1 /* 2 * linux/arch/arm/kernel/module.c 3 * 4 * Copyright (C) 2002 Russell King. 5 * Modified for nommu by Hyok S. Choi 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Module allocation method suggested by Andi Kleen. 12 */ 13 #include <linux/module.h> 14 #include <linux/moduleloader.h> 15 #include <linux/kernel.h> 16 #include <linux/mm.h> 17 #include <linux/elf.h> 18 #include <linux/vmalloc.h> 19 #include <linux/fs.h> 20 #include <linux/string.h> 21 #include <linux/gfp.h> 22 23 #include <asm/pgtable.h> 24 #include <asm/sections.h> 25 #include <asm/unwind.h> 26 27 #ifdef CONFIG_XIP_KERNEL 28 /* 29 * The XIP kernel text is mapped in the module area for modules and 30 * some other stuff to work without any indirect relocations. 31 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 32 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 33 */ 34 #undef MODULES_VADDR 35 #define MODULES_VADDR (((unsigned long)_etext + ~PGDIR_MASK) & PGDIR_MASK) 36 #endif 37 38 #ifdef CONFIG_MMU 39 void *module_alloc(unsigned long size) 40 { 41 struct vm_struct *area; 42 43 size = PAGE_ALIGN(size); 44 if (!size) 45 return NULL; 46 47 area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END); 48 if (!area) 49 return NULL; 50 51 return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC); 52 } 53 #else /* CONFIG_MMU */ 54 void *module_alloc(unsigned long size) 55 { 56 return size == 0 ? NULL : vmalloc(size); 57 } 58 #endif /* !CONFIG_MMU */ 59 60 void module_free(struct module *module, void *region) 61 { 62 vfree(region); 63 } 64 65 int module_frob_arch_sections(Elf_Ehdr *hdr, 66 Elf_Shdr *sechdrs, 67 char *secstrings, 68 struct module *mod) 69 { 70 #ifdef CONFIG_ARM_UNWIND 71 Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum; 72 struct arm_unwind_mapping *maps = mod->arch.map; 73 74 for (s = sechdrs; s < sechdrs_end; s++) { 75 char const *secname = secstrings + s->sh_name; 76 77 if (strcmp(".ARM.exidx.init.text", secname) == 0) 78 maps[ARM_SEC_INIT].unw_sec = s; 79 else if (strcmp(".ARM.exidx.devinit.text", secname) == 0) 80 maps[ARM_SEC_DEVINIT].unw_sec = s; 81 else if (strcmp(".ARM.exidx", secname) == 0) 82 maps[ARM_SEC_CORE].unw_sec = s; 83 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 84 maps[ARM_SEC_EXIT].unw_sec = s; 85 else if (strcmp(".ARM.exidx.devexit.text", secname) == 0) 86 maps[ARM_SEC_DEVEXIT].unw_sec = s; 87 else if (strcmp(".init.text", secname) == 0) 88 maps[ARM_SEC_INIT].sec_text = s; 89 else if (strcmp(".devinit.text", secname) == 0) 90 maps[ARM_SEC_DEVINIT].sec_text = s; 91 else if (strcmp(".text", secname) == 0) 92 maps[ARM_SEC_CORE].sec_text = s; 93 else if (strcmp(".exit.text", secname) == 0) 94 maps[ARM_SEC_EXIT].sec_text = s; 95 else if (strcmp(".devexit.text", secname) == 0) 96 maps[ARM_SEC_DEVEXIT].sec_text = s; 97 } 98 #endif 99 return 0; 100 } 101 102 int 103 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 104 unsigned int relindex, struct module *module) 105 { 106 Elf32_Shdr *symsec = sechdrs + symindex; 107 Elf32_Shdr *relsec = sechdrs + relindex; 108 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 109 Elf32_Rel *rel = (void *)relsec->sh_addr; 110 unsigned int i; 111 112 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 113 unsigned long loc; 114 Elf32_Sym *sym; 115 s32 offset; 116 #ifdef CONFIG_THUMB2_KERNEL 117 u32 upper, lower, sign, j1, j2; 118 #endif 119 120 offset = ELF32_R_SYM(rel->r_info); 121 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 122 printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n", 123 module->name, relindex, i); 124 return -ENOEXEC; 125 } 126 127 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 128 129 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 130 printk(KERN_ERR "%s: out of bounds relocation, " 131 "section %d reloc %d offset %d size %d\n", 132 module->name, relindex, i, rel->r_offset, 133 dstsec->sh_size); 134 return -ENOEXEC; 135 } 136 137 loc = dstsec->sh_addr + rel->r_offset; 138 139 switch (ELF32_R_TYPE(rel->r_info)) { 140 case R_ARM_NONE: 141 /* ignore */ 142 break; 143 144 case R_ARM_ABS32: 145 *(u32 *)loc += sym->st_value; 146 break; 147 148 case R_ARM_PC24: 149 case R_ARM_CALL: 150 case R_ARM_JUMP24: 151 offset = (*(u32 *)loc & 0x00ffffff) << 2; 152 if (offset & 0x02000000) 153 offset -= 0x04000000; 154 155 offset += sym->st_value - loc; 156 if (offset & 3 || 157 offset <= (s32)0xfe000000 || 158 offset >= (s32)0x02000000) { 159 printk(KERN_ERR 160 "%s: relocation out of range, section " 161 "%d reloc %d sym '%s'\n", module->name, 162 relindex, i, strtab + sym->st_name); 163 return -ENOEXEC; 164 } 165 166 offset >>= 2; 167 168 *(u32 *)loc &= 0xff000000; 169 *(u32 *)loc |= offset & 0x00ffffff; 170 break; 171 172 case R_ARM_V4BX: 173 /* Preserve Rm and the condition code. Alter 174 * other bits to re-code instruction as 175 * MOV PC,Rm. 176 */ 177 *(u32 *)loc &= 0xf000000f; 178 *(u32 *)loc |= 0x01a0f000; 179 break; 180 181 case R_ARM_PREL31: 182 offset = *(u32 *)loc + sym->st_value - loc; 183 *(u32 *)loc = offset & 0x7fffffff; 184 break; 185 186 case R_ARM_MOVW_ABS_NC: 187 case R_ARM_MOVT_ABS: 188 offset = *(u32 *)loc; 189 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 190 offset = (offset ^ 0x8000) - 0x8000; 191 192 offset += sym->st_value; 193 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 194 offset >>= 16; 195 196 *(u32 *)loc &= 0xfff0f000; 197 *(u32 *)loc |= ((offset & 0xf000) << 4) | 198 (offset & 0x0fff); 199 break; 200 201 #ifdef CONFIG_THUMB2_KERNEL 202 case R_ARM_THM_CALL: 203 case R_ARM_THM_JUMP24: 204 upper = *(u16 *)loc; 205 lower = *(u16 *)(loc + 2); 206 207 /* 208 * 25 bit signed address range (Thumb-2 BL and B.W 209 * instructions): 210 * S:I1:I2:imm10:imm11:0 211 * where: 212 * S = upper[10] = offset[24] 213 * I1 = ~(J1 ^ S) = offset[23] 214 * I2 = ~(J2 ^ S) = offset[22] 215 * imm10 = upper[9:0] = offset[21:12] 216 * imm11 = lower[10:0] = offset[11:1] 217 * J1 = lower[13] 218 * J2 = lower[11] 219 */ 220 sign = (upper >> 10) & 1; 221 j1 = (lower >> 13) & 1; 222 j2 = (lower >> 11) & 1; 223 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 224 ((~(j2 ^ sign) & 1) << 22) | 225 ((upper & 0x03ff) << 12) | 226 ((lower & 0x07ff) << 1); 227 if (offset & 0x01000000) 228 offset -= 0x02000000; 229 offset += sym->st_value - loc; 230 231 /* only Thumb addresses allowed (no interworking) */ 232 if (!(offset & 1) || 233 offset <= (s32)0xff000000 || 234 offset >= (s32)0x01000000) { 235 printk(KERN_ERR 236 "%s: relocation out of range, section " 237 "%d reloc %d sym '%s'\n", module->name, 238 relindex, i, strtab + sym->st_name); 239 return -ENOEXEC; 240 } 241 242 sign = (offset >> 24) & 1; 243 j1 = sign ^ (~(offset >> 23) & 1); 244 j2 = sign ^ (~(offset >> 22) & 1); 245 *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) | 246 ((offset >> 12) & 0x03ff)); 247 *(u16 *)(loc + 2) = (u16)((lower & 0xd000) | 248 (j1 << 13) | (j2 << 11) | 249 ((offset >> 1) & 0x07ff)); 250 break; 251 252 case R_ARM_THM_MOVW_ABS_NC: 253 case R_ARM_THM_MOVT_ABS: 254 upper = *(u16 *)loc; 255 lower = *(u16 *)(loc + 2); 256 257 /* 258 * MOVT/MOVW instructions encoding in Thumb-2: 259 * 260 * i = upper[10] 261 * imm4 = upper[3:0] 262 * imm3 = lower[14:12] 263 * imm8 = lower[7:0] 264 * 265 * imm16 = imm4:i:imm3:imm8 266 */ 267 offset = ((upper & 0x000f) << 12) | 268 ((upper & 0x0400) << 1) | 269 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 270 offset = (offset ^ 0x8000) - 0x8000; 271 offset += sym->st_value; 272 273 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 274 offset >>= 16; 275 276 *(u16 *)loc = (u16)((upper & 0xfbf0) | 277 ((offset & 0xf000) >> 12) | 278 ((offset & 0x0800) >> 1)); 279 *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) | 280 ((offset & 0x0700) << 4) | 281 (offset & 0x00ff)); 282 break; 283 #endif 284 285 default: 286 printk(KERN_ERR "%s: unknown relocation: %u\n", 287 module->name, ELF32_R_TYPE(rel->r_info)); 288 return -ENOEXEC; 289 } 290 } 291 return 0; 292 } 293 294 int 295 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab, 296 unsigned int symindex, unsigned int relsec, struct module *module) 297 { 298 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", 299 module->name); 300 return -ENOEXEC; 301 } 302 303 #ifdef CONFIG_ARM_UNWIND 304 static void register_unwind_tables(struct module *mod) 305 { 306 int i; 307 for (i = 0; i < ARM_SEC_MAX; ++i) { 308 struct arm_unwind_mapping *map = &mod->arch.map[i]; 309 if (map->unw_sec && map->sec_text) 310 map->unwind = unwind_table_add(map->unw_sec->sh_addr, 311 map->unw_sec->sh_size, 312 map->sec_text->sh_addr, 313 map->sec_text->sh_size); 314 } 315 } 316 317 static void unregister_unwind_tables(struct module *mod) 318 { 319 int i = ARM_SEC_MAX; 320 while (--i >= 0) 321 unwind_table_del(mod->arch.map[i].unwind); 322 } 323 #else 324 static inline void register_unwind_tables(struct module *mod) { } 325 static inline void unregister_unwind_tables(struct module *mod) { } 326 #endif 327 328 int 329 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 330 struct module *module) 331 { 332 register_unwind_tables(module); 333 return 0; 334 } 335 336 void 337 module_arch_cleanup(struct module *mod) 338 { 339 unregister_unwind_tables(mod); 340 } 341