linux/scripts/dtc/libfdt/fdt_rw.c
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   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_blocks_misordered_(const void *fdt,
  14                                  int mem_rsv_size, int struct_size)
  15{
  16        return (fdt_off_mem_rsvmap(fdt) < FDT_ALIGN(sizeof(struct fdt_header), 8))
  17                || (fdt_off_dt_struct(fdt) <
  18                    (fdt_off_mem_rsvmap(fdt) + mem_rsv_size))
  19                || (fdt_off_dt_strings(fdt) <
  20                    (fdt_off_dt_struct(fdt) + struct_size))
  21                || (fdt_totalsize(fdt) <
  22                    (fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt)));
  23}
  24
  25static int fdt_rw_probe_(void *fdt)
  26{
  27        if (can_assume(VALID_DTB))
  28                return 0;
  29        FDT_RO_PROBE(fdt);
  30
  31        if (!can_assume(LATEST) && fdt_version(fdt) < 17)
  32                return -FDT_ERR_BADVERSION;
  33        if (fdt_blocks_misordered_(fdt, sizeof(struct fdt_reserve_entry),
  34                                   fdt_size_dt_struct(fdt)))
  35                return -FDT_ERR_BADLAYOUT;
  36        if (!can_assume(LATEST) && fdt_version(fdt) > 17)
  37                fdt_set_version(fdt, 17);
  38
  39        return 0;
  40}
  41
  42#define FDT_RW_PROBE(fdt) \
  43        { \
  44                int err_; \
  45                if ((err_ = fdt_rw_probe_(fdt)) != 0) \
  46                        return err_; \
  47        }
  48
  49static inline unsigned int fdt_data_size_(void *fdt)
  50{
  51        return fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
  52}
  53
  54static int fdt_splice_(void *fdt, void *splicepoint, int oldlen, int newlen)
  55{
  56        char *p = splicepoint;
  57        unsigned int dsize = fdt_data_size_(fdt);
  58        size_t soff = p - (char *)fdt;
  59
  60        if ((oldlen < 0) || (soff + oldlen < soff) || (soff + oldlen > dsize))
  61                return -FDT_ERR_BADOFFSET;
  62        if ((p < (char *)fdt) || (dsize + newlen < (unsigned)oldlen))
  63                return -FDT_ERR_BADOFFSET;
  64        if (dsize - oldlen + newlen > fdt_totalsize(fdt))
  65                return -FDT_ERR_NOSPACE;
  66        memmove(p + newlen, p + oldlen, ((char *)fdt + dsize) - (p + oldlen));
  67        return 0;
  68}
  69
  70static int fdt_splice_mem_rsv_(void *fdt, struct fdt_reserve_entry *p,
  71                               int oldn, int newn)
  72{
  73        int delta = (newn - oldn) * sizeof(*p);
  74        int err;
  75        err = fdt_splice_(fdt, p, oldn * sizeof(*p), newn * sizeof(*p));
  76        if (err)
  77                return err;
  78        fdt_set_off_dt_struct(fdt, fdt_off_dt_struct(fdt) + delta);
  79        fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
  80        return 0;
  81}
  82
  83static int fdt_splice_struct_(void *fdt, void *p,
  84                              int oldlen, int newlen)
  85{
  86        int delta = newlen - oldlen;
  87        int err;
  88
  89        if ((err = fdt_splice_(fdt, p, oldlen, newlen)))
  90                return err;
  91
  92        fdt_set_size_dt_struct(fdt, fdt_size_dt_struct(fdt) + delta);
  93        fdt_set_off_dt_strings(fdt, fdt_off_dt_strings(fdt) + delta);
  94        return 0;
  95}
  96
  97/* Must only be used to roll back in case of error */
  98static void fdt_del_last_string_(void *fdt, const char *s)
  99{
 100        int newlen = strlen(s) + 1;
 101
 102        fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) - newlen);
 103}
 104
 105static int fdt_splice_string_(void *fdt, int newlen)
 106{
 107        void *p = (char *)fdt
 108                + fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
 109        int err;
 110
 111        if ((err = fdt_splice_(fdt, p, 0, newlen)))
 112                return err;
 113
 114        fdt_set_size_dt_strings(fdt, fdt_size_dt_strings(fdt) + newlen);
 115        return 0;
 116}
 117
 118/**
 119 * fdt_find_add_string_() - Find or allocate a string
 120 *
 121 * @fdt: pointer to the device tree to check/adjust
 122 * @s: string to find/add
 123 * @allocated: Set to 0 if the string was found, 1 if not found and so
 124 *      allocated. Ignored if can_assume(NO_ROLLBACK)
 125 * @return offset of string in the string table (whether found or added)
 126 */
 127static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
 128{
 129        char *strtab = (char *)fdt + fdt_off_dt_strings(fdt);
 130        const char *p;
 131        char *new;
 132        int len = strlen(s) + 1;
 133        int err;
 134
 135        if (!can_assume(NO_ROLLBACK))
 136                *allocated = 0;
 137
 138        p = fdt_find_string_(strtab, fdt_size_dt_strings(fdt), s);
 139        if (p)
 140                /* found it */
 141                return (p - strtab);
 142
 143        new = strtab + fdt_size_dt_strings(fdt);
 144        err = fdt_splice_string_(fdt, len);
 145        if (err)
 146                return err;
 147
 148        if (!can_assume(NO_ROLLBACK))
 149                *allocated = 1;
 150
 151        memcpy(new, s, len);
 152        return (new - strtab);
 153}
 154
 155int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size)
 156{
 157        struct fdt_reserve_entry *re;
 158        int err;
 159
 160        FDT_RW_PROBE(fdt);
 161
 162        re = fdt_mem_rsv_w_(fdt, fdt_num_mem_rsv(fdt));
 163        err = fdt_splice_mem_rsv_(fdt, re, 0, 1);
 164        if (err)
 165                return err;
 166
 167        re->address = cpu_to_fdt64(address);
 168        re->size = cpu_to_fdt64(size);
 169        return 0;
 170}
 171
 172int fdt_del_mem_rsv(void *fdt, int n)
 173{
 174        struct fdt_reserve_entry *re = fdt_mem_rsv_w_(fdt, n);
 175
 176        FDT_RW_PROBE(fdt);
 177
 178        if (n >= fdt_num_mem_rsv(fdt))
 179                return -FDT_ERR_NOTFOUND;
 180
 181        return fdt_splice_mem_rsv_(fdt, re, 1, 0);
 182}
 183
 184static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
 185                                int len, struct fdt_property **prop)
 186{
 187        int oldlen;
 188        int err;
 189
 190        *prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
 191        if (!*prop)
 192                return oldlen;
 193
 194        if ((err = fdt_splice_struct_(fdt, (*prop)->data, FDT_TAGALIGN(oldlen),
 195                                      FDT_TAGALIGN(len))))
 196                return err;
 197
 198        (*prop)->len = cpu_to_fdt32(len);
 199        return 0;
 200}
 201
 202static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
 203                             int len, struct fdt_property **prop)
 204{
 205        int proplen;
 206        int nextoffset;
 207        int namestroff;
 208        int err;
 209        int allocated;
 210
 211        if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
 212                return nextoffset;
 213
 214        namestroff = fdt_find_add_string_(fdt, name, &allocated);
 215        if (namestroff < 0)
 216                return namestroff;
 217
 218        *prop = fdt_offset_ptr_w_(fdt, nextoffset);
 219        proplen = sizeof(**prop) + FDT_TAGALIGN(len);
 220
 221        err = fdt_splice_struct_(fdt, *prop, 0, proplen);
 222        if (err) {
 223                /* Delete the string if we failed to add it */
 224                if (!can_assume(NO_ROLLBACK) && allocated)
 225                        fdt_del_last_string_(fdt, name);
 226                return err;
 227        }
 228
 229        (*prop)->tag = cpu_to_fdt32(FDT_PROP);
 230        (*prop)->nameoff = cpu_to_fdt32(namestroff);
 231        (*prop)->len = cpu_to_fdt32(len);
 232        return 0;
 233}
 234
 235int fdt_set_name(void *fdt, int nodeoffset, const char *name)
 236{
 237        char *namep;
 238        int oldlen, newlen;
 239        int err;
 240
 241        FDT_RW_PROBE(fdt);
 242
 243        namep = (char *)(uintptr_t)fdt_get_name(fdt, nodeoffset, &oldlen);
 244        if (!namep)
 245                return oldlen;
 246
 247        newlen = strlen(name);
 248
 249        err = fdt_splice_struct_(fdt, namep, FDT_TAGALIGN(oldlen+1),
 250                                 FDT_TAGALIGN(newlen+1));
 251        if (err)
 252                return err;
 253
 254        memcpy(namep, name, newlen+1);
 255        return 0;
 256}
 257
 258int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
 259                            int len, void **prop_data)
 260{
 261        struct fdt_property *prop;
 262        int err;
 263
 264        FDT_RW_PROBE(fdt);
 265
 266        err = fdt_resize_property_(fdt, nodeoffset, name, len, &prop);
 267        if (err == -FDT_ERR_NOTFOUND)
 268                err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
 269        if (err)
 270                return err;
 271
 272        *prop_data = prop->data;
 273        return 0;
 274}
 275
 276int fdt_setprop(void *fdt, int nodeoffset, const char *name,
 277                const void *val, int len)
 278{
 279        void *prop_data;
 280        int err;
 281
 282        err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
 283        if (err)
 284                return err;
 285
 286        if (len)
 287                memcpy(prop_data, val, len);
 288        return 0;
 289}
 290
 291int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
 292                   const void *val, int len)
 293{
 294        struct fdt_property *prop;
 295        int err, oldlen, newlen;
 296
 297        FDT_RW_PROBE(fdt);
 298
 299        prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
 300        if (prop) {
 301                newlen = len + oldlen;
 302                err = fdt_splice_struct_(fdt, prop->data,
 303                                         FDT_TAGALIGN(oldlen),
 304                                         FDT_TAGALIGN(newlen));
 305                if (err)
 306                        return err;
 307                prop->len = cpu_to_fdt32(newlen);
 308                memcpy(prop->data + oldlen, val, len);
 309        } else {
 310                err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
 311                if (err)
 312                        return err;
 313                memcpy(prop->data, val, len);
 314        }
 315        return 0;
 316}
 317
 318int fdt_delprop(void *fdt, int nodeoffset, const char *name)
 319{
 320        struct fdt_property *prop;
 321        int len, proplen;
 322
 323        FDT_RW_PROBE(fdt);
 324
 325        prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
 326        if (!prop)
 327                return len;
 328
 329        proplen = sizeof(*prop) + FDT_TAGALIGN(len);
 330        return fdt_splice_struct_(fdt, prop, proplen, 0);
 331}
 332
 333int fdt_add_subnode_namelen(void *fdt, int parentoffset,
 334                            const char *name, int namelen)
 335{
 336        struct fdt_node_header *nh;
 337        int offset, nextoffset;
 338        int nodelen;
 339        int err;
 340        uint32_t tag;
 341        fdt32_t *endtag;
 342
 343        FDT_RW_PROBE(fdt);
 344
 345        offset = fdt_subnode_offset_namelen(fdt, parentoffset, name, namelen);
 346        if (offset >= 0)
 347                return -FDT_ERR_EXISTS;
 348        else if (offset != -FDT_ERR_NOTFOUND)
 349                return offset;
 350
 351        /* Try to place the new node after the parent's properties */
 352        fdt_next_tag(fdt, parentoffset, &nextoffset); /* skip the BEGIN_NODE */
 353        do {
 354                offset = nextoffset;
 355                tag = fdt_next_tag(fdt, offset, &nextoffset);
 356        } while ((tag == FDT_PROP) || (tag == FDT_NOP));
 357
 358        nh = fdt_offset_ptr_w_(fdt, offset);
 359        nodelen = sizeof(*nh) + FDT_TAGALIGN(namelen+1) + FDT_TAGSIZE;
 360
 361        err = fdt_splice_struct_(fdt, nh, 0, nodelen);
 362        if (err)
 363                return err;
 364
 365        nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
 366        memset(nh->name, 0, FDT_TAGALIGN(namelen+1));
 367        memcpy(nh->name, name, namelen);
 368        endtag = (fdt32_t *)((char *)nh + nodelen - FDT_TAGSIZE);
 369        *endtag = cpu_to_fdt32(FDT_END_NODE);
 370
 371        return offset;
 372}
 373
 374int fdt_add_subnode(void *fdt, int parentoffset, const char *name)
 375{
 376        return fdt_add_subnode_namelen(fdt, parentoffset, name, strlen(name));
 377}
 378
 379int fdt_del_node(void *fdt, int nodeoffset)
 380{
 381        int endoffset;
 382
 383        FDT_RW_PROBE(fdt);
 384
 385        endoffset = fdt_node_end_offset_(fdt, nodeoffset);
 386        if (endoffset < 0)
 387                return endoffset;
 388
 389        return fdt_splice_struct_(fdt, fdt_offset_ptr_w_(fdt, nodeoffset),
 390                                  endoffset - nodeoffset, 0);
 391}
 392
 393static void fdt_packblocks_(const char *old, char *new,
 394                            int mem_rsv_size, int struct_size)
 395{
 396        int mem_rsv_off, struct_off, strings_off;
 397
 398        mem_rsv_off = FDT_ALIGN(sizeof(struct fdt_header), 8);
 399        struct_off = mem_rsv_off + mem_rsv_size;
 400        strings_off = struct_off + struct_size;
 401
 402        memmove(new + mem_rsv_off, old + fdt_off_mem_rsvmap(old), mem_rsv_size);
 403        fdt_set_off_mem_rsvmap(new, mem_rsv_off);
 404
 405        memmove(new + struct_off, old + fdt_off_dt_struct(old), struct_size);
 406        fdt_set_off_dt_struct(new, struct_off);
 407        fdt_set_size_dt_struct(new, struct_size);
 408
 409        memmove(new + strings_off, old + fdt_off_dt_strings(old),
 410                fdt_size_dt_strings(old));
 411        fdt_set_off_dt_strings(new, strings_off);
 412        fdt_set_size_dt_strings(new, fdt_size_dt_strings(old));
 413}
 414
 415int fdt_open_into(const void *fdt, void *buf, int bufsize)
 416{
 417        int err;
 418        int mem_rsv_size, struct_size;
 419        int newsize;
 420        const char *fdtstart = fdt;
 421        const char *fdtend = fdtstart + fdt_totalsize(fdt);
 422        char *tmp;
 423
 424        FDT_RO_PROBE(fdt);
 425
 426        mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
 427                * sizeof(struct fdt_reserve_entry);
 428
 429        if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
 430                struct_size = fdt_size_dt_struct(fdt);
 431        } else if (fdt_version(fdt) == 16) {
 432                struct_size = 0;
 433                while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
 434                        ;
 435                if (struct_size < 0)
 436                        return struct_size;
 437        } else {
 438                return -FDT_ERR_BADVERSION;
 439        }
 440
 441        if (can_assume(LIBFDT_ORDER) ||
 442            !fdt_blocks_misordered_(fdt, mem_rsv_size, struct_size)) {
 443                /* no further work necessary */
 444                err = fdt_move(fdt, buf, bufsize);
 445                if (err)
 446                        return err;
 447                fdt_set_version(buf, 17);
 448                fdt_set_size_dt_struct(buf, struct_size);
 449                fdt_set_totalsize(buf, bufsize);
 450                return 0;
 451        }
 452
 453        /* Need to reorder */
 454        newsize = FDT_ALIGN(sizeof(struct fdt_header), 8) + mem_rsv_size
 455                + struct_size + fdt_size_dt_strings(fdt);
 456
 457        if (bufsize < newsize)
 458                return -FDT_ERR_NOSPACE;
 459
 460        /* First attempt to build converted tree at beginning of buffer */
 461        tmp = buf;
 462        /* But if that overlaps with the old tree... */
 463        if (((tmp + newsize) > fdtstart) && (tmp < fdtend)) {
 464                /* Try right after the old tree instead */
 465                tmp = (char *)(uintptr_t)fdtend;
 466                if ((tmp + newsize) > ((char *)buf + bufsize))
 467                        return -FDT_ERR_NOSPACE;
 468        }
 469
 470        fdt_packblocks_(fdt, tmp, mem_rsv_size, struct_size);
 471        memmove(buf, tmp, newsize);
 472
 473        fdt_set_magic(buf, FDT_MAGIC);
 474        fdt_set_totalsize(buf, bufsize);
 475        fdt_set_version(buf, 17);
 476        fdt_set_last_comp_version(buf, 16);
 477        fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));
 478
 479        return 0;
 480}
 481
 482int fdt_pack(void *fdt)
 483{
 484        int mem_rsv_size;
 485
 486        FDT_RW_PROBE(fdt);
 487
 488        mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
 489                * sizeof(struct fdt_reserve_entry);
 490        fdt_packblocks_(fdt, fdt, mem_rsv_size, fdt_size_dt_struct(fdt));
 491        fdt_set_totalsize(fdt, fdt_data_size_(fdt));
 492
 493        return 0;
 494}
 495