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