1 /* Kernel module help for x86. 2 Copyright (C) 2001 Rusty Russell. 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 2 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program; if not, write to the Free Software 16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 */ 18 #include <linux/moduleloader.h> 19 #include <linux/elf.h> 20 #include <linux/vmalloc.h> 21 #include <linux/fs.h> 22 #include <linux/string.h> 23 #include <linux/kernel.h> 24 #include <linux/bug.h> 25 #include <linux/mm.h> 26 #include <linux/gfp.h> 27 28 #include <asm/system.h> 29 #include <asm/page.h> 30 #include <asm/pgtable.h> 31 32 #if 0 33 #define DEBUGP printk 34 #else 35 #define DEBUGP(fmt...) 36 #endif 37 38 void *module_alloc(unsigned long size) 39 { 40 if (PAGE_ALIGN(size) > MODULES_LEN) 41 return NULL; 42 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 43 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC, 44 -1, __builtin_return_address(0)); 45 } 46 47 /* Free memory returned from module_alloc */ 48 void module_free(struct module *mod, void *module_region) 49 { 50 vfree(module_region); 51 } 52 53 /* We don't need anything special. */ 54 int module_frob_arch_sections(Elf_Ehdr *hdr, 55 Elf_Shdr *sechdrs, 56 char *secstrings, 57 struct module *mod) 58 { 59 return 0; 60 } 61 62 #ifdef CONFIG_X86_32 63 int apply_relocate(Elf32_Shdr *sechdrs, 64 const char *strtab, 65 unsigned int symindex, 66 unsigned int relsec, 67 struct module *me) 68 { 69 unsigned int i; 70 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; 71 Elf32_Sym *sym; 72 uint32_t *location; 73 74 DEBUGP("Applying relocate section %u to %u\n", relsec, 75 sechdrs[relsec].sh_info); 76 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 77 /* This is where to make the change */ 78 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 79 + rel[i].r_offset; 80 /* This is the symbol it is referring to. Note that all 81 undefined symbols have been resolved. */ 82 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr 83 + ELF32_R_SYM(rel[i].r_info); 84 85 switch (ELF32_R_TYPE(rel[i].r_info)) { 86 case R_386_32: 87 /* We add the value into the location given */ 88 *location += sym->st_value; 89 break; 90 case R_386_PC32: 91 /* Add the value, subtract its postition */ 92 *location += sym->st_value - (uint32_t)location; 93 break; 94 default: 95 printk(KERN_ERR "module %s: Unknown relocation: %u\n", 96 me->name, ELF32_R_TYPE(rel[i].r_info)); 97 return -ENOEXEC; 98 } 99 } 100 return 0; 101 } 102 103 int apply_relocate_add(Elf32_Shdr *sechdrs, 104 const char *strtab, 105 unsigned int symindex, 106 unsigned int relsec, 107 struct module *me) 108 { 109 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", 110 me->name); 111 return -ENOEXEC; 112 } 113 #else /*X86_64*/ 114 int apply_relocate_add(Elf64_Shdr *sechdrs, 115 const char *strtab, 116 unsigned int symindex, 117 unsigned int relsec, 118 struct module *me) 119 { 120 unsigned int i; 121 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; 122 Elf64_Sym *sym; 123 void *loc; 124 u64 val; 125 126 DEBUGP("Applying relocate section %u to %u\n", relsec, 127 sechdrs[relsec].sh_info); 128 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 129 /* This is where to make the change */ 130 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 131 + rel[i].r_offset; 132 133 /* This is the symbol it is referring to. Note that all 134 undefined symbols have been resolved. */ 135 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 136 + ELF64_R_SYM(rel[i].r_info); 137 138 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", 139 (int)ELF64_R_TYPE(rel[i].r_info), 140 sym->st_value, rel[i].r_addend, (u64)loc); 141 142 val = sym->st_value + rel[i].r_addend; 143 144 switch (ELF64_R_TYPE(rel[i].r_info)) { 145 case R_X86_64_NONE: 146 break; 147 case R_X86_64_64: 148 *(u64 *)loc = val; 149 break; 150 case R_X86_64_32: 151 *(u32 *)loc = val; 152 if (val != *(u32 *)loc) 153 goto overflow; 154 break; 155 case R_X86_64_32S: 156 *(s32 *)loc = val; 157 if ((s64)val != *(s32 *)loc) 158 goto overflow; 159 break; 160 case R_X86_64_PC32: 161 val -= (u64)loc; 162 *(u32 *)loc = val; 163 #if 0 164 if ((s64)val != *(s32 *)loc) 165 goto overflow; 166 #endif 167 break; 168 default: 169 printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n", 170 me->name, ELF64_R_TYPE(rel[i].r_info)); 171 return -ENOEXEC; 172 } 173 } 174 return 0; 175 176 overflow: 177 printk(KERN_ERR "overflow in relocation type %d val %Lx\n", 178 (int)ELF64_R_TYPE(rel[i].r_info), val); 179 printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n", 180 me->name); 181 return -ENOEXEC; 182 } 183 184 int apply_relocate(Elf_Shdr *sechdrs, 185 const char *strtab, 186 unsigned int symindex, 187 unsigned int relsec, 188 struct module *me) 189 { 190 printk(KERN_ERR "non add relocation not supported\n"); 191 return -ENOSYS; 192 } 193 194 #endif 195 196 int module_finalize(const Elf_Ehdr *hdr, 197 const Elf_Shdr *sechdrs, 198 struct module *me) 199 { 200 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, 201 *para = NULL; 202 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 203 204 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 205 if (!strcmp(".text", secstrings + s->sh_name)) 206 text = s; 207 if (!strcmp(".altinstructions", secstrings + s->sh_name)) 208 alt = s; 209 if (!strcmp(".smp_locks", secstrings + s->sh_name)) 210 locks = s; 211 if (!strcmp(".parainstructions", secstrings + s->sh_name)) 212 para = s; 213 } 214 215 if (alt) { 216 /* patch .altinstructions */ 217 void *aseg = (void *)alt->sh_addr; 218 apply_alternatives(aseg, aseg + alt->sh_size); 219 } 220 if (locks && text) { 221 void *lseg = (void *)locks->sh_addr; 222 void *tseg = (void *)text->sh_addr; 223 alternatives_smp_module_add(me, me->name, 224 lseg, lseg + locks->sh_size, 225 tseg, tseg + text->sh_size); 226 } 227 228 if (para) { 229 void *pseg = (void *)para->sh_addr; 230 apply_paravirt(pseg, pseg + para->sh_size); 231 } 232 233 /* make jump label nops */ 234 jump_label_apply_nops(me); 235 236 return 0; 237 } 238 239 void module_arch_cleanup(struct module *mod) 240 { 241 alternatives_smp_module_del(mod); 242 } 243