1 /*- 2 * Copyright (c) 2008-2010 Rui Paulo <rpaulo@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/types.h> 31 #include <elf.h> 32 #include <bootstrap.h> 33 34 #if defined(__aarch64__) 35 #define ElfW_Rel Elf64_Rela 36 #define ElfW_Dyn Elf64_Dyn 37 #define ELFW_R_TYPE ELF64_R_TYPE 38 #define ELF_RELA 39 #elif defined(__arm__) || defined(__i386__) 40 #define ElfW_Rel Elf32_Rel 41 #define ElfW_Dyn Elf32_Dyn 42 #define ELFW_R_TYPE ELF32_R_TYPE 43 #elif defined(__amd64__) 44 #define ElfW_Rel Elf64_Rel 45 #define ElfW_Dyn Elf64_Dyn 46 #define ELFW_R_TYPE ELF64_R_TYPE 47 #else 48 #error architecture not supported 49 #endif 50 #if defined(__aarch64__) 51 #define RELOC_TYPE_NONE R_AARCH64_NONE 52 #define RELOC_TYPE_RELATIVE R_AARCH64_RELATIVE 53 #elif defined(__amd64__) 54 #define RELOC_TYPE_NONE R_X86_64_NONE 55 #define RELOC_TYPE_RELATIVE R_X86_64_RELATIVE 56 #elif defined(__arm__) 57 #define RELOC_TYPE_NONE R_ARM_NONE 58 #define RELOC_TYPE_RELATIVE R_ARM_RELATIVE 59 #elif defined(__i386__) 60 #define RELOC_TYPE_NONE R_386_NONE 61 #define RELOC_TYPE_RELATIVE R_386_RELATIVE 62 #endif 63 64 void self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic); 65 66 /* 67 * A simple elf relocator. 68 */ 69 void 70 self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic) 71 { 72 Elf_Word relsz, relent; 73 Elf_Addr *newaddr; 74 ElfW_Rel *rel = 0; 75 ElfW_Dyn *dynp; 76 77 /* 78 * Find the relocation address, its size and the relocation entry. 79 */ 80 relsz = 0; 81 relent = 0; 82 for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) { 83 switch (dynp->d_tag) { 84 case DT_REL: 85 case DT_RELA: 86 rel = (ElfW_Rel *)(dynp->d_un.d_ptr + baseaddr); 87 break; 88 case DT_RELSZ: 89 case DT_RELASZ: 90 relsz = dynp->d_un.d_val; 91 break; 92 case DT_RELENT: 93 case DT_RELAENT: 94 relent = dynp->d_un.d_val; 95 break; 96 default: 97 break; 98 } 99 } 100 101 /* 102 * Perform the actual relocation. 103 */ 104 for (; relsz > 0; relsz -= relent) { 105 switch (ELFW_R_TYPE(rel->r_info)) { 106 case RELOC_TYPE_NONE: 107 /* No relocation needs be performed. */ 108 break; 109 110 case RELOC_TYPE_RELATIVE: 111 /* Address relative to the base address. */ 112 newaddr = (Elf_Addr *)(rel->r_offset + baseaddr); 113 *newaddr += baseaddr; 114 /* Add the addend when the ABI uses them */ 115 #ifdef ELF_RELA 116 *newaddr += rel->r_addend; 117 #endif 118 break; 119 default: 120 /* XXX: do we need other relocations ? */ 121 break; 122 } 123 rel = (ElfW_Rel *)(void *)((caddr_t) rel + relent); 124 } 125 } 126