEL_CURRENT_VALUE, rd_attrbs,
+				    rd_data_size, 0, &return_code);
+	if (!data_size)
+		return -EIO;
+
+	cxl_ppr_ctx->op_class = rd_attrbs->hdr.op_class;
+	cxl_ppr_ctx->op_subclass = rd_attrbs->hdr.op_subclass;
+	cxl_ppr_ctx->cap_dpa = CXL_PPR_GET_CAP_DPA(rd_attrbs->ppr_flags);
+	cxl_ppr_ctx->cap_nib_mask =
+		CXL_PPR_GET_CAP_NIB_MASK(rd_attrbs->ppr_flags);
+
+	restriction_flags = le16_to_cpu(rd_attrbs->restriction_flags);
+	cxl_ppr_ctx->media_accessible =
+		CXL_PPR_GET_MEDIA_ACCESSIBLE(restriction_flags);
+	cxl_ppr_ctx->data_retained =
+		CXL_PPR_GET_DATA_RETAINED(restriction_flags);
+
+	return 0;
+}
+
+static int cxl_mem_perform_ppr(struct cxl_ppr_context *cxl_ppr_ctx)
+{
+	struct cxl_memdev_ppr_maintenance_attrbs maintenance_attrbs;
+	struct cxl_memdev *cxlmd = cxl_ppr_ctx->cxlmd;
+	struct cxl_mem_repair_attrbs attrbs = { 0 };
+
+	struct rw_semaphore *region_lock __free(rwsem_read_release) =
+		rwsem_read_intr_acquire(&cxl_region_rwsem);
+	if (!region_lock)
+		return -EINTR;
+
+	struct rw_semaphore *dpa_lock __free(rwsem_read_release) =
+		rwsem_read_intr_acquire(&cxl_dpa_rwsem);
+	if (!dpa_lock)
+		return -EINTR;
+
+	if (!cxl_ppr_ctx->media_accessible || !cxl_ppr_ctx->data_retained) {
+		/* Memory to repair must be offline */
+		if (cxl_is_memdev_memory_online(cxlmd))
+			return -EBUSY;
+	} else {
+		if (cxl_is_memdev_memory_online(cxlmd)) {
+			/* Check memory to repair is from the current boot */
+			attrbs.repair_type = CXL_PPR;
+			attrbs.dpa = cxl_ppr_ctx->dpa;
+			attrbs.nibble_mask = cxl_ppr_ctx->nibble_mask;
+			if (!cxl_find_rec_dram(cxlmd, &attrbs) &&
+			    !cxl_find_rec_gen_media(cxlmd, &attrbs))
+				return -EINVAL;
+		}
+	}
+
+	memset(&maintenance_attrbs, 0, sizeof(maintenance_attrbs));
+	maintenance_attrbs.flags = 0;
+	maintenance_attrbs.dpa = cpu_to_le64(cxl_ppr_ctx->dpa);
+	put_unaligned_le24(cxl_ppr_ctx->nibble_mask,
+			   maintenance_attrbs.nibble_mask);
+
+	return cxl_perform_maintenance(&cxlmd->cxlds->cxl_mbox,
+				       cxl_ppr_ctx->op_class,
+				       cxl_ppr_ctx->op_subclass,
+				       &maintenance_attrbs,
+				       sizeof(maintenance_attrbs));
+}
+
+static int cxl_ppr_get_repair_type(struct device *dev, void *drv_data,
+				   const char **repair_type)
+{
+	*repair_type = edac_repair_type[EDAC_REPAIR_PPR];
+
+	return 0;
+}
+
+static int cxl_ppr_get_persist_mode(struct device *dev, void *drv_data,
+				    bool *persist_mode)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	*persist_mode = cxl_ppr_ctx->persist_mode;
+
+	return 0;
+}
+
+static int cxl_get_ppr_safe_when_in_use(struct device *dev, void *drv_data,
+					bool *safe)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	*safe = cxl_ppr_ctx->media_accessible & cxl_ppr_ctx->data_retained;
+
+	return 0;
+}
+
+static int cxl_ppr_get_min_dpa(struct device *dev, void *drv_data, u64 *min_dpa)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+	struct cxl_memdev *cxlmd = cxl_ppr_ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	*min_dpa = cxlds->dpa_res.start;
+
+	return 0;
+}
+
+static int cxl_ppr_get_max_dpa(struct device *dev, void *drv_data, u64 *max_dpa)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+	struct cxl_memdev *cxlmd = cxl_ppr_ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	*max_dpa = cxlds->dpa_res.end;
+
+	return 0;
+}
+
+static int cxl_ppr_get_dpa(struct device *dev, void *drv_data, u64 *dpa)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	*dpa = cxl_ppr_ctx->dpa;
+
+	return 0;
+}
+
+static int cxl_ppr_set_dpa(struct device *dev, void *drv_data, u64 dpa)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+	struct cxl_memdev *cxlmd = cxl_ppr_ctx->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	if (dpa < cxlds->dpa_res.start || dpa > cxlds->dpa_res.end)
+		return -EINVAL;
+
+	cxl_ppr_ctx->dpa = dpa;
+
+	return 0;
+}
+
+static int cxl_ppr_get_nibble_mask(struct device *dev, void *drv_data,
+				   u32 *nibble_mask)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	*nibble_mask = cxl_ppr_ctx->nibble_mask;
+
+	return 0;
+}
+
+static int cxl_ppr_set_nibble_mask(struct device *dev, void *drv_data,
+				   u32 nibble_mask)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	cxl_ppr_ctx->nibble_mask = nibble_mask;
+
+	return 0;
+}
+
+static int cxl_do_ppr(struct device *dev, void *drv_data, u32 val)
+{
+	struct cxl_ppr_context *cxl_ppr_ctx = drv_data;
+
+	if (!cxl_ppr_ctx->dpa || val != EDAC_DO_MEM_REPAIR)
+		return -EINVAL;
+
+	return cxl_mem_perform_ppr(cxl_ppr_ctx);
+}
+
+static const struct edac_mem_repair_ops cxl_sppr_ops = {
+	.get_repair_type = cxl_ppr_get_repair_type,
+	.get_persist_mode = cxl_ppr_get_persist_mode,
+	.get_repair_safe_when_in_use = cxl_get_ppr_safe_when_in_use,
+	.get_min_dpa = cxl_ppr_get_min_dpa,
+	.get_max_dpa = cxl_ppr_get_max_dpa,
+	.get_dpa = cxl_ppr_get_dpa,
+	.set_dpa = cxl_ppr_set_dpa,
+	.get_nibble_mask = cxl_ppr_get_nibble_mask,
+	.set_nibble_mask = cxl_ppr_set_nibble_mask,
+	.do_repair = cxl_do_ppr,
+};
+
+static int cxl_memdev_soft_ppr_init(struct cxl_memdev *cxlmd,
+				    struct edac_dev_feature *ras_feature,
+				    u8 repair_inst)
+{
+	struct cxl_ppr_context *cxl_sppr_ctx;
+	struct cxl_feat_entry *feat_entry;
+	int ret;
+
+	feat_entry = cxl_feature_info(to_cxlfs(cxlmd->cxlds),
+				      &CXL_FEAT_SPPR_UUID);
+	if (!feat_entry)
+		return -EOPNOTSUPP;
+
+	if (!(le32_to_cpu(feat_entry->flags) & CXL_FEATURE_F_CHANGEABLE))
+		return -EOPNOTSUPP;
+
+	cxl_sppr_ctx =
+		devm_kzalloc(&cxlmd->dev, sizeof(*cxl_sppr_ctx), GFP_KERNEL);
+	if (!cxl_sppr_ctx)
+		return -ENOMEM;
+
+	*cxl_sppr_ctx = (struct cxl_ppr_context){
+		.get_feat_size = le16_to_cpu(feat_entry->get_feat_size),
+		.set_feat_size = le16_to_cpu(feat_entry->set_feat_size),
+		.get_version = feat_entry->get_feat_ver,
+		.set_version = feat_entry->set_feat_ver,
+		.effects = le16_to_cpu(feat_entry->effects),
+		.cxlmd = cxlmd,
+		.repair_type = EDAC_REPAIR_PPR,
+		.persist_mode = 0,
+		.instance = repair_inst,
+	};
+	uuid_copy(&cxl_sppr_ctx->repair_uuid, &CXL_FEAT_SPPR_UUID);
+
+	ret = cxl_mem_ppr_get_attrbs(cxl_sppr_ctx);
+	if (ret)
+		return ret;
+
+	ras_feature->ft_type = RAS_FEAT_MEM_REPAIR;
+	ras_feature->instance = cxl_sppr_ctx->instance;
+	ras_feature->mem_repair_ops = &cxl_sppr_ops;
+	ras_feature->ctx = cxl_sppr_ctx;
+
+	return 0;
+}
 #endif /* CONFIG_CXL_EDAC_MEM_REPAIR */
 
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
@@ -1697,6 +2013,16 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
 		repair_inst++;
 		num_ras_features++;
 	}
+
+	rc = cxl_memdev_soft_ppr_init(cxlmd, &ras_features[num_ras_features],
+				      repair_inst);
+	if (rc < 0 && rc != -EOPNOTSUPP)
+		return rc;
+
+	if (rc != -EOPNOTSUPP) {
+		repair_inst++;
+		num_ras_features++;
+	}
 #endif
 	char *cxl_dev_name __free(kfree) =
 		kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));
-- 
2.43.0

Re: [PATCH v5 1/8] EDAC: Update documentation for the CXL memory patrol scrub control feature

[Randy Dunlap]

On 5/15/25 4:59 AM, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> Update the Documentation/edac/scrub.rst to include use cases and
> policies for CXL memory device-based, CXL region-based patrol scrub
> control and CXL Error Check Scrub (ECS).
> 
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
> ---
>  Documentation/edac/scrub.rst | 76 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
> 
> diff --git a/Documentation/edac/scrub.rst b/Documentation/edac/scrub.rst
> index daab929cdba1..5c99f42eae0a 100644
> --- a/Documentation/edac/scrub.rst
> +++ b/Documentation/edac/scrub.rst
> @@ -264,3 +264,79 @@ Sysfs files are documented in
>  `Documentation/ABI/testing/sysfs-edac-scrub`
>  
>  `Documentation/ABI/testing/sysfs-edac-ecs`
> +
> +Examples
> +--------
> +
> +The usage takes the form shown in these examples:
> +
> +1. CXL memory Patrol Scrub
> +
> +The following are the use cases identified why we might increase the scrub rate.
> +
> +- Scrubbing is needed at device granularity because a device is showing
> +  unexpectedly high errors.
> +
> +- Scrubbing may apply to memory that isn't online at all yet. Likely this
> +  is a system wide default setting on boot.
> +
> +- Scrubbing at a higher rate because the monitor software has determined that
> +  more reliability is necessary for a particular data set. This is called
> +  Differentiated Reliability.
> +
> +1.1. Device based scrubbing
> +
> +CXL memory is exposed to memory management subsystem and ultimately userspace
> +via CXL devices. Device-based scrubbing is used for the first use case
> +described in "Section 1 CXL Memory Patrol Scrub".
> +
> +When combining control via the device interfaces and region interfaces,
> +"see Section 1.2 Region based scrubbing".
> +
> +Sysfs files for scrubbing are documented in
> +`Documentation/ABI/testing/sysfs-edac-scrub`
> +
> +1.2. Region based scrubbing
> +
> +CXL memory is exposed to memory management subsystem and ultimately userspace
> +via CXL regions. CXL Regions represent mapped memory capacity in system
> +physical address space. These can incorporate one or more parts of multiple CXL
> +memory devices with traffic interleaved across them. The user may want to control
> +the scrub rate via this more abstract region instead of having to figure out the
> +constituent devices and program them separately. The scrub rate for each device
> +covers the whole device. Thus if multiple regions use parts of that device then
> +requests for scrubbing of other regions may result in a higher scrub rate than
> +requested for this specific region.
> +
> +Region-based scrubbing is used for the third use case described in
> +"Section 1 CXL Memory Patrol Scrub".
> +
> +Userspace must follow below set of rules on how to set the scrub rates for any
> +mixture of requirements.
> +
> +1. Taking each region in turn from lowest desired scrub rate to highest and set
> +   their scrub rates. Later regions may override the scrub rate on individual
> +   devices (and hence potentially whole regions).
> +
> +2. Take each device for which enhanced scrubbing is required (higher rate) and
> +   set those scrub rates. This will override the scrub rates of individual devices,
> +   setting them to the maximum rate required for any of the regions they help back,
> +   unless a specific rate is already defined.
> +
> +Sysfs files for scrubbing are documented in
> +`Documentation/ABI/testing/sysfs-edac-scrub`
> +
> +2. CXL memory Error Check Scrub (ECS)
> +
> +The Error Check Scrub (ECS) feature enables a memory device to perform error
> +checking and correction (ECC) and count single-bit errors. The associated
> +memory controller sets the ECS mode with a trigger sent to the memory
> +device. CXL ECS control, allows the host, thus the userspace, to change the

   no comma:              ^

> +attributes for error count mode, threshold number of errors per segment
> +(indicating how many segments have at least that number of errors) for
> +reporting errors, and reset the ECS counter. Thus, the responsibility for
> +initiating Error Check Scrub on a memory device may lie with the memory
> +controller or platform when unexpectedly high error rates are detected.
> +
> +Sysfs files for scrubbing are documented in
> +`Documentation/ABI/testing/sysfs-edac-ecs`

-- 
~Randy

Re: [PATCH v5 8/8] cxl/edac: Add CXL memory device soft PPR control feature

[Randy Dunlap]

On 5/15/25 4:59 AM, shiju.jose@huawei.com wrote:
> diff --git a/Documentation/edac/memory_repair.rst b/Documentation/edac/memory_repair.rst
> index 5b1cd8297442..3a3fc11b8fea 100644
> --- a/Documentation/edac/memory_repair.rst
> +++ b/Documentation/edac/memory_repair.rst
> @@ -138,5 +138,15 @@ CXL device to perform a repair operation on its media. For example, a CXL
>  device with DRAM components that support memory sparing features may
>  implement sparing maintenance operations.
>  
> +2. CXL memory Soft Post Package Repair (sPPR)
> +
> +Post Package Repair (PPR) maintenance operations may be supported by CXL
> +devices that implement CXL.mem protocol. A PPR maintenance operation
> +requests the CXL device to perform a repair operation on its media.
> +For example, a CXL device with DRAM components that support PPR features
> +may implement PPR Maintenance operations. Soft PPR (sPPR), is a temporary

  no comma:                                                 ^

> +row repair. Soft PPR may be faster, but the repair is lost with a power
> +cycle.
> +
>  Sysfs files for memory repair are documented in
>  `Documentation/ABI/testing/sysfs-edac-memory-repair

-- 
~Randy

Re: [PATCH v5 7/8] cxl/edac: Add CXL memory device memory sparing control feature

[Alison Schofield]

On Thu, May 15, 2025 at 12:59:23PM +0100, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
>

snip

> diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
> index 489c9996bfbc..395d56457931 100644
> --- a/drivers/cxl/core/edac.c
> +++ b/drivers/cxl/core/edac.c
> @@ -21,7 +21,17 @@
>  #include "core.h"
>  #include "trace.h"
>  
> -#define CXL_NR_EDAC_DEV_FEATURES 2
> +#define CXL_NR_EDAC_DEV_FEATURES 6
> +
> +static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)
> +{
> +	struct cxl_port *port = cxlmd->endpoint;
> +
> +	if (port && cxl_num_decoders_committed(port))
> +		return true;
> +
> +	return false;
> +}
>  

Looks like above fcn needs to be inside the below #ifdef.
Smatch is warning this when EDAC_SCRUB is off

drivers/cxl/core/edac.c:27:13: warning: ‘cxl_is_memdev_memory_online’ defined but not used [-Wunused-function]
   27 | static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)


>  #ifdef CONFIG_CXL_EDAC_SCRUB

snip to end.

Re: [PATCH v5 7/8] cxl/edac: Add CXL memory device memory sparing control feature

[Dave Jiang]

On 5/19/25 2:01 PM, Alison Schofield wrote:
> On Thu, May 15, 2025 at 12:59:23PM +0100, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
> 
> snip
> 
>> diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
>> index 489c9996bfbc..395d56457931 100644
>> --- a/drivers/cxl/core/edac.c
>> +++ b/drivers/cxl/core/edac.c
>> @@ -21,7 +21,17 @@
>>  #include "core.h"
>>  #include "trace.h"
>>  
>> -#define CXL_NR_EDAC_DEV_FEATURES 2
>> +#define CXL_NR_EDAC_DEV_FEATURES 6
>> +
>> +static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)
>> +{
>> +	struct cxl_port *port = cxlmd->endpoint;
>> +
>> +	if (port && cxl_num_decoders_committed(port))
>> +		return true;
>> +
>> +	return false;
>> +}
>>  
> 
> Looks like above fcn needs to be inside the below #ifdef.
> Smatch is warning this when EDAC_SCRUB is off
> 
> drivers/cxl/core/edac.c:27:13: warning: ‘cxl_is_memdev_memory_online’ defined but not used [-Wunused-function]
>    27 | static bool cxl_is_memdev_memory_online(const struct cxl_memdev *cxlmd)
> 
> 
>>  #ifdef CONFIG_CXL_EDAC_SCRUB

I think the function can be moved to above cxl_mem_perform_sparing() as that is the only function that calls it. I'll do that when I apply if there's nothing else major need to be changed.

DJ


> 
> snip to end.
> 

RE: [PATCH v5 7/8] cxl/edac: Add CXL memory device memory sparing control feature

[Shiju Jose]

>-----Original Message-----
>From: Dave Jiang <dave.jiang@intel.com>
>Sent: 19 May 2025 22:16
>To: Alison Schofield <alison.schofield@intel.com>; Shiju Jose
><shiju.jose@huawei.com>
>Cc: linux-cxl@vger.kernel.org; dan.j.williams@intel.com; Jonathan Cameron
><jonathan.cameron@huawei.com>; dave@stgolabs.net;
>vishal.l.verma@intel.com; ira.weiny@intel.com; linux-edac@vger.kernel.org;
>linux-doc@vger.kernel.org; bp@alien8.de; tony.luck@intel.com;
>lenb@kernel.org; Yazen.Ghannam@amd.com; mchehab@kernel.org;
>nifan.cxl@gmail.com; Linuxarm <linuxarm@huawei.com>; tanxiaofei
><tanxiaofei@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>; Roberto
>Sassu <roberto.sassu@huawei.com>; kangkang.shen@futurewei.com;
>wanghuiqiang <wanghuiqiang@huawei.com>
>Subject: Re: [PATCH v5 7/8] cxl/edac: Add CXL memory device memory sparing
>control feature
>
>
>
>On 5/19/25 2:01 PM, Alison Schofield wrote:
>> On Thu, May 15, 2025 at 12:59:23PM +0100, shiju.jose@huawei.com wrote:
>>> From: Shiju Jose <shiju.jose@huawei.com>
>>>
>>
>> snip
>>
>>> diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c index
>>> 489c9996bfbc..395d56457931 100644
>>> --- a/drivers/cxl/core/edac.c
>>> +++ b/drivers/cxl/core/edac.c
>>> @@ -21,7 +21,17 @@
>>>  #include "core.h"
>>>  #include "trace.h"
>>>
>>> -#define CXL_NR_EDAC_DEV_FEATURES 2
>>> +#define CXL_NR_EDAC_DEV_FEATURES 6
>>> +
>>> +static bool cxl_is_memdev_memory_online(const struct cxl_memdev
>>> +*cxlmd) {
>>> +	struct cxl_port *port = cxlmd->endpoint;
>>> +
>>> +	if (port && cxl_num_decoders_committed(port))
>>> +		return true;
>>> +
>>> +	return false;
>>> +}
>>>
>>
>> Looks like above fcn needs to be inside the below #ifdef.
>> Smatch is warning this when EDAC_SCRUB is off
This warning is with 'EDAC_MEM_REPAIR' is off.
  
>>
>> drivers/cxl/core/edac.c:27:13: warning: ‘cxl_is_memdev_memory_online’
>defined but not used [-Wunused-function]
>>    27 | static bool cxl_is_memdev_memory_online(const struct
>> cxl_memdev *cxlmd)
>>
>>
>>>  #ifdef CONFIG_CXL_EDAC_SCRUB
>
>I think the function can be moved to above cxl_mem_perform_sparing() as that
>is the only function that calls it. I'll do that when I apply if there's nothing else
>major need to be changed.

Yes. Moving under  "#ifdef CONFIG_CXL_EDAC_MEM_REPAIR" which is present
at the start of memory repair features, solved  this warning. 
Presently 'cxl_is_memdev_memory_online' is used in  cxl_mem_perform_sparing() and 
cxl_mem_perform_ppr() only though I thought it will be used in other parts of the CXL code.

>
>DJ
>
>
>>
>> snip to end.
>>
>

Thanks,
Shiju

Re: [PATCH v5 0/8] cxl: support CXL memory RAS features

[Alison Schofield]

On Thu, May 15, 2025 at 12:59:16PM +0100, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
>
> Support for CXL memory EDAC features: patrol scrub, ECS, soft-PPR and
> memory sparing.

snip

> 
> Shiju Jose (8):
>   EDAC: Update documentation for the CXL memory patrol scrub control
>     feature
>   cxl: Update prototype of function get_support_feature_info()
>   cxl/edac: Add CXL memory device patrol scrub control feature
>   cxl/edac: Add CXL memory device ECS control feature
>   cxl/edac: Add support for PERFORM_MAINTENANCE command
>   cxl/edac: Support for finding memory operation attributes from the
>     current boot
>   cxl/edac: Add CXL memory device memory sparing control feature
>   cxl/edac: Add CXL memory device soft PPR control feature
> 
>  Documentation/edac/memory_repair.rst |   31 +
>  Documentation/edac/scrub.rst         |   76 +
>  drivers/cxl/Kconfig                  |   71 +
>  drivers/cxl/core/Makefile            |    1 +
>  drivers/cxl/core/core.h              |    2 +
>  drivers/cxl/core/edac.c              | 2082 ++++++++++++++++++++++++++

Hi Shiju, 

The file edac.c contains a scattering of ifdef's that can be replaced
with the IS_ENABLED() mechanism.

This issue touches many patches, looks like patches 3-7 all added to edac.c.

See Documentation/process/coding-style.rst  "Conditional Compilation".
You'll find a few usage example in drivers/cxl/ and of course many more
all over the kernel.

Conversely, in cxlmem.h, the patch uses IS_ENABLED() where an #ifdef
is perfectly fine and expected. See the surrounding ifdef's in cxlmem.h

I'm aware it's not a simple search and replace operation to rework this
but it is worth doing now to make the code more readable forever, and
there's also the benefit of allowing the compiler to check code inside
the block for correctness.

-- Alison

>  drivers/cxl/core/features.c          |   17 +-
>  drivers/cxl/core/mbox.c              |   11 +-
>  drivers/cxl/core/memdev.c            |    1 +
>  drivers/cxl/core/region.c            |   10 +
>  drivers/cxl/cxl.h                    |   10 +
>  drivers/cxl/cxlmem.h                 |   36 +
>  drivers/cxl/mem.c                    |    4 +
>  drivers/edac/mem_repair.c            |    9 +
>  include/linux/edac.h                 |    7 +
>  15 files changed, 2356 insertions(+), 12 deletions(-)
>  create mode 100644 drivers/cxl/core/edac.c
> 
> -- 
> 2.43.0
> 

Re: [PATCH v5 3/8] cxl/edac: Add CXL memory device patrol scrub control feature

[Alison Schofield]

On Thu, May 15, 2025 at 12:59:19PM +0100, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> CXL spec 3.2 section 8.2.10.9.11.1 describes the device patrol scrub
> control feature. The device patrol scrub proactively locates and makes
> corrections to errors in regular cycle.
> 

snip

> +
> +static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx,
> +				u8 *cap, u16 *cycle, u8 *flags, u8 *min_cycle)
> +{
> +	struct cxl_mailbox *cxl_mbox;
> +	u8 min_scrub_cycle = U8_MAX;
> +	struct cxl_memdev *cxlmd;
> +	int i, ret;
> +
> +	if (cxl_ps_ctx->cxlr) {
> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> +		struct cxl_region_params *p = &cxlr->params;

This function and the next, have a big if { } wrapper around
cxlr existence. Can this logic be reversed -

ie, declare cxl_region and cxl_region_params in the header and
then do something like - 

	if (!cxl_ps_ctx->cxlr) {
		cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
		return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags, min_cycle);
	}

	cxlr =  cxl_ps_ctx->cxlr;
	p = &cxlr->params;

Then all this code below can shift left.

> +
> +		struct rw_semaphore *region_lock __free(rwsem_read_release) =
> +			rwsem_read_intr_acquire(&cxl_region_rwsem);
> +		if (!region_lock)
> +			return -EINTR;
> +
> +		for (i = 0; i < p->nr_targets; i++) {
> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> +
> +			cxlmd = cxled_to_memdev(cxled);
> +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> +			ret = cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle,
> +						       flags, min_cycle);
> +			if (ret)
> +				return ret;
> +
> +			if (min_cycle)
> +				min_scrub_cycle =
> +					min(*min_cycle, min_scrub_cycle);
> +		}
> +
> +		if (min_cycle)
> +			*min_cycle = min_scrub_cycle;
> +
> +		return 0;
> +	}
> +	cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
> +
> +	return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags, min_cycle);
> +}
> +
> +static int cxl_scrub_set_attrbs(struct device *dev,
> +				struct cxl_patrol_scrub_context *cxl_ps_ctx,
> +				u8 cycle, u8 flags)
> +{
> +	struct cxl_scrub_wr_attrbs wr_attrbs;
> +	struct cxl_mailbox *cxl_mbox;
> +	struct cxl_memdev *cxlmd;
> +	int ret, i;
> +
> +	wr_attrbs.scrub_cycle_hours = cycle;
> +	wr_attrbs.scrub_flags = flags;
> +
> +	if (cxl_ps_ctx->cxlr) {
> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> +		struct cxl_region_params *p = &cxlr->params;

Similar to above function, but more work in the !cxlr case. Maybe a goto.


> +
> +		struct rw_semaphore *region_lock __free(rwsem_read_release) =
> +			rwsem_read_intr_acquire(&cxl_region_rwsem);
> +		if (!region_lock)
> +			return -EINTR;
> +
> +		for (i = 0; i < p->nr_targets; i++) {
> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> +
> +			cxlmd = cxled_to_memdev(cxled);
> +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> +			ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
> +					      cxl_ps_ctx->set_version, &wr_attrbs,
> +					      sizeof(wr_attrbs),
> +					      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
> +					      0, NULL);
> +			if (ret)
> +				return ret;
> +
> +			if (cycle != cxlmd->cur_scrub_cycle) {
> +				if (cxlmd->cur_region_id != -1)
> +					dev_info(dev,
> +						 "Device scrub rate(%d hours) set by region%d rate overwritten by region%d scrub rate(%d hours)\n",
> +						 cxlmd->cur_scrub_cycle,
> +						 cxlmd->cur_region_id, cxlr->id,
> +						 cycle);
> +
> +				cxlmd->cur_scrub_cycle = cycle;
> +				cxlmd->cur_region_id = cxlr->id;
> +			}
> +		}
> +
> +		return 0;
> +	}
> +
> +	cxlmd = cxl_ps_ctx->cxlmd;
> +	cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> +	ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
> +			      cxl_ps_ctx->set_version, &wr_attrbs,
> +			      sizeof(wr_attrbs),
> +			      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET, 0,
> +			      NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (cycle != cxlmd->cur_scrub_cycle) {
> +		if (cxlmd->cur_region_id != -1)
> +			dev_info(dev,
> +				 "Device scrub rate(%d hours) set by region%d rate overwritten with device local scrub rate(%d hours)\n",
> +				 cxlmd->cur_scrub_cycle, cxlmd->cur_region_id,
> +				 cycle);
> +
> +		cxlmd->cur_scrub_cycle = cycle;
> +		cxlmd->cur_region_id = -1;
> +	}
> +
> +	return 0;
> +}
> +

skip

> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 3ec6b906371b..685957b312ea 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -45,6 +45,8 @@
>   * @endpoint: connection to the CXL port topology for this memory device
>   * @id: id number of this memdev instance.
>   * @depth: endpoint port depth
> + * @cur_scrub_cycle: current scrub cycle set for this device
> + * @cur_region_id: id number of a backed region (if any) for which current scrub cycle set
>   */
>  struct cxl_memdev {
>  	struct device dev;
> @@ -56,6 +58,10 @@ struct cxl_memdev {
>  	struct cxl_port *endpoint;
>  	int id;
>  	int depth;
> +#ifdef CONFIG_CXL_EDAC_SCRUB
> +	u8 cur_scrub_cycle;
> +	int cur_region_id;
> +#endif
>  };


Why the cur_ prefix?  Seems like it's just 'the' scrub cycle.

How about:

s/cur_scrub_cycle/scrub_cycle
s/cur_region_id/scrub_region_id

That also makes it clear that the region_id is related to the scrub.

Somewhere later cur_region_id gets compared to -1 a few times.
Perhaps add a define for that like #define CXL_SCRUB_NO_REGION -1

>  
>  static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
> @@ -853,6 +859,16 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd);
>  int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
>  int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
>  
> +#if IS_ENABLED(CONFIG_CXL_EDAC_MEM_FEATURES)

that's the one I mentioned in cover letter that can be #ifdef

> +int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd);
> +int devm_cxl_region_edac_register(struct cxl_region *cxlr);
> +#else
> +static inline int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
> +{ return 0; }
> +static inline int devm_cxl_region_edac_register(struct cxl_region *cxlr)
> +{ return 0; }
> +#endif
> +
>  #ifdef CONFIG_CXL_SUSPEND
>  void cxl_mem_active_inc(void);
>  void cxl_mem_active_dec(void);
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 9675243bd05b..6e6777b7bafb 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -180,6 +180,10 @@ static int cxl_mem_probe(struct device *dev)
>  			return rc;
>  	}
>  
> +	rc = devm_cxl_memdev_edac_register(cxlmd);
> +	if (rc)
> +		dev_dbg(dev, "CXL memdev EDAC registration failed rc=%d\n", rc);
> +
>  	/*
>  	 * The kernel may be operating out of CXL memory on this device,
>  	 * there is no spec defined way to determine whether this device
> -- 
> 2.43.0
> 
> 

Re: [PATCH v5 6/8] cxl/edac: Support for finding memory operation attributes from the current boot

[Alison Schofield]

On Thu, May 15, 2025 at 12:59:22PM +0100, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
> 
> 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.

Using cxl-test I'm getting the below stack trace when trying to
modprobe -r cxl-test.

These cxl-test memdevs have num_ras_features == 0 so upon adding the memdevs
	edac_dev_register() returns -EINVAL,
as does
	devm_cxl_memdev_edac_register() 

Later on when I try to modprobe -r cxl-test, it seems odd that the
devm_cxl_memdev_edac_release() is being called for this device, but
it is, and that where the kfree() oops happens.  Are those register
and release functions intended to be paired/reciprocal ?

Here's the code segment (from this patch) where it is failing,
and the stack trace follows.

> +
> +void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
> +{
> +#ifdef CONFIG_CXL_EDAC_MEM_REPAIR
> +	struct cxl_mem_err_rec *array_rec = cxlmd->array_err_rec;
> +	struct cxl_event_gen_media *rec_gen_media;
> +	struct cxl_event_dram *rec_dram;
> +	unsigned long index;
> +
> +	if (!array_rec)
> +		return;
> +
> +	xa_for_each(&array_rec->rec_dram, index, rec_dram)
> +		kfree(rec_dram);

It fails above. That's as far as I've gotten. Hoping that you recognize
something with this case where num_ras_features == 0 that can lead to this.

Here's the stack trace, and I'll hop to the point in the diff below
where it's failing:


[  108.114491] cxl mem9: ALISON try_free_rec_dram
[  108.115654] Oops: general protection fault, probably for non-canonical address 0x1ad998badadad88: 0000 [#1] SMP NOPTI
[  108.118125] CPU: 0 UID: 0 PID: 1187 Comm: modprobe Tainted: G           O        6.15.0-rc4+ #1 PREEMPT(voluntary) 
[  108.120507] Tainted: [O]=OOT_MODULE
[  108.121202] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[  108.122466] RIP: 0010:kfree+0x6e/0x300
[  108.123099] Code: 80 48 01 d8 0f 82 98 02 00 00 48 c7 c2 00 00 00 80 48 2b 15 94 70 61 01 48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 72 70 61 01 <48> 8b 50 08 49 89 c5 f6 c2 01 0f 85 4c 01 00 00 0f 1f 44 00 00 41
[  108.126050] RSP: 0018:ffffc90002c03be0 EFLAGS: 00010203
[  108.126905] RAX: 01ad998badadad80 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000002
[  108.128035] RDX: 0000777f80000000 RSI: ffffffff82a44991 RDI: ffffffff82a5ac86
[  108.129194] RBP: ffffc90002c03c30 R08: 0000000000000000 R09: 0000000000000000
[  108.130346] R10: 0000000000000001 R11: ffff888276ffe000 R12: ffff8880075a5000
[  108.131414] R13: ffff88800680a578 R14: 0000000000000000 R15: 000000000000000b
[  108.132234] FS:  00007fce1dd38740(0000) GS:ffff8880fa52b000(0000) knlGS:0000000000000000
[  108.133256] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  108.133952] CR2: 00007ffce474e6e8 CR3: 0000000143296006 CR4: 0000000000370ef0
[  108.134787] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  108.135560] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  108.136375] Call Trace:
[  108.136694]  <TASK>
[  108.136939]  devm_cxl_memdev_edac_release+0x6d/0x130 [cxl_core]
[  108.137611]  cxl_memdev_release+0x22/0x40 [cxl_core]
[  108.138268]  device_release+0x30/0x90
[  108.138720]  kobject_put+0x85/0x1c0
[  108.139111]  put_device+0xe/0x20
[  108.139478]  cxl_memdev_unregister+0x42/0x50 [cxl_core]
[  108.140092]  devm_action_release+0xd/0x20
[  108.140531]  devres_release_all+0xa5/0xe0
[  108.141059]  device_unbind_cleanup+0xd/0x70
[  108.141416]  device_release_driver_internal+0x1d3/0x220
[  108.141890]  device_release_driver+0xd/0x20
[  108.142236]  bus_remove_device+0xd7/0x140
[  108.142578]  device_del+0x15a/0x3a0
[  108.142932]  platform_device_del.part.0+0x13/0x80
[  108.143330]  platform_device_unregister+0x1b/0x40
[  108.143786]  cxl_test_exit+0x1a/0xd80 [cxl_test]
[  108.144171]  __x64_sys_delete_module+0x17d/0x260
[  108.144579]  ? debug_smp_processor_id+0x17/0x20
[  108.145004]  x64_sys_call+0x19bd/0x1f90
[  108.145321]  do_syscall_64+0x64/0x140
[  108.145628]  entry_SYSCALL_64_after_hwframe+0x71/0x79
[  108.146284] RIP: 0033:0x7fce1d5128cb
[  108.146775] Code: 73 01 c3 48 8b 0d 55 55 0e 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 25 55 0e 00 f7 d8 64 89 01 48
[  108.148672] RSP: 002b:00007ffce4752768 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[  108.149490] RAX: ffffffffffffffda RBX: 0000556b12b5dd60 RCX: 00007fce1d5128cb
[  108.150284] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000556b12b5ddc8
[  108.151169] RBP: 0000556b12b5ddc8 R08: 1999999999999999 R09: 0000000000000000
[  108.151982] R10: 00007fce1d59dac0 R11: 0000000000000206 R12: 0000000000000001
[  108.152756] R13: 0000000000000000 R14: 00007ffce4754aa8 R15: 0000556b12b5def0
[  108.153523]  </TASK>
[  108.153925] Modules linked in: dax_pmem nd_pmem kmem nd_btt device_dax dax_cxl nd_e820 nfit cxl_mock_mem(O) cxl_test(O-) cxl_mem(O) cxl_pmem(O) cxl_acpi(O) cxl_port(O) cxl_mock(O) cxl_core(O) libnvdimm
[  108.155784] ---[ end trace 0000000000000000 ]---

Re: [PATCH v5 3/8] cxl/edac: Add CXL memory device patrol scrub control feature

[Jonathan Cameron]

On Mon, 19 May 2025 19:02:17 -0700
Alison Schofield <alison.schofield@intel.com> wrote:

> On Thu, May 15, 2025 at 12:59:19PM +0100, shiju.jose@huawei.com wrote:
> > From: Shiju Jose <shiju.jose@huawei.com>
> > 
> > CXL spec 3.2 section 8.2.10.9.11.1 describes the device patrol scrub
> > control feature. The device patrol scrub proactively locates and makes
> > corrections to errors in regular cycle.
> >   
> 
> snip
> 
> > +
> > +static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx,
> > +				u8 *cap, u16 *cycle, u8 *flags, u8 *min_cycle)
> > +{
> > +	struct cxl_mailbox *cxl_mbox;
> > +	u8 min_scrub_cycle = U8_MAX;
> > +	struct cxl_memdev *cxlmd;
> > +	int i, ret;
> > +
> > +	if (cxl_ps_ctx->cxlr) {
> > +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> > +		struct cxl_region_params *p = &cxlr->params;  
> 
> This function and the next, have a big if { } wrapper around
> cxlr existence. Can this logic be reversed -
> 
> ie, declare cxl_region and cxl_region_params in the header and
> then do something like - 
> 
> 	if (!cxl_ps_ctx->cxlr) {
> 		cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
> 		return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags, min_cycle);
> 	}
> 
> 	cxlr =  cxl_ps_ctx->cxlr;
> 	p = &cxlr->params;
> 
> Then all this code below can shift left.

See below - I'd factor out the region and no region cases because
then it will looks same as messier case below.

> 
> > +
> > +		struct rw_semaphore *region_lock __free(rwsem_read_release) =
> > +			rwsem_read_intr_acquire(&cxl_region_rwsem);
> > +		if (!region_lock)
> > +			return -EINTR;
> > +
> > +		for (i = 0; i < p->nr_targets; i++) {
> > +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> > +
> > +			cxlmd = cxled_to_memdev(cxled);
> > +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> > +			ret = cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle,
> > +						       flags, min_cycle);
> > +			if (ret)
> > +				return ret;
> > +
> > +			if (min_cycle)
> > +				min_scrub_cycle =
> > +					min(*min_cycle, min_scrub_cycle);
> > +		}
> > +
> > +		if (min_cycle)
> > +			*min_cycle = min_scrub_cycle;
> > +
> > +		return 0;
> > +	}
> > +	cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
> > +
> > +	return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags, min_cycle);
> > +}
> > +
> > +static int cxl_scrub_set_attrbs(struct device *dev,
> > +				struct cxl_patrol_scrub_context *cxl_ps_ctx,
> > +				u8 cycle, u8 flags)
> > +{
> > +	struct cxl_scrub_wr_attrbs wr_attrbs;
> > +	struct cxl_mailbox *cxl_mbox;
> > +	struct cxl_memdev *cxlmd;
> > +	int ret, i;
> > +
> > +	wr_attrbs.scrub_cycle_hours = cycle;
> > +	wr_attrbs.scrub_flags = flags;
> > +
> > +	if (cxl_ps_ctx->cxlr) {
> > +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
> > +		struct cxl_region_params *p = &cxlr->params;  
> 
> Similar to above function, but more work in the !cxlr case. Maybe a goto.
> 

A goto would be nasty. Given almost total lack of shared code
why not have
cxl_scrub_set_attrbs_region() and
cxl_scrub_set_attrbs_device() 

and this just becomes
	if (cxl_ps_cts->cxlr)
		return cxl_scrub_set_attrbs_region(dev, cxl_ps_ctx, cycle, flags);
	return cxl_scrub_set_attrbs_device(dev, cxl_ps_ctx, cycle, flags);

(or something along those lines anyway)

> 
> > +
> > +		struct rw_semaphore *region_lock __free(rwsem_read_release) =
> > +			rwsem_read_intr_acquire(&cxl_region_rwsem);
> > +		if (!region_lock)
> > +			return -EINTR;
> > +
> > +		for (i = 0; i < p->nr_targets; i++) {
> > +			struct cxl_endpoint_decoder *cxled = p->targets[i];
> > +
> > +			cxlmd = cxled_to_memdev(cxled);
> > +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> > +			ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
> > +					      cxl_ps_ctx->set_version, &wr_attrbs,
> > +					      sizeof(wr_attrbs),
> > +					      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
> > +					      0, NULL);
> > +			if (ret)
> > +				return ret;
> > +
> > +			if (cycle != cxlmd->cur_scrub_cycle) {
> > +				if (cxlmd->cur_region_id != -1)
> > +					dev_info(dev,
> > +						 "Device scrub rate(%d hours) set by region%d rate overwritten by region%d scrub rate(%d hours)\n",
> > +						 cxlmd->cur_scrub_cycle,
> > +						 cxlmd->cur_region_id, cxlr->id,
> > +						 cycle);
> > +
> > +				cxlmd->cur_scrub_cycle = cycle;
> > +				cxlmd->cur_region_id = cxlr->id;
> > +			}
> > +		}
> > +
> > +		return 0;
> > +	}
> > +
> > +	cxlmd = cxl_ps_ctx->cxlmd;
> > +	cxl_mbox = &cxlmd->cxlds->cxl_mbox;
> > +	ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
> > +			      cxl_ps_ctx->set_version, &wr_attrbs,
> > +			      sizeof(wr_attrbs),
> > +			      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET, 0,
> > +			      NULL);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (cycle != cxlmd->cur_scrub_cycle) {
> > +		if (cxlmd->cur_region_id != -1)
> > +			dev_info(dev,
> > +				 "Device scrub rate(%d hours) set by region%d rate overwritten with device local scrub rate(%d hours)\n",
> > +				 cxlmd->cur_scrub_cycle, cxlmd->cur_region_id,
> > +				 cycle);
> > +
> > +		cxlmd->cur_scrub_cycle = cycle;
> > +		cxlmd->cur_region_id = -1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +  

RE: [PATCH v5 0/8] cxl: support CXL memory RAS features

[Shiju Jose]

>-----Original Message-----
>From: Alison Schofield <alison.schofield@intel.com>
>Sent: 20 May 2025 02:36
>To: Shiju Jose <shiju.jose@huawei.com>
>Cc: linux-cxl@vger.kernel.org; dan.j.williams@intel.com; Jonathan Cameron
><jonathan.cameron@huawei.com>; dave.jiang@intel.com; dave@stgolabs.net;
>vishal.l.verma@intel.com; ira.weiny@intel.com; linux-edac@vger.kernel.org;
>linux-doc@vger.kernel.org; bp@alien8.de; tony.luck@intel.com;
>lenb@kernel.org; Yazen.Ghannam@amd.com; mchehab@kernel.org;
>nifan.cxl@gmail.com; Linuxarm <linuxarm@huawei.com>; tanxiaofei
><tanxiaofei@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>; Roberto
>Sassu <roberto.sassu@huawei.com>; kangkang.shen@futurewei.com;
>wanghuiqiang <wanghuiqiang@huawei.com>
>Subject: Re: [PATCH v5 0/8] cxl: support CXL memory RAS features
>
>On Thu, May 15, 2025 at 12:59:16PM +0100, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> Support for CXL memory EDAC features: patrol scrub, ECS, soft-PPR and
>> memory sparing.
>
>snip
>
>>
>> Shiju Jose (8):
>>   EDAC: Update documentation for the CXL memory patrol scrub control
>>     feature
>>   cxl: Update prototype of function get_support_feature_info()
>>   cxl/edac: Add CXL memory device patrol scrub control feature
>>   cxl/edac: Add CXL memory device ECS control feature
>>   cxl/edac: Add support for PERFORM_MAINTENANCE command
>>   cxl/edac: Support for finding memory operation attributes from the
>>     current boot
>>   cxl/edac: Add CXL memory device memory sparing control feature
>>   cxl/edac: Add CXL memory device soft PPR control feature
>>
>>  Documentation/edac/memory_repair.rst |   31 +
>>  Documentation/edac/scrub.rst         |   76 +
>>  drivers/cxl/Kconfig                  |   71 +
>>  drivers/cxl/core/Makefile            |    1 +
>>  drivers/cxl/core/core.h              |    2 +
>>  drivers/cxl/core/edac.c              | 2082 ++++++++++++++++++++++++++
>
>Hi Shiju,
>
>The file edac.c contains a scattering of ifdef's that can be replaced with the
>IS_ENABLED() mechanism.
>
>This issue touches many patches, looks like patches 3-7 all added to edac.c.
>
>See Documentation/process/coding-style.rst  "Conditional Compilation".
>You'll find a few usage example in drivers/cxl/ and of course many more all over
>the kernel.
>
>Conversely, in cxlmem.h, the patch uses IS_ENABLED() where an #ifdef is
>perfectly fine and expected. See the surrounding ifdef's in cxlmem.h
>
>I'm aware it's not a simple search and replace operation to rework this but it is
>worth doing now to make the code more readable forever, and there's also the
>benefit of allowing the compiler to check code inside the block for correctness.

Hi Alison,

Thanks for the feedback.

I replaced #ifdef  with  IS_ENABLED() in .c file and opposite in cxlmem.h.

Thanks,
Shiju

>
>-- Alison
>
>>  drivers/cxl/core/features.c          |   17 +-
>>  drivers/cxl/core/mbox.c              |   11 +-
>>  drivers/cxl/core/memdev.c            |    1 +
>>  drivers/cxl/core/region.c            |   10 +
>>  drivers/cxl/cxl.h                    |   10 +
>>  drivers/cxl/cxlmem.h                 |   36 +
>>  drivers/cxl/mem.c                    |    4 +
>>  drivers/edac/mem_repair.c            |    9 +
>>  include/linux/edac.h                 |    7 +
>>  15 files changed, 2356 insertions(+), 12 deletions(-)  create mode
>> 100644 drivers/cxl/core/edac.c
>>
>> --
>> 2.43.0
>>

RE: [PATCH v5 3/8] cxl/edac: Add CXL memory device patrol scrub control feature

[Shiju Jose]

>-----Original Message-----
>From: Alison Schofield <alison.schofield@intel.com>
>Sent: 20 May 2025 03:02
>To: Shiju Jose <shiju.jose@huawei.com>
>Cc: linux-cxl@vger.kernel.org; dan.j.williams@intel.com; Jonathan Cameron
><jonathan.cameron@huawei.com>; dave.jiang@intel.com; dave@stgolabs.net;
>vishal.l.verma@intel.com; ira.weiny@intel.com; linux-edac@vger.kernel.org;
>linux-doc@vger.kernel.org; bp@alien8.de; tony.luck@intel.com;
>lenb@kernel.org; Yazen.Ghannam@amd.com; mchehab@kernel.org;
>nifan.cxl@gmail.com; Linuxarm <linuxarm@huawei.com>; tanxiaofei
><tanxiaofei@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>; Roberto
>Sassu <roberto.sassu@huawei.com>; kangkang.shen@futurewei.com;
>wanghuiqiang <wanghuiqiang@huawei.com>
>Subject: Re: [PATCH v5 3/8] cxl/edac: Add CXL memory device patrol scrub
>control feature
>
>On Thu, May 15, 2025 at 12:59:19PM +0100, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> CXL spec 3.2 section 8.2.10.9.11.1 describes the device patrol scrub
>> control feature. The device patrol scrub proactively locates and makes
>> corrections to errors in regular cycle.
>>
>
>snip
>
>> +
>> +static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx,
>> +				u8 *cap, u16 *cycle, u8 *flags, u8 *min_cycle) {
>> +	struct cxl_mailbox *cxl_mbox;
>> +	u8 min_scrub_cycle = U8_MAX;
>> +	struct cxl_memdev *cxlmd;
>> +	int i, ret;
>> +
>> +	if (cxl_ps_ctx->cxlr) {
>> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
>> +		struct cxl_region_params *p = &cxlr->params;
>
>This function and the next, have a big if { } wrapper around cxlr existence. Can
>this logic be reversed -
>
>ie, declare cxl_region and cxl_region_params in the header and then do
>something like -
>
>	if (!cxl_ps_ctx->cxlr) {
>		cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
>		return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags,
>min_cycle);
>	}
>
>	cxlr =  cxl_ps_ctx->cxlr;
>	p = &cxlr->params;
>
>Then all this code below can shift left.
Changed.

>
>> +
>> +		struct rw_semaphore *region_lock
>__free(rwsem_read_release) =
>> +			rwsem_read_intr_acquire(&cxl_region_rwsem);
>> +		if (!region_lock)
>> +			return -EINTR;
>> +
>> +		for (i = 0; i < p->nr_targets; i++) {
>> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
>> +
>> +			cxlmd = cxled_to_memdev(cxled);
>> +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
>> +			ret = cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle,
>> +						       flags, min_cycle);
>> +			if (ret)
>> +				return ret;
>> +
>> +			if (min_cycle)
>> +				min_scrub_cycle =
>> +					min(*min_cycle, min_scrub_cycle);
>> +		}
>> +
>> +		if (min_cycle)
>> +			*min_cycle = min_scrub_cycle;
>> +
>> +		return 0;
>> +	}
>> +	cxl_mbox = &cxl_ps_ctx->cxlmd->cxlds->cxl_mbox;
>> +
>> +	return cxl_mem_scrub_get_attrbs(cxl_mbox, cap, cycle, flags,
>> +min_cycle); }
>> +
>> +static int cxl_scrub_set_attrbs(struct device *dev,
>> +				struct cxl_patrol_scrub_context *cxl_ps_ctx,
>> +				u8 cycle, u8 flags)
>> +{
>> +	struct cxl_scrub_wr_attrbs wr_attrbs;
>> +	struct cxl_mailbox *cxl_mbox;
>> +	struct cxl_memdev *cxlmd;
>> +	int ret, i;
>> +
>> +	wr_attrbs.scrub_cycle_hours = cycle;
>> +	wr_attrbs.scrub_flags = flags;
>> +
>> +	if (cxl_ps_ctx->cxlr) {
>> +		struct cxl_region *cxlr = cxl_ps_ctx->cxlr;
>> +		struct cxl_region_params *p = &cxlr->params;
>
>Similar to above function, but more work in the !cxlr case. Maybe a goto.
Modified with helper functions.
>
>
>> +
>> +		struct rw_semaphore *region_lock
>__free(rwsem_read_release) =
>> +			rwsem_read_intr_acquire(&cxl_region_rwsem);
>> +		if (!region_lock)
>> +			return -EINTR;
>> +
>> +		for (i = 0; i < p->nr_targets; i++) {
>> +			struct cxl_endpoint_decoder *cxled = p->targets[i];
>> +
>> +			cxlmd = cxled_to_memdev(cxled);
>> +			cxl_mbox = &cxlmd->cxlds->cxl_mbox;
>> +			ret = cxl_set_feature(cxl_mbox,
>&CXL_FEAT_PATROL_SCRUB_UUID,
>> +					      cxl_ps_ctx->set_version,
>&wr_attrbs,
>> +					      sizeof(wr_attrbs),
>> +
>CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
>> +					      0, NULL);
>> +			if (ret)
>> +				return ret;
>> +
>> +			if (cycle != cxlmd->cur_scrub_cycle) {
>> +				if (cxlmd->cur_region_id != -1)
>> +					dev_info(dev,
>> +						 "Device scrub rate(%d hours)
>set by region%d rate overwritten by region%d scrub rate(%d hours)\n",
>> +						 cxlmd->cur_scrub_cycle,
>> +						 cxlmd->cur_region_id, cxlr->id,
>> +						 cycle);
>> +
>> +				cxlmd->cur_scrub_cycle = cycle;
>> +				cxlmd->cur_region_id = cxlr->id;
>> +			}
>> +		}
>> +
>> +		return 0;
>> +	}
>> +
>> +	cxlmd = cxl_ps_ctx->cxlmd;
>> +	cxl_mbox = &cxlmd->cxlds->cxl_mbox;
>> +	ret = cxl_set_feature(cxl_mbox, &CXL_FEAT_PATROL_SCRUB_UUID,
>> +			      cxl_ps_ctx->set_version, &wr_attrbs,
>> +			      sizeof(wr_attrbs),
>> +			      CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET,
>0,
>> +			      NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (cycle != cxlmd->cur_scrub_cycle) {
>> +		if (cxlmd->cur_region_id != -1)
>> +			dev_info(dev,
>> +				 "Device scrub rate(%d hours) set by region%d
>rate overwritten with device local scrub rate(%d hours)\n",
>> +				 cxlmd->cur_scrub_cycle, cxlmd-
>>cur_region_id,
>> +				 cycle);
>> +
>> +		cxlmd->cur_scrub_cycle = cycle;
>> +		cxlmd->cur_region_id = -1;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>
>skip
>
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index
>> 3ec6b906371b..685957b312ea 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -45,6 +45,8 @@
>>   * @endpoint: connection to the CXL port topology for this memory device
>>   * @id: id number of this memdev instance.
>>   * @depth: endpoint port depth
>> + * @cur_scrub_cycle: current scrub cycle set for this device
>> + * @cur_region_id: id number of a backed region (if any) for which
>> + current scrub cycle set
>>   */
>>  struct cxl_memdev {
>>  	struct device dev;
>> @@ -56,6 +58,10 @@ struct cxl_memdev {
>>  	struct cxl_port *endpoint;
>>  	int id;
>>  	int depth;
>> +#ifdef CONFIG_CXL_EDAC_SCRUB
>> +	u8 cur_scrub_cycle;
>> +	int cur_region_id;
>> +#endif
>>  };
>
>
>Why the cur_ prefix?  Seems like it's just 'the' scrub cycle.
>
>How about:
>
>s/cur_scrub_cycle/scrub_cycle
>s/cur_region_id/scrub_region_id
>
>That also makes it clear that the region_id is related to the scrub.
Changed.

>
>Somewhere later cur_region_id gets compared to -1 a few times.
>Perhaps add a define for that like #define CXL_SCRUB_NO_REGION -1

Added and used CXL_SCRUB_NO_REGION.
>
>>
>>  static inline struct cxl_memdev *to_cxl_memdev(struct device *dev) @@
>> -853,6 +859,16 @@ int cxl_trigger_poison_list(struct cxl_memdev
>> *cxlmd);  int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
>> int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
>>
>> +#if IS_ENABLED(CONFIG_CXL_EDAC_MEM_FEATURES)
>
>that's the one I mentioned in cover letter that can be #ifdef
>
>> +int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd); int
>> +devm_cxl_region_edac_register(struct cxl_region *cxlr); #else static
>> +inline int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd) {
>> +return 0; } static inline int devm_cxl_region_edac_register(struct
>> +cxl_region *cxlr) { return 0; } #endif
>> +
>>  #ifdef CONFIG_CXL_SUSPEND
>>  void cxl_mem_active_inc(void);
>>  void cxl_mem_active_dec(void);
>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c index
>> 9675243bd05b..6e6777b7bafb 100644
>> --- a/drivers/cxl/mem.c
>> +++ b/drivers/cxl/mem.c
>> @@ -180,6 +180,10 @@ static int cxl_mem_probe(struct device *dev)
>>  			return rc;
>>  	}
>>
>> +	rc = devm_cxl_memdev_edac_register(cxlmd);
>> +	if (rc)
>> +		dev_dbg(dev, "CXL memdev EDAC registration failed rc=%d\n",
>rc);
>> +
>>  	/*
>>  	 * The kernel may be operating out of CXL memory on this device,
>>  	 * there is no spec defined way to determine whether this device
>> --
>> 2.43.0
>>
>>

Thanks,
Shiju

RE: [PATCH v5 6/8] cxl/edac: Support for finding memory operation attributes from the current boot

[Shiju Jose]

>-----Original Message-----
>From: Alison Schofield <alison.schofield@intel.com>
>Sent: 20 May 2025 05:31
>To: Shiju Jose <shiju.jose@huawei.com>
>Cc: linux-cxl@vger.kernel.org; dan.j.williams@intel.com; Jonathan Cameron
><jonathan.cameron@huawei.com>; dave.jiang@intel.com; dave@stgolabs.net;
>vishal.l.verma@intel.com; ira.weiny@intel.com; linux-edac@vger.kernel.org;
>linux-doc@vger.kernel.org; bp@alien8.de; tony.luck@intel.com;
>lenb@kernel.org; Yazen.Ghannam@amd.com; mchehab@kernel.org;
>nifan.cxl@gmail.com; Linuxarm <linuxarm@huawei.com>; tanxiaofei
><tanxiaofei@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>; Roberto
>Sassu <roberto.sassu@huawei.com>; kangkang.shen@futurewei.com;
>wanghuiqiang <wanghuiqiang@huawei.com>
>Subject: Re: [PATCH v5 6/8] cxl/edac: Support for finding memory operation
>attributes from the current boot
>
>On Thu, May 15, 2025 at 12:59:22PM +0100, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> 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.
>
>Using cxl-test I'm getting the below stack trace when trying to modprobe -r cxl-
>test.
>
>These cxl-test memdevs have num_ras_features == 0 so upon adding the
>memdevs
>	edac_dev_register() returns -EINVAL,
>as does
>	devm_cxl_memdev_edac_register()
>
>Later on when I try to modprobe -r cxl-test, it seems odd that the
>devm_cxl_memdev_edac_release() is being called for this device, but it is, and
>that where the kfree() oops happens.  Are those register and release functions
>intended to be paired/reciprocal ?
>
>Here's the code segment (from this patch) where it is failing, and the stack trace
>follows.
>
>> +
>> +void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd) { #ifdef
>> +CONFIG_CXL_EDAC_MEM_REPAIR
>> +	struct cxl_mem_err_rec *array_rec = cxlmd->array_err_rec;
>> +	struct cxl_event_gen_media *rec_gen_media;
>> +	struct cxl_event_dram *rec_dram;
>> +	unsigned long index;
>> +
>> +	if (!array_rec)
>> +		return;
>> +
>> +	xa_for_each(&array_rec->rec_dram, index, rec_dram)
>> +		kfree(rec_dram);
>
>It fails above. That's as far as I've gotten. Hoping that you recognize something
>with this case where num_ras_features == 0 that can lead to this.
>
>Here's the stack trace, and I'll hop to the point in the diff below where it's
>failing:

Thanks Alison for reporting and sharing the debug info.

I think following  changes should fix the issue.  
Dave verified fix in his test setup. Thanks Dave.

Thanks,
Shiju
===============================
diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c index 87b347c232b2..0f001f969228 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -1992,15 +1992,6 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)  #endif
 
 #ifdef CONFIG_CXL_EDAC_MEM_REPAIR
-       struct cxl_mem_err_rec *array_rec =
-               devm_kzalloc(&cxlmd->dev, sizeof(*array_rec), GFP_KERNEL);
-       if (!array_rec)
-               return -ENOMEM;
-
-       cxlmd->array_err_rec = array_rec;
-       xa_init(&array_rec->rec_gen_media);
-       xa_init(&array_rec->rec_dram);
-
        for (int i = 0; i < CXL_MEM_SPARING_MAX; i++) {
                rc = cxl_memdev_sparing_init(cxlmd,
                                             &ras_features[num_ras_features], @@ -2023,6 +2014,16 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
                repair_inst++;
                num_ras_features++;
        }
+       if (repair_inst) {
+               struct cxl_mem_err_rec *array_rec =
+                       devm_kzalloc(&cxlmd->dev, sizeof(*array_rec), GFP_KERNEL);
+               if (!array_rec)
+                       return -ENOMEM;
+
+               cxlmd->array_err_rec = array_rec;
+               xa_init(&array_rec->rec_gen_media);
+               xa_init(&array_rec->rec_dram);
+       }
 #endif
        char *cxl_dev_name __free(kfree) =
                kasprintf(GFP_KERNEL, "cxl_%s", dev_name(&cxlmd->dev));

==========================
>
>
>[  108.114491] cxl mem9: ALISON try_free_rec_dram [  108.115654] Oops:
>general protection fault, probably for non-canonical address
>0x1ad998badadad88: 0000 [#1] SMP NOPTI
>[  108.118125] CPU: 0 UID: 0 PID: 1187 Comm: modprobe Tainted: G           O
>6.15.0-rc4+ #1 PREEMPT(voluntary)
>[  108.120507] Tainted: [O]=OOT_MODULE
>[  108.121202] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
>0.0.0 02/06/2015 [  108.122466] RIP: 0010:kfree+0x6e/0x300 [  108.123099]
>Code: 80 48 01 d8 0f 82 98 02 00 00 48 c7 c2 00 00 00 80 48 2b 15 94 70 61 01
>48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 72 70 61 01 <48> 8b 50 08 49 89 c5 f6
>c2 01 0f 85 4c 01 00 00 0f 1f 44 00 00 41 [  108.126050] RSP:
>0018:ffffc90002c03be0 EFLAGS: 00010203 [  108.126905] RAX:
>01ad998badadad80 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000002 [
>108.128035] RDX: 0000777f80000000 RSI: ffffffff82a44991 RDI: ffffffff82a5ac86
>[  108.129194] RBP: ffffc90002c03c30 R08: 0000000000000000 R09:
>0000000000000000 [  108.130346] R10: 0000000000000001 R11:
>ffff888276ffe000 R12: ffff8880075a5000 [  108.131414] R13: ffff88800680a578
>R14: 0000000000000000 R15: 000000000000000b [  108.132234] FS:
>00007fce1dd38740(0000) GS:ffff8880fa52b000(0000) knlGS:0000000000000000
>[  108.133256] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [
>108.133952] CR2: 00007ffce474e6e8 CR3: 0000000143296006 CR4:
>0000000000370ef0 [  108.134787] DR0: 0000000000000000 DR1:
>0000000000000000 DR2: 0000000000000000 [  108.135560] DR3:
>0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [
>108.136375] Call Trace:
>[  108.136694]  <TASK>
>[  108.136939]  devm_cxl_memdev_edac_release+0x6d/0x130 [cxl_core] [
>108.137611]  cxl_memdev_release+0x22/0x40 [cxl_core] [  108.138268]
>device_release+0x30/0x90 [  108.138720]  kobject_put+0x85/0x1c0 [
>108.139111]  put_device+0xe/0x20 [  108.139478]
>cxl_memdev_unregister+0x42/0x50 [cxl_core] [  108.140092]
>devm_action_release+0xd/0x20 [  108.140531]  devres_release_all+0xa5/0xe0 [
>108.141059]  device_unbind_cleanup+0xd/0x70 [  108.141416]
>device_release_driver_internal+0x1d3/0x220
>[  108.141890]  device_release_driver+0xd/0x20 [  108.142236]
>bus_remove_device+0xd7/0x140 [  108.142578]  device_del+0x15a/0x3a0 [
>108.142932]  platform_device_del.part.0+0x13/0x80
>[  108.143330]  platform_device_unregister+0x1b/0x40
>[  108.143786]  cxl_test_exit+0x1a/0xd80 [cxl_test] [  108.144171]
>__x64_sys_delete_module+0x17d/0x260
>[  108.144579]  ? debug_smp_processor_id+0x17/0x20 [  108.145004]
>x64_sys_call+0x19bd/0x1f90 [  108.145321]  do_syscall_64+0x64/0x140 [
>108.145628]  entry_SYSCALL_64_after_hwframe+0x71/0x79
>[  108.146284] RIP: 0033:0x7fce1d5128cb
>[  108.146775] Code: 73 01 c3 48 8b 0d 55 55 0e 00 f7 d8 64 89 01 48 83 c8 ff c3
>66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff
>ff 73 01 c3 48 8b 0d 25 55 0e 00 f7 d8 64 89 01 48 [  108.148672] RSP:
>002b:00007ffce4752768 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 [
>108.149490] RAX: ffffffffffffffda RBX: 0000556b12b5dd60 RCX:
>00007fce1d5128cb [  108.150284] RDX: 0000000000000000 RSI:
>0000000000000800 RDI: 0000556b12b5ddc8 [  108.151169] RBP:
>0000556b12b5ddc8 R08: 1999999999999999 R09: 0000000000000000 [
>108.151982] R10: 00007fce1d59dac0 R11: 0000000000000206 R12:
>0000000000000001 [  108.152756] R13: 0000000000000000 R14:
>00007ffce4754aa8 R15: 0000556b12b5def0 [  108.153523]  </TASK> [
>108.153925] Modules linked in: dax_pmem nd_pmem kmem nd_btt device_dax
>dax_cxl nd_e820 nfit cxl_mock_mem(O) cxl_test(O-) cxl_mem(O) cxl_pmem(O)
>cxl_acpi(O) cxl_port(O) cxl_mock(O) cxl_core(O) libnvdimm [  108.155784] ---[
>end trace 0000000000000000 ]---
>