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> --- Changelog v6 - attribute names are stored locally, removing potential null pointer errors - added of_node_put for the corresponding of_find_node - folded exports node creation into opal_export_attr() - fixed kzalloc flags to GFP_KERNEL - fixed struct array indexing - fixed error message --- 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..953537e 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); +} + +static struct bin_attribute *exported_attrs; +static char **attr_name; +/* + * 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 *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"); -- 2.9.3