On 23/03/17 09:27, Matt Brown wrote:
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.
Signed-off-by: Matt Brown <matthew.brown....@gmail.com>
Reviewed-by: Andrew Donnellan <andrew.donnel...@au1.ibm.com>
---
Changelog:
v7:
- moved exported_attrs and attr_name into opal_export_attrs
---
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..b8f057f 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -604,6 +604,87 @@ 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)
+{
+ /* /sys/firmware/opal/exports */
+ struct kobject *opal_export_kobj;
+ struct bin_attribute *exported_attrs;
+ char **attr_name;
+
+ struct bin_attribute *attr_tmp;
+ const __be64 *syms;
+ unsigned int size;
+ struct device_node *fw;
+ struct property *prop;
+ int rc;
+ int attr_count = 0;
+ int n = 0;
+
+ /* Create new 'exports' directory */
+ 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;
+ }
+
+ 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 = kzalloc(sizeof(exported_attrs)*(attr_count-2),
+ GFP_KERNEL);
+ attr_name = kzalloc(sizeof(char *)*(attr_count-2), GFP_KERNEL);
+ }
+
+ for_each_property_of_node(fw, prop) {
+
+ attr_name[n] = kstrdup(prop->name, GFP_KERNEL);
+ syms = of_get_property(fw, attr_name[n], &size);
+
+ if (!strcmp(attr_name[n], "name") ||
+ !strcmp(attr_name[n], "phandle"))
+ continue;
+
+ if (!syms || size != 2 * sizeof(__be64))
+ continue;
+
+ attr_tmp = &exported_attrs[n];
+ attr_tmp->attr.name = attr_name[n];
+ attr_tmp->attr.mode = 0400;
+ attr_tmp->read = export_attr_read;
+ attr_tmp->private = __va(be64_to_cpu(syms[0]));
+ attr_tmp->size = be64_to_cpu(syms[1]);
+
+ rc = sysfs_create_bin_file(opal_export_kobj, attr_tmp);
+ if (rc)
+ pr_warn("Error %d creating OPAL sysfs exports/%s
file\n",
+ rc, attr_name[n]);
+ n++;
+ }
+
+ of_node_put(fw);
+
+}
+
static void __init opal_dump_region_init(void)
{
void *addr;
@@ -742,6 +823,9 @@ 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");
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnel...@au1.ibm.com IBM Australia Limited
