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 int offset = fdt_size_dt_struct(fdt); 97 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 size_t 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 headsize = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 156 tailsize = fdt_size_dt_strings(fdt); 157 158 if (!can_assume(VALID_DTB) && 159 headsize + tailsize > fdt_totalsize(fdt)) 160 return -FDT_ERR_INTERNAL; 161 162 if ((headsize + tailsize) > bufsize) 163 return -FDT_ERR_NOSPACE; 164 165 oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize; 166 newtail = (char *)buf + bufsize - tailsize; 167 168 /* Two cases to avoid clobbering data if the old and new 169 * buffers partially overlap */ 170 if (buf <= fdt) { 171 memmove(buf, fdt, headsize); 172 memmove(newtail, oldtail, tailsize); 173 } else { 174 memmove(newtail, oldtail, tailsize); 175 memmove(buf, fdt, headsize); 176 } 177 178 fdt_set_totalsize(buf, bufsize); 179 if (fdt_off_dt_strings(buf)) 180 fdt_set_off_dt_strings(buf, bufsize); 181 182 return 0; 183 } 184 185 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size) 186 { 187 struct fdt_reserve_entry *re; 188 int offset; 189 190 FDT_SW_PROBE_MEMRSV(fdt); 191 192 offset = fdt_off_dt_struct(fdt); 193 if ((offset + sizeof(*re)) > fdt_totalsize(fdt)) 194 return -FDT_ERR_NOSPACE; 195 196 re = (struct fdt_reserve_entry *)((char *)fdt + offset); 197 re->address = cpu_to_fdt64(addr); 198 re->size = cpu_to_fdt64(size); 199 200 fdt_set_off_dt_struct(fdt, offset + sizeof(*re)); 201 202 return 0; 203 } 204 205 int fdt_finish_reservemap(void *fdt) 206 { 207 int err = fdt_add_reservemap_entry(fdt, 0, 0); 208 209 if (err) 210 return err; 211 212 fdt_set_off_dt_strings(fdt, fdt_totalsize(fdt)); 213 return 0; 214 } 215 216 int fdt_begin_node(void *fdt, const char *name) 217 { 218 struct fdt_node_header *nh; 219 int namelen; 220 221 FDT_SW_PROBE_STRUCT(fdt); 222 223 namelen = strlen(name) + 1; 224 nh = fdt_grab_space_(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen)); 225 if (! nh) 226 return -FDT_ERR_NOSPACE; 227 228 nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE); 229 memcpy(nh->name, name, namelen); 230 return 0; 231 } 232 233 int fdt_end_node(void *fdt) 234 { 235 fdt32_t *en; 236 237 FDT_SW_PROBE_STRUCT(fdt); 238 239 en = fdt_grab_space_(fdt, FDT_TAGSIZE); 240 if (! en) 241 return -FDT_ERR_NOSPACE; 242 243 *en = cpu_to_fdt32(FDT_END_NODE); 244 return 0; 245 } 246 247 static int fdt_add_string_(void *fdt, const char *s) 248 { 249 char *strtab = (char *)fdt + fdt_totalsize(fdt); 250 int strtabsize = fdt_size_dt_strings(fdt); 251 int len = strlen(s) + 1; 252 int struct_top, offset; 253 254 offset = -strtabsize - len; 255 struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 256 if (fdt_totalsize(fdt) + offset < struct_top) 257 return 0; /* no more room :( */ 258 259 memcpy(strtab + offset, s, len); 260 fdt_set_size_dt_strings(fdt, strtabsize + len); 261 return offset; 262 } 263 264 /* Must only be used to roll back in case of error */ 265 static void fdt_del_last_string_(void *fdt, const char *s) 266 { 267 int strtabsize = fdt_size_dt_strings(fdt); 268 int len = strlen(s) + 1; 269 270 fdt_set_size_dt_strings(fdt, strtabsize - len); 271 } 272 273 static int fdt_find_add_string_(void *fdt, const char *s, int *allocated) 274 { 275 char *strtab = (char *)fdt + fdt_totalsize(fdt); 276 int strtabsize = fdt_size_dt_strings(fdt); 277 const char *p; 278 279 *allocated = 0; 280 281 p = fdt_find_string_(strtab - strtabsize, strtabsize, s); 282 if (p) 283 return p - strtab; 284 285 *allocated = 1; 286 287 return fdt_add_string_(fdt, s); 288 } 289 290 int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp) 291 { 292 struct fdt_property *prop; 293 int nameoff; 294 int allocated; 295 296 FDT_SW_PROBE_STRUCT(fdt); 297 298 /* String de-duplication can be slow, _NO_NAME_DEDUP skips it */ 299 if (sw_flags(fdt) & FDT_CREATE_FLAG_NO_NAME_DEDUP) { 300 allocated = 1; 301 nameoff = fdt_add_string_(fdt, name); 302 } else { 303 nameoff = fdt_find_add_string_(fdt, name, &allocated); 304 } 305 if (nameoff == 0) 306 return -FDT_ERR_NOSPACE; 307 308 prop = fdt_grab_space_(fdt, sizeof(*prop) + FDT_TAGALIGN(len)); 309 if (! prop) { 310 if (allocated) 311 fdt_del_last_string_(fdt, name); 312 return -FDT_ERR_NOSPACE; 313 } 314 315 prop->tag = cpu_to_fdt32(FDT_PROP); 316 prop->nameoff = cpu_to_fdt32(nameoff); 317 prop->len = cpu_to_fdt32(len); 318 *valp = prop->data; 319 return 0; 320 } 321 322 int fdt_property(void *fdt, const char *name, const void *val, int len) 323 { 324 void *ptr; 325 int ret; 326 327 ret = fdt_property_placeholder(fdt, name, len, &ptr); 328 if (ret) 329 return ret; 330 memcpy(ptr, val, len); 331 return 0; 332 } 333 334 int fdt_finish(void *fdt) 335 { 336 char *p = (char *)fdt; 337 fdt32_t *end; 338 int oldstroffset, newstroffset; 339 uint32_t tag; 340 int offset, nextoffset; 341 342 FDT_SW_PROBE_STRUCT(fdt); 343 344 /* Add terminator */ 345 end = fdt_grab_space_(fdt, sizeof(*end)); 346 if (! end) 347 return -FDT_ERR_NOSPACE; 348 *end = cpu_to_fdt32(FDT_END); 349 350 /* Relocate the string table */ 351 oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt); 352 newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 353 memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt)); 354 fdt_set_off_dt_strings(fdt, newstroffset); 355 356 /* Walk the structure, correcting string offsets */ 357 offset = 0; 358 while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) { 359 if (tag == FDT_PROP) { 360 struct fdt_property *prop = 361 fdt_offset_ptr_w_(fdt, offset); 362 int nameoff; 363 364 nameoff = fdt32_to_cpu(prop->nameoff); 365 nameoff += fdt_size_dt_strings(fdt); 366 prop->nameoff = cpu_to_fdt32(nameoff); 367 } 368 offset = nextoffset; 369 } 370 if (nextoffset < 0) 371 return nextoffset; 372 373 /* Finally, adjust the header */ 374 fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt)); 375 376 /* And fix up fields that were keeping intermediate state. */ 377 fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION); 378 fdt_set_magic(fdt, FDT_MAGIC); 379 380 return 0; 381 } 382