fdt_rw.c

  1// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
  2/*
  3 * libfdt - Flat Device Tree manipulation
  4 * Copyright (C) 2006 David Gibson, IBM Corporation.
  5 */
  6#include "libfdt_env.h"
  7
  8#include <fdt.h>
  9#include <libfdt.h>
 10
 11#include "libfdt_internal.h"
 12
 13static int fdt_blocks_misordered_(const void *fdt,
 14				  int mem_rsv_size, int struct_size)
 15{
 16	return (fdt_off_mem_rsvmap(fdt) < FDT_ALIGN(sizeof(struct fdt_header), 8))
 17		|| (fdt_off_dt_struct(fdt) <
 18		    (fdt_off_mem_rsvmap(fdt) + mem_rsv_size))
 19		|| (fdt_off_dt_strings(fdt) <
 20		    (fdt_off_dt_struct(fdt) + struct_size))
 21		|| (fdt_totalsize(fdt) <
 22		    (fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt)));
 23}
 24
 25static int fdt_rw_probe_(void *fdt)
 26{
 27	if (can_assume(VALID_DTB))
 28		return 0;
 29	FDT_RO_PROBE(fdt);
 30
 31	if (!can_assume(LATEST) && fdt_version(fdt) < 17)
 32		return -FDT_ERR_BADVERSION;
 33	if (fdt_blocks_misordered_(fdt, sizeof(struct fdt_reserve_entry),
 34				   fdt_size_dt_struct(fdt)))
 35		return -FDT_ERR_BADLAYOUT;
 36	if (!can_assume(LATEST) && fdt_version(fdt) > 17)
 37		fdt_set_version(fdt, 17);
 38
 39	return 0;
 40}
 41
 42#define FDT_RW_PROBE(fdt) \
 43	{ \
 44		int err_; \
 45		if ((err_ = fdt_rw_probe_(fdt)) != 0) \
 46			return err_; \
 47	}
 48
 49static inline unsigned int fdt_data_size_(void *fdt)
 50{
 51	return fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
 52}
 53
 54static int fdt_splice_(void *fdt, void *splicepoint, int oldlen, int newlen)
 55{
 56	char *p = splicepoint;
 57	unsigned int dsize = fdt_data_size_(fdt);
 58	size_t soff = p - (char *)fdt;
 59
 60	if ((oldlen < 0) || (soff + oldlen < soff) || (soff + oldlen > dsize))
 61		return -FDT_ERR_BADOFFSET;
 62	if ((p < (char *)fdt) || (dsize + newlen < (unsigned)oldlen))
 63		return -FDT_ERR_BADOFFSET;
 64	if (dsize - oldlen + newlen > fdt_totalsize(fdt))
 65		return -FDT_ERR_NOSPACE;
 66	memmove(p + newlen, p + oldlen, ((char *)fdt + dsize) - (p + oldlen));
 67	return 0;
 68}
 69
 70static int fdt_splice_mem_rsv_(void *fdt, struct fdt_reserve_entry *p,
 71			       int oldn, int newn)
 72{
 73	int delta = (newn - oldn) * sizeof(*p);
 74	int err;
 75	err = fdt_splice_(fdt, p, oldn * sizeof(*p), newn * sizeof(*p));
 76	if (err)
 77		return err;
 78	fdt_set_off_dt_struct(fdt, fdt_off_dt_struct(fdt) + delta);
 79	fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
 80	return 0;
 81}
 82
 83static int fdt_splice_struct_(void *fdt, void *p,
 84			      int oldlen, int newlen)
 85{
 86	int delta = newlen - oldlen;
 87	int err;
 88
 89	if ((err = fdt_splice_(fdt, p, oldlen, newlen)))
 90		return err;
 91
 92	fdt_set_size_dt_struct(fdt, fdt_size_dt_struct(fdt) + delta);
 93	fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
 94	return 0;
 95}
 96
 97/* Must only be used to roll back in case of error */
 98static void fdt_del_last_string_(void *fdt, const char *s)
 99{
100	int newlen = strlen(s) + 1;
101
102	fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) - newlen);
103}
104
105static int fdt_splice_string_(void *fdt, int newlen)
106{
107	void *p = (char *)fdt
108		+ fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
109	int err;
110
111	if ((err = fdt_splice_(fdt, p, 0, newlen)))
112		return err;
113
114	fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) + newlen);
115	return 0;
116}
117
118/**
119 * fdt_find_add_string_() - Find or allocate a string
120 *
121 * @fdt: pointer to the device tree to check/adjust
122 * @s: string to find/add
123 * @allocated: Set to 0 if the string was found, 1 if not found and so
124 *	allocated. Ignored if can_assume(NO_ROLLBACK)
125 * @return offset of string in the string table (whether found or added)
126 */
127static int fdt_find_add_string_(void *fdt, const char *s, int slen,
128				int *allocated)
129{
130	char *strtab = (char *)fdt + fdt_off_dt_strings(fdt);
131	const char *p;
132	char *new;
133	int err;
134
135	if (!can_assume(NO_ROLLBACK))
136		*allocated = 0;
137
138	p = fdt_find_string_len_(strtab, fdt_size_dt_strings(fdt), s, slen);
139	if (p)
140		/* found it */
141		return (p - strtab);
142
143	new = strtab + fdt_size_dt_strings(fdt);
144	err = fdt_splice_string_(fdt, slen + 1);
145	if (err)
146		return err;
147
148	if (!can_assume(NO_ROLLBACK))
149		*allocated = 1;
150
151	memcpy(new, s, slen);
152	new[slen] = '\0';
153
154	return (new - strtab);
155}
156
157int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size)
158{
159	struct fdt_reserve_entry *re;
160	int err;
161
162	FDT_RW_PROBE(fdt);
163
164	re = fdt_mem_rsv_w_(fdt, fdt_num_mem_rsv(fdt));
165	err = fdt_splice_mem_rsv_(fdt, re, 0, 1);
166	if (err)
167		return err;
168
169	re->address = cpu_to_fdt64(address);
170	re->size = cpu_to_fdt64(size);
171	return 0;
172}
173
174int fdt_del_mem_rsv(void *fdt, int n)
175{
176	struct fdt_reserve_entry *re = fdt_mem_rsv_w_(fdt, n);
177
178	FDT_RW_PROBE(fdt);
179
180	if (n >= fdt_num_mem_rsv(fdt))
181		return -FDT_ERR_NOTFOUND;
182
183	return fdt_splice_mem_rsv_(fdt, re, 1, 0);
184}
185
186static int fdt_resize_property_(void *fdt, int nodeoffset,
187				const char *name, int namelen,
188				int len, struct fdt_property **prop)
189{
190	int oldlen;
191	int err;
192
193	*prop = fdt_get_property_namelen_w(fdt, nodeoffset, name, namelen,
194					   &oldlen);
195	if (!*prop)
196		return oldlen;
197
198	if ((err = fdt_splice_struct_(fdt, (*prop)->data, FDT_TAGALIGN(oldlen),
199				      FDT_TAGALIGN(len))))
200		return err;
201
202	(*prop)->len = cpu_to_fdt32(len);
203	return 0;
204}
205
206static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
207			     int namelen, int len, struct fdt_property **prop)
208{
209	int proplen;
210	int nextoffset;
211	int namestroff;
212	int err;
213	int allocated;
214
215	if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
216		return nextoffset;
217
218	namestroff = fdt_find_add_string_(fdt, name, namelen, &allocated);
219	if (namestroff < 0)
220		return namestroff;
221
222	*prop = fdt_offset_ptr_w_(fdt, nextoffset);
223	proplen = sizeof(**prop) + FDT_TAGALIGN(len);
224
225	err = fdt_splice_struct_(fdt, *prop, 0, proplen);
226	if (err) {
227		/* Delete the string if we failed to add it */
228		if (!can_assume(NO_ROLLBACK) && allocated)
229			fdt_del_last_string_(fdt, name);
230		return err;
231	}
232
233	(*prop)->tag = cpu_to_fdt32(FDT_PROP);
234	(*prop)->nameoff = cpu_to_fdt32(namestroff);
235	(*prop)->len = cpu_to_fdt32(len);
236	return 0;
237}
238
239int fdt_set_name(void *fdt, int nodeoffset, const char *name)
240{
241	char *namep;
242	int oldlen, newlen;
243	int err;
244
245	FDT_RW_PROBE(fdt);
246
247	namep = (char *)(uintptr_t)fdt_get_name(fdt, nodeoffset, &oldlen);
248	if (!namep)
249		return oldlen;
250
251	newlen = strlen(name);
252
253	err = fdt_splice_struct_(fdt, namep, FDT_TAGALIGN(oldlen+1),
254				 FDT_TAGALIGN(newlen+1));
255	if (err)
256		return err;
257
258	memcpy(namep, name, newlen+1);
259	return 0;
260}
261
262int fdt_setprop_placeholder_namelen(void *fdt, int nodeoffset, const char *name,
263				    int namelen, int len, void **prop_data)
264{
265	struct fdt_property *prop;
266	int err;
267
268	FDT_RW_PROBE(fdt);
269
270	err = fdt_resize_property_(fdt, nodeoffset, name, namelen, len, &prop);
271	if (err == -FDT_ERR_NOTFOUND)
272		err = fdt_add_property_(fdt, nodeoffset, name, namelen, len,
273					&prop);
274	if (err)
275		return err;
276
277	*prop_data = prop->data;
278	return 0;
279}
280
281int fdt_setprop_namelen(void *fdt, int nodeoffset, const char *name,
282			int namelen, const void *val, int len)
283{
284	void *prop_data;
285	int err;
286
287	err = fdt_setprop_placeholder_namelen(fdt, nodeoffset, name, namelen,
288					      len, &prop_data);
289	if (err)
290		return err;
291
292	if (len)
293		memcpy(prop_data, val, len);
294	return 0;
295}
296
297int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
298		   const void *val, int len)
299{
300	struct fdt_property *prop;
301	int err, oldlen, newlen;
302
303	FDT_RW_PROBE(fdt);
304
305	prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
306	if (prop) {
307		newlen = len + oldlen;
308		err = fdt_splice_struct_(fdt, prop->data,
309					 FDT_TAGALIGN(oldlen),
310					 FDT_TAGALIGN(newlen));
311		if (err)
312			return err;
313		prop->len = cpu_to_fdt32(newlen);
314		memcpy(prop->data + oldlen, val, len);
315	} else {
316		err = fdt_add_property_(fdt, nodeoffset, name, strlen(name),
317					len, &prop);
318		if (err)
319			return err;
320		memcpy(prop->data, val, len);
321	}
322	return 0;
323}
324
325int fdt_delprop(void *fdt, int nodeoffset, const char *name)
326{
327	struct fdt_property *prop;
328	int len, proplen;
329
330	FDT_RW_PROBE(fdt);
331
332	prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
333	if (!prop)
334		return len;
335
336	proplen = sizeof(*prop) + FDT_TAGALIGN(len);
337	return fdt_splice_struct_(fdt, prop, proplen, 0);
338}
339
340int fdt_add_subnode_namelen(void *fdt, int parentoffset,
341			    const char *name, int namelen)
342{
343	struct fdt_node_header *nh;
344	int offset, nextoffset;
345	int nodelen;
346	int err;
347	uint32_t tag;
348	fdt32_t *endtag;
349
350	FDT_RW_PROBE(fdt);
351
352	offset = fdt_subnode_offset_namelen(fdt, parentoffset, name, namelen);
353	if (offset >= 0)
354		return -FDT_ERR_EXISTS;
355	else if (offset != -FDT_ERR_NOTFOUND)
356		return offset;
357
358	/* Try to place the new node after the parent's properties */
359	tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
360	/* the fdt_subnode_offset_namelen() should ensure this never hits */
361	if (!can_assume(LIBFDT_FLAWLESS) && (tag != FDT_BEGIN_NODE))
362		return -FDT_ERR_INTERNAL;
363	do {
364		offset = nextoffset;
365		tag = fdt_next_tag(fdt, offset, &nextoffset);
366	} while ((tag == FDT_PROP) || (tag == FDT_NOP));
367
368	nh = fdt_offset_ptr_w_(fdt, offset);
369	nodelen = sizeof(*nh) + FDT_TAGALIGN(namelen+1) + FDT_TAGSIZE;
370
371	err = fdt_splice_struct_(fdt, nh, 0, nodelen);
372	if (err)
373		return err;
374
375	nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
376	memset(nh->name, 0, FDT_TAGALIGN(namelen+1));
377	memcpy(nh->name, name, namelen);
378	endtag = (fdt32_t *)((char *)nh + nodelen - FDT_TAGSIZE);
379	*endtag = cpu_to_fdt32(FDT_END_NODE);
380
381	return offset;
382}
383
384int fdt_add_subnode(void *fdt, int parentoffset, const char *name)
385{
386	return fdt_add_subnode_namelen(fdt, parentoffset, name, strlen(name));
387}
388
389int fdt_del_node(void *fdt, int nodeoffset)
390{
391	int endoffset;
392
393	FDT_RW_PROBE(fdt);
394
395	endoffset = fdt_node_end_offset_(fdt, nodeoffset);
396	if (endoffset < 0)
397		return endoffset;
398
399	return fdt_splice_struct_(fdt, fdt_offset_ptr_w_(fdt, nodeoffset),
400				  endoffset - nodeoffset, 0);
401}
402
403static void fdt_packblocks_(const char *old, char *new,
404			    int mem_rsv_size,
405			    int struct_size,
406			    int strings_size)
407{
408	int mem_rsv_off, struct_off, strings_off;
409
410	mem_rsv_off = FDT_ALIGN(sizeof(struct fdt_header), 8);
411	struct_off = mem_rsv_off + mem_rsv_size;
412	strings_off = struct_off + struct_size;
413
414	memmove(new + mem_rsv_off, old + fdt_off_mem_rsvmap(old), mem_rsv_size);
415	fdt_set_off_mem_rsvmap(new, mem_rsv_off);
416
417	memmove(new + struct_off, old + fdt_off_dt_struct(old), struct_size);
418	fdt_set_off_dt_struct(new, struct_off);
419	fdt_set_size_dt_struct(new, struct_size);
420
421	memmove(new + strings_off, old + fdt_off_dt_strings(old), strings_size);
422	fdt_set_off_dt_strings(new, strings_off);
423	fdt_set_size_dt_strings(new, fdt_size_dt_strings(old));
424}
425
426int fdt_open_into(const void *fdt, void *buf, int bufsize)
427{
428	int err;
429	int mem_rsv_size, struct_size;
430	int newsize;
431	const char *fdtstart = fdt;
432	const char *fdtend = fdtstart + fdt_totalsize(fdt);
433	char *tmp;
434
435	FDT_RO_PROBE(fdt);
436
437	mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
438		* sizeof(struct fdt_reserve_entry);
439
440	if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
441		struct_size = fdt_size_dt_struct(fdt);
442	} else if (fdt_version(fdt) == 16) {
443		struct_size = 0;
444		while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
445			;
446		if (struct_size < 0)
447			return struct_size;
448	} else {
449		return -FDT_ERR_BADVERSION;
450	}
451
452	if (can_assume(LIBFDT_ORDER) ||
453	    !fdt_blocks_misordered_(fdt, mem_rsv_size, struct_size)) {
454		/* no further work necessary */
455		err = fdt_move(fdt, buf, bufsize);
456		if (err)
457			return err;
458		fdt_set_version(buf, 17);
459		fdt_set_size_dt_struct(buf, struct_size);
460		fdt_set_totalsize(buf, bufsize);
461		return 0;
462	}
463
464	/* Need to reorder */
465	newsize = FDT_ALIGN(sizeof(struct fdt_header), 8) + mem_rsv_size
466		+ struct_size + fdt_size_dt_strings(fdt);
467
468	if (bufsize < newsize)
469		return -FDT_ERR_NOSPACE;
470
471	/* First attempt to build converted tree at beginning of buffer */
472	tmp = buf;
473	/* But if that overlaps with the old tree... */
474	if (((tmp + newsize) > fdtstart) && (tmp < fdtend)) {
475		/* Try right after the old tree instead */
476		tmp = (char *)(uintptr_t)fdtend;
477		if ((tmp + newsize) > ((char *)buf + bufsize))
478			return -FDT_ERR_NOSPACE;
479	}
480
481	fdt_packblocks_(fdt, tmp, mem_rsv_size, struct_size,
482			fdt_size_dt_strings(fdt));
483	memmove(buf, tmp, newsize);
484
485	fdt_set_magic(buf, FDT_MAGIC);
486	fdt_set_totalsize(buf, bufsize);
487	fdt_set_version(buf, 17);
488	fdt_set_last_comp_version(buf, 16);
489	fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));
490
491	return 0;
492}
493
494int fdt_pack(void *fdt)
495{
496	int mem_rsv_size;
497
498	FDT_RW_PROBE(fdt);
499
500	mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
501		* sizeof(struct fdt_reserve_entry);
502	fdt_packblocks_(fdt, fdt, mem_rsv_size, fdt_size_dt_struct(fdt),
503			fdt_size_dt_strings(fdt));
504	fdt_set_totalsize(fdt, fdt_data_size_(fdt));
505
506	return 0;
507}