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_sw_probe_(void *fdt)
14{
15	if (fdt_chk_basic()) {
16		if (fdt_magic(fdt) == FDT_MAGIC)
17			return -FDT_ERR_BADSTATE;
18		else if (fdt_magic(fdt) != FDT_SW_MAGIC)
19			return -FDT_ERR_BADMAGIC;
20	}
21
22	return 0;
23}
24
25#define FDT_SW_PROBE(fdt) \
26	{ \
27		int err; \
28		if (fdt_chk_basic() && (err = fdt_sw_probe_(fdt)) != 0) \
29			return err; \
30	}
31
32/* 'memrsv' state:	Initial state after fdt_create()
33 *
34 * Allowed functions:
35 *	fdt_add_reservmap_entry()
36 *	fdt_finish_reservemap()		[moves to 'struct' state]
37 */
38static int fdt_sw_probe_memrsv_(void *fdt)
39{
40	int err = fdt_sw_probe_(fdt);
41	if (err)
42		return err;
43
44	if (fdt_chk_extra() && fdt_off_dt_strings(fdt) != 0)
45		return -FDT_ERR_BADSTATE;
46	return 0;
47}
48
49#define FDT_SW_PROBE_MEMRSV(fdt) \
50	{ \
51		int err; \
52		if (fdt_chk_extra() && (err = fdt_sw_probe_memrsv_(fdt)) != 0) \
53			return err; \
54	}
55
56/* 'struct' state:	Enter this state after fdt_finish_reservemap()
57 *
58 * Allowed functions:
59 *	fdt_begin_node()
60 *	fdt_end_node()
61 *	fdt_property*()
62 *	fdt_finish()			[moves to 'complete' state]
63 */
64static int fdt_sw_probe_struct_(void *fdt)
65{
66	int err;
67
68	if (!fdt_chk_extra())
69		return 0;
70	err = fdt_sw_probe_(fdt);
71	if (err)
72		return err;
73
74	if (fdt_off_dt_strings(fdt) != fdt_totalsize(fdt))
75		return -FDT_ERR_BADSTATE;
76	return 0;
77}
78
79#define FDT_SW_PROBE_STRUCT(fdt) \
80	{ \
81		int err; \
82		if (fdt_chk_extra() && (err = fdt_sw_probe_struct_(fdt)) != 0) \
83			return err; \
84	}
85
86static inline uint32_t sw_flags(void *fdt)
87{
88	/* assert: (fdt_magic(fdt) == FDT_SW_MAGIC) */
89	return fdt_last_comp_version(fdt);
90}
91
92/* 'complete' state:	Enter this state after fdt_finish()
93 *
94 * Allowed functions: none
95 */
96
97static void *fdt_grab_space_(void *fdt, size_t len)
98{
99	unsigned int offset = fdt_size_dt_struct(fdt);
100	unsigned int spaceleft;
101
102	spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
103		- fdt_size_dt_strings(fdt);
104
105	if ((offset + len < offset) || (offset + len > spaceleft))
106		return NULL;
107
108	fdt_set_size_dt_struct(fdt, offset + len);
109	return fdt_offset_ptr_w_(fdt, offset);
110}
111
112int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags)
113{
114	const int hdrsize = FDT_ALIGN(sizeof(struct fdt_header),
115				      sizeof(struct fdt_reserve_entry));
116	void *fdt = buf;
117
118	if (bufsize < hdrsize)
119		return -FDT_ERR_NOSPACE;
120
121	if (flags & ~FDT_CREATE_FLAGS_ALL)
122		return -FDT_ERR_BADFLAGS;
123
124	memset(buf, 0, bufsize);
125
126	/*
127	 * magic and last_comp_version keep intermediate state during the fdt
128	 * creation process, which is replaced with the proper FDT format by
129	 * fdt_finish().
130	 *
131	 * flags should be accessed with sw_flags().
132	 */
133	fdt_set_magic(fdt, FDT_SW_MAGIC);
134	fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
135	fdt_set_last_comp_version(fdt, flags);
136
137	fdt_set_totalsize(fdt,  bufsize);
138
139	fdt_set_off_mem_rsvmap(fdt, hdrsize);
140	fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
141	fdt_set_off_dt_strings(fdt, 0);
142
143	return 0;
144}
145
146int fdt_create(void *buf, int bufsize)
147{
148	return fdt_create_with_flags(buf, bufsize, 0);
149}
150
151int fdt_resize(void *fdt, void *buf, int bufsize)
152{
153	size_t headsize, tailsize;
154	char *oldtail, *newtail;
155
156	FDT_SW_PROBE(fdt);
157
158	if (bufsize < 0)
159		return -FDT_ERR_NOSPACE;
160
161	headsize = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
162	tailsize = fdt_size_dt_strings(fdt);
163
164	if (fdt_chk_extra() && (headsize + tailsize) > fdt_totalsize(fdt))
165		return -FDT_ERR_INTERNAL;
166
167	if ((headsize + tailsize) > (unsigned)bufsize)
168		return -FDT_ERR_NOSPACE;
169
170	oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize;
171	newtail = (char *)buf + bufsize - tailsize;
172
173	/* Two cases to avoid clobbering data if the old and new
174	 * buffers partially overlap */
175	if (buf <= fdt) {
176		memmove(buf, fdt, headsize);
177		memmove(newtail, oldtail, tailsize);
178	} else {
179		memmove(newtail, oldtail, tailsize);
180		memmove(buf, fdt, headsize);
181	}
182
183	fdt_set_totalsize(buf, bufsize);
184	if (fdt_off_dt_strings(buf))
185		fdt_set_off_dt_strings(buf, bufsize);
186
187	return 0;
188}
189
190int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
191{
192	struct fdt_reserve_entry *re;
193	int offset;
194
195	FDT_SW_PROBE_MEMRSV(fdt);
196
197	offset = fdt_off_dt_struct(fdt);
198	if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
199		return -FDT_ERR_NOSPACE;
200
201	re = (struct fdt_reserve_entry *)((char *)fdt + offset);
202	re->address = cpu_to_fdt64(addr);
203	re->size = cpu_to_fdt64(size);
204
205	fdt_set_off_dt_struct(fdt, offset + sizeof(*re));
206
207	return 0;
208}
209
210int fdt_finish_reservemap(void *fdt)
211{
212	int err = fdt_add_reservemap_entry(fdt, 0, 0);
213
214	if (err)
215		return err;
216
217	fdt_set_off_dt_strings(fdt, fdt_totalsize(fdt));
218	return 0;
219}
220
221int fdt_begin_node(void *fdt, const char *name)
222{
223	struct fdt_node_header *nh;
224	int namelen;
225
226	FDT_SW_PROBE_STRUCT(fdt);
227
228	namelen = strlen(name) + 1;
229	nh = fdt_grab_space_(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
230	if (! nh)
231		return -FDT_ERR_NOSPACE;
232
233	nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
234	memcpy(nh->name, name, namelen);
235	return 0;
236}
237
238int fdt_end_node(void *fdt)
239{
240	fdt32_t *en;
241
242	FDT_SW_PROBE_STRUCT(fdt);
243
244	en = fdt_grab_space_(fdt, FDT_TAGSIZE);
245	if (! en)
246		return -FDT_ERR_NOSPACE;
247
248	*en = cpu_to_fdt32(FDT_END_NODE);
249	return 0;
250}
251
252static int fdt_add_string_(void *fdt, const char *s)
253{
254	char *strtab = (char *)fdt + fdt_totalsize(fdt);
255	unsigned int strtabsize = fdt_size_dt_strings(fdt);
256	unsigned int len = strlen(s) + 1;
257	unsigned int struct_top, offset;
258
259	offset = strtabsize + len;
260	struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
261	if (fdt_totalsize(fdt) - offset < struct_top)
262		return 0; /* no more room :( */
263
264	memcpy(strtab - offset, s, len);
265	fdt_set_size_dt_strings(fdt, strtabsize + len);
266	return -offset;
267}
268
269/* Must only be used to roll back in case of error */
270static void fdt_del_last_string_(void *fdt, const char *s)
271{
272	int strtabsize = fdt_size_dt_strings(fdt);
273	int len = strlen(s) + 1;
274
275	fdt_set_size_dt_strings(fdt, strtabsize - len);
276}
277
278static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
279{
280	char *strtab = (char *)fdt + fdt_totalsize(fdt);
281	int strtabsize = fdt_size_dt_strings(fdt);
282	const char *p;
283
284	*allocated = 0;
285
286	p = fdt_find_string_(strtab - strtabsize, strtabsize, s);
287	if (p)
288		return p - strtab;
289
290	*allocated = 1;
291
292	return fdt_add_string_(fdt, s);
293}
294
295int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp)
296{
297	struct fdt_property *prop;
298	int nameoff;
299	int allocated;
300
301	FDT_SW_PROBE_STRUCT(fdt);
302
303	/* String de-duplication can be slow, _NO_NAME_DEDUP skips it */
304	if (sw_flags(fdt) & FDT_CREATE_FLAG_NO_NAME_DEDUP) {
305		allocated = 1;
306		nameoff = fdt_add_string_(fdt, name);
307	} else {
308		nameoff = fdt_find_add_string_(fdt, name, &allocated);
309	}
310	if (nameoff == 0)
311		return -FDT_ERR_NOSPACE;
312
313	prop = fdt_grab_space_(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
314	if (! prop) {
315		if (allocated)
316			fdt_del_last_string_(fdt, name);
317		return -FDT_ERR_NOSPACE;
318	}
319
320	prop->tag = cpu_to_fdt32(FDT_PROP);
321	prop->nameoff = cpu_to_fdt32(nameoff);
322	prop->len = cpu_to_fdt32(len);
323	*valp = prop->data;
324	return 0;
325}
326
327int fdt_property(void *fdt, const char *name, const void *val, int len)
328{
329	void *ptr;
330	int ret;
331
332	ret = fdt_property_placeholder(fdt, name, len, &ptr);
333	if (ret)
334		return ret;
335	memcpy(ptr, val, len);
336	return 0;
337}
338
339int fdt_finish(void *fdt)
340{
341	char *p = (char *)fdt;
342	fdt32_t *end;
343	int oldstroffset, newstroffset;
344	uint32_t tag;
345	int offset, nextoffset;
346
347	FDT_SW_PROBE_STRUCT(fdt);
348
349	/* Add terminator */
350	end = fdt_grab_space_(fdt, sizeof(*end));
351	if (! end)
352		return -FDT_ERR_NOSPACE;
353	*end = cpu_to_fdt32(FDT_END);
354
355	/* Relocate the string table */
356	oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
357	newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
358	memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
359	fdt_set_off_dt_strings(fdt, newstroffset);
360
361	/* Walk the structure, correcting string offsets */
362	offset = 0;
363	while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
364		if (tag == FDT_PROP) {
365			struct fdt_property *prop =
366				fdt_offset_ptr_w_(fdt, offset);
367			int nameoff;
368
369			nameoff = fdt32_to_cpu(prop->nameoff);
370			nameoff += fdt_size_dt_strings(fdt);
371			prop->nameoff = cpu_to_fdt32(nameoff);
372		}
373		offset = nextoffset;
374	}
375	if (nextoffset < 0)
376		return nextoffset;
377
378	/* Finally, adjust the header */
379	fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
380
381	/* And fix up fields that were keeping intermediate state. */
382	fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
383	fdt_set_magic(fdt, FDT_MAGIC);
384
385	return 0;
386}
387