drivers/of/resolver.c - kernel/lockdown - Git at Google

 /*
  * Functions for dealing with DT resolution
  *
  * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
  * Copyright (C) 2012 Texas Instruments Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/string.h>
 #include <linux/ctype.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/slab.h>

 /* illegal phandle value (set when unresolved) */
 #define OF_PHANDLE_ILLEGAL	0xdeadbeef

 /**
  * Find a node with the give full name by recursively following any of
  * the child node links.
  */
 static struct device_node *__of_find_node_by_full_name(struct device_node *node,
 		const char *full_name)
 {
 	struct device_node *child, *found;

 	if (node == NULL)
 		return NULL;

 	/* check */
 	if (of_node_cmp(node->full_name, full_name) == 0)
 		return node;

 	for_each_child_of_node(node, child) {
 		found = __of_find_node_by_full_name(child, full_name);
 		if (found != NULL)
 			return found;
 	}

 	return NULL;
 }

 /*
  * Find live tree's maximum phandle value.
  */
 static phandle of_get_tree_max_phandle(void)
 {
 	struct device_node *node;
 	phandle phandle;
 	unsigned long flags;

 	/* now search recursively */
 	raw_spin_lock_irqsave(&devtree_lock, flags);
 	phandle = 0;
 	for_each_of_allnodes(node) {
 		if (node->phandle != OF_PHANDLE_ILLEGAL &&
 				node->phandle > phandle)
 			phandle = node->phandle;
 	}
 	raw_spin_unlock_irqrestore(&devtree_lock, flags);

 	return phandle;
 }

 /*
  * Adjust a subtree's phandle values by a given delta.
  * Makes sure not to just adjust the device node's phandle value,
  * but modify the phandle properties values as well.
  */
 static void __of_adjust_tree_phandles(struct device_node *node,
 		int phandle_delta)
 {
 	struct device_node *child;
 	struct property *prop;
 	phandle phandle;

 	/* first adjust the node's phandle direct value */
 	if (node->phandle != 0 && node->phandle != OF_PHANDLE_ILLEGAL)
 		node->phandle += phandle_delta;

 	/* now adjust phandle & linux,phandle values */
 	for_each_property_of_node(node, prop) {

 		/* only look for these two */
 		if (of_prop_cmp(prop->name, "phandle") != 0 &&
 		    of_prop_cmp(prop->name, "linux,phandle") != 0)
 			continue;

 		/* must be big enough */
 		if (prop->length < 4)
 			continue;

 		/* read phandle value */
 		phandle = be32_to_cpup(prop->value);
 		if (phandle == OF_PHANDLE_ILLEGAL)	/* unresolved */
 			continue;

 		/* adjust */
 		*(uint32_t *)prop->value = cpu_to_be32(node->phandle);
 	}

 	/* now do the children recursively */
 	for_each_child_of_node(node, child)
 		__of_adjust_tree_phandles(child, phandle_delta);
 }

 static int __of_adjust_phandle_ref(struct device_node *node,
 		struct property *rprop, int value)
 {
 	phandle phandle;
 	struct device_node *refnode;
 	struct property *sprop;
 	char *propval, *propcur, *propend, *nodestr, *propstr, *s;
 	int offset, propcurlen;
 	int err = 0;

 	/* make a copy */
 	propval = kmalloc(rprop->length, GFP_KERNEL);
 	if (!propval) {
 		pr_err("%s: Could not copy value of '%s'\n",
 				__func__, rprop->name);
 		return -ENOMEM;
 	}
 	memcpy(propval, rprop->value, rprop->length);

 	propend = propval + rprop->length;
 	for (propcur = propval; propcur < propend; propcur += propcurlen + 1) {
 		propcurlen = strlen(propcur);

 		nodestr = propcur;
 		s = strchr(propcur, ':');
 		if (!s) {
 			pr_err("%s: Illegal symbol entry '%s' (1)\n",
 				__func__, propcur);
 			err = -EINVAL;
 			goto err_fail;
 		}
 		*s++ = '\0';

 		propstr = s;
 		s = strchr(s, ':');
 		if (!s) {
 			pr_err("%s: Illegal symbol entry '%s' (2)\n",
 				__func__, (char *)rprop->value);
 			err = -EINVAL;
 			goto err_fail;
 		}

 		*s++ = '\0';
 		err = kstrtoint(s, 10, &offset);
 		if (err != 0) {
 			pr_err("%s: Could get offset '%s'\n",
 				__func__, (char *)rprop->value);
 			goto err_fail;
 		}

 		/* look into the resolve node for the full path */
 		refnode = __of_find_node_by_full_name(node, nodestr);
 		if (!refnode) {
 			pr_warn("%s: Could not find refnode '%s'\n",
 				__func__, (char *)rprop->value);
 			continue;
 		}

 		/* now find the property */
 		for_each_property_of_node(refnode, sprop) {
 			if (of_prop_cmp(sprop->name, propstr) == 0)
 				break;
 		}

 		if (!sprop) {
 			pr_err("%s: Could not find property '%s'\n",
 				__func__, (char *)rprop->value);
 			err = -ENOENT;
 			goto err_fail;
 		}

 		phandle = value;
 		*(__be32 *)(sprop->value + offset) = cpu_to_be32(phandle);
 	}

 err_fail:
 	kfree(propval);
 	return err;
 }

 /* compare nodes taking into account that 'name' strips out the @ part */
 static int __of_node_name_cmp(const struct device_node *dn1,
 		const struct device_node *dn2)
 {
 	const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
 	const char *n2 = strrchr(dn2->full_name, '/') ? : "/";

 	return of_node_cmp(n1, n2);
 }

 /*
  * Adjust the local phandle references by the given phandle delta.
  * Assumes the existances of a __local_fixups__ node at the root.
  * Assumes that __of_verify_tree_phandle_references has been called.
  * Does not take any devtree locks so make sure you call this on a tree
  * which is at the detached state.
  */
 static int __of_adjust_tree_phandle_references(struct device_node *node,
 		struct device_node *target, int phandle_delta)
 {
 	struct device_node *child, *childtarget;
 	struct property *rprop, *sprop;
 	int err, i, count;
 	unsigned int off;
 	phandle phandle;

 	if (node == NULL)
 		return 0;

 	for_each_property_of_node(node, rprop) {

 		/* skip properties added automatically */
 		if (of_prop_cmp(rprop->name, "name") == 0 ||
 		    of_prop_cmp(rprop->name, "phandle") == 0 ||
 		    of_prop_cmp(rprop->name, "linux,phandle") == 0)
 			continue;

 		if ((rprop->length % 4) != 0 || rprop->length == 0) {
 			pr_err("%s: Illegal property (size) '%s' @%s\n",
 					__func__, rprop->name, node->full_name);
 			return -EINVAL;
 		}
 		count = rprop->length / sizeof(__be32);

 		/* now find the target property */
 		for_each_property_of_node(target, sprop) {
 			if (of_prop_cmp(sprop->name, rprop->name) == 0)
 				break;
 		}

 		if (sprop == NULL) {
 			pr_err("%s: Could not find target property '%s' @%s\n",
 					__func__, rprop->name, node->full_name);
 			return -EINVAL;
 		}

 		for (i = 0; i < count; i++) {
 			off = be32_to_cpu(((__be32 *)rprop->value)[i]);
 			/* make sure the offset doesn't overstep (even wrap) */
 			if (off >= sprop->length ||
 					(off + 4) > sprop->length) {
 				pr_err("%s: Illegal property '%s' @%s\n",
 						__func__, rprop->name,
 						node->full_name);
 				return -EINVAL;
 			}

 			if (phandle_delta) {
 				/* adjust */
 				phandle = be32_to_cpu(*(__be32 *)(sprop->value + off));
 				phandle += phandle_delta;
 				*(__be32 *)(sprop->value + off) = cpu_to_be32(phandle);
 			}
 		}
 	}

 	for_each_child_of_node(node, child) {

 		for_each_child_of_node(target, childtarget)
 			if (__of_node_name_cmp(child, childtarget) == 0)
 				break;

 		if (!childtarget) {
 			pr_err("%s: Could not find target child '%s' @%s\n",
 					__func__, child->name, node->full_name);
 			return -EINVAL;
 		}

 		err = __of_adjust_tree_phandle_references(child, childtarget,
 				phandle_delta);
 		if (err != 0)
 			return err;
 	}

 	return 0;
 }

 /**
  * of_resolve	- Resolve the given node against the live tree.
  *
  * @resolve:	Node to resolve
  *
  * Perform dynamic Device Tree resolution against the live tree
  * to the given node to resolve. This depends on the live tree
  * having a __symbols__ node, and the resolve node the __fixups__ &
  * __local_fixups__ nodes (if needed).
  * The result of the operation is a resolve node that it's contents
  * are fit to be inserted or operate upon the live tree.
  * Returns 0 on success or a negative error value on error.
  */
 int of_resolve_phandles(struct device_node *resolve)
 {
 	struct device_node *child, *childroot, *refnode;
 	struct device_node *root_sym, *resolve_sym, *resolve_fix;
 	struct property *rprop;
 	const char *refpath;
 	phandle phandle, phandle_delta;
 	int err;

 	/* the resolve node must exist, and be detached */
 	if (!resolve || !of_node_check_flag(resolve, OF_DETACHED))
 		return -EINVAL;

 	/* first we need to adjust the phandles */
 	phandle_delta = of_get_tree_max_phandle() + 1;
 	__of_adjust_tree_phandles(resolve, phandle_delta);

 	/* locate the local fixups */
 	childroot = NULL;
 	for_each_child_of_node(resolve, childroot)
 		if (of_node_cmp(childroot->name, "__local_fixups__") == 0)
 			break;

 	if (childroot != NULL) {
 		/* resolve root is guaranteed to be the '/' */
 		err = __of_adjust_tree_phandle_references(childroot,
 				resolve, 0);
 		if (err != 0)
 			return err;

 		BUG_ON(__of_adjust_tree_phandle_references(childroot,
 				resolve, phandle_delta));
 	}

 	root_sym = NULL;
 	resolve_sym = NULL;
 	resolve_fix = NULL;

 	/* this may fail (if no fixups are required) */
 	root_sym = of_find_node_by_path("/__symbols__");

 	/* locate the symbols & fixups nodes on resolve */
 	for_each_child_of_node(resolve, child) {

 		if (!resolve_sym &&
 				of_node_cmp(child->name, "__symbols__") == 0)
 			resolve_sym = child;

 		if (!resolve_fix &&
 				of_node_cmp(child->name, "__fixups__") == 0)
 			resolve_fix = child;

 		/* both found, don't bother anymore */
 		if (resolve_sym && resolve_fix)
 			break;
 	}

 	/* we do allow for the case where no fixups are needed */
 	if (!resolve_fix) {
 		err = 0;	/* no error */
 		goto out;
 	}

 	/* we need to fixup, but no root symbols... */
 	if (!root_sym) {
 		err = -EINVAL;
 		goto out;
 	}

 	for_each_property_of_node(resolve_fix, rprop) {

 		/* skip properties added automatically */
 		if (of_prop_cmp(rprop->name, "name") == 0)
 			continue;

 		err = of_property_read_string(root_sym,
 				rprop->name, &refpath);
 		if (err != 0) {
 			pr_err("%s: Could not find symbol '%s'\n",
 					__func__, rprop->name);
 			goto out;
 		}

 		refnode = of_find_node_by_path(refpath);
 		if (!refnode) {
 			pr_err("%s: Could not find node by path '%s'\n",
 					__func__, refpath);
 			err = -ENOENT;
 			goto out;
 		}

 		phandle = refnode->phandle;
 		of_node_put(refnode);

 		pr_debug("%s: %s phandle is 0x%08x\n",
 				__func__, rprop->name, phandle);

 		err = __of_adjust_phandle_ref(resolve, rprop, phandle);
 		if (err)
 			break;
 	}

 out:
 	/* NULL is handled by of_node_put as NOP */
 	of_node_put(root_sym);

 	return err;
 }
 EXPORT_SYMBOL_GPL(of_resolve_phandles);
	/*
	* Functions for dealing with DT resolution
	*
	* Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
	* Copyright (C) 2012 Texas Instruments Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/string.h>
	#include <linux/ctype.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/slab.h>

	/* illegal phandle value (set when unresolved) */
	#define OF_PHANDLE_ILLEGAL 0xdeadbeef

	/**
	* Find a node with the give full name by recursively following any of
	* the child node links.
	*/
	static struct device_node __of_find_node_by_full_name(struct device_node node,
	const char *full_name)
	{
	struct device_node child, found;

	if (node == NULL)
	return NULL;

	/* check */
	if (of_node_cmp(node->full_name, full_name) == 0)
	return node;

	for_each_child_of_node(node, child) {
	found = __of_find_node_by_full_name(child, full_name);
	if (found != NULL)
	return found;
	}

	return NULL;
	}

	/*
	* Find live tree's maximum phandle value.
	*/
	static phandle of_get_tree_max_phandle(void)
	{
	struct device_node *node;
	phandle phandle;
	unsigned long flags;

	/* now search recursively */
	raw_spin_lock_irqsave(&devtree_lock, flags);
	phandle = 0;
	for_each_of_allnodes(node) {
	if (node->phandle != OF_PHANDLE_ILLEGAL &&
	node->phandle > phandle)
	phandle = node->phandle;
	}
	raw_spin_unlock_irqrestore(&devtree_lock, flags);

	return phandle;
	}

	/*
	* Adjust a subtree's phandle values by a given delta.
	* Makes sure not to just adjust the device node's phandle value,
	* but modify the phandle properties values as well.
	*/
	static void __of_adjust_tree_phandles(struct device_node *node,
	int phandle_delta)
	{
	struct device_node *child;
	struct property *prop;
	phandle phandle;

	/* first adjust the node's phandle direct value */
	if (node->phandle != 0 && node->phandle != OF_PHANDLE_ILLEGAL)
	node->phandle += phandle_delta;

	/* now adjust phandle & linux,phandle values */
	for_each_property_of_node(node, prop) {

	/* only look for these two */
	if (of_prop_cmp(prop->name, "phandle") != 0 &&
	of_prop_cmp(prop->name, "linux,phandle") != 0)
	continue;

	/* must be big enough */
	if (prop->length < 4)
	continue;

	/* read phandle value */
	phandle = be32_to_cpup(prop->value);
	if (phandle == OF_PHANDLE_ILLEGAL) /* unresolved */
	continue;

	/* adjust */
	(uint32_t )prop->value = cpu_to_be32(node->phandle);
	}

	/* now do the children recursively */
	for_each_child_of_node(node, child)
	__of_adjust_tree_phandles(child, phandle_delta);
	}

	static int __of_adjust_phandle_ref(struct device_node *node,
	struct property *rprop, int value)
	{
	phandle phandle;
	struct device_node *refnode;
	struct property *sprop;
	char propval, propcur, propend, nodestr, propstr, s;
	int offset, propcurlen;
	int err = 0;

	/* make a copy */
	propval = kmalloc(rprop->length, GFP_KERNEL);
	if (!propval) {
	pr_err("%s: Could not copy value of '%s'\n",
	__func__, rprop->name);
	return -ENOMEM;
	}
	memcpy(propval, rprop->value, rprop->length);

	propend = propval + rprop->length;
	for (propcur = propval; propcur < propend; propcur += propcurlen + 1) {
	propcurlen = strlen(propcur);

	nodestr = propcur;
	s = strchr(propcur, ':');
	if (!s) {
	pr_err("%s: Illegal symbol entry '%s' (1)\n",
	__func__, propcur);
	err = -EINVAL;
	goto err_fail;
	}
	*s++ = '\0';

	propstr = s;
	s = strchr(s, ':');
	if (!s) {
	pr_err("%s: Illegal symbol entry '%s' (2)\n",
	__func__, (char *)rprop->value);
	err = -EINVAL;
	goto err_fail;
	}

	*s++ = '\0';
	err = kstrtoint(s, 10, &offset);
	if (err != 0) {
	pr_err("%s: Could get offset '%s'\n",
	__func__, (char *)rprop->value);
	goto err_fail;
	}

	/* look into the resolve node for the full path */
	refnode = __of_find_node_by_full_name(node, nodestr);
	if (!refnode) {
	pr_warn("%s: Could not find refnode '%s'\n",
	__func__, (char *)rprop->value);
	continue;
	}

	/* now find the property */
	for_each_property_of_node(refnode, sprop) {
	if (of_prop_cmp(sprop->name, propstr) == 0)
	break;
	}

	if (!sprop) {
	pr_err("%s: Could not find property '%s'\n",
	__func__, (char *)rprop->value);
	err = -ENOENT;
	goto err_fail;
	}

	phandle = value;
	(__be32 )(sprop->value + offset) = cpu_to_be32(phandle);
	}

	err_fail:
	kfree(propval);
	return err;
	}

	/* compare nodes taking into account that 'name' strips out the @ part */
	static int __of_node_name_cmp(const struct device_node *dn1,
	const struct device_node *dn2)
	{
	const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
	const char *n2 = strrchr(dn2->full_name, '/') ? : "/";

	return of_node_cmp(n1, n2);
	}

	/*
	* Adjust the local phandle references by the given phandle delta.
	* Assumes the existances of a __local_fixups__ node at the root.
	* Assumes that __of_verify_tree_phandle_references has been called.
	* Does not take any devtree locks so make sure you call this on a tree
	* which is at the detached state.
	*/
	static int __of_adjust_tree_phandle_references(struct device_node *node,
	struct device_node *target, int phandle_delta)
	{
	struct device_node child, childtarget;
	struct property rprop, sprop;
	int err, i, count;
	unsigned int off;
	phandle phandle;

	if (node == NULL)
	return 0;

	for_each_property_of_node(node, rprop) {

	/* skip properties added automatically */
	if (of_prop_cmp(rprop->name, "name") == 0 \|\|
	of_prop_cmp(rprop->name, "phandle") == 0 \|\|
	of_prop_cmp(rprop->name, "linux,phandle") == 0)
	continue;

	if ((rprop->length % 4) != 0 \|\| rprop->length == 0) {
	pr_err("%s: Illegal property (size) '%s' @%s\n",
	__func__, rprop->name, node->full_name);
	return -EINVAL;
	}
	count = rprop->length / sizeof(__be32);

	/* now find the target property */
	for_each_property_of_node(target, sprop) {
	if (of_prop_cmp(sprop->name, rprop->name) == 0)
	break;
	}

	if (sprop == NULL) {
	pr_err("%s: Could not find target property '%s' @%s\n",
	__func__, rprop->name, node->full_name);
	return -EINVAL;
	}

	for (i = 0; i < count; i++) {
	off = be32_to_cpu(((__be32 *)rprop->value)[i]);
	/* make sure the offset doesn't overstep (even wrap) */
	if (off >= sprop->length \|\|
	(off + 4) > sprop->length) {
	pr_err("%s: Illegal property '%s' @%s\n",
	__func__, rprop->name,
	node->full_name);
	return -EINVAL;
	}

	if (phandle_delta) {
	/* adjust */
	phandle = be32_to_cpu((__be32 )(sprop->value + off));
	phandle += phandle_delta;
	(__be32 )(sprop->value + off) = cpu_to_be32(phandle);
	}
	}
	}

	for_each_child_of_node(node, child) {

	for_each_child_of_node(target, childtarget)
	if (__of_node_name_cmp(child, childtarget) == 0)
	break;

	if (!childtarget) {
	pr_err("%s: Could not find target child '%s' @%s\n",
	__func__, child->name, node->full_name);
	return -EINVAL;
	}

	err = __of_adjust_tree_phandle_references(child, childtarget,
	phandle_delta);
	if (err != 0)
	return err;
	}

	return 0;
	}

	/**
	* of_resolve - Resolve the given node against the live tree.
	*
	* @resolve: Node to resolve
	*
	* Perform dynamic Device Tree resolution against the live tree
	* to the given node to resolve. This depends on the live tree
	* having a __symbols__ node, and the resolve node the __fixups__ &
	* __local_fixups__ nodes (if needed).
	* The result of the operation is a resolve node that it's contents
	* are fit to be inserted or operate upon the live tree.
	* Returns 0 on success or a negative error value on error.
	*/
	int of_resolve_phandles(struct device_node *resolve)
	{
	struct device_node child, childroot, *refnode;
	struct device_node root_sym, resolve_sym, *resolve_fix;
	struct property *rprop;
	const char *refpath;
	phandle phandle, phandle_delta;
	int err;

	/* the resolve node must exist, and be detached */
	if (!resolve \|\| !of_node_check_flag(resolve, OF_DETACHED))
	return -EINVAL;

	/* first we need to adjust the phandles */
	phandle_delta = of_get_tree_max_phandle() + 1;
	__of_adjust_tree_phandles(resolve, phandle_delta);

	/* locate the local fixups */
	childroot = NULL;
	for_each_child_of_node(resolve, childroot)
	if (of_node_cmp(childroot->name, "__local_fixups__") == 0)
	break;

	if (childroot != NULL) {
	/* resolve root is guaranteed to be the '/' */
	err = __of_adjust_tree_phandle_references(childroot,
	resolve, 0);
	if (err != 0)
	return err;

	BUG_ON(__of_adjust_tree_phandle_references(childroot,
	resolve, phandle_delta));
	}

	root_sym = NULL;
	resolve_sym = NULL;
	resolve_fix = NULL;

	/* this may fail (if no fixups are required) */
	root_sym = of_find_node_by_path("/__symbols__");

	/* locate the symbols & fixups nodes on resolve */
	for_each_child_of_node(resolve, child) {

	if (!resolve_sym &&
	of_node_cmp(child->name, "__symbols__") == 0)
	resolve_sym = child;

	if (!resolve_fix &&
	of_node_cmp(child->name, "__fixups__") == 0)
	resolve_fix = child;

	/* both found, don't bother anymore */
	if (resolve_sym && resolve_fix)
	break;
	}

	/* we do allow for the case where no fixups are needed */
	if (!resolve_fix) {
	err = 0; /* no error */
	goto out;
	}

	/* we need to fixup, but no root symbols... */
	if (!root_sym) {
	err = -EINVAL;
	goto out;
	}

	for_each_property_of_node(resolve_fix, rprop) {

	/* skip properties added automatically */
	if (of_prop_cmp(rprop->name, "name") == 0)
	continue;

	err = of_property_read_string(root_sym,
	rprop->name, &refpath);
	if (err != 0) {
	pr_err("%s: Could not find symbol '%s'\n",
	__func__, rprop->name);
	goto out;
	}

	refnode = of_find_node_by_path(refpath);
	if (!refnode) {
	pr_err("%s: Could not find node by path '%s'\n",
	__func__, refpath);
	err = -ENOENT;
	goto out;
	}

	phandle = refnode->phandle;
	of_node_put(refnode);

	pr_debug("%s: %s phandle is 0x%08x\n",
	__func__, rprop->name, phandle);

	err = __of_adjust_phandle_ref(resolve, rprop, phandle);
	if (err)
	break;
	}

	out:
	/* NULL is handled by of_node_put as NOP */
	of_node_put(root_sym);

	return err;
	}
	EXPORT_SYMBOL_GPL(of_resolve_phandles);