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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions for working with device tree overlays
4 *
5 * Copyright (C) 2012 Pantelis Antoniou <[email protected]>
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
87static int of_prop_val_eq(const struct property *p1, const struct property *p2)
88{
89 return p1->length == p2->length &&
90 !memcmp(p1->value, p2->value, (size_t)p1->length);
91}
92
93/*
94 * If a changeset apply or revert encounters an error, an attempt will
95 * be made to undo partial changes, but may fail. If the undo fails
96 * we do not know the state of the devicetree.
97 */
98static int devicetree_corrupt(void)
99{
100 return devicetree_state_flags &
101 (DTSF_APPLY_FAIL | DTSF_REVERT_FAIL);
102}
103
104static int build_changeset_next_level(struct overlay_changeset *ovcs,
105 struct target *target, const struct device_node *overlay_node);
106
107/*
108 * of_resolve_phandles() finds the largest phandle in the live tree.
109 * of_overlay_apply() may add a larger phandle to the live tree.
110 * Do not allow race between two overlays being applied simultaneously:
111 * mutex_lock(&of_overlay_phandle_mutex)
112 * of_resolve_phandles()
113 * of_overlay_apply()
114 * mutex_unlock(&of_overlay_phandle_mutex)
115 */
116static DEFINE_MUTEX(of_overlay_phandle_mutex);
117
118void of_overlay_mutex_lock(void)
119{
120 mutex_lock(&of_overlay_phandle_mutex);
121}
122
123void of_overlay_mutex_unlock(void)
124{
125 mutex_unlock(&of_overlay_phandle_mutex);
126}
127
128static LIST_HEAD(ovcs_list);
129static DEFINE_IDR(ovcs_idr);
130
131static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain);
132
133/**
134 * of_overlay_notifier_register() - Register notifier for overlay operations
135 * @nb: Notifier block to register
136 *
137 * Register for notification on overlay operations on device tree nodes. The
138 * reported actions defined by @of_reconfig_change. The notifier callback
139 * furthermore receives a pointer to the affected device tree node.
140 *
141 * Note that a notifier callback is not supposed to store pointers to a device
142 * tree node or its content beyond @OF_OVERLAY_POST_REMOVE corresponding to the
143 * respective node it received.
144 */
145int of_overlay_notifier_register(struct notifier_block *nb)
146{
147 return blocking_notifier_chain_register(&overlay_notify_chain, nb);
148}
149EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
150
151/**
152 * of_overlay_notifier_unregister() - Unregister notifier for overlay operations
153 * @nb: Notifier block to unregister
154 */
155int of_overlay_notifier_unregister(struct notifier_block *nb)
156{
157 return blocking_notifier_chain_unregister(&overlay_notify_chain, nb);
158}
159EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
160
161static int overlay_notify(struct overlay_changeset *ovcs,
162 enum of_overlay_notify_action action)
163{
164 struct of_overlay_notify_data nd;
165 int i, ret;
166
167 ovcs->notify_state = action;
168
169 for (i = 0; i < ovcs->count; i++) {
170 struct fragment *fragment = &ovcs->fragments[i];
171
172 nd.target = fragment->target;
173 nd.overlay = fragment->overlay;
174
175 ret = blocking_notifier_call_chain(&overlay_notify_chain,
176 action, &nd);
177 if (notifier_to_errno(ret)) {
178 ret = notifier_to_errno(ret);
179 pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
180 of_overlay_action_name(action), ret, nd.target);
181 return ret;
182 }
183 }
184
185 return 0;
186}
187
188static void overlay_fw_devlink_refresh(struct overlay_changeset *ovcs)
189{
190 for (int i = 0; i < ovcs->count; i++) {
191 struct device_node *np = ovcs->fragments[i].target;
192
193 fw_devlink_refresh_fwnode(of_fwnode_handle(np));
194 }
195}
196
197/*
198 * The values of properties in the "/__symbols__" node are paths in
199 * the ovcs->overlay_root. When duplicating the properties, the paths
200 * need to be adjusted to be the correct path for the live device tree.
201 *
202 * The paths refer to a node in the subtree of a fragment node's "__overlay__"
203 * node, for example "/fragment@0/__overlay__/symbol_path_tail",
204 * where symbol_path_tail can be a single node or it may be a multi-node path.
205 *
206 * The duplicated property value will be modified by replacing the
207 * "/fragment_name/__overlay/" portion of the value with the target
208 * path from the fragment node.
209 */
210static struct property *dup_and_fixup_symbol_prop(
211 struct overlay_changeset *ovcs, const struct property *prop)
212{
213 struct fragment *fragment;
214 struct property *new_prop;
215 struct device_node *fragment_node;
216 struct device_node *overlay_node;
217 const char *path;
218 const char *path_tail;
219 const char *target_path;
220 int k;
221 int overlay_name_len;
222 int path_len;
223 int path_tail_len;
224 int target_path_len;
225
226 if (!prop->value)
227 return NULL;
228 if (strnlen(prop->value, prop->length) >= prop->length)
229 return NULL;
230 path = prop->value;
231 path_len = strlen(path);
232
233 if (path_len < 1)
234 return NULL;
235 fragment_node = __of_find_node_by_path(ovcs->overlay_root, path + 1);
236 overlay_node = __of_find_node_by_path(fragment_node, "__overlay__/");
237 of_node_put(fragment_node);
238 of_node_put(overlay_node);
239
240 for (k = 0; k < ovcs->count; k++) {
241 fragment = &ovcs->fragments[k];
242 if (fragment->overlay == overlay_node)
243 break;
244 }
245 if (k >= ovcs->count)
246 return NULL;
247
248 overlay_name_len = snprintf(NULL, 0, "%pOF", fragment->overlay);
249
250 if (overlay_name_len > path_len)
251 return NULL;
252 path_tail = path + overlay_name_len;
253 path_tail_len = strlen(path_tail);
254
255 target_path = kasprintf(GFP_KERNEL, "%pOF", fragment->target);
256 if (!target_path)
257 return NULL;
258 target_path_len = strlen(target_path);
259 /* a root target renders as "/"; drop it to avoid "//" results */
260 if (target_path_len == 1 && target_path[0] == '/' && path_tail_len)
261 target_path_len = 0;
262
263 new_prop = kzalloc_obj(*new_prop);
264 if (!new_prop)
265 goto err_free_target_path;
266
267 new_prop->name = kstrdup(prop->name, GFP_KERNEL);
268 new_prop->length = target_path_len + path_tail_len + 1;
269 new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
270 if (!new_prop->name || !new_prop->value)
271 goto err_free_new_prop;
272
273 memcpy(new_prop->value, target_path, target_path_len);
274 memcpy(new_prop->value + target_path_len, path_tail, path_tail_len);
275
276 of_property_set_flag(new_prop, OF_DYNAMIC);
277
278 kfree(target_path);
279
280 return new_prop;
281
282err_free_new_prop:
283 __of_prop_free(new_prop);
284err_free_target_path:
285 kfree(target_path);
286
287 return NULL;
288}
289
290/**
291 * add_changeset_property() - add @overlay_prop to overlay changeset
292 * @ovcs: overlay changeset
293 * @target: where @overlay_prop will be placed
294 * @overlay_prop: property to add or update, from overlay tree
295 * @is_symbols_prop: 1 if @overlay_prop is from node "/__symbols__"
296 *
297 * If @overlay_prop does not already exist in live devicetree, add changeset
298 * entry to add @overlay_prop in @target, else add changeset entry to update
299 * value of @overlay_prop.
300 *
301 * @target may be either in the live devicetree or in a new subtree that
302 * is contained in the changeset.
303 *
304 * Some special properties are not added or updated (no error returned):
305 * "name", "phandle", "linux,phandle".
306 *
307 * Properties "#address-cells" and "#size-cells" are not updated if they
308 * are already in the live tree, but if present in the live tree, the values
309 * in the overlay must match the values in the live tree.
310 *
311 * Update of property in symbols node is not allowed.
312 *
313 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
314 * invalid @overlay.
315 */
316static int add_changeset_property(struct overlay_changeset *ovcs,
317 struct target *target, const struct property *overlay_prop,
318 bool is_symbols_prop)
319{
320 struct property *new_prop = NULL;
321 const struct property *prop;
322 int ret = 0;
323
324 if (target->in_livetree)
325 if (is_pseudo_property(overlay_prop->name))
326 return 0;
327
328 if (target->in_livetree)
329 prop = of_find_property(target->np, overlay_prop->name, NULL);
330 else
331 prop = NULL;
332
333 if (prop) {
334 if (!of_prop_cmp(prop->name, "#address-cells")) {
335 if (!of_prop_val_eq(prop, overlay_prop)) {
336 pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
337 target->np);
338 ret = -EINVAL;
339 }
340 return ret;
341
342 } else if (!of_prop_cmp(prop->name, "#size-cells")) {
343 if (!of_prop_val_eq(prop, overlay_prop)) {
344 pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
345 target->np);
346 ret = -EINVAL;
347 }
348 return ret;
349 }
350 }
351
352 if (is_symbols_prop) {
353 if (prop)
354 return -EINVAL;
355 new_prop = dup_and_fixup_symbol_prop(ovcs, overlay_prop);
356 } else {
357 new_prop = __of_prop_dup(overlay_prop, GFP_KERNEL);
358 }
359
360 if (!new_prop)
361 return -ENOMEM;
362
363 if (!prop) {
364 ret = of_changeset_add_property(&ovcs->cset, target->np,
365 new_prop);
366 /* the detached node owns the property until the apply */
367 if (!ret && !target->in_livetree) {
368 new_prop->next = target->np->deadprops;
369 target->np->deadprops = new_prop;
370 }
371 } else {
372 ret = of_changeset_update_property(&ovcs->cset, target->np,
373 new_prop);
374 }
375
376 if (!of_node_check_flag(target->np, OF_OVERLAY))
377 pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
378 target->np, new_prop->name);
379
380 if (ret)
381 __of_prop_free(new_prop);
382 return ret;
383}
384
385/**
386 * add_changeset_node() - add @node (and children) to overlay changeset
387 * @ovcs: overlay changeset
388 * @target: where @node will be placed in live tree or changeset
389 * @node: node from within overlay device tree fragment
390 *
391 * If @node does not already exist in @target, add changeset entry
392 * to add @node in @target.
393 *
394 * If @node already exists in @target, and the existing node has
395 * a phandle, the overlay node is not allowed to have a phandle.
396 *
397 * If @node has child nodes, add the children recursively via
398 * build_changeset_next_level().
399 *
400 * NOTE_1: A live devicetree created from a flattened device tree (FDT) will
401 * not contain the full path in node->full_name. Thus an overlay
402 * created from an FDT also will not contain the full path in
403 * node->full_name. However, a live devicetree created from Open
404 * Firmware may have the full path in node->full_name.
405 *
406 * add_changeset_node() follows the FDT convention and does not include
407 * the full path in node->full_name. Even though it expects the overlay
408 * to not contain the full path, it uses kbasename() to remove the
409 * full path should it exist. It also uses kbasename() in comparisons
410 * to nodes in the live devicetree so that it can apply an overlay to
411 * a live devicetree created from Open Firmware.
412 *
413 * NOTE_2: Multiple mods of created nodes not supported.
414 *
415 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
416 * invalid @overlay.
417 */
418static int add_changeset_node(struct overlay_changeset *ovcs,
419 struct target *target, const struct device_node *node)
420{
421 const char *node_kbasename;
422 const __be32 *phandle;
423 struct device_node *tchild;
424 struct target target_child;
425 int ret = 0, size;
426
427 node_kbasename = kbasename(node->full_name);
428
429 for_each_child_of_node(target->np, tchild)
430 if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
431 break;
432
433 if (!tchild) {
434 tchild = __of_node_dup(NULL, node_kbasename);
435 if (!tchild)
436 return -ENOMEM;
437
438 tchild->parent = target->np;
439 tchild->name = __of_get_property(node, "name", NULL);
440
441 if (!tchild->name)
442 tchild->name = "<NULL>";
443
444 /* ignore obsolete "linux,phandle" */
445 phandle = __of_get_property(node, "phandle", &size);
446 if (phandle && (size == 4))
447 tchild->phandle = be32_to_cpup(phandle);
448
449 of_node_set_flag(tchild, OF_OVERLAY);
450
451 ret = of_changeset_attach_node(&ovcs->cset, tchild);
452 if (ret)
453 return ret;
454
455 target_child.np = tchild;
456 target_child.in_livetree = false;
457
458 ret = build_changeset_next_level(ovcs, &target_child, node);
459 of_node_put(tchild);
460 return ret;
461 }
462
463 if (node->phandle && tchild->phandle) {
464 ret = -EINVAL;
465 } else {
466 target_child.np = tchild;
467 target_child.in_livetree = target->in_livetree;
468 ret = build_changeset_next_level(ovcs, &target_child, node);
469 }
470 of_node_put(tchild);
471
472 return ret;
473}
474
475/**
476 * build_changeset_next_level() - add level of overlay changeset
477 * @ovcs: overlay changeset
478 * @target: where to place @overlay_node in live tree
479 * @overlay_node: node from within an overlay device tree fragment
480 *
481 * Add the properties (if any) and nodes (if any) from @overlay_node to the
482 * @ovcs->cset changeset. If an added node has child nodes, they will
483 * be added recursively.
484 *
485 * Do not allow symbols node to have any children.
486 *
487 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
488 * invalid @overlay_node.
489 */
490static int build_changeset_next_level(struct overlay_changeset *ovcs,
491 struct target *target, const struct device_node *overlay_node)
492{
493 struct property *prop;
494 int ret;
495
496 for_each_property_of_node(overlay_node, prop) {
497 ret = add_changeset_property(ovcs, target, prop, 0);
498 if (ret) {
499 pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
500 target->np, prop->name, ret);
501 return ret;
502 }
503 }
504
505 for_each_child_of_node_scoped(overlay_node, child) {
506 ret = add_changeset_node(ovcs, target, child);
507 if (ret) {
508 pr_debug("Failed to apply node @%pOF/%pOFn, err=%d\n",
509 target->np, child, ret);
510 return ret;
511 }
512 }
513
514 return 0;
515}
516
517/*
518 * Add the properties from __overlay__ node to the @ovcs->cset changeset.
519 */
520static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
521 struct target *target,
522 const struct device_node *overlay_symbols_node)
523{
524 struct property *prop;
525 int ret;
526
527 for_each_property_of_node(overlay_symbols_node, prop) {
528 ret = add_changeset_property(ovcs, target, prop, 1);
529 if (ret) {
530 pr_debug("Failed to apply symbols prop @%pOF/%s, err=%d\n",
531 target->np, prop->name, ret);
532 return ret;
533 }
534 }
535
536 return 0;
537}
538
539static int find_dup_cset_node_entry(struct overlay_changeset *ovcs,
540 struct of_changeset_entry *ce_1)
541{
542 struct of_changeset_entry *ce_2;
543 char *fn_1, *fn_2;
544 int node_path_match;
545
546 if (ce_1->action != OF_RECONFIG_ATTACH_NODE &&
547 ce_1->action != OF_RECONFIG_DETACH_NODE)
548 return 0;
549
550 ce_2 = ce_1;
551 list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
552 if ((ce_2->action != OF_RECONFIG_ATTACH_NODE &&
553 ce_2->action != OF_RECONFIG_DETACH_NODE) ||
554 of_node_cmp(ce_1->np->full_name, ce_2->np->full_name))
555 continue;
556
557 fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
558 fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
559 node_path_match = !fn_1 || !fn_2 || !strcmp(fn_1, fn_2);
560 kfree(fn_1);
561 kfree(fn_2);
562 if (node_path_match) {
563 pr_err("ERROR: multiple fragments add and/or delete node %pOF\n",
564 ce_1->np);
565 return -EINVAL;
566 }
567 }
568
569 return 0;
570}
571
572static int find_dup_cset_prop(struct overlay_changeset *ovcs,
573 struct of_changeset_entry *ce_1)
574{
575 struct of_changeset_entry *ce_2;
576 char *fn_1, *fn_2;
577 int node_path_match;
578
579 if (ce_1->action != OF_RECONFIG_ADD_PROPERTY &&
580 ce_1->action != OF_RECONFIG_REMOVE_PROPERTY &&
581 ce_1->action != OF_RECONFIG_UPDATE_PROPERTY)
582 return 0;
583
584 ce_2 = ce_1;
585 list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
586 if ((ce_2->action != OF_RECONFIG_ADD_PROPERTY &&
587 ce_2->action != OF_RECONFIG_REMOVE_PROPERTY &&
588 ce_2->action != OF_RECONFIG_UPDATE_PROPERTY) ||
589 of_node_cmp(ce_1->np->full_name, ce_2->np->full_name))
590 continue;
591
592 fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
593 fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
594 node_path_match = !fn_1 || !fn_2 || !strcmp(fn_1, fn_2);
595 kfree(fn_1);
596 kfree(fn_2);
597 if (node_path_match &&
598 !of_prop_cmp(ce_1->prop->name, ce_2->prop->name)) {
599 pr_err("ERROR: multiple fragments add, update, and/or delete property %pOF/%s\n",
600 ce_1->np, ce_1->prop->name);
601 return -EINVAL;
602 }
603 }
604
605 return 0;
606}
607
608/**
609 * changeset_dup_entry_check() - check for duplicate entries
610 * @ovcs: Overlay changeset
611 *
612 * Check changeset @ovcs->cset for multiple {add or delete} node entries for
613 * the same node or duplicate {add, delete, or update} properties entries
614 * for the same property.
615 *
616 * Return: 0 on success, or -EINVAL if duplicate changeset entry found.
617 */
618static int changeset_dup_entry_check(struct overlay_changeset *ovcs)
619{
620 struct of_changeset_entry *ce_1;
621 int dup_entry = 0;
622
623 list_for_each_entry(ce_1, &ovcs->cset.entries, node) {
624 dup_entry |= find_dup_cset_node_entry(ovcs, ce_1);
625 dup_entry |= find_dup_cset_prop(ovcs, ce_1);
626 }
627
628 return dup_entry ? -EINVAL : 0;
629}
630
631/**
632 * build_changeset() - populate overlay changeset in @ovcs from @ovcs->fragments
633 * @ovcs: Overlay changeset
634 *
635 * Create changeset @ovcs->cset to contain the nodes and properties of the
636 * overlay device tree fragments in @ovcs->fragments[]. If an error occurs,
637 * any portions of the changeset that were successfully created will remain
638 * in @ovcs->cset.
639 *
640 * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
641 * invalid overlay in @ovcs->fragments[].
642 */
643static int build_changeset(struct overlay_changeset *ovcs)
644{
645 struct fragment *fragment;
646 struct target target;
647 int fragments_count, i, ret;
648
649 /*
650 * if there is a symbols fragment in ovcs->fragments[i] it is
651 * the final element in the array
652 */
653 if (ovcs->symbols_fragment)
654 fragments_count = ovcs->count - 1;
655 else
656 fragments_count = ovcs->count;
657
658 for (i = 0; i < fragments_count; i++) {
659 fragment = &ovcs->fragments[i];
660
661 target.np = fragment->target;
662 target.in_livetree = true;
663 ret = build_changeset_next_level(ovcs, &target,
664 fragment->overlay);
665 if (ret) {
666 pr_debug("fragment apply failed '%pOF'\n",
667 fragment->target);
668 return ret;
669 }
670 }
671
672 if (ovcs->symbols_fragment) {
673 fragment = &ovcs->fragments[ovcs->count - 1];
674
675 target.np = fragment->target;
676 target.in_livetree = true;
677 ret = build_changeset_symbols_node(ovcs, &target,
678 fragment->overlay);
679 if (ret) {
680 pr_debug("symbols fragment apply failed '%pOF'\n",
681 fragment->target);
682 return ret;
683 }
684 }
685
686 return changeset_dup_entry_check(ovcs);
687}
688
689/*
690 * Find the target node using a number of different strategies
691 * in order of preference:
692 *
693 * 1) "target" property containing the phandle of the target
694 * 2) "target-path" property containing the path of the target
695 */
696static struct device_node *find_target(const struct device_node *info_node,
697 const struct device_node *target_base)
698{
699 struct device_node *node;
700 char *target_path;
701 const char *path;
702 u32 val;
703 int ret;
704
705 ret = of_property_read_u32(info_node, "target", &val);
706 if (!ret) {
707 node = of_find_node_by_phandle(val);
708 if (!node)
709 pr_err("find target, node: %pOF, phandle 0x%x not found\n",
710 info_node, val);
711 return node;
712 }
713
714 ret = of_property_read_string(info_node, "target-path", &path);
715 if (!ret) {
716 if (target_base) {
717 target_path = kasprintf(GFP_KERNEL, "%pOF%s", target_base, path);
718 if (!target_path)
719 return NULL;
720 node = of_find_node_by_path(target_path);
721 if (!node) {
722 pr_err("find target, node: %pOF, path '%s' not found\n",
723 info_node, target_path);
724 }
725 kfree(target_path);
726 } else {
727 node = of_find_node_by_path(path);
728 if (!node) {
729 pr_err("find target, node: %pOF, path '%s' not found\n",
730 info_node, path);
731 }
732 }
733 return node;
734 }
735
736 pr_err("find target, node: %pOF, no target property\n", info_node);
737
738 return NULL;
739}
740
741/**
742 * init_overlay_changeset() - initialize overlay changeset from overlay tree
743 * @ovcs: Overlay changeset to build
744 * @target_base: Point to the target node to apply overlay
745 *
746 * Initialize @ovcs. Populate @ovcs->fragments with node information from
747 * the top level of @overlay_root. The relevant top level nodes are the
748 * fragment nodes and the __symbols__ node. Any other top level node will
749 * be ignored. Populate other @ovcs fields.
750 *
751 * Return: 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error
752 * detected in @overlay_root. On error return, the caller of
753 * init_overlay_changeset() must call free_overlay_changeset().
754 */
755static int init_overlay_changeset(struct overlay_changeset *ovcs,
756 const struct device_node *target_base)
757{
758 struct device_node *node, *overlay_node;
759 struct fragment *fragment;
760 struct fragment *fragments;
761 int cnt, ret;
762
763 /*
764 * None of the resources allocated by this function will be freed in
765 * the error paths. Instead the caller of this function is required
766 * to call free_overlay_changeset() (which will free the resources)
767 * if error return.
768 */
769
770 /*
771 * Warn for some issues. Can not return -EINVAL for these until
772 * of_unittest_apply_overlay() is fixed to pass these checks.
773 */
774 if (!of_node_check_flag(ovcs->overlay_root, OF_DYNAMIC))
775 pr_debug("%s() ovcs->overlay_root is not dynamic\n", __func__);
776
777 if (!of_node_check_flag(ovcs->overlay_root, OF_DETACHED))
778 pr_debug("%s() ovcs->overlay_root is not detached\n", __func__);
779
780 if (!of_node_is_root(ovcs->overlay_root))
781 pr_debug("%s() ovcs->overlay_root is not root\n", __func__);
782
783 cnt = 0;
784
785 /* fragment nodes */
786 for_each_child_of_node(ovcs->overlay_root, node) {
787 overlay_node = of_get_child_by_name(node, "__overlay__");
788 if (overlay_node) {
789 cnt++;
790 of_node_put(overlay_node);
791 }
792 }
793
794 node = of_get_child_by_name(ovcs->overlay_root, "__symbols__");
795 if (node) {
796 cnt++;
797 of_node_put(node);
798 }
799
800 fragments = kzalloc_objs(*fragments, cnt);
801 if (!fragments) {
802 ret = -ENOMEM;
803 goto err_out;
804 }
805 ovcs->fragments = fragments;
806
807 cnt = 0;
808 for_each_child_of_node(ovcs->overlay_root, node) {
809 overlay_node = of_get_child_by_name(node, "__overlay__");
810 if (!overlay_node)
811 continue;
812
813 fragment = &fragments[cnt];
814 fragment->overlay = overlay_node;
815 fragment->target = find_target(node, target_base);
816 if (!fragment->target) {
817 of_node_put(fragment->overlay);
818 ret = -EINVAL;
819 of_node_put(node);
820 goto err_out;
821 }
822
823 cnt++;
824 }
825
826 /*
827 * if there is a symbols fragment in ovcs->fragments[i] it is
828 * the final element in the array
829 */
830 node = of_get_child_by_name(ovcs->overlay_root, "__symbols__");
831 if (node) {
832 ovcs->symbols_fragment = 1;
833 fragment = &fragments[cnt];
834 fragment->overlay = node;
835 fragment->target = of_find_node_by_path("/__symbols__");
836
837 if (!fragment->target) {
838 pr_err("symbols in overlay, but not in live tree\n");
839 ret = -EINVAL;
840 of_node_put(node);
841 goto err_out;
842 }
843
844 cnt++;
845 }
846
847 if (!cnt) {
848 pr_err("no fragments or symbols in overlay\n");
849 ret = -EINVAL;
850 goto err_out;
851 }
852
853 ovcs->count = cnt;
854
855 return 0;
856
857err_out:
858 pr_err("%s() failed, ret = %d\n", __func__, ret);
859
860 /* let free_overlay_changeset() put the fragments set up so far */
861 if (ovcs->fragments)
862 ovcs->count = cnt;
863
864 return ret;
865}
866
867static void free_overlay_changeset(struct overlay_changeset *ovcs)
868{
869 int i;
870
871 if (ovcs->cset.entries.next)
872 of_changeset_destroy(&ovcs->cset);
873
874 /* a failed idr_alloc() leaves its negative error in ovcs->id */
875 if (ovcs->id > 0) {
876 idr_remove(&ovcs_idr, ovcs->id);
877 list_del(&ovcs->ovcs_list);
878 ovcs->id = 0;
879 }
880
881
882 for (i = 0; i < ovcs->count; i++) {
883 of_node_put(ovcs->fragments[i].target);
884 of_node_put(ovcs->fragments[i].overlay);
885 }
886 kfree(ovcs->fragments);
887
888 /*
889 * There should be no live pointers into ovcs->overlay_mem and
890 * ovcs->new_fdt due to the policy that overlay notifiers are not
891 * allowed to retain pointers into the overlay devicetree other
892 * than during the window from OF_OVERLAY_PRE_APPLY overlay
893 * notifiers until the OF_OVERLAY_POST_REMOVE overlay notifiers.
894 *
895 * A memory leak will occur here if within the window.
896 */
897
898 if (ovcs->notify_state == OF_OVERLAY_INIT ||
899 ovcs->notify_state == OF_OVERLAY_POST_REMOVE) {
900 kfree(ovcs->overlay_mem);
901 kfree(ovcs->new_fdt);
902 }
903 kfree(ovcs);
904}
905
906/*
907 * internal documentation
908 *
909 * of_overlay_apply() - Create and apply an overlay changeset
910 * @ovcs: overlay changeset
911 * @base: point to the target node to apply overlay
912 *
913 * Creates and applies an overlay changeset.
914 *
915 * If an error is returned by an overlay changeset pre-apply notifier
916 * then no further overlay changeset pre-apply notifier will be called.
917 *
918 * If an error is returned by an overlay changeset post-apply notifier
919 * then no further overlay changeset post-apply notifier will be called.
920 *
921 * If more than one notifier returns an error, then the last notifier
922 * error to occur is returned.
923 *
924 * If an error occurred while applying the overlay changeset, then an
925 * attempt is made to revert any changes that were made to the
926 * device tree. If there were any errors during the revert attempt
927 * then the state of the device tree can not be determined, and any
928 * following attempt to apply or remove an overlay changeset will be
929 * refused.
930 *
931 * Returns 0 on success, or a negative error number. On error return,
932 * the caller of of_overlay_apply() must call free_overlay_changeset().
933 */
934
935static int of_overlay_apply(struct overlay_changeset *ovcs,
936 const struct device_node *base)
937{
938 int ret = 0, ret_revert, ret_tmp;
939
940 ret = of_resolve_phandles(ovcs->overlay_root);
941 if (ret)
942 goto out;
943
944 ret = init_overlay_changeset(ovcs, base);
945 if (ret)
946 goto out;
947
948 ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY);
949 if (ret)
950 goto out;
951
952 ret = build_changeset(ovcs);
953 if (ret)
954 goto out;
955
956 ret_revert = 0;
957 ret = __of_changeset_apply_entries(&ovcs->cset, &ret_revert);
958 if (ret) {
959 if (ret_revert) {
960 pr_debug("overlay changeset revert error %d\n",
961 ret_revert);
962 devicetree_state_flags |= DTSF_APPLY_FAIL;
963 }
964 goto out;
965 }
966
967 ret = __of_changeset_apply_notify(&ovcs->cset);
968 if (ret)
969 pr_err("overlay apply changeset entry notify error %d\n", ret);
970 /* notify failure is not fatal, continue */
971
972 /*
973 * Needs to happen after changeset notify to give the listeners a chance
974 * to finish creating all the devices they need to create.
975 */
976 overlay_fw_devlink_refresh(ovcs);
977
978 ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY);
979 if (ret_tmp)
980 if (!ret)
981 ret = ret_tmp;
982
983out:
984 pr_debug("%s() err=%d\n", __func__, ret);
985
986 return ret;
987}
988
989/**
990 * of_overlay_fdt_apply() - Create and apply an overlay changeset
991 * @overlay_fdt: pointer to overlay FDT
992 * @overlay_fdt_size: number of bytes in @overlay_fdt
993 * @ret_ovcs_id: pointer for returning created changeset id
994 * @base: pointer for the target node to apply overlay
995 *
996 * Creates and applies an overlay changeset.
997 *
998 * See of_overlay_apply() for important behavior information.
999 *
1000 * Return: 0 on success, or a negative error number. *@ret_ovcs_id is set to
1001 * the value of overlay changeset id, which can be passed to of_overlay_remove()
1002 * to remove the overlay.
1003 *
1004 * On error return, the changeset may be partially applied. This is especially
1005 * likely if an OF_OVERLAY_POST_APPLY notifier returns an error. In this case
1006 * the caller should call of_overlay_remove() with the value in *@ret_ovcs_id.
1007 */
1008
1009int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
1010 int *ret_ovcs_id, const struct device_node *base)
1011{
1012 void *new_fdt;
1013 void *new_fdt_align;
1014 void *overlay_mem;
1015 int ret;
1016 u32 size;
1017 struct overlay_changeset *ovcs;
1018
1019 *ret_ovcs_id = 0;
1020
1021 if (devicetree_corrupt()) {
1022 pr_err("devicetree state suspect, refuse to apply overlay\n");
1023 return -EBUSY;
1024 }
1025
1026 if (overlay_fdt_size < sizeof(struct fdt_header) ||
1027 fdt_check_header(overlay_fdt)) {
1028 pr_err("Invalid overlay_fdt header\n");
1029 return -EINVAL;
1030 }
1031
1032 size = fdt_totalsize(overlay_fdt);
1033 if (overlay_fdt_size < size)
1034 return -EINVAL;
1035
1036 ovcs = kzalloc_obj(*ovcs);
1037 if (!ovcs)
1038 return -ENOMEM;
1039
1040 of_overlay_mutex_lock();
1041 mutex_lock(&of_mutex);
1042
1043 /*
1044 * ovcs->notify_state must be set to OF_OVERLAY_INIT before allocating
1045 * ovcs resources, implicitly set by kzalloc() of ovcs
1046 */
1047
1048 ovcs->id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL);
1049 if (ovcs->id <= 0) {
1050 ret = ovcs->id;
1051 goto err_free_ovcs;
1052 }
1053
1054 INIT_LIST_HEAD(&ovcs->ovcs_list);
1055 list_add_tail(&ovcs->ovcs_list, &ovcs_list);
1056 of_changeset_init(&ovcs->cset);
1057
1058 /*
1059 * Must create permanent copy of FDT because of_fdt_unflatten_tree()
1060 * will create pointers to the passed in FDT in the unflattened tree.
1061 */
1062 new_fdt = kmalloc(size + FDT_ALIGN_SIZE, GFP_KERNEL);
1063 if (!new_fdt) {
1064 ret = -ENOMEM;
1065 goto err_free_ovcs;
1066 }
1067 ovcs->new_fdt = new_fdt;
1068
1069 new_fdt_align = PTR_ALIGN(new_fdt, FDT_ALIGN_SIZE);
1070 memcpy(new_fdt_align, overlay_fdt, size);
1071
1072 overlay_mem = of_fdt_unflatten_tree(new_fdt_align, NULL,
1073 &ovcs->overlay_root);
1074 if (!overlay_mem) {
1075 pr_err("unable to unflatten overlay_fdt\n");
1076 ret = -EINVAL;
1077 goto err_free_ovcs;
1078 }
1079 ovcs->overlay_mem = overlay_mem;
1080
1081 ret = of_overlay_apply(ovcs, base);
1082 /*
1083 * If of_overlay_apply() error, calling free_overlay_changeset() may
1084 * result in a memory leak if the apply partly succeeded, so do NOT
1085 * goto err_free_ovcs. Instead, the caller of of_overlay_fdt_apply()
1086 * can call of_overlay_remove();
1087 */
1088 *ret_ovcs_id = ovcs->id;
1089 goto out_unlock;
1090
1091err_free_ovcs:
1092 free_overlay_changeset(ovcs);
1093
1094out_unlock:
1095 mutex_unlock(&of_mutex);
1096 of_overlay_mutex_unlock();
1097 return ret;
1098}
1099EXPORT_SYMBOL_GPL(of_overlay_fdt_apply);
1100
1101/*
1102 * Find @np in @tree.
1103 *
1104 * Returns 1 if @np is @tree or is contained in @tree, else 0
1105 */
1106static int find_node(const struct device_node *tree, struct device_node *np)
1107{
1108 if (tree == np)
1109 return 1;
1110
1111 for_each_child_of_node_scoped(tree, child) {
1112 if (find_node(child, np))
1113 return 1;
1114 }
1115
1116 return 0;
1117}
1118
1119/*
1120 * Is @remove_ce_node a child of, a parent of, or the same as any
1121 * node in an overlay changeset more topmost than @remove_ovcs?
1122 *
1123 * Returns 1 if found, else 0
1124 */
1125static int node_overlaps_later_cs(struct overlay_changeset *remove_ovcs,
1126 struct device_node *remove_ce_node)
1127{
1128 struct overlay_changeset *ovcs;
1129 struct of_changeset_entry *ce;
1130
1131 list_for_each_entry_reverse(ovcs, &ovcs_list, ovcs_list) {
1132 if (ovcs == remove_ovcs)
1133 break;
1134
1135 list_for_each_entry(ce, &ovcs->cset.entries, node) {
1136 if (find_node(ce->np, remove_ce_node)) {
1137 pr_err("%s: #%d overlaps with #%d @%pOF\n",
1138 __func__, remove_ovcs->id, ovcs->id,
1139 remove_ce_node);
1140 return 1;
1141 }
1142 if (find_node(remove_ce_node, ce->np)) {
1143 pr_err("%s: #%d overlaps with #%d @%pOF\n",
1144 __func__, remove_ovcs->id, ovcs->id,
1145 remove_ce_node);
1146 return 1;
1147 }
1148 }
1149 }
1150
1151 return 0;
1152}
1153
1154/*
1155 * We can safely remove the overlay only if it's the top-most one.
1156 * Newly applied overlays are inserted at the tail of the overlay list,
1157 * so a top most overlay is the one that is closest to the tail.
1158 *
1159 * The topmost check is done by exploiting this property. For each
1160 * affected device node in the log list we check if this overlay is
1161 * the one closest to the tail. If another overlay has affected this
1162 * device node and is closest to the tail, then removal is not permitted.
1163 */
1164static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs)
1165{
1166 struct of_changeset_entry *remove_ce;
1167
1168 list_for_each_entry(remove_ce, &remove_ovcs->cset.entries, node) {
1169 if (node_overlaps_later_cs(remove_ovcs, remove_ce->np)) {
1170 pr_err("overlay #%d is not topmost\n", remove_ovcs->id);
1171 return 0;
1172 }
1173 }
1174
1175 return 1;
1176}
1177
1178/**
1179 * of_overlay_remove() - Revert and free an overlay changeset
1180 * @ovcs_id: Pointer to overlay changeset id
1181 *
1182 * Removes an overlay if it is permissible. @ovcs_id was previously returned
1183 * by of_overlay_fdt_apply().
1184 *
1185 * If an error occurred while attempting to revert the overlay changeset,
1186 * then an attempt is made to re-apply any changeset entry that was
1187 * reverted. If an error occurs on re-apply then the state of the device
1188 * tree can not be determined, and any following attempt to apply or remove
1189 * an overlay changeset will be refused.
1190 *
1191 * A non-zero return value will not revert the changeset if error is from:
1192 * - parameter checks
1193 * - overlay changeset pre-remove notifier
1194 * - overlay changeset entry revert
1195 *
1196 * If an error is returned by an overlay changeset pre-remove notifier
1197 * then no further overlay changeset pre-remove notifier will be called.
1198 *
1199 * If more than one notifier returns an error, then the last notifier
1200 * error to occur is returned.
1201 *
1202 * A non-zero return value will revert the changeset if error is from:
1203 * - overlay changeset entry notifier
1204 * - overlay changeset post-remove notifier
1205 *
1206 * If an error is returned by an overlay changeset post-remove notifier
1207 * then no further overlay changeset post-remove notifier will be called.
1208 *
1209 * Return: 0 on success, or a negative error number. *@ovcs_id is set to
1210 * zero after reverting the changeset, even if a subsequent error occurs.
1211 */
1212int of_overlay_remove(int *ovcs_id)
1213{
1214 struct overlay_changeset *ovcs;
1215 int ret, ret_apply, ret_tmp;
1216
1217 if (*ovcs_id == 0)
1218 return 0;
1219
1220 if (devicetree_corrupt()) {
1221 pr_err("suspect devicetree state, refuse to remove overlay\n");
1222 ret = -EBUSY;
1223 goto out;
1224 }
1225
1226 mutex_lock(&of_mutex);
1227
1228 ovcs = idr_find(&ovcs_idr, *ovcs_id);
1229 if (!ovcs) {
1230 ret = -ENODEV;
1231 pr_err("remove: Could not find overlay #%d\n", *ovcs_id);
1232 goto err_unlock;
1233 }
1234
1235 if (!overlay_removal_is_ok(ovcs)) {
1236 ret = -EBUSY;
1237 goto err_unlock;
1238 }
1239
1240 ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
1241 if (ret)
1242 goto err_unlock;
1243
1244 ret_apply = 0;
1245 ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply);
1246 if (ret) {
1247 if (ret_apply)
1248 devicetree_state_flags |= DTSF_REVERT_FAIL;
1249 goto err_unlock;
1250 }
1251
1252 ret = __of_changeset_revert_notify(&ovcs->cset);
1253 if (ret)
1254 pr_err("overlay remove changeset entry notify error %d\n", ret);
1255 /* notify failure is not fatal, continue */
1256
1257 *ovcs_id = 0;
1258
1259 /*
1260 * Note that the overlay memory will be kfree()ed by
1261 * free_overlay_changeset() even if the notifier for
1262 * OF_OVERLAY_POST_REMOVE returns an error.
1263 */
1264 ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE);
1265 if (ret_tmp)
1266 if (!ret)
1267 ret = ret_tmp;
1268
1269 free_overlay_changeset(ovcs);
1270
1271err_unlock:
1272 /*
1273 * If jumped over free_overlay_changeset(), then did not kfree()
1274 * overlay related memory. This is a memory leak unless a subsequent
1275 * of_overlay_remove() of this overlay is successful.
1276 */
1277 mutex_unlock(&of_mutex);
1278
1279out:
1280 pr_debug("%s() err=%d\n", __func__, ret);
1281
1282 return ret;
1283}
1284EXPORT_SYMBOL_GPL(of_overlay_remove);
1285
1286/**
1287 * of_overlay_remove_all() - Reverts and frees all overlay changesets
1288 *
1289 * Removes all overlays from the system in the correct order.
1290 *
1291 * Return: 0 on success, or a negative error number
1292 */
1293int of_overlay_remove_all(void)
1294{
1295 struct overlay_changeset *ovcs, *ovcs_n;
1296 int ret;
1297
1298 /* the tail of list is guaranteed to be safe to remove */
1299 list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) {
1300 ret = of_overlay_remove(&ovcs->id);
1301 if (ret)
1302 return ret;
1303 }
1304
1305 return 0;
1306}
1307EXPORT_SYMBOL_GPL(of_overlay_remove_all);