The HDAT data area is consumed by skiboot and turned into a device-tree.
In some cases we would like to look directly at the HDAT, so this patch
adds a sysfs node to allow it to be viewed. This is not possible through
/dev/mem as it is reserved memory which is stopped by the /dev/mem filter.
This patch also adds sysfs nodes for all properties in the device-tree
under /ibm,opal/firmware/exports.
Signed-off-by: Matt Brown <matthew.brown....@gmail.com>
---
Changes between v4 and v5:
- all properties under /ibm,opal/firmware/exports in the device-tree
are now added as new sysfs nodes
- the new sysfs nodes are now placed under /opal/exports
- added a generic read function for all exported attributes
---
arch/powerpc/platforms/powernv/opal.c | 84 +++++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/opal.c
b/arch/powerpc/platforms/powernv/opal.c
index 2822935..fbb8264 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -36,6 +36,9 @@
/* /sys/firmware/opal */
struct kobject *opal_kobj;
+/* /sys/firmware/opal/exports */
+struct kobject *opal_export_kobj;
+
struct opal {
u64 base;
u64 entry;
@@ -604,6 +607,82 @@ static void opal_export_symmap(void)
pr_warn("Error %d creating OPAL symbols file\n", rc);
}
+
+static int opal_exports_sysfs_init(void)
+{
+ opal_export_kobj = kobject_create_and_add("exports", opal_kobj);
+ if (!opal_export_kobj) {
+ pr_warn("kobject_create_and_add opal_exports failed\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+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);
+}
+
+static struct bin_attribute *exported_attrs;
+/*
+ * 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)
+{
+ const __be64 *syms;
+ unsigned int size;
+ struct device_node *fw;
+ struct property *prop;
+ int rc;
+ int attr_count = 0;
+ int n = 0;
+
+ fw = of_find_node_by_path("/ibm,opal/firmware/exports");
+ if (!fw)
+ return;
+
+ for (prop = fw->properties; prop != NULL; prop = prop->next)
+ attr_count++;
+
+ if (attr_count > 2)
+ exported_attrs = kmalloc(sizeof(exported_attrs)*(attr_count-2),
+ __GFP_IO | __GFP_FS);
+
+
+ for_each_property_of_node(fw, prop) {
+
+ syms = of_get_property(fw, prop->name, &size);
+
+ if (!strcmp(prop->name, "name") ||
+ !strcmp(prop->name, "phandle"))
+ continue;
+
+ if (!syms || size != 2 * sizeof(__be64))
+ continue;
+
+ (exported_attrs+n)->attr.name = prop->name;
+ (exported_attrs+n)->attr.mode = 0400;
+ (exported_attrs+n)->read = export_attr_read;
+ (exported_attrs+n)->private = __va(be64_to_cpu(syms[0]));
+ (exported_attrs+n)->size = be64_to_cpu(syms[1]);
+
+ rc = sysfs_create_bin_file(opal_export_kobj, exported_attrs+n);
+ if (rc)
+ pr_warn("Error %d creating OPAL %s file\n", rc,
+ prop->name);
+ n++;
+ }
+
+}
+
static void __init opal_dump_region_init(void)
{
void *addr;
@@ -742,6 +821,11 @@ static int __init opal_init(void)
opal_msglog_sysfs_init();
}
+ rc = opal_exports_sysfs_init();
+ if (rc == 0) {
+ /* 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");
--
2.9.3
