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1/*
2 * Functions for working with device tree overlays
3 *
4 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
5 * Copyright (C) 2012 Texas Instruments Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
10 */
11#undef DEBUG
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16#include <linux/string.h>
17#include <linux/ctype.h>
18#include <linux/errno.h>
19#include <linux/string.h>
20#include <linux/slab.h>
21#include <linux/err.h>
22#include <linux/idr.h>
23
24#include "of_private.h"
25
26/**
27 * struct of_overlay_info - Holds a single overlay info
28 * @target: target of the overlay operation
29 * @overlay: pointer to the overlay contents node
30 *
31 * Holds a single overlay state, including all the overlay logs &
32 * records.
33 */
34struct of_overlay_info {
35 struct device_node *target;
36 struct device_node *overlay;
37};
38
39/**
40 * struct of_overlay - Holds a complete overlay transaction
41 * @node: List on which we are located
42 * @count: Count of ovinfo structures
43 * @ovinfo_tab: Overlay info table (count sized)
44 * @cset: Changeset to be used
45 *
46 * Holds a complete overlay transaction
47 */
48struct of_overlay {
49 int id;
50 struct list_head node;
51 int count;
52 struct of_overlay_info *ovinfo_tab;
53 struct of_changeset cset;
54};
55
56static int of_overlay_apply_one(struct of_overlay *ov,
57 struct device_node *target, const struct device_node *overlay);
58
59static int of_overlay_apply_single_property(struct of_overlay *ov,
60 struct device_node *target, struct property *prop)
61{
62 struct property *propn, *tprop;
63
64 /* NOTE: Multiple changes of single properties not supported */
65 tprop = of_find_property(target, prop->name, NULL);
66
67 /* special properties are not meant to be updated (silent NOP) */
68 if (of_prop_cmp(prop->name, "name") == 0 ||
69 of_prop_cmp(prop->name, "phandle") == 0 ||
70 of_prop_cmp(prop->name, "linux,phandle") == 0)
71 return 0;
72
73 propn = __of_prop_dup(prop, GFP_KERNEL);
74 if (propn == NULL)
75 return -ENOMEM;
76
77 /* not found? add */
78 if (tprop == NULL)
79 return of_changeset_add_property(&ov->cset, target, propn);
80
81 /* found? update */
82 return of_changeset_update_property(&ov->cset, target, propn);
83}
84
85static int of_overlay_apply_single_device_node(struct of_overlay *ov,
86 struct device_node *target, struct device_node *child)
87{
88 const char *cname;
89 struct device_node *tchild;
90 int ret = 0;
91
92 cname = kbasename(child->full_name);
93 if (cname == NULL)
94 return -ENOMEM;
95
96 /* NOTE: Multiple mods of created nodes not supported */
97 tchild = of_get_child_by_name(target, cname);
98 if (tchild != NULL) {
99 /* apply overlay recursively */
100 ret = of_overlay_apply_one(ov, tchild, child);
101 of_node_put(tchild);
102 } else {
103 /* create empty tree as a target */
104 tchild = __of_node_dup(child, "%s/%s", target->full_name, cname);
105 if (!tchild)
106 return -ENOMEM;
107
108 /* point to parent */
109 tchild->parent = target;
110
111 ret = of_changeset_attach_node(&ov->cset, tchild);
112 if (ret)
113 return ret;
114
115 ret = of_overlay_apply_one(ov, tchild, child);
116 if (ret)
117 return ret;
118 }
119
120 return ret;
121}
122
123/*
124 * Apply a single overlay node recursively.
125 *
126 * Note that the in case of an error the target node is left
127 * in a inconsistent state. Error recovery should be performed
128 * by using the changeset.
129 */
130static int of_overlay_apply_one(struct of_overlay *ov,
131 struct device_node *target, const struct device_node *overlay)
132{
133 struct device_node *child;
134 struct property *prop;
135 int ret;
136
137 for_each_property_of_node(overlay, prop) {
138 ret = of_overlay_apply_single_property(ov, target, prop);
139 if (ret) {
140 pr_err("%s: Failed to apply prop @%s/%s\n",
141 __func__, target->full_name, prop->name);
142 return ret;
143 }
144 }
145
146 for_each_child_of_node(overlay, child) {
147 ret = of_overlay_apply_single_device_node(ov, target, child);
148 if (ret != 0) {
149 pr_err("%s: Failed to apply single node @%s/%s\n",
150 __func__, target->full_name,
151 child->name);
152 of_node_put(child);
153 return ret;
154 }
155 }
156
157 return 0;
158}
159
160/**
161 * of_overlay_apply() - Apply @count overlays pointed at by @ovinfo_tab
162 * @ov: Overlay to apply
163 *
164 * Applies the overlays given, while handling all error conditions
165 * appropriately. Either the operation succeeds, or if it fails the
166 * live tree is reverted to the state before the attempt.
167 * Returns 0, or an error if the overlay attempt failed.
168 */
169static int of_overlay_apply(struct of_overlay *ov)
170{
171 int i, err;
172
173 /* first we apply the overlays atomically */
174 for (i = 0; i < ov->count; i++) {
175 struct of_overlay_info *ovinfo = &ov->ovinfo_tab[i];
176
177 err = of_overlay_apply_one(ov, ovinfo->target, ovinfo->overlay);
178 if (err != 0) {
179 pr_err("%s: overlay failed '%s'\n",
180 __func__, ovinfo->target->full_name);
181 return err;
182 }
183 }
184
185 return 0;
186}
187
188/*
189 * Find the target node using a number of different strategies
190 * in order of preference
191 *
192 * "target" property containing the phandle of the target
193 * "target-path" property containing the path of the target
194 */
195static struct device_node *find_target_node(struct device_node *info_node)
196{
197 const char *path;
198 u32 val;
199 int ret;
200
201 /* first try to go by using the target as a phandle */
202 ret = of_property_read_u32(info_node, "target", &val);
203 if (ret == 0)
204 return of_find_node_by_phandle(val);
205
206 /* now try to locate by path */
207 ret = of_property_read_string(info_node, "target-path", &path);
208 if (ret == 0)
209 return of_find_node_by_path(path);
210
211 pr_err("%s: Failed to find target for node %p (%s)\n", __func__,
212 info_node, info_node->name);
213
214 return NULL;
215}
216
217/**
218 * of_fill_overlay_info() - Fill an overlay info structure
219 * @ov Overlay to fill
220 * @info_node: Device node containing the overlay
221 * @ovinfo: Pointer to the overlay info structure to fill
222 *
223 * Fills an overlay info structure with the overlay information
224 * from a device node. This device node must have a target property
225 * which contains a phandle of the overlay target node, and an
226 * __overlay__ child node which has the overlay contents.
227 * Both ovinfo->target & ovinfo->overlay have their references taken.
228 *
229 * Returns 0 on success, or a negative error value.
230 */
231static int of_fill_overlay_info(struct of_overlay *ov,
232 struct device_node *info_node, struct of_overlay_info *ovinfo)
233{
234 ovinfo->overlay = of_get_child_by_name(info_node, "__overlay__");
235 if (ovinfo->overlay == NULL)
236 goto err_fail;
237
238 ovinfo->target = find_target_node(info_node);
239 if (ovinfo->target == NULL)
240 goto err_fail;
241
242 return 0;
243
244err_fail:
245 of_node_put(ovinfo->target);
246 of_node_put(ovinfo->overlay);
247
248 memset(ovinfo, 0, sizeof(*ovinfo));
249 return -EINVAL;
250}
251
252/**
253 * of_build_overlay_info() - Build an overlay info array
254 * @ov Overlay to build
255 * @tree: Device node containing all the overlays
256 *
257 * Helper function that given a tree containing overlay information,
258 * allocates and builds an overlay info array containing it, ready
259 * for use using of_overlay_apply.
260 *
261 * Returns 0 on success with the @cntp @ovinfop pointers valid,
262 * while on error a negative error value is returned.
263 */
264static int of_build_overlay_info(struct of_overlay *ov,
265 struct device_node *tree)
266{
267 struct device_node *node;
268 struct of_overlay_info *ovinfo;
269 int cnt, err;
270
271 /* worst case; every child is a node */
272 cnt = 0;
273 for_each_child_of_node(tree, node)
274 cnt++;
275
276 ovinfo = kcalloc(cnt, sizeof(*ovinfo), GFP_KERNEL);
277 if (ovinfo == NULL)
278 return -ENOMEM;
279
280 cnt = 0;
281 for_each_child_of_node(tree, node) {
282 memset(&ovinfo[cnt], 0, sizeof(*ovinfo));
283 err = of_fill_overlay_info(ov, node, &ovinfo[cnt]);
284 if (err == 0)
285 cnt++;
286 }
287
288 /* if nothing filled, return error */
289 if (cnt == 0) {
290 kfree(ovinfo);
291 return -ENODEV;
292 }
293
294 ov->count = cnt;
295 ov->ovinfo_tab = ovinfo;
296
297 return 0;
298}
299
300/**
301 * of_free_overlay_info() - Free an overlay info array
302 * @ov Overlay to free the overlay info from
303 * @ovinfo_tab: Array of overlay_info's to free
304 *
305 * Releases the memory of a previously allocated ovinfo array
306 * by of_build_overlay_info.
307 * Returns 0, or an error if the arguments are bogus.
308 */
309static int of_free_overlay_info(struct of_overlay *ov)
310{
311 struct of_overlay_info *ovinfo;
312 int i;
313
314 /* do it in reverse */
315 for (i = ov->count - 1; i >= 0; i--) {
316 ovinfo = &ov->ovinfo_tab[i];
317
318 of_node_put(ovinfo->target);
319 of_node_put(ovinfo->overlay);
320 }
321 kfree(ov->ovinfo_tab);
322
323 return 0;
324}
325
326static LIST_HEAD(ov_list);
327static DEFINE_IDR(ov_idr);
328
329/**
330 * of_overlay_create() - Create and apply an overlay
331 * @tree: Device node containing all the overlays
332 *
333 * Creates and applies an overlay while also keeping track
334 * of the overlay in a list. This list can be used to prevent
335 * illegal overlay removals.
336 *
337 * Returns the id of the created overlay, or a negative error number
338 */
339int of_overlay_create(struct device_node *tree)
340{
341 struct of_overlay *ov;
342 int err, id;
343
344 /* allocate the overlay structure */
345 ov = kzalloc(sizeof(*ov), GFP_KERNEL);
346 if (ov == NULL)
347 return -ENOMEM;
348 ov->id = -1;
349
350 INIT_LIST_HEAD(&ov->node);
351
352 of_changeset_init(&ov->cset);
353
354 mutex_lock(&of_mutex);
355
356 id = idr_alloc(&ov_idr, ov, 0, 0, GFP_KERNEL);
357 if (id < 0) {
358 pr_err("%s: idr_alloc() failed for tree@%s\n",
359 __func__, tree->full_name);
360 err = id;
361 goto err_destroy_trans;
362 }
363 ov->id = id;
364
365 /* build the overlay info structures */
366 err = of_build_overlay_info(ov, tree);
367 if (err) {
368 pr_err("%s: of_build_overlay_info() failed for tree@%s\n",
369 __func__, tree->full_name);
370 goto err_free_idr;
371 }
372
373 /* apply the overlay */
374 err = of_overlay_apply(ov);
375 if (err) {
376 pr_err("%s: of_overlay_apply() failed for tree@%s\n",
377 __func__, tree->full_name);
378 goto err_abort_trans;
379 }
380
381 /* apply the changeset */
382 err = __of_changeset_apply(&ov->cset);
383 if (err) {
384 pr_err("%s: __of_changeset_apply() failed for tree@%s\n",
385 __func__, tree->full_name);
386 goto err_revert_overlay;
387 }
388
389 /* add to the tail of the overlay list */
390 list_add_tail(&ov->node, &ov_list);
391
392 mutex_unlock(&of_mutex);
393
394 return id;
395
396err_revert_overlay:
397err_abort_trans:
398 of_free_overlay_info(ov);
399err_free_idr:
400 idr_remove(&ov_idr, ov->id);
401err_destroy_trans:
402 of_changeset_destroy(&ov->cset);
403 kfree(ov);
404 mutex_unlock(&of_mutex);
405
406 return err;
407}
408EXPORT_SYMBOL_GPL(of_overlay_create);
409
410/* check whether the given node, lies under the given tree */
411static int overlay_subtree_check(struct device_node *tree,
412 struct device_node *dn)
413{
414 struct device_node *child;
415
416 /* match? */
417 if (tree == dn)
418 return 1;
419
420 for_each_child_of_node(tree, child) {
421 if (overlay_subtree_check(child, dn)) {
422 of_node_put(child);
423 return 1;
424 }
425 }
426
427 return 0;
428}
429
430/* check whether this overlay is the topmost */
431static int overlay_is_topmost(struct of_overlay *ov, struct device_node *dn)
432{
433 struct of_overlay *ovt;
434 struct of_changeset_entry *ce;
435
436 list_for_each_entry_reverse(ovt, &ov_list, node) {
437 /* if we hit ourselves, we're done */
438 if (ovt == ov)
439 break;
440
441 /* check against each subtree affected by this overlay */
442 list_for_each_entry(ce, &ovt->cset.entries, node) {
443 if (overlay_subtree_check(ce->np, dn)) {
444 pr_err("%s: #%d clashes #%d @%s\n",
445 __func__, ov->id, ovt->id,
446 dn->full_name);
447 return 0;
448 }
449 }
450 }
451
452 /* overlay is topmost */
453 return 1;
454}
455
456/*
457 * We can safely remove the overlay only if it's the top-most one.
458 * Newly applied overlays are inserted at the tail of the overlay list,
459 * so a top most overlay is the one that is closest to the tail.
460 *
461 * The topmost check is done by exploiting this property. For each
462 * affected device node in the log list we check if this overlay is
463 * the one closest to the tail. If another overlay has affected this
464 * device node and is closest to the tail, then removal is not permited.
465 */
466static int overlay_removal_is_ok(struct of_overlay *ov)
467{
468 struct of_changeset_entry *ce;
469
470 list_for_each_entry(ce, &ov->cset.entries, node) {
471 if (!overlay_is_topmost(ov, ce->np)) {
472 pr_err("%s: overlay #%d is not topmost\n",
473 __func__, ov->id);
474 return 0;
475 }
476 }
477
478 return 1;
479}
480
481/**
482 * of_overlay_destroy() - Removes an overlay
483 * @id: Overlay id number returned by a previous call to of_overlay_create
484 *
485 * Removes an overlay if it is permissible.
486 *
487 * Returns 0 on success, or a negative error number
488 */
489int of_overlay_destroy(int id)
490{
491 struct of_overlay *ov;
492 int err;
493
494 mutex_lock(&of_mutex);
495
496 ov = idr_find(&ov_idr, id);
497 if (ov == NULL) {
498 err = -ENODEV;
499 pr_err("%s: Could not find overlay #%d\n",
500 __func__, id);
501 goto out;
502 }
503
504 /* check whether the overlay is safe to remove */
505 if (!overlay_removal_is_ok(ov)) {
506 err = -EBUSY;
507 pr_err("%s: removal check failed for overlay #%d\n",
508 __func__, id);
509 goto out;
510 }
511
512
513 list_del(&ov->node);
514 __of_changeset_revert(&ov->cset);
515 of_free_overlay_info(ov);
516 idr_remove(&ov_idr, id);
517 of_changeset_destroy(&ov->cset);
518 kfree(ov);
519
520 err = 0;
521
522out:
523 mutex_unlock(&of_mutex);
524
525 return err;
526}
527EXPORT_SYMBOL_GPL(of_overlay_destroy);
528
529/**
530 * of_overlay_destroy_all() - Removes all overlays from the system
531 *
532 * Removes all overlays from the system in the correct order.
533 *
534 * Returns 0 on success, or a negative error number
535 */
536int of_overlay_destroy_all(void)
537{
538 struct of_overlay *ov, *ovn;
539
540 mutex_lock(&of_mutex);
541
542 /* the tail of list is guaranteed to be safe to remove */
543 list_for_each_entry_safe_reverse(ov, ovn, &ov_list, node) {
544 list_del(&ov->node);
545 __of_changeset_revert(&ov->cset);
546 of_free_overlay_info(ov);
547 idr_remove(&ov_idr, ov->id);
548 kfree(ov);
549 }
550
551 mutex_unlock(&of_mutex);
552
553 return 0;
554}
555EXPORT_SYMBOL_GPL(of_overlay_destroy_all);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions for working with device tree overlays
4 *
5 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
6 * Copyright (C) 2012 Texas Instruments Inc.
7 */
8
9#define pr_fmt(fmt) "OF: overlay: " fmt
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/of_device.h>
15#include <linux/of_fdt.h>
16#include <linux/string.h>
17#include <linux/ctype.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/libfdt.h>
21#include <linux/err.h>
22#include <linux/idr.h>
23
24#include "of_private.h"
25
26/**
27 * struct target - info about current target node as recursing through overlay
28 * @np: node where current level of overlay will be applied
29 * @in_livetree: @np is a node in the live devicetree
30 *
31 * Used in the algorithm to create the portion of a changeset that describes
32 * an overlay fragment, which is a devicetree subtree. Initially @np is a node
33 * in the live devicetree where the overlay subtree is targeted to be grafted
34 * into. When recursing to the next level of the overlay subtree, the target
35 * also recurses to the next level of the live devicetree, as long as overlay
36 * subtree node also exists in the live devicetree. When a node in the overlay
37 * subtree does not exist at the same level in the live devicetree, target->np
38 * points to a newly allocated node, and all subsequent targets in the subtree
39 * will be newly allocated nodes.
40 */
41struct target {
42 struct device_node *np;
43 bool in_livetree;
44};
45
46/**
47 * struct fragment - info about fragment nodes in overlay expanded device tree
48 * @overlay: pointer to the __overlay__ node
49 * @target: target of the overlay operation
50 */
51struct fragment {
52 struct device_node *overlay;
53 struct device_node *target;
54};
55
56/**
57 * struct overlay_changeset
58 * @id: changeset identifier
59 * @ovcs_list: list on which we are located
60 * @new_fdt: Memory allocated to hold unflattened aligned FDT
61 * @overlay_mem: the memory chunk that contains @overlay_root
62 * @overlay_root: expanded device tree that contains the fragment nodes
63 * @notify_state: most recent notify action used on overlay
64 * @count: count of fragment structures
65 * @fragments: fragment nodes in the overlay expanded device tree
66 * @symbols_fragment: last element of @fragments[] is the __symbols__ node
67 * @cset: changeset to apply fragments to live device tree
68 */
69struct overlay_changeset {
70 int id;
71 struct list_head ovcs_list;
72 const void *new_fdt;
73 const void *overlay_mem;
74 struct device_node *overlay_root;
75 enum of_overlay_notify_action notify_state;
76 int count;
77 struct fragment *fragments;
78 bool symbols_fragment;
79 struct of_changeset cset;
80};
81
82/* flags are sticky - once set, do not reset */
83static int devicetree_state_flags;
84#define DTSF_APPLY_FAIL 0x01
85#define DTSF_REVERT_FAIL 0x02
86
87/*
88 * If a changeset apply or revert encounters an error, an attempt will
89 * be made to undo partial changes, but may fail. If the undo fails
90 * we do not know the state of the devicetree.
91 */
92static int devicetree_corrupt(void)
93{
94 return devicetree_state_flags &
95 (DTSF_APPLY_FAIL | DTSF_REVERT_FAIL);
96}
97
98static int build_changeset_next_level(struct overlay_changeset *ovcs,
99 struct target *target, const struct device_node *overlay_node);
100
101/*
102 * of_resolve_phandles() finds the largest phandle in the live tree.
103 * of_overlay_apply() may add a larger phandle to the live tree.
104 * Do not allow race between two overlays being applied simultaneously:
105 * mutex_lock(&of_overlay_phandle_mutex)
106 * of_resolve_phandles()
107 * of_overlay_apply()
108 * mutex_unlock(&of_overlay_phandle_mutex)
109 */
110static DEFINE_MUTEX(of_overlay_phandle_mutex);
111
112void of_overlay_mutex_lock(void)
113{
114 mutex_lock(&of_overlay_phandle_mutex);
115}
116
117void of_overlay_mutex_unlock(void)
118{
119 mutex_unlock(&of_overlay_phandle_mutex);
120}
121
122static LIST_HEAD(ovcs_list);
123static DEFINE_IDR(ovcs_idr);
124
125static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain);
126
127/**
128 * of_overlay_notifier_register() - Register notifier for overlay operations
129 * @nb: Notifier block to register
130 *
131 * Register for notification on overlay operations on device tree nodes. The
132 * reported actions definied by @of_reconfig_change. The notifier callback
133 * furthermore receives a pointer to the affected device tree node.
134 *
135 * Note that a notifier callback is not supposed to store pointers to a device
136 * tree node or its content beyond @OF_OVERLAY_POST_REMOVE corresponding to the
137 * respective node it received.
138 */
139int of_overlay_notifier_register(struct notifier_block *nb)
140{
141 return blocking_notifier_chain_register(&overlay_notify_chain, nb);
142}
143EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
144
145/**
146 * of_overlay_notifier_unregister() - Unregister notifier for overlay operations
147 * @nb: Notifier block to unregister
148 */
149int of_overlay_notifier_unregister(struct notifier_block *nb)
150{
151 return blocking_notifier_chain_unregister(&overlay_notify_chain, nb);
152}
153EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
154
155static int overlay_notify(struct overlay_changeset *ovcs,
156 enum of_overlay_notify_action action)
157{
158 struct of_overlay_notify_data nd;
159 int i, ret;
160
161 ovcs->notify_state = action;
162
163 for (i = 0; i < ovcs->count; i++) {
164 struct fragment *fragment = &ovcs->fragments[i];
165
166 nd.target = fragment->target;
167 nd.overlay = fragment->overlay;
168
169 ret = blocking_notifier_call_chain(&overlay_notify_chain,
170 action, &nd);
171 if (notifier_to_errno(ret)) {
172 ret = notifier_to_errno(ret);
173 pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
174 of_overlay_action_name(action), ret, nd.target);
175 return ret;
176 }
177 }
178
179 return 0;
180}
181
182/*
183 * The values of properties in the "/__symbols__" node are paths in
184 * the ovcs->overlay_root. When duplicating the properties, the paths
185 * need to be adjusted to be the correct path for the live device tree.
186 *
187 * The paths refer to a node in the subtree of a fragment node's "__overlay__"
188 * node, for example "/fragment@0/__overlay__/symbol_path_tail",
189 * where symbol_path_tail can be a single node or it may be a multi-node path.
190 *
191 * The duplicated property value will be modified by replacing the
192 * "/fragment_name/__overlay/" portion of the value with the target
193 * path from the fragment node.
194 */
195static struct property *dup_and_fixup_symbol_prop(
196 struct overlay_changeset *ovcs, const struct property *prop)
197{
198 struct fragment *fragment;
199 struct property *new_prop;
200 struct device_node *fragment_node;
201 struct device_node *overlay_node;
202 const char *path;
203 const char *path_tail;
204 const char *target_path;
205 int k;
206 int overlay_name_len;
207 int path_len;
208 int path_tail_len;
209 int target_path_len;
210
211 if (!prop->value)
212 return NULL;
213 if (strnlen(prop->value, prop->length) >= prop->length)
214 return NULL;
215 path = prop->value;
216 path_len = strlen(path);
217
218 if (path_len < 1)
219 return NULL;
220 fragment_node = __of_find_node_by_path(ovcs->overlay_root, path + 1);
221 overlay_node = __of_find_node_by_path(fragment_node, "__overlay__/");
222 of_node_put(fragment_node);
223 of_node_put(overlay_node);
224
225 for (k = 0; k < ovcs->count; k++) {
226 fragment = &ovcs->fragments[k];
227 if (fragment->overlay == overlay_node)
228 break;
229 }
230 if (k >= ovcs->count)
231 return NULL;
232
233 overlay_name_len = snprintf(NULL, 0, "%pOF", fragment->overlay);
234
235 if (overlay_name_len > path_len)
236 return NULL;
237 path_tail = path + overlay_name_len;
238 path_tail_len = strlen(path_tail);
239
240 target_path = kasprintf(GFP_KERNEL, "%pOF", fragment->target);
241 if (!target_path)
242 return NULL;
243 target_path_len = strlen(target_path);
244
245 new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
246 if (!new_prop)
247 goto err_free_target_path;
248
249 new_prop->name = kstrdup(prop->name, GFP_KERNEL);
250 new_prop->length = target_path_len + path_tail_len + 1;
251 new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
252 if (!new_prop->name || !new_prop->value)
253 goto err_free_new_prop;
254
255 strcpy(new_prop->value, target_path);
256 strcpy(new_prop->value + target_path_len, path_tail);
257
258 of_property_set_flag(new_prop, OF_DYNAMIC);
259
260 kfree(target_path);
261
262 return new_prop;
263
264err_free_new_prop:
265 __of_prop_free(new_prop);
266err_free_target_path:
267 kfree(target_path);
268
269 return NULL;
270}
271
272/**
273 * add_changeset_property() - add @overlay_prop to overlay changeset
274 * @ovcs: overlay changeset
275 * @target: where @overlay_prop will be placed
276 * @overlay_prop: property to add or update, from overlay tree
277 * @is_symbols_prop: 1 if @overlay_prop is from node "/__symbols__"
278 *
279 * If @overlay_prop does not already exist in live devicetree, add changeset
280 * entry to add @overlay_prop in @target, else add changeset entry to update
281 * value of @overlay_prop.
282 *
283 * @target may be either in the live devicetree or in a new subtree that
284 * is contained in the changeset.
285 *
286 * Some special properties are not added or updated (no error returned):
287 * "name", "phandle", "linux,phandle".
288 *
289 * Properties "#address-cells" and "#size-cells" are not updated if they
290 * are already in the live tree, but if present in the live tree, the values
291 * in the overlay must match the values in the live tree.
292 *
293 * Update of property in symbols node is not allowed.
294 *
295 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
296 * invalid @overlay.
297 */
298static int add_changeset_property(struct overlay_changeset *ovcs,
299 struct target *target, const struct property *overlay_prop,
300 bool is_symbols_prop)
301{
302 struct property *new_prop = NULL;
303 const struct property *prop;
304 int ret = 0;
305
306 if (target->in_livetree)
307 if (!of_prop_cmp(overlay_prop->name, "name") ||
308 !of_prop_cmp(overlay_prop->name, "phandle") ||
309 !of_prop_cmp(overlay_prop->name, "linux,phandle"))
310 return 0;
311
312 if (target->in_livetree)
313 prop = of_find_property(target->np, overlay_prop->name, NULL);
314 else
315 prop = NULL;
316
317 if (prop) {
318 if (!of_prop_cmp(prop->name, "#address-cells")) {
319 if (!of_prop_val_eq(prop, overlay_prop)) {
320 pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
321 target->np);
322 ret = -EINVAL;
323 }
324 return ret;
325
326 } else if (!of_prop_cmp(prop->name, "#size-cells")) {
327 if (!of_prop_val_eq(prop, overlay_prop)) {
328 pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
329 target->np);
330 ret = -EINVAL;
331 }
332 return ret;
333 }
334 }
335
336 if (is_symbols_prop) {
337 if (prop)
338 return -EINVAL;
339 new_prop = dup_and_fixup_symbol_prop(ovcs, overlay_prop);
340 } else {
341 new_prop = __of_prop_dup(overlay_prop, GFP_KERNEL);
342 }
343
344 if (!new_prop)
345 return -ENOMEM;
346
347 if (!prop) {
348 if (!target->in_livetree) {
349 new_prop->next = target->np->deadprops;
350 target->np->deadprops = new_prop;
351 }
352 ret = of_changeset_add_property(&ovcs->cset, target->np,
353 new_prop);
354 } else {
355 ret = of_changeset_update_property(&ovcs->cset, target->np,
356 new_prop);
357 }
358
359 if (!of_node_check_flag(target->np, OF_OVERLAY))
360 pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
361 target->np, new_prop->name);
362
363 if (ret)
364 __of_prop_free(new_prop);
365 return ret;
366}
367
368/**
369 * add_changeset_node() - add @node (and children) to overlay changeset
370 * @ovcs: overlay changeset
371 * @target: where @node will be placed in live tree or changeset
372 * @node: node from within overlay device tree fragment
373 *
374 * If @node does not already exist in @target, add changeset entry
375 * to add @node in @target.
376 *
377 * If @node already exists in @target, and the existing node has
378 * a phandle, the overlay node is not allowed to have a phandle.
379 *
380 * If @node has child nodes, add the children recursively via
381 * build_changeset_next_level().
382 *
383 * NOTE_1: A live devicetree created from a flattened device tree (FDT) will
384 * not contain the full path in node->full_name. Thus an overlay
385 * created from an FDT also will not contain the full path in
386 * node->full_name. However, a live devicetree created from Open
387 * Firmware may have the full path in node->full_name.
388 *
389 * add_changeset_node() follows the FDT convention and does not include
390 * the full path in node->full_name. Even though it expects the overlay
391 * to not contain the full path, it uses kbasename() to remove the
392 * full path should it exist. It also uses kbasename() in comparisons
393 * to nodes in the live devicetree so that it can apply an overlay to
394 * a live devicetree created from Open Firmware.
395 *
396 * NOTE_2: Multiple mods of created nodes not supported.
397 *
398 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
399 * invalid @overlay.
400 */
401static int add_changeset_node(struct overlay_changeset *ovcs,
402 struct target *target, const struct device_node *node)
403{
404 const char *node_kbasename;
405 const __be32 *phandle;
406 struct device_node *tchild;
407 struct target target_child;
408 int ret = 0, size;
409
410 node_kbasename = kbasename(node->full_name);
411
412 for_each_child_of_node(target->np, tchild)
413 if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
414 break;
415
416 if (!tchild) {
417 tchild = __of_node_dup(NULL, node_kbasename);
418 if (!tchild)
419 return -ENOMEM;
420
421 tchild->parent = target->np;
422 tchild->name = __of_get_property(node, "name", NULL);
423
424 if (!tchild->name)
425 tchild->name = "<NULL>";
426
427 /* ignore obsolete "linux,phandle" */
428 phandle = __of_get_property(node, "phandle", &size);
429 if (phandle && (size == 4))
430 tchild->phandle = be32_to_cpup(phandle);
431
432 of_node_set_flag(tchild, OF_OVERLAY);
433
434 ret = of_changeset_attach_node(&ovcs->cset, tchild);
435 if (ret)
436 return ret;
437
438 target_child.np = tchild;
439 target_child.in_livetree = false;
440
441 ret = build_changeset_next_level(ovcs, &target_child, node);
442 of_node_put(tchild);
443 return ret;
444 }
445
446 if (node->phandle && tchild->phandle) {
447 ret = -EINVAL;
448 } else {
449 target_child.np = tchild;
450 target_child.in_livetree = target->in_livetree;
451 ret = build_changeset_next_level(ovcs, &target_child, node);
452 }
453 of_node_put(tchild);
454
455 return ret;
456}
457
458/**
459 * build_changeset_next_level() - add level of overlay changeset
460 * @ovcs: overlay changeset
461 * @target: where to place @overlay_node in live tree
462 * @overlay_node: node from within an overlay device tree fragment
463 *
464 * Add the properties (if any) and nodes (if any) from @overlay_node to the
465 * @ovcs->cset changeset. If an added node has child nodes, they will
466 * be added recursively.
467 *
468 * Do not allow symbols node to have any children.
469 *
470 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
471 * invalid @overlay_node.
472 */
473static int build_changeset_next_level(struct overlay_changeset *ovcs,
474 struct target *target, const struct device_node *overlay_node)
475{
476 struct property *prop;
477 int ret;
478
479 for_each_property_of_node(overlay_node, prop) {
480 ret = add_changeset_property(ovcs, target, prop, 0);
481 if (ret) {
482 pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
483 target->np, prop->name, ret);
484 return ret;
485 }
486 }
487
488 for_each_child_of_node_scoped(overlay_node, child) {
489 ret = add_changeset_node(ovcs, target, child);
490 if (ret) {
491 pr_debug("Failed to apply node @%pOF/%pOFn, err=%d\n",
492 target->np, child, ret);
493 return ret;
494 }
495 }
496
497 return 0;
498}
499
500/*
501 * Add the properties from __overlay__ node to the @ovcs->cset changeset.
502 */
503static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
504 struct target *target,
505 const struct device_node *overlay_symbols_node)
506{
507 struct property *prop;
508 int ret;
509
510 for_each_property_of_node(overlay_symbols_node, prop) {
511 ret = add_changeset_property(ovcs, target, prop, 1);
512 if (ret) {
513 pr_debug("Failed to apply symbols prop @%pOF/%s, err=%d\n",
514 target->np, prop->name, ret);
515 return ret;
516 }
517 }
518
519 return 0;
520}
521
522static int find_dup_cset_node_entry(struct overlay_changeset *ovcs,
523 struct of_changeset_entry *ce_1)
524{
525 struct of_changeset_entry *ce_2;
526 char *fn_1, *fn_2;
527 int node_path_match;
528
529 if (ce_1->action != OF_RECONFIG_ATTACH_NODE &&
530 ce_1->action != OF_RECONFIG_DETACH_NODE)
531 return 0;
532
533 ce_2 = ce_1;
534 list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
535 if ((ce_2->action != OF_RECONFIG_ATTACH_NODE &&
536 ce_2->action != OF_RECONFIG_DETACH_NODE) ||
537 of_node_cmp(ce_1->np->full_name, ce_2->np->full_name))
538 continue;
539
540 fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
541 fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
542 node_path_match = !fn_1 || !fn_2 || !strcmp(fn_1, fn_2);
543 kfree(fn_1);
544 kfree(fn_2);
545 if (node_path_match) {
546 pr_err("ERROR: multiple fragments add and/or delete node %pOF\n",
547 ce_1->np);
548 return -EINVAL;
549 }
550 }
551
552 return 0;
553}
554
555static int find_dup_cset_prop(struct overlay_changeset *ovcs,
556 struct of_changeset_entry *ce_1)
557{
558 struct of_changeset_entry *ce_2;
559 char *fn_1, *fn_2;
560 int node_path_match;
561
562 if (ce_1->action != OF_RECONFIG_ADD_PROPERTY &&
563 ce_1->action != OF_RECONFIG_REMOVE_PROPERTY &&
564 ce_1->action != OF_RECONFIG_UPDATE_PROPERTY)
565 return 0;
566
567 ce_2 = ce_1;
568 list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
569 if ((ce_2->action != OF_RECONFIG_ADD_PROPERTY &&
570 ce_2->action != OF_RECONFIG_REMOVE_PROPERTY &&
571 ce_2->action != OF_RECONFIG_UPDATE_PROPERTY) ||
572 of_node_cmp(ce_1->np->full_name, ce_2->np->full_name))
573 continue;
574
575 fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
576 fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
577 node_path_match = !fn_1 || !fn_2 || !strcmp(fn_1, fn_2);
578 kfree(fn_1);
579 kfree(fn_2);
580 if (node_path_match &&
581 !of_prop_cmp(ce_1->prop->name, ce_2->prop->name)) {
582 pr_err("ERROR: multiple fragments add, update, and/or delete property %pOF/%s\n",
583 ce_1->np, ce_1->prop->name);
584 return -EINVAL;
585 }
586 }
587
588 return 0;
589}
590
591/**
592 * changeset_dup_entry_check() - check for duplicate entries
593 * @ovcs: Overlay changeset
594 *
595 * Check changeset @ovcs->cset for multiple {add or delete} node entries for
596 * the same node or duplicate {add, delete, or update} properties entries
597 * for the same property.
598 *
599 * Return: 0 on success, or -EINVAL if duplicate changeset entry found.
600 */
601static int changeset_dup_entry_check(struct overlay_changeset *ovcs)
602{
603 struct of_changeset_entry *ce_1;
604 int dup_entry = 0;
605
606 list_for_each_entry(ce_1, &ovcs->cset.entries, node) {
607 dup_entry |= find_dup_cset_node_entry(ovcs, ce_1);
608 dup_entry |= find_dup_cset_prop(ovcs, ce_1);
609 }
610
611 return dup_entry ? -EINVAL : 0;
612}
613
614/**
615 * build_changeset() - populate overlay changeset in @ovcs from @ovcs->fragments
616 * @ovcs: Overlay changeset
617 *
618 * Create changeset @ovcs->cset to contain the nodes and properties of the
619 * overlay device tree fragments in @ovcs->fragments[]. If an error occurs,
620 * any portions of the changeset that were successfully created will remain
621 * in @ovcs->cset.
622 *
623 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
624 * invalid overlay in @ovcs->fragments[].
625 */
626static int build_changeset(struct overlay_changeset *ovcs)
627{
628 struct fragment *fragment;
629 struct target target;
630 int fragments_count, i, ret;
631
632 /*
633 * if there is a symbols fragment in ovcs->fragments[i] it is
634 * the final element in the array
635 */
636 if (ovcs->symbols_fragment)
637 fragments_count = ovcs->count - 1;
638 else
639 fragments_count = ovcs->count;
640
641 for (i = 0; i < fragments_count; i++) {
642 fragment = &ovcs->fragments[i];
643
644 target.np = fragment->target;
645 target.in_livetree = true;
646 ret = build_changeset_next_level(ovcs, &target,
647 fragment->overlay);
648 if (ret) {
649 pr_debug("fragment apply failed '%pOF'\n",
650 fragment->target);
651 return ret;
652 }
653 }
654
655 if (ovcs->symbols_fragment) {
656 fragment = &ovcs->fragments[ovcs->count - 1];
657
658 target.np = fragment->target;
659 target.in_livetree = true;
660 ret = build_changeset_symbols_node(ovcs, &target,
661 fragment->overlay);
662 if (ret) {
663 pr_debug("symbols fragment apply failed '%pOF'\n",
664 fragment->target);
665 return ret;
666 }
667 }
668
669 return changeset_dup_entry_check(ovcs);
670}
671
672/*
673 * Find the target node using a number of different strategies
674 * in order of preference:
675 *
676 * 1) "target" property containing the phandle of the target
677 * 2) "target-path" property containing the path of the target
678 */
679static struct device_node *find_target(const struct device_node *info_node,
680 const struct device_node *target_base)
681{
682 struct device_node *node;
683 char *target_path;
684 const char *path;
685 u32 val;
686 int ret;
687
688 ret = of_property_read_u32(info_node, "target", &val);
689 if (!ret) {
690 node = of_find_node_by_phandle(val);
691 if (!node)
692 pr_err("find target, node: %pOF, phandle 0x%x not found\n",
693 info_node, val);
694 return node;
695 }
696
697 ret = of_property_read_string(info_node, "target-path", &path);
698 if (!ret) {
699 if (target_base) {
700 target_path = kasprintf(GFP_KERNEL, "%pOF%s", target_base, path);
701 if (!target_path)
702 return NULL;
703 node = of_find_node_by_path(target_path);
704 if (!node) {
705 pr_err("find target, node: %pOF, path '%s' not found\n",
706 info_node, target_path);
707 }
708 kfree(target_path);
709 } else {
710 node = of_find_node_by_path(path);
711 if (!node) {
712 pr_err("find target, node: %pOF, path '%s' not found\n",
713 info_node, path);
714 }
715 }
716 return node;
717 }
718
719 pr_err("find target, node: %pOF, no target property\n", info_node);
720
721 return NULL;
722}
723
724/**
725 * init_overlay_changeset() - initialize overlay changeset from overlay tree
726 * @ovcs: Overlay changeset to build
727 * @target_base: Point to the target node to apply overlay
728 *
729 * Initialize @ovcs. Populate @ovcs->fragments with node information from
730 * the top level of @overlay_root. The relevant top level nodes are the
731 * fragment nodes and the __symbols__ node. Any other top level node will
732 * be ignored. Populate other @ovcs fields.
733 *
734 * Return: 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error
735 * detected in @overlay_root. On error return, the caller of
736 * init_overlay_changeset() must call free_overlay_changeset().
737 */
738static int init_overlay_changeset(struct overlay_changeset *ovcs,
739 const struct device_node *target_base)
740{
741 struct device_node *node, *overlay_node;
742 struct fragment *fragment;
743 struct fragment *fragments;
744 int cnt, ret;
745
746 /*
747 * None of the resources allocated by this function will be freed in
748 * the error paths. Instead the caller of this function is required
749 * to call free_overlay_changeset() (which will free the resources)
750 * if error return.
751 */
752
753 /*
754 * Warn for some issues. Can not return -EINVAL for these until
755 * of_unittest_apply_overlay() is fixed to pass these checks.
756 */
757 if (!of_node_check_flag(ovcs->overlay_root, OF_DYNAMIC))
758 pr_debug("%s() ovcs->overlay_root is not dynamic\n", __func__);
759
760 if (!of_node_check_flag(ovcs->overlay_root, OF_DETACHED))
761 pr_debug("%s() ovcs->overlay_root is not detached\n", __func__);
762
763 if (!of_node_is_root(ovcs->overlay_root))
764 pr_debug("%s() ovcs->overlay_root is not root\n", __func__);
765
766 cnt = 0;
767
768 /* fragment nodes */
769 for_each_child_of_node(ovcs->overlay_root, node) {
770 overlay_node = of_get_child_by_name(node, "__overlay__");
771 if (overlay_node) {
772 cnt++;
773 of_node_put(overlay_node);
774 }
775 }
776
777 node = of_get_child_by_name(ovcs->overlay_root, "__symbols__");
778 if (node) {
779 cnt++;
780 of_node_put(node);
781 }
782
783 fragments = kcalloc(cnt, sizeof(*fragments), GFP_KERNEL);
784 if (!fragments) {
785 ret = -ENOMEM;
786 goto err_out;
787 }
788 ovcs->fragments = fragments;
789
790 cnt = 0;
791 for_each_child_of_node(ovcs->overlay_root, node) {
792 overlay_node = of_get_child_by_name(node, "__overlay__");
793 if (!overlay_node)
794 continue;
795
796 fragment = &fragments[cnt];
797 fragment->overlay = overlay_node;
798 fragment->target = find_target(node, target_base);
799 if (!fragment->target) {
800 of_node_put(fragment->overlay);
801 ret = -EINVAL;
802 of_node_put(node);
803 goto err_out;
804 }
805
806 cnt++;
807 }
808
809 /*
810 * if there is a symbols fragment in ovcs->fragments[i] it is
811 * the final element in the array
812 */
813 node = of_get_child_by_name(ovcs->overlay_root, "__symbols__");
814 if (node) {
815 ovcs->symbols_fragment = 1;
816 fragment = &fragments[cnt];
817 fragment->overlay = node;
818 fragment->target = of_find_node_by_path("/__symbols__");
819
820 if (!fragment->target) {
821 pr_err("symbols in overlay, but not in live tree\n");
822 ret = -EINVAL;
823 of_node_put(node);
824 goto err_out;
825 }
826
827 cnt++;
828 }
829
830 if (!cnt) {
831 pr_err("no fragments or symbols in overlay\n");
832 ret = -EINVAL;
833 goto err_out;
834 }
835
836 ovcs->count = cnt;
837
838 return 0;
839
840err_out:
841 pr_err("%s() failed, ret = %d\n", __func__, ret);
842
843 return ret;
844}
845
846static void free_overlay_changeset(struct overlay_changeset *ovcs)
847{
848 int i;
849
850 if (ovcs->cset.entries.next)
851 of_changeset_destroy(&ovcs->cset);
852
853 if (ovcs->id) {
854 idr_remove(&ovcs_idr, ovcs->id);
855 list_del(&ovcs->ovcs_list);
856 ovcs->id = 0;
857 }
858
859
860 for (i = 0; i < ovcs->count; i++) {
861 of_node_put(ovcs->fragments[i].target);
862 of_node_put(ovcs->fragments[i].overlay);
863 }
864 kfree(ovcs->fragments);
865
866 /*
867 * There should be no live pointers into ovcs->overlay_mem and
868 * ovcs->new_fdt due to the policy that overlay notifiers are not
869 * allowed to retain pointers into the overlay devicetree other
870 * than during the window from OF_OVERLAY_PRE_APPLY overlay
871 * notifiers until the OF_OVERLAY_POST_REMOVE overlay notifiers.
872 *
873 * A memory leak will occur here if within the window.
874 */
875
876 if (ovcs->notify_state == OF_OVERLAY_INIT ||
877 ovcs->notify_state == OF_OVERLAY_POST_REMOVE) {
878 kfree(ovcs->overlay_mem);
879 kfree(ovcs->new_fdt);
880 }
881 kfree(ovcs);
882}
883
884/*
885 * internal documentation
886 *
887 * of_overlay_apply() - Create and apply an overlay changeset
888 * @ovcs: overlay changeset
889 * @base: point to the target node to apply overlay
890 *
891 * Creates and applies an overlay changeset.
892 *
893 * If an error is returned by an overlay changeset pre-apply notifier
894 * then no further overlay changeset pre-apply notifier will be called.
895 *
896 * If an error is returned by an overlay changeset post-apply notifier
897 * then no further overlay changeset post-apply notifier will be called.
898 *
899 * If more than one notifier returns an error, then the last notifier
900 * error to occur is returned.
901 *
902 * If an error occurred while applying the overlay changeset, then an
903 * attempt is made to revert any changes that were made to the
904 * device tree. If there were any errors during the revert attempt
905 * then the state of the device tree can not be determined, and any
906 * following attempt to apply or remove an overlay changeset will be
907 * refused.
908 *
909 * Returns 0 on success, or a negative error number. On error return,
910 * the caller of of_overlay_apply() must call free_overlay_changeset().
911 */
912
913static int of_overlay_apply(struct overlay_changeset *ovcs,
914 const struct device_node *base)
915{
916 int ret = 0, ret_revert, ret_tmp;
917
918 ret = of_resolve_phandles(ovcs->overlay_root);
919 if (ret)
920 goto out;
921
922 ret = init_overlay_changeset(ovcs, base);
923 if (ret)
924 goto out;
925
926 ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY);
927 if (ret)
928 goto out;
929
930 ret = build_changeset(ovcs);
931 if (ret)
932 goto out;
933
934 ret_revert = 0;
935 ret = __of_changeset_apply_entries(&ovcs->cset, &ret_revert);
936 if (ret) {
937 if (ret_revert) {
938 pr_debug("overlay changeset revert error %d\n",
939 ret_revert);
940 devicetree_state_flags |= DTSF_APPLY_FAIL;
941 }
942 goto out;
943 }
944
945 ret = __of_changeset_apply_notify(&ovcs->cset);
946 if (ret)
947 pr_err("overlay apply changeset entry notify error %d\n", ret);
948 /* notify failure is not fatal, continue */
949
950 ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY);
951 if (ret_tmp)
952 if (!ret)
953 ret = ret_tmp;
954
955out:
956 pr_debug("%s() err=%d\n", __func__, ret);
957
958 return ret;
959}
960
961/**
962 * of_overlay_fdt_apply() - Create and apply an overlay changeset
963 * @overlay_fdt: pointer to overlay FDT
964 * @overlay_fdt_size: number of bytes in @overlay_fdt
965 * @ret_ovcs_id: pointer for returning created changeset id
966 * @base: pointer for the target node to apply overlay
967 *
968 * Creates and applies an overlay changeset.
969 *
970 * See of_overlay_apply() for important behavior information.
971 *
972 * Return: 0 on success, or a negative error number. *@ret_ovcs_id is set to
973 * the value of overlay changeset id, which can be passed to of_overlay_remove()
974 * to remove the overlay.
975 *
976 * On error return, the changeset may be partially applied. This is especially
977 * likely if an OF_OVERLAY_POST_APPLY notifier returns an error. In this case
978 * the caller should call of_overlay_remove() with the value in *@ret_ovcs_id.
979 */
980
981int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
982 int *ret_ovcs_id, const struct device_node *base)
983{
984 void *new_fdt;
985 void *new_fdt_align;
986 void *overlay_mem;
987 int ret;
988 u32 size;
989 struct overlay_changeset *ovcs;
990
991 *ret_ovcs_id = 0;
992
993 if (devicetree_corrupt()) {
994 pr_err("devicetree state suspect, refuse to apply overlay\n");
995 return -EBUSY;
996 }
997
998 if (overlay_fdt_size < sizeof(struct fdt_header) ||
999 fdt_check_header(overlay_fdt)) {
1000 pr_err("Invalid overlay_fdt header\n");
1001 return -EINVAL;
1002 }
1003
1004 size = fdt_totalsize(overlay_fdt);
1005 if (overlay_fdt_size < size)
1006 return -EINVAL;
1007
1008 ovcs = kzalloc(sizeof(*ovcs), GFP_KERNEL);
1009 if (!ovcs)
1010 return -ENOMEM;
1011
1012 of_overlay_mutex_lock();
1013 mutex_lock(&of_mutex);
1014
1015 /*
1016 * ovcs->notify_state must be set to OF_OVERLAY_INIT before allocating
1017 * ovcs resources, implicitly set by kzalloc() of ovcs
1018 */
1019
1020 ovcs->id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL);
1021 if (ovcs->id <= 0) {
1022 ret = ovcs->id;
1023 goto err_free_ovcs;
1024 }
1025
1026 INIT_LIST_HEAD(&ovcs->ovcs_list);
1027 list_add_tail(&ovcs->ovcs_list, &ovcs_list);
1028 of_changeset_init(&ovcs->cset);
1029
1030 /*
1031 * Must create permanent copy of FDT because of_fdt_unflatten_tree()
1032 * will create pointers to the passed in FDT in the unflattened tree.
1033 */
1034 new_fdt = kmalloc(size + FDT_ALIGN_SIZE, GFP_KERNEL);
1035 if (!new_fdt) {
1036 ret = -ENOMEM;
1037 goto err_free_ovcs;
1038 }
1039 ovcs->new_fdt = new_fdt;
1040
1041 new_fdt_align = PTR_ALIGN(new_fdt, FDT_ALIGN_SIZE);
1042 memcpy(new_fdt_align, overlay_fdt, size);
1043
1044 overlay_mem = of_fdt_unflatten_tree(new_fdt_align, NULL,
1045 &ovcs->overlay_root);
1046 if (!overlay_mem) {
1047 pr_err("unable to unflatten overlay_fdt\n");
1048 ret = -EINVAL;
1049 goto err_free_ovcs;
1050 }
1051 ovcs->overlay_mem = overlay_mem;
1052
1053 ret = of_overlay_apply(ovcs, base);
1054 /*
1055 * If of_overlay_apply() error, calling free_overlay_changeset() may
1056 * result in a memory leak if the apply partly succeeded, so do NOT
1057 * goto err_free_ovcs. Instead, the caller of of_overlay_fdt_apply()
1058 * can call of_overlay_remove();
1059 */
1060 *ret_ovcs_id = ovcs->id;
1061 goto out_unlock;
1062
1063err_free_ovcs:
1064 free_overlay_changeset(ovcs);
1065
1066out_unlock:
1067 mutex_unlock(&of_mutex);
1068 of_overlay_mutex_unlock();
1069 return ret;
1070}
1071EXPORT_SYMBOL_GPL(of_overlay_fdt_apply);
1072
1073/*
1074 * Find @np in @tree.
1075 *
1076 * Returns 1 if @np is @tree or is contained in @tree, else 0
1077 */
1078static int find_node(const struct device_node *tree, struct device_node *np)
1079{
1080 if (tree == np)
1081 return 1;
1082
1083 for_each_child_of_node_scoped(tree, child) {
1084 if (find_node(child, np))
1085 return 1;
1086 }
1087
1088 return 0;
1089}
1090
1091/*
1092 * Is @remove_ce_node a child of, a parent of, or the same as any
1093 * node in an overlay changeset more topmost than @remove_ovcs?
1094 *
1095 * Returns 1 if found, else 0
1096 */
1097static int node_overlaps_later_cs(struct overlay_changeset *remove_ovcs,
1098 struct device_node *remove_ce_node)
1099{
1100 struct overlay_changeset *ovcs;
1101 struct of_changeset_entry *ce;
1102
1103 list_for_each_entry_reverse(ovcs, &ovcs_list, ovcs_list) {
1104 if (ovcs == remove_ovcs)
1105 break;
1106
1107 list_for_each_entry(ce, &ovcs->cset.entries, node) {
1108 if (find_node(ce->np, remove_ce_node)) {
1109 pr_err("%s: #%d overlaps with #%d @%pOF\n",
1110 __func__, remove_ovcs->id, ovcs->id,
1111 remove_ce_node);
1112 return 1;
1113 }
1114 if (find_node(remove_ce_node, ce->np)) {
1115 pr_err("%s: #%d overlaps with #%d @%pOF\n",
1116 __func__, remove_ovcs->id, ovcs->id,
1117 remove_ce_node);
1118 return 1;
1119 }
1120 }
1121 }
1122
1123 return 0;
1124}
1125
1126/*
1127 * We can safely remove the overlay only if it's the top-most one.
1128 * Newly applied overlays are inserted at the tail of the overlay list,
1129 * so a top most overlay is the one that is closest to the tail.
1130 *
1131 * The topmost check is done by exploiting this property. For each
1132 * affected device node in the log list we check if this overlay is
1133 * the one closest to the tail. If another overlay has affected this
1134 * device node and is closest to the tail, then removal is not permitted.
1135 */
1136static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs)
1137{
1138 struct of_changeset_entry *remove_ce;
1139
1140 list_for_each_entry(remove_ce, &remove_ovcs->cset.entries, node) {
1141 if (node_overlaps_later_cs(remove_ovcs, remove_ce->np)) {
1142 pr_err("overlay #%d is not topmost\n", remove_ovcs->id);
1143 return 0;
1144 }
1145 }
1146
1147 return 1;
1148}
1149
1150/**
1151 * of_overlay_remove() - Revert and free an overlay changeset
1152 * @ovcs_id: Pointer to overlay changeset id
1153 *
1154 * Removes an overlay if it is permissible. @ovcs_id was previously returned
1155 * by of_overlay_fdt_apply().
1156 *
1157 * If an error occurred while attempting to revert the overlay changeset,
1158 * then an attempt is made to re-apply any changeset entry that was
1159 * reverted. If an error occurs on re-apply then the state of the device
1160 * tree can not be determined, and any following attempt to apply or remove
1161 * an overlay changeset will be refused.
1162 *
1163 * A non-zero return value will not revert the changeset if error is from:
1164 * - parameter checks
1165 * - overlay changeset pre-remove notifier
1166 * - overlay changeset entry revert
1167 *
1168 * If an error is returned by an overlay changeset pre-remove notifier
1169 * then no further overlay changeset pre-remove notifier will be called.
1170 *
1171 * If more than one notifier returns an error, then the last notifier
1172 * error to occur is returned.
1173 *
1174 * A non-zero return value will revert the changeset if error is from:
1175 * - overlay changeset entry notifier
1176 * - overlay changeset post-remove notifier
1177 *
1178 * If an error is returned by an overlay changeset post-remove notifier
1179 * then no further overlay changeset post-remove notifier will be called.
1180 *
1181 * Return: 0 on success, or a negative error number. *@ovcs_id is set to
1182 * zero after reverting the changeset, even if a subsequent error occurs.
1183 */
1184int of_overlay_remove(int *ovcs_id)
1185{
1186 struct overlay_changeset *ovcs;
1187 int ret, ret_apply, ret_tmp;
1188
1189 if (devicetree_corrupt()) {
1190 pr_err("suspect devicetree state, refuse to remove overlay\n");
1191 ret = -EBUSY;
1192 goto out;
1193 }
1194
1195 mutex_lock(&of_mutex);
1196
1197 ovcs = idr_find(&ovcs_idr, *ovcs_id);
1198 if (!ovcs) {
1199 ret = -ENODEV;
1200 pr_err("remove: Could not find overlay #%d\n", *ovcs_id);
1201 goto err_unlock;
1202 }
1203
1204 if (!overlay_removal_is_ok(ovcs)) {
1205 ret = -EBUSY;
1206 goto err_unlock;
1207 }
1208
1209 ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
1210 if (ret)
1211 goto err_unlock;
1212
1213 ret_apply = 0;
1214 ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply);
1215 if (ret) {
1216 if (ret_apply)
1217 devicetree_state_flags |= DTSF_REVERT_FAIL;
1218 goto err_unlock;
1219 }
1220
1221 ret = __of_changeset_revert_notify(&ovcs->cset);
1222 if (ret)
1223 pr_err("overlay remove changeset entry notify error %d\n", ret);
1224 /* notify failure is not fatal, continue */
1225
1226 *ovcs_id = 0;
1227
1228 /*
1229 * Note that the overlay memory will be kfree()ed by
1230 * free_overlay_changeset() even if the notifier for
1231 * OF_OVERLAY_POST_REMOVE returns an error.
1232 */
1233 ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE);
1234 if (ret_tmp)
1235 if (!ret)
1236 ret = ret_tmp;
1237
1238 free_overlay_changeset(ovcs);
1239
1240err_unlock:
1241 /*
1242 * If jumped over free_overlay_changeset(), then did not kfree()
1243 * overlay related memory. This is a memory leak unless a subsequent
1244 * of_overlay_remove() of this overlay is successful.
1245 */
1246 mutex_unlock(&of_mutex);
1247
1248out:
1249 pr_debug("%s() err=%d\n", __func__, ret);
1250
1251 return ret;
1252}
1253EXPORT_SYMBOL_GPL(of_overlay_remove);
1254
1255/**
1256 * of_overlay_remove_all() - Reverts and frees all overlay changesets
1257 *
1258 * Removes all overlays from the system in the correct order.
1259 *
1260 * Return: 0 on success, or a negative error number
1261 */
1262int of_overlay_remove_all(void)
1263{
1264 struct overlay_changeset *ovcs, *ovcs_n;
1265 int ret;
1266
1267 /* the tail of list is guaranteed to be safe to remove */
1268 list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) {
1269 ret = of_overlay_remove(&ovcs->id);
1270 if (ret)
1271 return ret;
1272 }
1273
1274 return 0;
1275}
1276EXPORT_SYMBOL_GPL(of_overlay_remove_all);