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