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Commit 11fe909d authored by Matt Brown's avatar Matt Brown Committed by Michael Ellerman
Browse files

powerpc/powernv: Add OPAL exports attributes to sysfs 



New versions of OPAL have a device node /ibm,opal/firmware/exports, each
property of which describes a range of memory in OPAL that Linux might
want to export to userspace for debugging.

This patch adds a sysfs file under 'opal/exports' for each property
found there, and makes it read-only by root.

Signed-off-by: default avatarMatt Brown <matthew.brown.dev@gmail.com>
[mpe: Drop counting of props, rename to attr, free on sysfs error, c'log]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 687da8fc

arch/powerpc/platforms/powernv/opal.c

+76 −0
Original line number Diff line number Diff line
@@ -595,6 +595,79 @@ static void opal_export_symmap(void) 
		pr_warn("Error %d creating OPAL symbols file\n", rc);

}



static ssize_t export_attr_read(struct file *fp, struct kobject *kobj,

				struct bin_attribute *bin_attr, char *buf,

				loff_t off, size_t count)

{

	return memory_read_from_buffer(buf, count, &off, bin_attr->private,

				       bin_attr->size);

}



/*

 * opal_export_attrs: creates a sysfs node for each property listed in

 * the device-tree under /ibm,opal/firmware/exports/

 * All new sysfs nodes are created under /opal/exports/.

 * This allows for reserved memory regions (e.g. HDAT) to be read.

 * The new sysfs nodes are only readable by root.

 */

static void opal_export_attrs(void)

{

	struct bin_attribute *attr;

	struct device_node *np;

	struct property *prop;

	struct kobject *kobj;

	u64 vals[2];

	int rc;



	np = of_find_node_by_path("/ibm,opal/firmware/exports");

	if (!np)

		return;



	/* Create new 'exports' directory - /sys/firmware/opal/exports */

	kobj = kobject_create_and_add("exports", opal_kobj);

	if (!kobj) {

		pr_warn("kobject_create_and_add() of exports failed\n");

		return;

	}



	for_each_property_of_node(np, prop) {

		if (!strcmp(prop->name, "name") || !strcmp(prop->name, "phandle"))

			continue;



		if (of_property_read_u64_array(np, prop->name, &vals[0], 2))

			continue;



		attr = kmalloc(sizeof(*attr), GFP_KERNEL);



		if (attr == NULL) {

			pr_warn("Failed kmalloc for bin_attribute!");

			continue;

		}



		attr->attr.name = kstrdup(prop->name, GFP_KERNEL);

		attr->attr.mode = 0400;

		attr->read = export_attr_read;

		attr->private = __va(vals[0]);

		attr->size = vals[1];



		if (attr->attr.name == NULL) {

			pr_warn("Failed kstrdup for bin_attribute attr.name");

			kfree(attr);

			continue;

		}



		rc = sysfs_create_bin_file(kobj, attr);

		if (rc) {

			pr_warn("Error %d creating OPAL sysfs exports/%s file\n",

				 rc, prop->name);

			kfree(attr->attr.name);

			kfree(attr);

		}

	}



	of_node_put(np);

}



static void __init opal_dump_region_init(void)

{

	void *addr;
@@ -733,6 +806,9 @@ static int __init opal_init(void) 
		opal_msglog_sysfs_init();

	}



	/* Export all properties */

	opal_export_attrs();



	/* Initialize platform devices: IPMI backend, PRD & flash interface */

	opal_pdev_init("ibm,opal-ipmi");

	opal_pdev_init("ibm,opal-flash");