1 /* 2 * Kernel module loader for Hexagon 3 * 4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #include <asm/module.h> 22 #include <linux/elf.h> 23 #include <linux/module.h> 24 #include <linux/moduleloader.h> 25 #include <linux/vmalloc.h> 26 27 #if 0 28 #define DEBUGP printk 29 #else 30 #define DEBUGP(fmt , ...) 31 #endif 32 33 /* 34 * module_frob_arch_sections - tweak got/plt sections. 35 * @hdr - pointer to elf header 36 * @sechdrs - pointer to elf load section headers 37 * @secstrings - symbol names 38 * @mod - pointer to module 39 */ 40 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 41 char *secstrings, 42 struct module *mod) 43 { 44 unsigned int i; 45 int found = 0; 46 47 /* Look for .plt and/or .got.plt and/or .init.plt sections */ 48 for (i = 0; i < hdr->e_shnum; i++) { 49 DEBUGP("Section %d is %s\n", i, 50 secstrings + sechdrs[i].sh_name); 51 if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) 52 found = i+1; 53 if (strcmp(secstrings + sechdrs[i].sh_name, ".got.plt") == 0) 54 found = i+1; 55 if (strcmp(secstrings + sechdrs[i].sh_name, ".rela.plt") == 0) 56 found = i+1; 57 } 58 59 /* At this time, we don't support modules comiled with -shared */ 60 if (found) { 61 printk(KERN_WARNING 62 "Module '%s' contains unexpected .plt/.got sections.\n", 63 mod->name); 64 /* return -ENOEXEC; */ 65 } 66 67 return 0; 68 } 69 70 /* 71 * apply_relocate_add - perform rela relocations. 72 * @sechdrs - pointer to section headers 73 * @strtab - some sort of start address? 74 * @symindex - symbol index offset or something? 75 * @relsec - address to relocate to? 76 * @module - pointer to module 77 * 78 * Perform rela relocations. 79 */ 80 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 81 unsigned int symindex, unsigned int relsec, 82 struct module *module) 83 { 84 unsigned int i; 85 Elf32_Sym *sym; 86 uint32_t *location; 87 uint32_t value; 88 unsigned int nrelocs = sechdrs[relsec].sh_size / sizeof(Elf32_Rela); 89 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; 90 Elf32_Word sym_info = sechdrs[relsec].sh_info; 91 Elf32_Sym *sym_base = (Elf32_Sym *) sechdrs[symindex].sh_addr; 92 void *loc_base = (void *) sechdrs[sym_info].sh_addr; 93 94 DEBUGP("Applying relocations in section %u to section %u base=%p\n", 95 relsec, sym_info, loc_base); 96 97 for (i = 0; i < nrelocs; i++) { 98 99 /* Symbol to relocate */ 100 sym = sym_base + ELF32_R_SYM(rela[i].r_info); 101 102 /* Where to make the change */ 103 location = loc_base + rela[i].r_offset; 104 105 /* `Everything is relative'. */ 106 value = sym->st_value + rela[i].r_addend; 107 108 DEBUGP("%d: value=%08x loc=%p reloc=%d symbol=%s\n", 109 i, value, location, ELF32_R_TYPE(rela[i].r_info), 110 sym->st_name ? 111 &strtab[sym->st_name] : "(anonymous)"); 112 113 switch (ELF32_R_TYPE(rela[i].r_info)) { 114 case R_HEXAGON_B22_PCREL: { 115 int dist = (int)(value - (uint32_t)location); 116 if ((dist < -0x00800000) || 117 (dist >= 0x00800000)) { 118 printk(KERN_ERR 119 "%s: %s: %08x=%08x-%08x %s\n", 120 module->name, 121 "R_HEXAGON_B22_PCREL reloc out of range", 122 dist, value, (uint32_t)location, 123 sym->st_name ? 124 &strtab[sym->st_name] : "(anonymous)"); 125 return -ENOEXEC; 126 } 127 DEBUGP("B22_PCREL contents: %08X.\n", *location); 128 *location &= ~0x01ff3fff; 129 *location |= 0x00003fff & dist; 130 *location |= 0x01ff0000 & (dist<<2); 131 DEBUGP("Contents after reloc: %08x\n", *location); 132 break; 133 } 134 case R_HEXAGON_HI16: 135 value = (value>>16) & 0xffff; 136 /* fallthrough */ 137 case R_HEXAGON_LO16: 138 *location &= ~0x00c03fff; 139 *location |= value & 0x3fff; 140 *location |= (value & 0xc000) << 8; 141 break; 142 case R_HEXAGON_32: 143 *location = value; 144 break; 145 case R_HEXAGON_32_PCREL: 146 *location = value - (uint32_t)location; 147 break; 148 case R_HEXAGON_PLT_B22_PCREL: 149 case R_HEXAGON_GOTOFF_LO16: 150 case R_HEXAGON_GOTOFF_HI16: 151 printk(KERN_ERR "%s: GOT/PLT relocations unsupported\n", 152 module->name); 153 return -ENOEXEC; 154 default: 155 printk(KERN_ERR "%s: unknown relocation: %u\n", 156 module->name, 157 ELF32_R_TYPE(rela[i].r_info)); 158 return -ENOEXEC; 159 } 160 } 161 return 0; 162 } 163