xref: /openbmc/qemu/include/hw/elf_ops.h.inc (revision 34cc54fb)
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 void 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;
111    g_autofree struct elf_shdr *shdr_table = NULL;
112    g_autofree struct elf_sym *syms = NULL;
113    g_autofree char *str = NULL;
114    struct syminfo *s;
115    int nsyms, i;
116
117    shdr_table = load_at(fd, ehdr->e_shoff,
118                         sizeof(struct elf_shdr) * ehdr->e_shnum);
119    if (!shdr_table) {
120        return;
121    }
122
123    if (must_swab) {
124        for (i = 0; i < ehdr->e_shnum; i++) {
125            glue(bswap_shdr, SZ)(shdr_table + i);
126        }
127    }
128
129    symtab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_SYMTAB);
130    if (!symtab) {
131        return;
132    }
133    syms = load_at(fd, symtab->sh_offset, symtab->sh_size);
134    if (!syms) {
135        return;
136    }
137
138    nsyms = symtab->sh_size / sizeof(struct elf_sym);
139
140    /* String table */
141    if (symtab->sh_link >= ehdr->e_shnum) {
142        return;
143    }
144    strtab = &shdr_table[symtab->sh_link];
145
146    str = load_at(fd, strtab->sh_offset, strtab->sh_size);
147    if (!str) {
148        return;
149    }
150
151    i = 0;
152    while (i < nsyms) {
153        if (must_swab) {
154            glue(bswap_sym, SZ)(&syms[i]);
155        }
156        if (sym_cb) {
157            sym_cb(str + syms[i].st_name, syms[i].st_info,
158                   syms[i].st_value, syms[i].st_size);
159        }
160        /* We are only interested in function symbols.
161           Throw everything else away.  */
162        if (syms[i].st_shndx == SHN_UNDEF ||
163                syms[i].st_shndx >= SHN_LORESERVE ||
164                ELF_ST_TYPE(syms[i].st_info) != STT_FUNC) {
165            nsyms--;
166            if (i < nsyms) {
167                syms[i] = syms[nsyms];
168            }
169            continue;
170        }
171        if (clear_lsb) {
172            /* The bottom address bit marks a Thumb or MIPS16 symbol.  */
173            syms[i].st_value &= ~(glue(glue(Elf, SZ), _Addr))1;
174        }
175        i++;
176    }
177
178    /* check we have symbols left */
179    if (nsyms == 0) {
180        return;
181    }
182
183    syms = g_realloc(syms, nsyms * sizeof(*syms));
184    qsort(syms, nsyms, sizeof(*syms), glue(symcmp, SZ));
185    for (i = 0; i < nsyms - 1; i++) {
186        if (syms[i].st_size == 0) {
187            syms[i].st_size = syms[i + 1].st_value - syms[i].st_value;
188        }
189    }
190
191    /* Commit */
192    s = g_malloc0(sizeof(*s));
193    s->lookup_symbol = glue(lookup_symbol, SZ);
194    glue(s->disas_symtab.elf, SZ) = g_steal_pointer(&syms);
195    s->disas_num_syms = nsyms;
196    s->disas_strtab = g_steal_pointer(&str);
197    s->next = syminfos;
198    syminfos = s;
199}
200
201static int glue(elf_reloc, SZ)(struct elfhdr *ehdr, int fd, int must_swab,
202                               uint64_t (*translate_fn)(void *, uint64_t),
203                               void *translate_opaque, uint8_t *data,
204                               struct elf_phdr *ph, int elf_machine)
205{
206    struct elf_shdr *reltab, *shdr_table = NULL;
207    struct elf_rela *rels = NULL;
208    int nrels, i, ret = -1;
209    elf_word wordval;
210    void *addr;
211
212    shdr_table = load_at(fd, ehdr->e_shoff,
213                         sizeof(struct elf_shdr) * ehdr->e_shnum);
214    if (!shdr_table) {
215        return -1;
216    }
217    if (must_swab) {
218        for (i = 0; i < ehdr->e_shnum; i++) {
219            glue(bswap_shdr, SZ)(&shdr_table[i]);
220        }
221    }
222
223    reltab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_RELA);
224    if (!reltab) {
225        goto fail;
226    }
227    rels = load_at(fd, reltab->sh_offset, reltab->sh_size);
228    if (!rels) {
229        goto fail;
230    }
231    nrels = reltab->sh_size / sizeof(struct elf_rela);
232
233    for (i = 0; i < nrels; i++) {
234        if (must_swab) {
235            glue(bswap_rela, SZ)(&rels[i]);
236        }
237        if (rels[i].r_offset < ph->p_vaddr ||
238            rels[i].r_offset >= ph->p_vaddr + ph->p_filesz) {
239            continue;
240        }
241        addr = &data[rels[i].r_offset - ph->p_vaddr];
242        switch (elf_machine) {
243        case EM_S390:
244            switch (rels[i].r_info) {
245            case R_390_RELATIVE:
246                wordval = *(elf_word *)addr;
247                if (must_swab) {
248                    bswapSZs(&wordval);
249                }
250                wordval = translate_fn(translate_opaque, wordval);
251                if (must_swab) {
252                    bswapSZs(&wordval);
253                }
254                *(elf_word *)addr = wordval;
255                break;
256            default:
257                fprintf(stderr, "Unsupported relocation type %i!\n",
258                        (int)rels[i].r_info);
259            }
260        }
261    }
262
263    ret = 0;
264fail:
265    g_free(rels);
266    g_free(shdr_table);
267    return ret;
268}
269
270/*
271 * Given 'nhdr', a pointer to a range of ELF Notes, search through them
272 * for a note matching type 'elf_note_type' and return a pointer to
273 * the matching ELF note.
274 */
275static struct elf_note *glue(get_elf_note_type, SZ)(struct elf_note *nhdr,
276                                                    elf_word note_size,
277                                                    elf_word phdr_align,
278                                                    elf_word elf_note_type)
279{
280    elf_word nhdr_size = sizeof(struct elf_note);
281    elf_word elf_note_entry_offset = 0;
282    elf_word note_type;
283    elf_word nhdr_namesz;
284    elf_word nhdr_descsz;
285
286    if (nhdr == NULL) {
287        return NULL;
288    }
289
290    note_type = nhdr->n_type;
291    while (note_type != elf_note_type) {
292        nhdr_namesz = nhdr->n_namesz;
293        nhdr_descsz = nhdr->n_descsz;
294
295        elf_note_entry_offset = nhdr_size +
296            QEMU_ALIGN_UP(nhdr_namesz, phdr_align) +
297            QEMU_ALIGN_UP(nhdr_descsz, phdr_align);
298
299        /*
300         * If the offset calculated in this iteration exceeds the
301         * supplied size, we are done and no matching note was found.
302         */
303        if (elf_note_entry_offset > note_size) {
304            return NULL;
305        }
306
307        /* skip to the next ELF Note entry */
308        nhdr = (void *)nhdr + elf_note_entry_offset;
309        note_type = nhdr->n_type;
310    }
311
312    return nhdr;
313}
314
315static ssize_t glue(load_elf, SZ)(const char *name, int fd,
316                                  uint64_t (*elf_note_fn)(void *, void *, bool),
317                                  uint64_t (*translate_fn)(void *, uint64_t),
318                                  void *translate_opaque,
319                                  int must_swab, uint64_t *pentry,
320                                  uint64_t *lowaddr, uint64_t *highaddr,
321                                  uint32_t *pflags, int elf_machine,
322                                  int clear_lsb, int data_swab,
323                                  AddressSpace *as, bool load_rom,
324                                  symbol_fn_t sym_cb)
325{
326    struct elfhdr ehdr;
327    struct elf_phdr *phdr = NULL, *ph;
328    int size, i;
329    ssize_t total_size;
330    elf_word mem_size, file_size, data_offset;
331    uint64_t addr, low = (uint64_t)-1, high = 0;
332    GMappedFile *mapped_file = NULL;
333    uint8_t *data = NULL;
334    ssize_t ret = ELF_LOAD_FAILED;
335
336    if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
337        goto fail;
338    if (must_swab) {
339        glue(bswap_ehdr, SZ)(&ehdr);
340    }
341
342    if (elf_machine <= EM_NONE) {
343        /* The caller didn't specify an ARCH, we can figure it out */
344        elf_machine = ehdr.e_machine;
345    }
346
347    switch (elf_machine) {
348        case EM_PPC64:
349            if (ehdr.e_machine != EM_PPC64) {
350                if (ehdr.e_machine != EM_PPC) {
351                    ret = ELF_LOAD_WRONG_ARCH;
352                    goto fail;
353                }
354            }
355            break;
356        case EM_X86_64:
357            if (ehdr.e_machine != EM_X86_64) {
358                if (ehdr.e_machine != EM_386) {
359                    ret = ELF_LOAD_WRONG_ARCH;
360                    goto fail;
361                }
362            }
363            break;
364        case EM_MICROBLAZE:
365            if (ehdr.e_machine != EM_MICROBLAZE) {
366                if (ehdr.e_machine != EM_MICROBLAZE_OLD) {
367                    ret = ELF_LOAD_WRONG_ARCH;
368                    goto fail;
369                }
370            }
371            break;
372        case EM_MIPS:
373        case EM_NANOMIPS:
374            if ((ehdr.e_machine != EM_MIPS) &&
375                (ehdr.e_machine != EM_NANOMIPS)) {
376                ret = ELF_LOAD_WRONG_ARCH;
377                goto fail;
378            }
379            break;
380        default:
381            if (elf_machine != ehdr.e_machine) {
382                ret = ELF_LOAD_WRONG_ARCH;
383                goto fail;
384            }
385    }
386
387    if (pflags) {
388        *pflags = ehdr.e_flags;
389    }
390    if (pentry) {
391        *pentry = ehdr.e_entry;
392    }
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    /*
413     * Since we want to be able to modify the mapped buffer, we set the
414     * 'writable' parameter to 'true'. Modifications to the buffer are not
415     * written back to the file.
416     */
417    mapped_file = g_mapped_file_new_from_fd(fd, true, NULL);
418    if (!mapped_file) {
419        goto fail;
420    }
421
422    total_size = 0;
423    for(i = 0; i < ehdr.e_phnum; i++) {
424        ph = &phdr[i];
425        if (ph->p_type == PT_LOAD) {
426            mem_size = ph->p_memsz; /* Size of the ROM */
427            file_size = ph->p_filesz; /* Size of the allocated data */
428            data_offset = ph->p_offset; /* Offset where the data is located */
429
430            if (file_size > 0) {
431                if (g_mapped_file_get_length(mapped_file) <
432                    file_size + data_offset) {
433                    goto fail;
434                }
435
436                data = (uint8_t *)g_mapped_file_get_contents(mapped_file);
437                data += data_offset;
438            }
439
440            /* The ELF spec is somewhat vague about the purpose of the
441             * physical address field. One common use in the embedded world
442             * is that physical address field specifies the load address
443             * and the virtual address field specifies the execution address.
444             * Segments are packed into ROM or flash, and the relocation
445             * and zero-initialization of data is done at runtime. This
446             * means that the memsz header represents the runtime size of the
447             * segment, but the filesz represents the loadtime size. If
448             * we try to honour the memsz value for an ELF file like this
449             * we will end up with overlapping segments (which the
450             * loader.c code will later reject).
451             * We support ELF files using this scheme by by checking whether
452             * paddr + memsz for this segment would overlap with any other
453             * segment. If so, then we assume it's using this scheme and
454             * truncate the loaded segment to the filesz size.
455             * If the segment considered as being memsz size doesn't overlap
456             * then we use memsz for the segment length, to handle ELF files
457             * which assume that the loader will do the zero-initialization.
458             */
459            if (mem_size > file_size) {
460                /* If this segment's zero-init portion overlaps another
461                 * segment's data or zero-init portion, then truncate this one.
462                 * Invalid ELF files where the segments overlap even when
463                 * only file_size bytes are loaded will be rejected by
464                 * the ROM overlap check in loader.c, so we don't try to
465                 * explicitly detect those here.
466                 */
467                int j;
468                elf_word zero_start = ph->p_paddr + file_size;
469                elf_word zero_end = ph->p_paddr + mem_size;
470
471                for (j = 0; j < ehdr.e_phnum; j++) {
472                    struct elf_phdr *jph = &phdr[j];
473
474                    if (i != j && jph->p_type == PT_LOAD) {
475                        elf_word other_start = jph->p_paddr;
476                        elf_word other_end = jph->p_paddr + jph->p_memsz;
477
478                        if (!(other_start >= zero_end ||
479                              zero_start >= other_end)) {
480                            mem_size = file_size;
481                            break;
482                        }
483                    }
484                }
485            }
486
487            if (mem_size > SSIZE_MAX - total_size) {
488                ret = ELF_LOAD_TOO_BIG;
489                goto fail;
490            }
491
492            /* address_offset is hack for kernel images that are
493               linked at the wrong physical address.  */
494            if (translate_fn) {
495                addr = translate_fn(translate_opaque, ph->p_paddr);
496                glue(elf_reloc, SZ)(&ehdr, fd, must_swab,  translate_fn,
497                                    translate_opaque, data, ph, elf_machine);
498            } else {
499                addr = ph->p_paddr;
500            }
501
502            if (data_swab) {
503                elf_word j;
504                for (j = 0; j < file_size; j += (1 << data_swab)) {
505                    uint8_t *dp = data + j;
506                    switch (data_swab) {
507                    case (1):
508                        *(uint16_t *)dp = bswap16(*(uint16_t *)dp);
509                        break;
510                    case (2):
511                        *(uint32_t *)dp = bswap32(*(uint32_t *)dp);
512                        break;
513                    case (3):
514                        *(uint64_t *)dp = bswap64(*(uint64_t *)dp);
515                        break;
516                    default:
517                        g_assert_not_reached();
518                    }
519                }
520            }
521
522            /* the entry pointer in the ELF header is a virtual
523             * address, if the text segments paddr and vaddr differ
524             * we need to adjust the entry */
525            if (pentry && !translate_fn &&
526                    ph->p_vaddr != ph->p_paddr &&
527                    ehdr.e_entry >= ph->p_vaddr &&
528                    ehdr.e_entry < ph->p_vaddr + ph->p_filesz &&
529                    ph->p_flags & PF_X) {
530                *pentry = ehdr.e_entry - ph->p_vaddr + ph->p_paddr;
531            }
532
533            /* Some ELF files really do have segments of zero size;
534             * just ignore them rather than trying to create empty
535             * ROM blobs, because the zero-length blob can falsely
536             * trigger the overlapping-ROM-blobs check.
537             */
538            if (mem_size != 0) {
539                if (load_rom) {
540                    g_autofree char *label =
541                        g_strdup_printf("%s ELF program header segment %d",
542                                        name, i);
543
544                    /*
545                     * rom_add_elf_program() takes its own reference to
546                     * 'mapped_file'.
547                     */
548                    rom_add_elf_program(label, mapped_file, data, file_size,
549                                        mem_size, addr, as);
550                } else {
551                    MemTxResult res;
552
553                    res = address_space_write(as ? as : &address_space_memory,
554                                              addr, MEMTXATTRS_UNSPECIFIED,
555                                              data, file_size);
556                    if (res != MEMTX_OK) {
557                        goto fail;
558                    }
559                    /*
560                     * We need to zero'ify the space that is not copied
561                     * from file
562                     */
563                    if (file_size < mem_size) {
564                        res = address_space_set(as ? as : &address_space_memory,
565                                                addr + file_size, 0,
566                                                mem_size - file_size,
567                                                MEMTXATTRS_UNSPECIFIED);
568                        if (res != MEMTX_OK) {
569                            goto fail;
570                        }
571                    }
572                }
573            }
574
575            total_size += mem_size;
576            if (addr < low)
577                low = addr;
578            if ((addr + mem_size) > high)
579                high = addr + mem_size;
580
581            data = NULL;
582
583        } else if (ph->p_type == PT_NOTE && elf_note_fn) {
584            struct elf_note *nhdr = NULL;
585
586            file_size = ph->p_filesz; /* Size of the range of ELF notes */
587            data_offset = ph->p_offset; /* Offset where the notes are located */
588
589            if (file_size > 0) {
590                if (g_mapped_file_get_length(mapped_file) <
591                    file_size + data_offset) {
592                    goto fail;
593                }
594
595                data = (uint8_t *)g_mapped_file_get_contents(mapped_file);
596                data += data_offset;
597            }
598
599            /*
600             * Search the ELF notes to find one with a type matching the
601             * value passed in via 'translate_opaque'
602             */
603            nhdr = (struct elf_note *)data;
604            assert(translate_opaque != NULL);
605            nhdr = glue(get_elf_note_type, SZ)(nhdr, file_size, ph->p_align,
606                                               *(uint64_t *)translate_opaque);
607            if (nhdr != NULL) {
608                elf_note_fn((void *)nhdr, (void *)&ph->p_align, SZ == 64);
609            }
610            data = NULL;
611        }
612    }
613
614    if (lowaddr) {
615        *lowaddr = low;
616    }
617    if (highaddr) {
618        *highaddr = high;
619    }
620    ret = total_size;
621 fail:
622    if (mapped_file) {
623        g_mapped_file_unref(mapped_file);
624    }
625    g_free(phdr);
626    return ret;
627}
628