// SPDX-License-Identifier: GPL-2.0/* * Support for dynamic device trees. * * On some platforms, the device tree can be manipulated at runtime. * The routines in this section support adding, removing and changing * device tree nodes. */ #define pr_fmt(fmt)	"OF: " fmt #include <linux/cleanup.h>#include <linux/device.h>#include <linux/of.h>#include <linux/spinlock.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/proc_fs.h> #include "of_private.h" static struct device_node *kobj_to_device_node(struct kobject *kobj){	return container_of(kobj, struct device_node, kobj);} /** * of_node_get() - Increment refcount of a node * @node:	Node to inc refcount, NULL is supported to simplify writing of *		callers * * Return: The node with refcount incremented. */struct device_node *of_node_get(struct device_node *node){	if (node)		kobject_get(&node->kobj);	return node;}EXPORT_SYMBOL(of_node_get); /** * of_node_put() - Decrement refcount of a node * @node:	Node to dec refcount, NULL is supported to simplify writing of *		callers */void of_node_put(struct device_node *node){	if (node)		kobject_put(&node->kobj);}EXPORT_SYMBOL(of_node_put); static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain); int of_reconfig_notifier_register(struct notifier_block *nb){	return blocking_notifier_chain_register(&of_reconfig_chain, nb);}EXPORT_SYMBOL_GPL(of_reconfig_notifier_register); int of_reconfig_notifier_unregister(struct notifier_block *nb){	return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);}EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister); static const char *action_names[] = {	[0] = "INVALID",	[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",	[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",	[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",	[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",	[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",}; static bool of_property_status_ok(const struct property *prop){	const char *status; 	if (!prop || !prop->value || prop->length <= 0)		return false; 	status = prop->value;	if (strnlen(status, prop->length) >= prop->length)		return false; 	return !strcmp(status, "okay") || !strcmp(status, "ok");} #define _do_print(func, prefix, action, node, prop, ...) ({	\	func("changeset: " prefix "%-15s %pOF%s%s\n",		\	     ##__VA_ARGS__, action_names[action], node,		\	     prop ? ":" : "", prop ? prop->name : "");		\})#define of_changeset_action_err(...) _do_print(pr_err, __VA_ARGS__)#define of_changeset_action_debug(...) _do_print(pr_debug, __VA_ARGS__) int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p){	int rc;	struct of_reconfig_data *pr = p; 	of_changeset_action_debug("notify: ", action, pr->dn, pr->prop); 	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);	return notifier_to_errno(rc);} /* * of_reconfig_get_state_change()	- Returns new state of device * @action	- action of the of notifier * @arg		- argument of the of notifier * * Returns the new state of a device based on the notifier used. * * Return: OF_RECONFIG_CHANGE_REMOVE on device going from enabled to * disabled, OF_RECONFIG_CHANGE_ADD on device going from disabled to * enabled and OF_RECONFIG_NO_CHANGE on no change. */int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr){	struct property *prop, *old_prop = NULL;	int is_status, status_state, old_status_state, prev_state, new_state; 	/* figure out if a device should be created or destroyed */	switch (action) {	case OF_RECONFIG_ATTACH_NODE:	case OF_RECONFIG_DETACH_NODE:		prop = of_find_property(pr->dn, "status", NULL);		break;	case OF_RECONFIG_ADD_PROPERTY:	case OF_RECONFIG_REMOVE_PROPERTY:		prop = pr->prop;		break;	case OF_RECONFIG_UPDATE_PROPERTY:		prop = pr->prop;		old_prop = pr->old_prop;		break;	default:		return OF_RECONFIG_NO_CHANGE;	} 	is_status = 0;	status_state = -1;	old_status_state = -1;	prev_state = -1;	new_state = -1; 	if (prop && !strcmp(prop->name, "status")) {		is_status = 1;		status_state = of_property_status_ok(prop);		if (old_prop)			old_status_state = of_property_status_ok(old_prop);	} 	switch (action) {	case OF_RECONFIG_ATTACH_NODE:		prev_state = 0;		/* -1 & 0 status either missing or okay */		new_state = status_state != 0;		break;	case OF_RECONFIG_DETACH_NODE:		/* -1 & 0 status either missing or okay */		prev_state = status_state != 0;		new_state = 0;		break;	case OF_RECONFIG_ADD_PROPERTY:		if (is_status) {			/* no status property -> enabled (legacy) */			prev_state = 1;			new_state = status_state;		}		break;	case OF_RECONFIG_REMOVE_PROPERTY:		if (is_status) {			prev_state = status_state;			/* no status property -> enabled (legacy) */			new_state = 1;		}		break;	case OF_RECONFIG_UPDATE_PROPERTY:		if (is_status) {			prev_state = old_status_state != 0;			new_state = status_state != 0;		}		break;	} 	if (prev_state == new_state)		return OF_RECONFIG_NO_CHANGE; 	return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;}EXPORT_SYMBOL_GPL(of_reconfig_get_state_change); int of_property_notify(int action, struct device_node *np,		       struct property *prop, struct property *oldprop){	struct of_reconfig_data pr; 	/* only call notifiers if the node is attached */	if (!of_node_is_attached(np))		return 0; 	pr.dn = np;	pr.prop = prop;	pr.old_prop = oldprop;	return of_reconfig_notify(action, &pr);} static void __of_attach_node(struct device_node *np){	const __be32 *phandle;	int sz;	unsigned long flags; 	raw_spin_lock_irqsave(&devtree_lock, flags); 	if (!of_node_check_flag(np, OF_OVERLAY)) {		np->name = __of_get_property(np, "name", NULL);		if (!np->name)			np->name = "<NULL>"; 		phandle = __of_get_property(np, "phandle", &sz);		if (!phandle)			phandle = __of_get_property(np, "linux,phandle", &sz);		if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)			phandle = __of_get_property(np, "ibm,phandle", &sz);		if (phandle && (sz >= 4))			np->phandle = be32_to_cpup(phandle);		else			np->phandle = 0;	} 	np->child = NULL;	np->sibling = np->parent->child;	np->parent->child = np;	of_node_clear_flag(np, OF_DETACHED); 	raw_spin_unlock_irqrestore(&devtree_lock, flags); 	__of_attach_node_sysfs(np);} /** * of_attach_node() - Plug a device node into the tree and global list. * @np:		Pointer to the caller's Device Node */int of_attach_node(struct device_node *np){	struct of_reconfig_data rd; 	memset(&rd, 0, sizeof(rd));	rd.dn = np; 	mutex_lock(&of_mutex);	__of_attach_node(np);	mutex_unlock(&of_mutex); 	of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd); 	return 0;} void __of_detach_node(struct device_node *np){	struct device_node *parent;	unsigned long flags; 	raw_spin_lock_irqsave(&devtree_lock, flags); 	parent = np->parent;	if (WARN_ON(of_node_check_flag(np, OF_DETACHED) || !parent)) {		raw_spin_unlock_irqrestore(&devtree_lock, flags);		return;	} 	if (parent->child == np)		parent->child = np->sibling;	else {		struct device_node *prevsib;		for (prevsib = np->parent->child;		     prevsib->sibling != np;		     prevsib = prevsib->sibling)			;		prevsib->sibling = np->sibling;	} 	of_node_set_flag(np, OF_DETACHED); 	/* race with of_find_node_by_phandle() prevented by devtree_lock */	__of_phandle_cache_inv_entry(np->phandle); 	raw_spin_unlock_irqrestore(&devtree_lock, flags); 	__of_detach_node_sysfs(np);} /** * of_detach_node() - "Unplug" a node from the device tree. * @np:		Pointer to the caller's Device Node */int of_detach_node(struct device_node *np){	struct of_reconfig_data rd; 	memset(&rd, 0, sizeof(rd));	rd.dn = np; 	mutex_lock(&of_mutex);	__of_detach_node(np);	mutex_unlock(&of_mutex); 	of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd); 	return 0;}EXPORT_SYMBOL_GPL(of_detach_node); void __of_prop_free(struct property *prop){	kfree(prop->name);	kfree(prop->value);	kfree(prop);} static void property_list_free(struct property *prop_list){	struct property *prop, *next; 	for (prop = prop_list; prop != NULL; prop = next) {		next = prop->next;		__of_prop_free(prop);	}} /** * of_node_release() - release a dynamically allocated node * @kobj: kernel object of the node to be released * * In of_node_put() this function is passed to kref_put() as the destructor. */void of_node_release(struct kobject *kobj){	struct device_node *node = kobj_to_device_node(kobj); 	/*	 * can not use '"%pOF", node' in pr_err() calls from this function	 * because an of_node_get(node) when refcount is already zero	 * will result in an error and a stack dump	 */ 	/* We should never be releasing nodes that haven't been detached. */	if (!of_node_check_flag(node, OF_DETACHED)) { 		pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",			__func__, node->parent, node->full_name); 		/*		 * of unittests will test this path.  Do not print the stack		 * trace when the error is caused by unittest so that we do		 * not display what a normal developer might reasonably		 * consider a real bug.		 */		if (!IS_ENABLED(CONFIG_OF_UNITTEST) ||		    strcmp(node->parent->full_name, "testcase-data")) {			dump_stack();			pr_err("ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'\n");		} 		return;	}	if (!of_node_check_flag(node, OF_DYNAMIC))		return; 	if (of_node_check_flag(node, OF_OVERLAY)) { 		if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {			/* premature refcount of zero, do not free memory */			pr_err("ERROR: memory leak before free overlay changeset,  %pOF\n",			       node);			return;		} 		/*		 * If node->properties non-empty then properties were added		 * to this node either by different overlay that has not		 * yet been removed, or by a non-overlay mechanism.		 */		if (node->properties)			pr_err("ERROR: %s(), unexpected properties in %pOF\n",			       __func__, node);	} 	if (node->child)		pr_err("ERROR: %s() unexpected children for %pOF/%s\n",			__func__, node->parent, node->full_name); 	property_list_free(node->properties);	property_list_free(node->deadprops);	fwnode_links_purge(of_fwnode_handle(node)); 	kfree(node->full_name);	kfree(node->data);	kfree(node);} /** * __of_prop_dup - Copy a property dynamically. * @prop:	Property to copy * @allocflags:	Allocation flags (typically pass GFP_KERNEL) * * Copy a property by dynamically allocating the memory of both the * property structure and the property name & contents. The property's * flags have the OF_DYNAMIC bit set so that we can differentiate between * dynamically allocated properties and not. * * Return: The newly allocated property or NULL on out of memory error. */struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags){	struct property *new; 	new = kzalloc_obj(*new, allocflags);	if (!new)		return NULL; 	/*	 * NOTE: There is no check for zero length value.	 * In case of a boolean property, this will allocate a value	 * of zero bytes. We do this to work around the use	 * of of_get_property() calls on boolean values.	 */	new->name = kstrdup(prop->name, allocflags);	new->value = kmemdup(prop->value, prop->length, allocflags);	new->length = prop->length;	if (!new->name || !new->value)		goto err_free; 	/* mark the property as dynamic */	of_property_set_flag(new, OF_DYNAMIC); 	return new;  err_free:	__of_prop_free(new);	return NULL;} /** * __of_node_dup() - Duplicate or create an empty device node dynamically. * @np:		if not NULL, contains properties to be duplicated in new node * @full_name:	string value to be duplicated into new node's full_name field * * Create a device tree node, optionally duplicating the properties of * another node.  The node data are dynamically allocated and all the node * flags have the OF_DYNAMIC & OF_DETACHED bits set. * * Return: The newly allocated node or NULL on out of memory error.  Use * of_node_put() on it when done to free the memory allocated for it. */struct device_node *__of_node_dup(const struct device_node *np,				  const char *full_name){	struct device_node *node; 	node = kzalloc_obj(*node);	if (!node)		return NULL;	node->full_name = kstrdup(full_name, GFP_KERNEL);	if (!node->full_name) {		kfree(node);		return NULL;	} 	of_node_set_flag(node, OF_DYNAMIC);	of_node_set_flag(node, OF_DETACHED);	of_node_init(node); 	/* Iterate over and duplicate all properties */	if (np) {		struct property *pp, *new_pp;		for_each_property_of_node(np, pp) {			new_pp = __of_prop_dup(pp, GFP_KERNEL);			if (!new_pp)				goto err_prop;			if (__of_add_property(node, new_pp)) {				__of_prop_free(new_pp);				goto err_prop;			}		}	}	return node;  err_prop:	of_node_put(node); /* Frees the node and properties */	return NULL;} 

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