[PATCH v5 3/5] cxl/memdev: Add trigger_poison_list sysfs attribute

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

When a boolean 'true' is written to this attribute the memdev driver
retrieves the poison list from the device. The list consists of
addresses that are poisoned, or would result in poison if accessed,
and the source of the poison. This attribute is only visible for
devices supporting the capability. The retrieved errors are logged
as kernel trace events with the label 'cxl_poison'.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 Documentation/ABI/testing/sysfs-bus-cxl | 14 ++++++++
 drivers/cxl/core/memdev.c               | 45 +++++++++++++++++++++++++
 drivers/cxl/cxlmem.h                    |  2 +-
 3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
index 8494ef27e8d2..df40ed09ea67 100644
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -388,3 +388,17 @@ Description:
 		1), and checks that the hardware accepts the commit request.
 		Reading this value indicates whether the region is committed or
 		not.
+
+
+What:		/sys/bus/cxl/devices/memX/trigger_poison_list
+Date:		November, 2022
+KernelVersion:	v6.2
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(WO) When a boolean 'true' is written to this attribute the
+		memdev driver retrieves the poison list from the device. The
+		list consists of addresses that are poisoned, or would result
+		in poison if accessed, and the source of the poison. This
+		attribute is only visible for devices supporting the
+		capability. The retrieved errors are logged as kernel
+		trace events with the label 'cxl_poison'.
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index a74a93310d26..e0af7e9c9989 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -106,12 +106,49 @@ static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(numa_node);
 
+static ssize_t trigger_poison_list_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t len)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	u64 offset, length;
+	bool tmp;
+	int rc;
+
+	if (kstrtobool(buf, &tmp))
+		return -EINVAL;
+
+	/* CXL 3.0 Spec 8.2.9.8.4.1 Separate pmem and ram poison requests */
+	if (resource_size(&cxlds->pmem_res)) {
+		offset = cxlds->pmem_res.start;
+		length = resource_size(&cxlds->pmem_res);
+		rc = cxl_mem_get_poison(cxlmd, offset, length, NULL);
+		if (rc)
+			return rc;
+	}
+	if (resource_size(&cxlds->ram_res)) {
+		offset = cxlds->ram_res.start;
+		length = resource_size(&cxlds->ram_res);
+		rc = cxl_mem_get_poison(cxlmd, offset, length, NULL);
+		/*
+		 * Invalid Physical Address is not an error for
+		 * volatile addresses. Device support is optional.
+		 */
+		if (rc && rc != -EFAULT)
+			return rc;
+	}
+	return len;
+}
+static DEVICE_ATTR_WO(trigger_poison_list);
+
 static struct attribute *cxl_memdev_attributes[] = {
 	&dev_attr_serial.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_payload_max.attr,
 	&dev_attr_label_storage_size.attr,
 	&dev_attr_numa_node.attr,
+	&dev_attr_trigger_poison_list.attr,
 	NULL,
 };
 
@@ -130,6 +167,14 @@ static umode_t cxl_memdev_visible(struct kobject *kobj, struct attribute *a,
 {
 	if (!IS_ENABLED(CONFIG_NUMA) && a == &dev_attr_numa_node.attr)
 		return 0;
+
+	if (a == &dev_attr_trigger_poison_list.attr) {
+		struct device *dev = kobj_to_dev(kobj);
+
+		if (!test_bit(CXL_MEM_COMMAND_ID_GET_POISON,
+			      to_cxl_memdev(dev)->cxlds->enabled_cmds))
+			return 0;
+	}
 	return a->mode;
 }
 
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index f53fae20f502..28ba0cd8f2d3 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -139,7 +139,7 @@ struct cxl_mbox_cmd {
 	C(FWROLLBACK, -ENXIO, "rolled back to the previous active FW"),         \
 	C(FWRESET, -ENXIO, "FW failed to activate, needs cold reset"),		\
 	C(HANDLE, -ENXIO, "one or more Event Record Handles were invalid"),     \
-	C(PADDR, -ENXIO, "physical address specified is invalid"),		\
+	C(PADDR, -EFAULT, "physical address specified is invalid"),		\
 	C(POISONLMT, -ENXIO, "poison injection limit has been reached"),        \
 	C(MEDIAFAILURE, -ENXIO, "permanent issue with the media"),		\
 	C(ABORT, -ENXIO, "background cmd was aborted by device"),               \
-- 
2.37.3