From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x244.google.com (mail-qt0-x244.google.com [IPv6:2607:f8b0:400d:c0d::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vzDLC2mTTzDqTK for ; Thu, 6 Apr 2017 17:07:31 +1000 (AEST) Received: by mail-qt0-x244.google.com with SMTP id r45so4574888qte.0 for ; Thu, 06 Apr 2017 00:07:31 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170329232801.20544-1-matthew.brown.dev@gmail.com> References: <20170329232801.20544-1-matthew.brown.dev@gmail.com> From: "Oliver O'Halloran" Date: Thu, 6 Apr 2017 17:07:28 +1000 Message-ID: Subject: Re: [v8] powerpc/powernv: add 'firmware/exports' attributes to sysfs To: Matt Brown Cc: linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset=UTF-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Mar 30, 2017 at 10:28 AM, 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. This is not possible > through /dev/mem as it is reserved memory which is stopped by the /dev/mem > filter. There are also other memory areas which are reserved but could be > useful to view for debugging purposes. > > This patch adds sysfs nodes to allow specified memory areas to be viewed. > sysfs nodes are created for each property in the device-tree under > /ibm,opal/firmware/exports/, and adds them to /sys/firmware/opal/exports/ > with root read-only permissions. > > Signed-off-by: Matt Brown > --- > Changelog > v8 > - fixed error handling > - added dynamic allocation of attributes > - using of_property_read_u64_array for reading attr vals > - reordered vars > - renaming vars > --- > arch/powerpc/platforms/powernv/opal.c | 81 +++++++++++++++++++++++++++++++++++ > 1 file changed, 81 insertions(+) > > diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c > index 2822935..232f94e 100644 > --- a/arch/powerpc/platforms/powernv/opal.c > +++ b/arch/powerpc/platforms/powernv/opal.c > @@ -604,6 +604,84 @@ 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_tmp; > + struct device_node *np; > + struct property *prop; > + struct kobject *kobj; > + u64 vals[2]; > + int rc, n; > + > + /* Create new 'exports' directory - /sys/firmware/opal/exports */ > + kobj = kobject_create_and_add("exports", opal_kobj); > + if (!kobj) { > + pr_warn("kobject_create_and_add exports failed\n"); > + return; > + } > + > + np = of_find_node_by_path("/ibm,opal/firmware/exports"); > + if (!np) > + return; > + > + n = 0; > + for (prop = np->properties; prop != NULL; prop = prop->next) > + n++; > + > + if (n < 2) > + goto cleanup; > + > + 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_tmp = kmalloc(sizeof(*attr_tmp), GFP_KERNEL); > + > + if (attr_tmp == NULL) { > + pr_warn("Failed kmalloc for bin_attribute attr_tmp"); > + continue; > + } > + > + attr_tmp->attr.name = kstrdup(prop->name, GFP_KERNEL); > + attr_tmp->attr.mode = 0400; > + attr_tmp->read = export_attr_read; > + attr_tmp->private = __va(vals[0]); > + attr_tmp->size = vals[1]; > + > + if (attr_tmp->attr.name == NULL) { > + pr_warn("Failed kstrdup for bin_attribute attr.name"); > + kfree(attr_tmp); > + continue; > + } > + rc = sysfs_create_bin_file(kobj, attr_tmp); > + if (rc) > + pr_warn("Error %d creating OPAL sysfs exports/%s file\n", > + rc, prop->name); > + } > + > +cleanup: > + of_node_put(np); > +} > + > static void __init opal_dump_region_init(void) > { > void *addr; > @@ -742,6 +820,9 @@ 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 > Reviewed-by: Oliver O'Halloran