From 11fe909d236263f62808dc3c73caf798e026d7aa Mon Sep 17 00:00:00 2001 From: Matt Brown Date: Thu, 30 Mar 2017 10:28:01 +1100 Subject: [PATCH] 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: Matt Brown [mpe: Drop counting of props, rename to attr, free on sysfs error, c'log] Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/powernv/opal.c | 76 +++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c index 296c9426f72b..76e153fc1f93 100644 --- a/arch/powerpc/platforms/powernv/opal.c +++ b/arch/powerpc/platforms/powernv/opal.c @@ -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"); -- 2.39.5