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![Thomas Weißschuh](/assets/img/avatar_default.png)
Since commit ee6d3dd4ed
("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.
Take advantage of this to constify the structure definition to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230204-kobj_type-of-v1-1-5910c8ecb7a3@weissschuh.net
Signed-off-by: Rob Herring <robh@kernel.org>
165 lines
3.9 KiB
C
165 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/of.h>
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#include <linux/slab.h>
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#include "of_private.h"
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/* true when node is initialized */
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static int of_node_is_initialized(const struct device_node *node)
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{
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return node && node->kobj.state_initialized;
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}
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/* true when node is attached (i.e. present on sysfs) */
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int of_node_is_attached(const struct device_node *node)
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{
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return node && node->kobj.state_in_sysfs;
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}
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#ifndef CONFIG_OF_DYNAMIC
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static void of_node_release(struct kobject *kobj)
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{
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/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
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}
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#endif /* CONFIG_OF_DYNAMIC */
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const struct kobj_type of_node_ktype = {
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.release = of_node_release,
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};
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static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t offset, size_t count)
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{
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struct property *pp = container_of(bin_attr, struct property, attr);
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return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
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}
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/* always return newly allocated name, caller must free after use */
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static const char *safe_name(struct kobject *kobj, const char *orig_name)
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{
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const char *name = orig_name;
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struct kernfs_node *kn;
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int i = 0;
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/* don't be a hero. After 16 tries give up */
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while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
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sysfs_put(kn);
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if (name != orig_name)
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kfree(name);
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name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
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}
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if (name == orig_name) {
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name = kstrdup(orig_name, GFP_KERNEL);
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} else {
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pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
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kobject_name(kobj), name);
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}
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return name;
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}
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int __of_add_property_sysfs(struct device_node *np, struct property *pp)
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{
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int rc;
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/* Important: Don't leak passwords */
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bool secure = strncmp(pp->name, "security-", 9) == 0;
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if (!IS_ENABLED(CONFIG_SYSFS))
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return 0;
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if (!of_kset || !of_node_is_attached(np))
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return 0;
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sysfs_bin_attr_init(&pp->attr);
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pp->attr.attr.name = safe_name(&np->kobj, pp->name);
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pp->attr.attr.mode = secure ? 0400 : 0444;
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pp->attr.size = secure ? 0 : pp->length;
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pp->attr.read = of_node_property_read;
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rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
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WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
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return rc;
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}
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void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
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{
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if (!IS_ENABLED(CONFIG_SYSFS))
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return;
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sysfs_remove_bin_file(&np->kobj, &prop->attr);
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kfree(prop->attr.attr.name);
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}
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void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
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{
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/* at early boot, bail here and defer setup to of_init() */
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if (of_kset && of_node_is_attached(np))
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__of_sysfs_remove_bin_file(np, prop);
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}
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void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
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struct property *oldprop)
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{
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/* At early boot, bail out and defer setup to of_init() */
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if (!of_kset)
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return;
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if (oldprop)
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__of_sysfs_remove_bin_file(np, oldprop);
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__of_add_property_sysfs(np, newprop);
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}
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int __of_attach_node_sysfs(struct device_node *np)
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{
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const char *name;
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struct kobject *parent;
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struct property *pp;
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int rc;
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if (!IS_ENABLED(CONFIG_SYSFS) || !of_kset)
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return 0;
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np->kobj.kset = of_kset;
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if (!np->parent) {
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/* Nodes without parents are new top level trees */
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name = safe_name(&of_kset->kobj, "base");
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parent = NULL;
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} else {
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name = safe_name(&np->parent->kobj, kbasename(np->full_name));
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parent = &np->parent->kobj;
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}
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if (!name)
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return -ENOMEM;
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rc = kobject_add(&np->kobj, parent, "%s", name);
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kfree(name);
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if (rc)
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return rc;
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for_each_property_of_node(np, pp)
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__of_add_property_sysfs(np, pp);
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of_node_get(np);
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return 0;
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}
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void __of_detach_node_sysfs(struct device_node *np)
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{
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struct property *pp;
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BUG_ON(!of_node_is_initialized(np));
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if (!of_kset)
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return;
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/* only remove properties if on sysfs */
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if (of_node_is_attached(np)) {
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for_each_property_of_node(np, pp)
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__of_sysfs_remove_bin_file(np, pp);
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kobject_del(&np->kobj);
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}
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of_node_put(np);
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}
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