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432 lines
9.5 KiB
432 lines
9.5 KiB
// 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, load_sz; |
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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_Phdr *phdr32; |
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Elf64_Phdr *phdr64; |
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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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phdr32 = elf + ehdr_field(e_phoff); |
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phdr64 = elf + ehdr_field(e_phoff); |
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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, ".rel")) { |
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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, "Relocs overflowed .rel section\n"); |
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return -ENOMEM; |
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} |
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/* Update the .rel section's size */ |
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set_shdr_field(i_rel_shdr, sh_size, rel_actual_size); |
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/* Shrink the PT_LOAD program header filesz (ie. shrink u-boot.bin) */ |
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for (i = 0; i < ehdr_field(e_phnum); i++) { |
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if (phdr_field(i, p_type) != PT_LOAD) |
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continue; |
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load_sz = phdr_field(i, p_filesz); |
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load_sz -= rel_size - rel_actual_size; |
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set_phdr_field(i, p_filesz, load_sz); |
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break; |
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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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