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
fdt_sw_probe_(void * fdt)13 static 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 */
fdt_sw_probe_memrsv_(void * fdt)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 (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 */
fdt_sw_probe_struct_(void * fdt)64 static 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
sw_flags(void * fdt)86 static 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
fdt_grab_space_(void * fdt,size_t len)97 static 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
fdt_create_with_flags(void * buf,int bufsize,uint32_t flags)112 int 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
fdt_create(void * buf,int bufsize)146 int fdt_create(void *buf, int bufsize)
147 {
148 return fdt_create_with_flags(buf, bufsize, 0);
149 }
150
fdt_resize(void * fdt,void * buf,int bufsize)151 int 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
fdt_add_reservemap_entry(void * fdt,uint64_t addr,uint64_t size)190 int 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
fdt_finish_reservemap(void * fdt)210 int 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
fdt_begin_node(void * fdt,const char * name)221 int 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
fdt_end_node(void * fdt)238 int 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
fdt_add_string_(void * fdt,const char * s)252 static 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 */
fdt_del_last_string_(void * fdt,const char * s)270 static 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
fdt_find_add_string_(void * fdt,const char * s,int * allocated)278 static 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
fdt_property_placeholder(void * fdt,const char * name,int len,void ** valp)295 int 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
fdt_property(void * fdt,const char * name,const void * val,int len)327 int 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
fdt_finish(void * fdt)339 int 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