cxl/memdev: Add trigger_poison_list sysfs attribute

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 events when cxl_poison event tracing is enabled.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/1081cfdc8a349dc754779642d584707e56db26ba.1681838291.git.alison.schofield@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 39c4b54f0715..b6a413facbd7 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -176,10 +176,53 @@ unlock:
 	return devm_add_action_or_reset(dev, enable_suspend, NULL);
 }
 
+static ssize_t trigger_poison_list_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t len)
+{
+	bool trigger;
+	int rc;
+
+	if (kstrtobool(buf, &trigger) || !trigger)
+		return -EINVAL;
+
+	rc = cxl_trigger_poison_list(to_cxl_memdev(dev));
+
+	return rc ? rc : len;
+}
+static DEVICE_ATTR_WO(trigger_poison_list);
+
+static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	if (a == &dev_attr_trigger_poison_list.attr) {
+		struct device *dev = kobj_to_dev(kobj);
+
+		if (!test_bit(CXL_POISON_ENABLED_LIST,
+			      to_cxl_memdev(dev)->cxlds->poison.enabled_cmds))
+			return 0;
+	}
+	return a->mode;
+}
+
+static struct attribute *cxl_mem_attrs[] = {
+	&dev_attr_trigger_poison_list.attr,
+	NULL
+};
+
+static struct attribute_group cxl_mem_group = {
+	.attrs = cxl_mem_attrs,
+	.is_visible = cxl_mem_visible,
+};
+
+__ATTRIBUTE_GROUPS(cxl_mem);
+
 static struct cxl_driver cxl_mem_driver = {
 	.name = "cxl_mem",
 	.probe = cxl_mem_probe,
 	.id = CXL_DEVICE_MEMORY_EXPANDER,
+	.drv = {
+		.dev_groups = cxl_mem_groups,
+	},
 };
 
 module_cxl_driver(cxl_mem_driver);