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![Daniel Schwierzeck](/assets/img/avatar_default.png)
Currently the size of the relocation table will be shrunk to the actual size needed. Although this gives a maximal space saving, it messes up the _end symbol. This breaks features like appended DTBs because the _end symbol doesn't point to the real end of the U-Boot binary. Remove the size shrinking and make the size of the relocation table fixed but configurable. This follows the Linux approach and the user can adjust the size to his needs. Also rename the relocation table section from .rel to .data.reloc to follow the Linux approach and to avoid ambiguities with the .rel.* sections added by the linker. Reported-by: Lars Povlsen <lars.povlsen@microsemi.com> Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
419 lines
9.2 KiB
C
419 lines
9.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* MIPS Relocation Data Generator
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*
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* Copyright (c) 2017 Imagination Technologies Ltd.
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*/
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#include <assert.h>
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#include <elf.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <asm/relocs.h>
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#define hdr_field(pfx, idx, field) ({ \
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uint64_t _val; \
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unsigned int _size; \
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\
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if (is_64) { \
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_val = pfx##hdr64[idx].field; \
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_size = sizeof(pfx##hdr64[0].field); \
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} else { \
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_val = pfx##hdr32[idx].field; \
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_size = sizeof(pfx##hdr32[0].field); \
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} \
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\
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switch (_size) { \
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case 1: \
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break; \
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case 2: \
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_val = is_be ? be16toh(_val) : le16toh(_val); \
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break; \
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case 4: \
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_val = is_be ? be32toh(_val) : le32toh(_val); \
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break; \
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case 8: \
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_val = is_be ? be64toh(_val) : le64toh(_val); \
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break; \
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} \
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\
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_val; \
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})
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#define set_hdr_field(pfx, idx, field, val) ({ \
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uint64_t _val; \
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unsigned int _size; \
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\
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if (is_64) \
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_size = sizeof(pfx##hdr64[0].field); \
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else \
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_size = sizeof(pfx##hdr32[0].field); \
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\
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switch (_size) { \
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case 1: \
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_val = val; \
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break; \
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case 2: \
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_val = is_be ? htobe16(val) : htole16(val); \
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break; \
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case 4: \
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_val = is_be ? htobe32(val) : htole32(val); \
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break; \
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case 8: \
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_val = is_be ? htobe64(val) : htole64(val); \
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break; \
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default: \
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/* We should never reach here */ \
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_val = 0; \
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assert(0); \
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break; \
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} \
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\
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if (is_64) \
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pfx##hdr64[idx].field = _val; \
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else \
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pfx##hdr32[idx].field = _val; \
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})
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#define ehdr_field(field) \
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hdr_field(e, 0, field)
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#define phdr_field(idx, field) \
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hdr_field(p, idx, field)
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#define shdr_field(idx, field) \
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hdr_field(s, idx, field)
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#define set_phdr_field(idx, field, val) \
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set_hdr_field(p, idx, field, val)
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#define set_shdr_field(idx, field, val) \
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set_hdr_field(s, idx, field, val)
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#define shstr(idx) (&shstrtab[idx])
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bool is_64, is_be;
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uint64_t text_base;
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struct mips_reloc {
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uint8_t type;
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uint64_t offset;
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} *relocs;
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size_t relocs_sz, relocs_idx;
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static int add_reloc(unsigned int type, uint64_t off)
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{
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struct mips_reloc *new;
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size_t new_sz;
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switch (type) {
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case R_MIPS_NONE:
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case R_MIPS_LO16:
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case R_MIPS_PC16:
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case R_MIPS_HIGHER:
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case R_MIPS_HIGHEST:
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case R_MIPS_PC21_S2:
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case R_MIPS_PC26_S2:
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/* Skip these relocs */
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return 0;
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default:
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break;
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}
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if (relocs_idx == relocs_sz) {
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new_sz = relocs_sz ? relocs_sz * 2 : 128;
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new = realloc(relocs, new_sz * sizeof(*relocs));
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if (!new) {
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fprintf(stderr, "Out of memory\n");
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return -ENOMEM;
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}
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relocs = new;
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relocs_sz = new_sz;
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}
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relocs[relocs_idx++] = (struct mips_reloc){
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.type = type,
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.offset = off,
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};
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return 0;
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}
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static int parse_mips32_rel(const void *_rel)
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{
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const Elf32_Rel *rel = _rel;
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uint32_t off, type;
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off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset);
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off -= text_base;
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type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info);
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type = ELF32_R_TYPE(type);
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return add_reloc(type, off);
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}
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static int parse_mips64_rela(const void *_rel)
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{
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const Elf64_Rela *rel = _rel;
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uint64_t off, type;
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off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset);
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off -= text_base;
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type = rel->r_info >> (64 - 8);
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return add_reloc(type, off);
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}
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static void output_uint(uint8_t **buf, uint64_t val)
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{
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uint64_t tmp;
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do {
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tmp = val & 0x7f;
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val >>= 7;
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tmp |= !!val << 7;
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*(*buf)++ = tmp;
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} while (val);
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}
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static int compare_relocs(const void *a, const void *b)
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{
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const struct mips_reloc *ra = a, *rb = b;
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return ra->offset - rb->offset;
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}
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int main(int argc, char *argv[])
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{
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unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries;
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size_t rel_size, rel_actual_size;
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const char *shstrtab, *sh_name, *rel_pfx;
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int (*parse_fn)(const void *rel);
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uint8_t *buf_start, *buf;
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const Elf32_Ehdr *ehdr32;
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const Elf64_Ehdr *ehdr64;
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uintptr_t sh_offset;
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Elf32_Shdr *shdr32;
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Elf64_Shdr *shdr64;
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struct stat st;
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int err, fd;
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void *elf;
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bool skip;
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fd = open(argv[1], O_RDWR);
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if (fd == -1) {
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fprintf(stderr, "Unable to open input file %s\n", argv[1]);
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err = errno;
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goto out_ret;
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}
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err = fstat(fd, &st);
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if (err) {
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fprintf(stderr, "Unable to fstat() input file\n");
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goto out_close_fd;
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}
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elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (elf == MAP_FAILED) {
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fprintf(stderr, "Unable to mmap() input file\n");
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err = errno;
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goto out_close_fd;
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}
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ehdr32 = elf;
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ehdr64 = elf;
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if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) {
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fprintf(stderr, "Input file is not an ELF\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) {
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fprintf(stderr, "Unrecognised ELF version\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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switch (ehdr32->e_ident[EI_CLASS]) {
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case ELFCLASS32:
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is_64 = false;
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break;
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case ELFCLASS64:
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is_64 = true;
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break;
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default:
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fprintf(stderr, "Unrecognised ELF class\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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switch (ehdr32->e_ident[EI_DATA]) {
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case ELFDATA2LSB:
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is_be = false;
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break;
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case ELFDATA2MSB:
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is_be = true;
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break;
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default:
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fprintf(stderr, "Unrecognised ELF data encoding\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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if (ehdr_field(e_type) != ET_EXEC) {
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fprintf(stderr, "Input ELF is not an executable\n");
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printf("type 0x%lx\n", ehdr_field(e_type));
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err = -EINVAL;
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goto out_free_relocs;
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}
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if (ehdr_field(e_machine) != EM_MIPS) {
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fprintf(stderr, "Input ELF does not target MIPS\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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shdr32 = elf + ehdr_field(e_shoff);
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shdr64 = elf + ehdr_field(e_shoff);
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shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset);
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i_rel_shdr = UINT_MAX;
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for (i = 0; i < ehdr_field(e_shnum); i++) {
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sh_name = shstr(shdr_field(i, sh_name));
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if (!strcmp(sh_name, ".data.reloc")) {
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i_rel_shdr = i;
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continue;
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}
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if (!strcmp(sh_name, ".text")) {
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text_base = shdr_field(i, sh_addr);
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continue;
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}
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}
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if (i_rel_shdr == UINT_MAX) {
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fprintf(stderr, "Unable to find .rel section\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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if (!text_base) {
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fprintf(stderr, "Unable to find .text base address\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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rel_pfx = is_64 ? ".rela." : ".rel.";
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for (i = 0; i < ehdr_field(e_shnum); i++) {
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sh_type = shdr_field(i, sh_type);
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if ((sh_type != SHT_REL) && (sh_type != SHT_RELA))
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continue;
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sh_name = shstr(shdr_field(i, sh_name));
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if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) {
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if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn"))
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fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name);
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continue;
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}
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/*
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* Skip reloc sections which either don't correspond to another
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* section in the ELF, or whose corresponding section isn't
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* loaded as part of the U-Boot binary (ie. doesn't have the
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* alloc flags set).
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*/
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skip = true;
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for (j = 0; j < ehdr_field(e_shnum); j++) {
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if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name))))
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continue;
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skip = !(shdr_field(j, sh_flags) & SHF_ALLOC);
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break;
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}
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if (skip)
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continue;
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sh_offset = shdr_field(i, sh_offset);
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sh_entsize = shdr_field(i, sh_entsize);
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sh_entries = shdr_field(i, sh_size) / sh_entsize;
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if (sh_type == SHT_REL) {
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if (is_64) {
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fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n");
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err = -EINVAL;
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goto out_free_relocs;
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} else {
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parse_fn = parse_mips32_rel;
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}
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} else {
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if (is_64) {
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parse_fn = parse_mips64_rela;
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} else {
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fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n");
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err = -EINVAL;
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goto out_free_relocs;
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}
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}
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for (j = 0; j < sh_entries; j++) {
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err = parse_fn(elf + sh_offset + (j * sh_entsize));
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if (err)
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goto out_free_relocs;
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}
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}
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/* Sort relocs in ascending order of offset */
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qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs);
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/* Make reloc offsets relative to their predecessor */
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for (i = relocs_idx - 1; i > 0; i--)
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relocs[i].offset -= relocs[i - 1].offset;
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/* Write the relocations to the .rel section */
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buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset);
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for (i = 0; i < relocs_idx; i++) {
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output_uint(&buf, relocs[i].type);
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output_uint(&buf, relocs[i].offset >> 2);
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}
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/* Write a terminating R_MIPS_NONE (0) */
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output_uint(&buf, R_MIPS_NONE);
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/* Ensure the relocs didn't overflow the .rel section */
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rel_size = shdr_field(i_rel_shdr, sh_size);
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rel_actual_size = buf - buf_start;
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if (rel_actual_size > rel_size) {
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fprintf(stderr, "Relocations overflow available space of 0x%lx (required 0x%lx)!\n",
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rel_size, rel_actual_size);
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fprintf(stderr, "Please adjust CONFIG_MIPS_RELOCATION_TABLE_SIZE to at least 0x%lx\n",
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(rel_actual_size + 0x100) & ~0xFF);
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err = -ENOMEM;
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goto out_free_relocs;
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}
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/* Make sure data is written back to the file */
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err = msync(elf, st.st_size, MS_SYNC);
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if (err) {
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fprintf(stderr, "Failed to msync: %d\n", errno);
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goto out_free_relocs;
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}
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out_free_relocs:
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free(relocs);
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munmap(elf, st.st_size);
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out_close_fd:
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close(fd);
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out_ret:
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return err;
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}
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