qemu/include/hw/elf_ops.h
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   1static void glue(bswap_ehdr, SZ)(struct elfhdr *ehdr)
   2{
   3    bswap16s(&ehdr->e_type);                    /* Object file type */
   4    bswap16s(&ehdr->e_machine);         /* Architecture */
   5    bswap32s(&ehdr->e_version);         /* Object file version */
   6    bswapSZs(&ehdr->e_entry);           /* Entry point virtual address */
   7    bswapSZs(&ehdr->e_phoff);           /* Program header table file offset */
   8    bswapSZs(&ehdr->e_shoff);           /* Section header table file offset */
   9    bswap32s(&ehdr->e_flags);           /* Processor-specific flags */
  10    bswap16s(&ehdr->e_ehsize);          /* ELF header size in bytes */
  11    bswap16s(&ehdr->e_phentsize);               /* Program header table entry size */
  12    bswap16s(&ehdr->e_phnum);           /* Program header table entry count */
  13    bswap16s(&ehdr->e_shentsize);               /* Section header table entry size */
  14    bswap16s(&ehdr->e_shnum);           /* Section header table entry count */
  15    bswap16s(&ehdr->e_shstrndx);                /* Section header string table index */
  16}
  17
  18static void glue(bswap_phdr, SZ)(struct elf_phdr *phdr)
  19{
  20    bswap32s(&phdr->p_type);                    /* Segment type */
  21    bswapSZs(&phdr->p_offset);          /* Segment file offset */
  22    bswapSZs(&phdr->p_vaddr);           /* Segment virtual address */
  23    bswapSZs(&phdr->p_paddr);           /* Segment physical address */
  24    bswapSZs(&phdr->p_filesz);          /* Segment size in file */
  25    bswapSZs(&phdr->p_memsz);           /* Segment size in memory */
  26    bswap32s(&phdr->p_flags);           /* Segment flags */
  27    bswapSZs(&phdr->p_align);           /* Segment alignment */
  28}
  29
  30static void glue(bswap_shdr, SZ)(struct elf_shdr *shdr)
  31{
  32    bswap32s(&shdr->sh_name);
  33    bswap32s(&shdr->sh_type);
  34    bswapSZs(&shdr->sh_flags);
  35    bswapSZs(&shdr->sh_addr);
  36    bswapSZs(&shdr->sh_offset);
  37    bswapSZs(&shdr->sh_size);
  38    bswap32s(&shdr->sh_link);
  39    bswap32s(&shdr->sh_info);
  40    bswapSZs(&shdr->sh_addralign);
  41    bswapSZs(&shdr->sh_entsize);
  42}
  43
  44static void glue(bswap_sym, SZ)(struct elf_sym *sym)
  45{
  46    bswap32s(&sym->st_name);
  47    bswapSZs(&sym->st_value);
  48    bswapSZs(&sym->st_size);
  49    bswap16s(&sym->st_shndx);
  50}
  51
  52static void glue(bswap_rela, SZ)(struct elf_rela *rela)
  53{
  54    bswapSZs(&rela->r_offset);
  55    bswapSZs(&rela->r_info);
  56    bswapSZs((elf_word *)&rela->r_addend);
  57}
  58
  59static struct elf_shdr *glue(find_section, SZ)(struct elf_shdr *shdr_table,
  60                                               int n, int type)
  61{
  62    int i;
  63    for(i=0;i<n;i++) {
  64        if (shdr_table[i].sh_type == type)
  65            return shdr_table + i;
  66    }
  67    return NULL;
  68}
  69
  70static int glue(symfind, SZ)(const void *s0, const void *s1)
  71{
  72    hwaddr addr = *(hwaddr *)s0;
  73    struct elf_sym *sym = (struct elf_sym *)s1;
  74    int result = 0;
  75    if (addr < sym->st_value) {
  76        result = -1;
  77    } else if (addr >= sym->st_value + sym->st_size) {
  78        result = 1;
  79    }
  80    return result;
  81}
  82
  83static const char *glue(lookup_symbol, SZ)(struct syminfo *s,
  84                                           hwaddr orig_addr)
  85{
  86    struct elf_sym *syms = glue(s->disas_symtab.elf, SZ);
  87    struct elf_sym *sym;
  88
  89    sym = bsearch(&orig_addr, syms, s->disas_num_syms, sizeof(*syms),
  90                  glue(symfind, SZ));
  91    if (sym != NULL) {
  92        return s->disas_strtab + sym->st_name;
  93    }
  94
  95    return "";
  96}
  97
  98static int glue(symcmp, SZ)(const void *s0, const void *s1)
  99{
 100    struct elf_sym *sym0 = (struct elf_sym *)s0;
 101    struct elf_sym *sym1 = (struct elf_sym *)s1;
 102    return (sym0->st_value < sym1->st_value)
 103        ? -1
 104        : ((sym0->st_value > sym1->st_value) ? 1 : 0);
 105}
 106
 107static int glue(load_symbols, SZ)(struct elfhdr *ehdr, int fd, int must_swab,
 108                                  int clear_lsb, symbol_fn_t sym_cb)
 109{
 110    struct elf_shdr *symtab, *strtab, *shdr_table = NULL;
 111    struct elf_sym *syms = NULL;
 112    struct syminfo *s;
 113    int nsyms, i;
 114    char *str = NULL;
 115
 116    shdr_table = load_at(fd, ehdr->e_shoff,
 117                         sizeof(struct elf_shdr) * ehdr->e_shnum);
 118    if (!shdr_table)
 119        return -1;
 120
 121    if (must_swab) {
 122        for (i = 0; i < ehdr->e_shnum; i++) {
 123            glue(bswap_shdr, SZ)(shdr_table + i);
 124        }
 125    }
 126
 127    symtab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_SYMTAB);
 128    if (!symtab)
 129        goto fail;
 130    syms = load_at(fd, symtab->sh_offset, symtab->sh_size);
 131    if (!syms)
 132        goto fail;
 133
 134    nsyms = symtab->sh_size / sizeof(struct elf_sym);
 135
 136    /* String table */
 137    if (symtab->sh_link >= ehdr->e_shnum) {
 138        goto fail;
 139    }
 140    strtab = &shdr_table[symtab->sh_link];
 141
 142    str = load_at(fd, strtab->sh_offset, strtab->sh_size);
 143    if (!str) {
 144        goto fail;
 145    }
 146
 147    i = 0;
 148    while (i < nsyms) {
 149        if (must_swab) {
 150            glue(bswap_sym, SZ)(&syms[i]);
 151        }
 152        if (sym_cb) {
 153            sym_cb(str + syms[i].st_name, syms[i].st_info,
 154                   syms[i].st_value, syms[i].st_size);
 155        }
 156        /* We are only interested in function symbols.
 157           Throw everything else away.  */
 158        if (syms[i].st_shndx == SHN_UNDEF ||
 159                syms[i].st_shndx >= SHN_LORESERVE ||
 160                ELF_ST_TYPE(syms[i].st_info) != STT_FUNC) {
 161            nsyms--;
 162            if (i < nsyms) {
 163                syms[i] = syms[nsyms];
 164            }
 165            continue;
 166        }
 167        if (clear_lsb) {
 168            /* The bottom address bit marks a Thumb or MIPS16 symbol.  */
 169            syms[i].st_value &= ~(glue(glue(Elf, SZ), _Addr))1;
 170        }
 171        i++;
 172    }
 173    syms = g_realloc(syms, nsyms * sizeof(*syms));
 174
 175    qsort(syms, nsyms, sizeof(*syms), glue(symcmp, SZ));
 176    for (i = 0; i < nsyms - 1; i++) {
 177        if (syms[i].st_size == 0) {
 178            syms[i].st_size = syms[i + 1].st_value - syms[i].st_value;
 179        }
 180    }
 181
 182    /* Commit */
 183    s = g_malloc0(sizeof(*s));
 184    s->lookup_symbol = glue(lookup_symbol, SZ);
 185    glue(s->disas_symtab.elf, SZ) = syms;
 186    s->disas_num_syms = nsyms;
 187    s->disas_strtab = str;
 188    s->next = syminfos;
 189    syminfos = s;
 190    g_free(shdr_table);
 191    return 0;
 192 fail:
 193    g_free(syms);
 194    g_free(str);
 195    g_free(shdr_table);
 196    return -1;
 197}
 198
 199static int glue(elf_reloc, SZ)(struct elfhdr *ehdr, int fd, int must_swab,
 200                               uint64_t (*translate_fn)(void *, uint64_t),
 201                               void *translate_opaque, uint8_t *data,
 202                               struct elf_phdr *ph, int elf_machine)
 203{
 204    struct elf_shdr *reltab, *shdr_table = NULL;
 205    struct elf_rela *rels = NULL;
 206    int nrels, i, ret = -1;
 207    elf_word wordval;
 208    void *addr;
 209
 210    shdr_table = load_at(fd, ehdr->e_shoff,
 211                         sizeof(struct elf_shdr) * ehdr->e_shnum);
 212    if (!shdr_table) {
 213        return -1;
 214    }
 215    if (must_swab) {
 216        for (i = 0; i < ehdr->e_shnum; i++) {
 217            glue(bswap_shdr, SZ)(&shdr_table[i]);
 218        }
 219    }
 220
 221    reltab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_RELA);
 222    if (!reltab) {
 223        goto fail;
 224    }
 225    rels = load_at(fd, reltab->sh_offset, reltab->sh_size);
 226    if (!rels) {
 227        goto fail;
 228    }
 229    nrels = reltab->sh_size / sizeof(struct elf_rela);
 230
 231    for (i = 0; i < nrels; i++) {
 232        if (must_swab) {
 233            glue(bswap_rela, SZ)(&rels[i]);
 234        }
 235        if (rels[i].r_offset < ph->p_vaddr ||
 236            rels[i].r_offset >= ph->p_vaddr + ph->p_filesz) {
 237            continue;
 238        }
 239        addr = &data[rels[i].r_offset - ph->p_vaddr];
 240        switch (elf_machine) {
 241        case EM_S390:
 242            switch (rels[i].r_info) {
 243            case R_390_RELATIVE:
 244                wordval = *(elf_word *)addr;
 245                if (must_swab) {
 246                    bswapSZs(&wordval);
 247                }
 248                wordval = translate_fn(translate_opaque, wordval);
 249                if (must_swab) {
 250                    bswapSZs(&wordval);
 251                }
 252                *(elf_word *)addr = wordval;
 253                break;
 254            default:
 255                fprintf(stderr, "Unsupported relocation type %i!\n",
 256                        (int)rels[i].r_info);
 257            }
 258        }
 259    }
 260
 261    ret = 0;
 262fail:
 263    g_free(rels);
 264    g_free(shdr_table);
 265    return ret;
 266}
 267
 268/*
 269 * Given 'nhdr', a pointer to a range of ELF Notes, search through them
 270 * for a note matching type 'elf_note_type' and return a pointer to
 271 * the matching ELF note.
 272 */
 273static struct elf_note *glue(get_elf_note_type, SZ)(struct elf_note *nhdr,
 274                                                    elf_word note_size,
 275                                                    elf_word phdr_align,
 276                                                    elf_word elf_note_type)
 277{
 278    elf_word nhdr_size = sizeof(struct elf_note);
 279    elf_word elf_note_entry_offset = 0;
 280    elf_word note_type;
 281    elf_word nhdr_namesz;
 282    elf_word nhdr_descsz;
 283
 284    if (nhdr == NULL) {
 285        return NULL;
 286    }
 287
 288    note_type = nhdr->n_type;
 289    while (note_type != elf_note_type) {
 290        nhdr_namesz = nhdr->n_namesz;
 291        nhdr_descsz = nhdr->n_descsz;
 292
 293        elf_note_entry_offset = nhdr_size +
 294            QEMU_ALIGN_UP(nhdr_namesz, phdr_align) +
 295            QEMU_ALIGN_UP(nhdr_descsz, phdr_align);
 296
 297        /*
 298         * If the offset calculated in this iteration exceeds the
 299         * supplied size, we are done and no matching note was found.
 300         */
 301        if (elf_note_entry_offset > note_size) {
 302            return NULL;
 303        }
 304
 305        /* skip to the next ELF Note entry */
 306        nhdr = (void *)nhdr + elf_note_entry_offset;
 307        note_type = nhdr->n_type;
 308    }
 309
 310    return nhdr;
 311}
 312
 313static int glue(load_elf, SZ)(const char *name, int fd,
 314                              uint64_t (*elf_note_fn)(void *, void *, bool),
 315                              uint64_t (*translate_fn)(void *, uint64_t),
 316                              void *translate_opaque,
 317                              int must_swab, uint64_t *pentry,
 318                              uint64_t *lowaddr, uint64_t *highaddr,
 319                              int elf_machine, int clear_lsb, int data_swab,
 320                              AddressSpace *as, bool load_rom,
 321                              symbol_fn_t sym_cb)
 322{
 323    struct elfhdr ehdr;
 324    struct elf_phdr *phdr = NULL, *ph;
 325    int size, i, total_size;
 326    elf_word mem_size, file_size;
 327    uint64_t addr, low = (uint64_t)-1, high = 0;
 328    uint8_t *data = NULL;
 329    char label[128];
 330    int ret = ELF_LOAD_FAILED;
 331
 332    if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
 333        goto fail;
 334    if (must_swab) {
 335        glue(bswap_ehdr, SZ)(&ehdr);
 336    }
 337
 338    if (elf_machine <= EM_NONE) {
 339        /* The caller didn't specify an ARCH, we can figure it out */
 340        elf_machine = ehdr.e_machine;
 341    }
 342
 343    switch (elf_machine) {
 344        case EM_PPC64:
 345            if (ehdr.e_machine != EM_PPC64) {
 346                if (ehdr.e_machine != EM_PPC) {
 347                    ret = ELF_LOAD_WRONG_ARCH;
 348                    goto fail;
 349                }
 350            }
 351            break;
 352        case EM_X86_64:
 353            if (ehdr.e_machine != EM_X86_64) {
 354                if (ehdr.e_machine != EM_386) {
 355                    ret = ELF_LOAD_WRONG_ARCH;
 356                    goto fail;
 357                }
 358            }
 359            break;
 360        case EM_MICROBLAZE:
 361            if (ehdr.e_machine != EM_MICROBLAZE) {
 362                if (ehdr.e_machine != EM_MICROBLAZE_OLD) {
 363                    ret = ELF_LOAD_WRONG_ARCH;
 364                    goto fail;
 365                }
 366            }
 367            break;
 368        case EM_MOXIE:
 369            if (ehdr.e_machine != EM_MOXIE) {
 370                if (ehdr.e_machine != EM_MOXIE_OLD) {
 371                    ret = ELF_LOAD_WRONG_ARCH;
 372                    goto fail;
 373                }
 374            }
 375            break;
 376        case EM_MIPS:
 377        case EM_NANOMIPS:
 378            if ((ehdr.e_machine != EM_MIPS) &&
 379                (ehdr.e_machine != EM_NANOMIPS)) {
 380                ret = ELF_LOAD_WRONG_ARCH;
 381                goto fail;
 382            }
 383            break;
 384        default:
 385            if (elf_machine != ehdr.e_machine) {
 386                ret = ELF_LOAD_WRONG_ARCH;
 387                goto fail;
 388            }
 389    }
 390
 391    if (pentry)
 392        *pentry = (uint64_t)(elf_sword)ehdr.e_entry;
 393
 394    glue(load_symbols, SZ)(&ehdr, fd, must_swab, clear_lsb, sym_cb);
 395
 396    size = ehdr.e_phnum * sizeof(phdr[0]);
 397    if (lseek(fd, ehdr.e_phoff, SEEK_SET) != ehdr.e_phoff) {
 398        goto fail;
 399    }
 400    phdr = g_malloc0(size);
 401    if (!phdr)
 402        goto fail;
 403    if (read(fd, phdr, size) != size)
 404        goto fail;
 405    if (must_swab) {
 406        for(i = 0; i < ehdr.e_phnum; i++) {
 407            ph = &phdr[i];
 408            glue(bswap_phdr, SZ)(ph);
 409        }
 410    }
 411
 412    total_size = 0;
 413    for(i = 0; i < ehdr.e_phnum; i++) {
 414        ph = &phdr[i];
 415        if (ph->p_type == PT_LOAD) {
 416            mem_size = ph->p_memsz; /* Size of the ROM */
 417            file_size = ph->p_filesz; /* Size of the allocated data */
 418            data = g_malloc0(file_size);
 419            if (ph->p_filesz > 0) {
 420                if (lseek(fd, ph->p_offset, SEEK_SET) < 0) {
 421                    goto fail;
 422                }
 423                if (read(fd, data, file_size) != file_size) {
 424                    goto fail;
 425                }
 426            }
 427
 428            /* The ELF spec is somewhat vague about the purpose of the
 429             * physical address field. One common use in the embedded world
 430             * is that physical address field specifies the load address
 431             * and the virtual address field specifies the execution address.
 432             * Segments are packed into ROM or flash, and the relocation
 433             * and zero-initialization of data is done at runtime. This
 434             * means that the memsz header represents the runtime size of the
 435             * segment, but the filesz represents the loadtime size. If
 436             * we try to honour the memsz value for an ELF file like this
 437             * we will end up with overlapping segments (which the
 438             * loader.c code will later reject).
 439             * We support ELF files using this scheme by by checking whether
 440             * paddr + memsz for this segment would overlap with any other
 441             * segment. If so, then we assume it's using this scheme and
 442             * truncate the loaded segment to the filesz size.
 443             * If the segment considered as being memsz size doesn't overlap
 444             * then we use memsz for the segment length, to handle ELF files
 445             * which assume that the loader will do the zero-initialization.
 446             */
 447            if (mem_size > file_size) {
 448                /* If this segment's zero-init portion overlaps another
 449                 * segment's data or zero-init portion, then truncate this one.
 450                 * Invalid ELF files where the segments overlap even when
 451                 * only file_size bytes are loaded will be rejected by
 452                 * the ROM overlap check in loader.c, so we don't try to
 453                 * explicitly detect those here.
 454                 */
 455                int j;
 456                elf_word zero_start = ph->p_paddr + file_size;
 457                elf_word zero_end = ph->p_paddr + mem_size;
 458
 459                for (j = 0; j < ehdr.e_phnum; j++) {
 460                    struct elf_phdr *jph = &phdr[j];
 461
 462                    if (i != j && jph->p_type == PT_LOAD) {
 463                        elf_word other_start = jph->p_paddr;
 464                        elf_word other_end = jph->p_paddr + jph->p_memsz;
 465
 466                        if (!(other_start >= zero_end ||
 467                              zero_start >= other_end)) {
 468                            mem_size = file_size;
 469                            break;
 470                        }
 471                    }
 472                }
 473            }
 474
 475            /* address_offset is hack for kernel images that are
 476               linked at the wrong physical address.  */
 477            if (translate_fn) {
 478                addr = translate_fn(translate_opaque, ph->p_paddr);
 479                glue(elf_reloc, SZ)(&ehdr, fd, must_swab,  translate_fn,
 480                                    translate_opaque, data, ph, elf_machine);
 481            } else {
 482                addr = ph->p_paddr;
 483            }
 484
 485            if (data_swab) {
 486                int j;
 487                for (j = 0; j < file_size; j += (1 << data_swab)) {
 488                    uint8_t *dp = data + j;
 489                    switch (data_swab) {
 490                    case (1):
 491                        *(uint16_t *)dp = bswap16(*(uint16_t *)dp);
 492                        break;
 493                    case (2):
 494                        *(uint32_t *)dp = bswap32(*(uint32_t *)dp);
 495                        break;
 496                    case (3):
 497                        *(uint64_t *)dp = bswap64(*(uint64_t *)dp);
 498                        break;
 499                    default:
 500                        g_assert_not_reached();
 501                    }
 502                }
 503            }
 504
 505            /* the entry pointer in the ELF header is a virtual
 506             * address, if the text segments paddr and vaddr differ
 507             * we need to adjust the entry */
 508            if (pentry && !translate_fn &&
 509                    ph->p_vaddr != ph->p_paddr &&
 510                    ehdr.e_entry >= ph->p_vaddr &&
 511                    ehdr.e_entry < ph->p_vaddr + ph->p_filesz &&
 512                    ph->p_flags & PF_X) {
 513                *pentry = ehdr.e_entry - ph->p_vaddr + ph->p_paddr;
 514            }
 515
 516            if (mem_size == 0) {
 517                /* Some ELF files really do have segments of zero size;
 518                 * just ignore them rather than trying to create empty
 519                 * ROM blobs, because the zero-length blob can falsely
 520                 * trigger the overlapping-ROM-blobs check.
 521                 */
 522                g_free(data);
 523            } else {
 524                if (load_rom) {
 525                    snprintf(label, sizeof(label), "phdr #%d: %s", i, name);
 526
 527                    /* rom_add_elf_program() seize the ownership of 'data' */
 528                    rom_add_elf_program(label, data, file_size, mem_size,
 529                                        addr, as);
 530                } else {
 531                    address_space_write(as ? as : &address_space_memory,
 532                                        addr, MEMTXATTRS_UNSPECIFIED,
 533                                        data, file_size);
 534                    g_free(data);
 535                }
 536            }
 537
 538            total_size += mem_size;
 539            if (addr < low)
 540                low = addr;
 541            if ((addr + mem_size) > high)
 542                high = addr + mem_size;
 543
 544            data = NULL;
 545
 546        } else if (ph->p_type == PT_NOTE && elf_note_fn) {
 547            struct elf_note *nhdr = NULL;
 548
 549            file_size = ph->p_filesz; /* Size of the range of ELF notes */
 550            data = g_malloc0(file_size);
 551            if (ph->p_filesz > 0) {
 552                if (lseek(fd, ph->p_offset, SEEK_SET) < 0) {
 553                    goto fail;
 554                }
 555                if (read(fd, data, file_size) != file_size) {
 556                    goto fail;
 557                }
 558            }
 559
 560            /*
 561             * Search the ELF notes to find one with a type matching the
 562             * value passed in via 'translate_opaque'
 563             */
 564            nhdr = (struct elf_note *)data;
 565            assert(translate_opaque != NULL);
 566            nhdr = glue(get_elf_note_type, SZ)(nhdr, file_size, ph->p_align,
 567                                               *(uint64_t *)translate_opaque);
 568            if (nhdr != NULL) {
 569                bool is64 =
 570                    sizeof(struct elf_note) == sizeof(struct elf64_note);
 571                elf_note_fn((void *)nhdr, (void *)&ph->p_align, is64);
 572            }
 573            g_free(data);
 574            data = NULL;
 575        }
 576    }
 577
 578    g_free(phdr);
 579    if (lowaddr)
 580        *lowaddr = (uint64_t)(elf_sword)low;
 581    if (highaddr)
 582        *highaddr = (uint64_t)(elf_sword)high;
 583    return total_size;
 584 fail:
 585    g_free(data);
 586    g_free(phdr);
 587    return ret;
 588}
 589