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/smp_plat.h> 26 #include <asm/unwind.h> 27 #include <asm/opcodes.h> 28 29 #ifdef CONFIG_XIP_KERNEL 30 /* 31 * The XIP kernel text is mapped in the module area for modules and 32 * some other stuff to work without any indirect relocations. 33 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 34 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 35 */ 36 #undef MODULES_VADDR 37 #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK) 38 #endif 39 40 #ifdef CONFIG_MMU 41 void *module_alloc(unsigned long size) 42 { 43 void *p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 44 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 45 __builtin_return_address(0)); 46 if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p) 47 return p; 48 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, 49 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 50 __builtin_return_address(0)); 51 } 52 #endif 53 54 int 55 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 56 unsigned int relindex, struct module *module) 57 { 58 Elf32_Shdr *symsec = sechdrs + symindex; 59 Elf32_Shdr *relsec = sechdrs + relindex; 60 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 61 Elf32_Rel *rel = (void *)relsec->sh_addr; 62 unsigned int i; 63 64 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 65 unsigned long loc; 66 Elf32_Sym *sym; 67 const char *symname; 68 s32 offset; 69 u32 tmp; 70 #ifdef CONFIG_THUMB2_KERNEL 71 u32 upper, lower, sign, j1, j2; 72 #endif 73 74 offset = ELF32_R_SYM(rel->r_info); 75 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 76 pr_err("%s: section %u reloc %u: bad relocation sym offset\n", 77 module->name, relindex, i); 78 return -ENOEXEC; 79 } 80 81 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 82 symname = strtab + sym->st_name; 83 84 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 85 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n", 86 module->name, relindex, i, symname, 87 rel->r_offset, dstsec->sh_size); 88 return -ENOEXEC; 89 } 90 91 loc = dstsec->sh_addr + rel->r_offset; 92 93 switch (ELF32_R_TYPE(rel->r_info)) { 94 case R_ARM_NONE: 95 /* ignore */ 96 break; 97 98 case R_ARM_ABS32: 99 case R_ARM_TARGET1: 100 *(u32 *)loc += sym->st_value; 101 break; 102 103 case R_ARM_PC24: 104 case R_ARM_CALL: 105 case R_ARM_JUMP24: 106 if (sym->st_value & 3) { 107 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n", 108 module->name, relindex, i, symname); 109 return -ENOEXEC; 110 } 111 112 offset = __mem_to_opcode_arm(*(u32 *)loc); 113 offset = (offset & 0x00ffffff) << 2; 114 if (offset & 0x02000000) 115 offset -= 0x04000000; 116 117 offset += sym->st_value - loc; 118 119 /* 120 * Route through a PLT entry if 'offset' exceeds the 121 * supported range. Note that 'offset + loc + 8' 122 * contains the absolute jump target, i.e., 123 * @sym + addend, corrected for the +8 PC bias. 124 */ 125 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 126 (offset <= (s32)0xfe000000 || 127 offset >= (s32)0x02000000)) 128 offset = get_module_plt(module, loc, 129 offset + loc + 8) 130 - loc - 8; 131 132 if (offset <= (s32)0xfe000000 || 133 offset >= (s32)0x02000000) { 134 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 135 module->name, relindex, i, symname, 136 ELF32_R_TYPE(rel->r_info), loc, 137 sym->st_value); 138 return -ENOEXEC; 139 } 140 141 offset >>= 2; 142 offset &= 0x00ffffff; 143 144 *(u32 *)loc &= __opcode_to_mem_arm(0xff000000); 145 *(u32 *)loc |= __opcode_to_mem_arm(offset); 146 break; 147 148 case R_ARM_V4BX: 149 /* Preserve Rm and the condition code. Alter 150 * other bits to re-code instruction as 151 * MOV PC,Rm. 152 */ 153 *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f); 154 *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000); 155 break; 156 157 case R_ARM_PREL31: 158 offset = (*(s32 *)loc << 1) >> 1; /* sign extend */ 159 offset += sym->st_value - loc; 160 if (offset >= 0x40000000 || offset < -0x40000000) { 161 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 162 module->name, relindex, i, symname, 163 ELF32_R_TYPE(rel->r_info), loc, 164 sym->st_value); 165 return -ENOEXEC; 166 } 167 *(u32 *)loc &= 0x80000000; 168 *(u32 *)loc |= offset & 0x7fffffff; 169 break; 170 171 case R_ARM_MOVW_ABS_NC: 172 case R_ARM_MOVT_ABS: 173 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc); 174 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 175 offset = (offset ^ 0x8000) - 0x8000; 176 177 offset += sym->st_value; 178 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 179 offset >>= 16; 180 181 tmp &= 0xfff0f000; 182 tmp |= ((offset & 0xf000) << 4) | 183 (offset & 0x0fff); 184 185 *(u32 *)loc = __opcode_to_mem_arm(tmp); 186 break; 187 188 #ifdef CONFIG_THUMB2_KERNEL 189 case R_ARM_THM_CALL: 190 case R_ARM_THM_JUMP24: 191 /* 192 * For function symbols, only Thumb addresses are 193 * allowed (no interworking). 194 * 195 * For non-function symbols, the destination 196 * has no specific ARM/Thumb disposition, so 197 * the branch is resolved under the assumption 198 * that interworking is not required. 199 */ 200 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 201 !(sym->st_value & 1)) { 202 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n", 203 module->name, relindex, i, symname); 204 return -ENOEXEC; 205 } 206 207 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 208 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 209 210 /* 211 * 25 bit signed address range (Thumb-2 BL and B.W 212 * instructions): 213 * S:I1:I2:imm10:imm11:0 214 * where: 215 * S = upper[10] = offset[24] 216 * I1 = ~(J1 ^ S) = offset[23] 217 * I2 = ~(J2 ^ S) = offset[22] 218 * imm10 = upper[9:0] = offset[21:12] 219 * imm11 = lower[10:0] = offset[11:1] 220 * J1 = lower[13] 221 * J2 = lower[11] 222 */ 223 sign = (upper >> 10) & 1; 224 j1 = (lower >> 13) & 1; 225 j2 = (lower >> 11) & 1; 226 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 227 ((~(j2 ^ sign) & 1) << 22) | 228 ((upper & 0x03ff) << 12) | 229 ((lower & 0x07ff) << 1); 230 if (offset & 0x01000000) 231 offset -= 0x02000000; 232 offset += sym->st_value - loc; 233 234 /* 235 * Route through a PLT entry if 'offset' exceeds the 236 * supported range. 237 */ 238 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 239 (offset <= (s32)0xff000000 || 240 offset >= (s32)0x01000000)) 241 offset = get_module_plt(module, loc, 242 offset + loc + 4) 243 - loc - 4; 244 245 if (offset <= (s32)0xff000000 || 246 offset >= (s32)0x01000000) { 247 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 248 module->name, relindex, i, symname, 249 ELF32_R_TYPE(rel->r_info), loc, 250 sym->st_value); 251 return -ENOEXEC; 252 } 253 254 sign = (offset >> 24) & 1; 255 j1 = sign ^ (~(offset >> 23) & 1); 256 j2 = sign ^ (~(offset >> 22) & 1); 257 upper = (u16)((upper & 0xf800) | (sign << 10) | 258 ((offset >> 12) & 0x03ff)); 259 lower = (u16)((lower & 0xd000) | 260 (j1 << 13) | (j2 << 11) | 261 ((offset >> 1) & 0x07ff)); 262 263 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 264 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 265 break; 266 267 case R_ARM_THM_MOVW_ABS_NC: 268 case R_ARM_THM_MOVT_ABS: 269 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 270 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 271 272 /* 273 * MOVT/MOVW instructions encoding in Thumb-2: 274 * 275 * i = upper[10] 276 * imm4 = upper[3:0] 277 * imm3 = lower[14:12] 278 * imm8 = lower[7:0] 279 * 280 * imm16 = imm4:i:imm3:imm8 281 */ 282 offset = ((upper & 0x000f) << 12) | 283 ((upper & 0x0400) << 1) | 284 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 285 offset = (offset ^ 0x8000) - 0x8000; 286 offset += sym->st_value; 287 288 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 289 offset >>= 16; 290 291 upper = (u16)((upper & 0xfbf0) | 292 ((offset & 0xf000) >> 12) | 293 ((offset & 0x0800) >> 1)); 294 lower = (u16)((lower & 0x8f00) | 295 ((offset & 0x0700) << 4) | 296 (offset & 0x00ff)); 297 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 298 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 299 break; 300 #endif 301 302 default: 303 pr_err("%s: unknown relocation: %u\n", 304 module->name, ELF32_R_TYPE(rel->r_info)); 305 return -ENOEXEC; 306 } 307 } 308 return 0; 309 } 310 311 struct mod_unwind_map { 312 const Elf_Shdr *unw_sec; 313 const Elf_Shdr *txt_sec; 314 }; 315 316 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 317 const Elf_Shdr *sechdrs, const char *name) 318 { 319 const Elf_Shdr *s, *se; 320 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 321 322 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 323 if (strcmp(name, secstrs + s->sh_name) == 0) 324 return s; 325 326 return NULL; 327 } 328 329 extern void fixup_pv_table(const void *, unsigned long); 330 extern void fixup_smp(const void *, unsigned long); 331 332 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 333 struct module *mod) 334 { 335 const Elf_Shdr *s = NULL; 336 #ifdef CONFIG_ARM_UNWIND 337 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 338 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 339 struct mod_unwind_map maps[ARM_SEC_MAX]; 340 int i; 341 342 memset(maps, 0, sizeof(maps)); 343 344 for (s = sechdrs; s < sechdrs_end; s++) { 345 const char *secname = secstrs + s->sh_name; 346 347 if (!(s->sh_flags & SHF_ALLOC)) 348 continue; 349 350 if (strcmp(".ARM.exidx.init.text", secname) == 0) 351 maps[ARM_SEC_INIT].unw_sec = s; 352 else if (strcmp(".ARM.exidx", secname) == 0) 353 maps[ARM_SEC_CORE].unw_sec = s; 354 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 355 maps[ARM_SEC_EXIT].unw_sec = s; 356 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) 357 maps[ARM_SEC_UNLIKELY].unw_sec = s; 358 else if (strcmp(".ARM.exidx.text.hot", secname) == 0) 359 maps[ARM_SEC_HOT].unw_sec = s; 360 else if (strcmp(".init.text", secname) == 0) 361 maps[ARM_SEC_INIT].txt_sec = s; 362 else if (strcmp(".text", secname) == 0) 363 maps[ARM_SEC_CORE].txt_sec = s; 364 else if (strcmp(".exit.text", secname) == 0) 365 maps[ARM_SEC_EXIT].txt_sec = s; 366 else if (strcmp(".text.unlikely", secname) == 0) 367 maps[ARM_SEC_UNLIKELY].txt_sec = s; 368 else if (strcmp(".text.hot", secname) == 0) 369 maps[ARM_SEC_HOT].txt_sec = s; 370 } 371 372 for (i = 0; i < ARM_SEC_MAX; i++) 373 if (maps[i].unw_sec && maps[i].txt_sec) 374 mod->arch.unwind[i] = 375 unwind_table_add(maps[i].unw_sec->sh_addr, 376 maps[i].unw_sec->sh_size, 377 maps[i].txt_sec->sh_addr, 378 maps[i].txt_sec->sh_size); 379 #endif 380 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 381 s = find_mod_section(hdr, sechdrs, ".pv_table"); 382 if (s) 383 fixup_pv_table((void *)s->sh_addr, s->sh_size); 384 #endif 385 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 386 if (s && !is_smp()) 387 #ifdef CONFIG_SMP_ON_UP 388 fixup_smp((void *)s->sh_addr, s->sh_size); 389 #else 390 return -EINVAL; 391 #endif 392 return 0; 393 } 394 395 void 396 module_arch_cleanup(struct module *mod) 397 { 398 #ifdef CONFIG_ARM_UNWIND 399 int i; 400 401 for (i = 0; i < ARM_SEC_MAX; i++) 402 if (mod->arch.unwind[i]) 403 unwind_table_del(mod->arch.unwind[i]); 404 #endif 405 } 406