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 gfp_t gfp_mask = GFP_KERNEL; 44 void *p; 45 46 /* Silence the initial allocation */ 47 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS)) 48 gfp_mask |= __GFP_NOWARN; 49 50 p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 51 gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 52 __builtin_return_address(0)); 53 if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p) 54 return p; 55 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, 56 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 57 __builtin_return_address(0)); 58 } 59 #endif 60 61 int 62 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 63 unsigned int relindex, struct module *module) 64 { 65 Elf32_Shdr *symsec = sechdrs + symindex; 66 Elf32_Shdr *relsec = sechdrs + relindex; 67 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 68 Elf32_Rel *rel = (void *)relsec->sh_addr; 69 unsigned int i; 70 71 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 72 unsigned long loc; 73 Elf32_Sym *sym; 74 const char *symname; 75 s32 offset; 76 u32 tmp; 77 #ifdef CONFIG_THUMB2_KERNEL 78 u32 upper, lower, sign, j1, j2; 79 #endif 80 81 offset = ELF32_R_SYM(rel->r_info); 82 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 83 pr_err("%s: section %u reloc %u: bad relocation sym offset\n", 84 module->name, relindex, i); 85 return -ENOEXEC; 86 } 87 88 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 89 symname = strtab + sym->st_name; 90 91 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 92 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n", 93 module->name, relindex, i, symname, 94 rel->r_offset, dstsec->sh_size); 95 return -ENOEXEC; 96 } 97 98 loc = dstsec->sh_addr + rel->r_offset; 99 100 switch (ELF32_R_TYPE(rel->r_info)) { 101 case R_ARM_NONE: 102 /* ignore */ 103 break; 104 105 case R_ARM_ABS32: 106 case R_ARM_TARGET1: 107 *(u32 *)loc += sym->st_value; 108 break; 109 110 case R_ARM_PC24: 111 case R_ARM_CALL: 112 case R_ARM_JUMP24: 113 if (sym->st_value & 3) { 114 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n", 115 module->name, relindex, i, symname); 116 return -ENOEXEC; 117 } 118 119 offset = __mem_to_opcode_arm(*(u32 *)loc); 120 offset = (offset & 0x00ffffff) << 2; 121 if (offset & 0x02000000) 122 offset -= 0x04000000; 123 124 offset += sym->st_value - loc; 125 126 /* 127 * Route through a PLT entry if 'offset' exceeds the 128 * supported range. Note that 'offset + loc + 8' 129 * contains the absolute jump target, i.e., 130 * @sym + addend, corrected for the +8 PC bias. 131 */ 132 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 133 (offset <= (s32)0xfe000000 || 134 offset >= (s32)0x02000000)) 135 offset = get_module_plt(module, loc, 136 offset + loc + 8) 137 - loc - 8; 138 139 if (offset <= (s32)0xfe000000 || 140 offset >= (s32)0x02000000) { 141 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 142 module->name, relindex, i, symname, 143 ELF32_R_TYPE(rel->r_info), loc, 144 sym->st_value); 145 return -ENOEXEC; 146 } 147 148 offset >>= 2; 149 offset &= 0x00ffffff; 150 151 *(u32 *)loc &= __opcode_to_mem_arm(0xff000000); 152 *(u32 *)loc |= __opcode_to_mem_arm(offset); 153 break; 154 155 case R_ARM_V4BX: 156 /* Preserve Rm and the condition code. Alter 157 * other bits to re-code instruction as 158 * MOV PC,Rm. 159 */ 160 *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f); 161 *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000); 162 break; 163 164 case R_ARM_PREL31: 165 offset = (*(s32 *)loc << 1) >> 1; /* sign extend */ 166 offset += sym->st_value - loc; 167 if (offset >= 0x40000000 || offset < -0x40000000) { 168 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 169 module->name, relindex, i, symname, 170 ELF32_R_TYPE(rel->r_info), loc, 171 sym->st_value); 172 return -ENOEXEC; 173 } 174 *(u32 *)loc &= 0x80000000; 175 *(u32 *)loc |= offset & 0x7fffffff; 176 break; 177 178 case R_ARM_MOVW_ABS_NC: 179 case R_ARM_MOVT_ABS: 180 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc); 181 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 182 offset = (offset ^ 0x8000) - 0x8000; 183 184 offset += sym->st_value; 185 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 186 offset >>= 16; 187 188 tmp &= 0xfff0f000; 189 tmp |= ((offset & 0xf000) << 4) | 190 (offset & 0x0fff); 191 192 *(u32 *)loc = __opcode_to_mem_arm(tmp); 193 break; 194 195 #ifdef CONFIG_THUMB2_KERNEL 196 case R_ARM_THM_CALL: 197 case R_ARM_THM_JUMP24: 198 /* 199 * For function symbols, only Thumb addresses are 200 * allowed (no interworking). 201 * 202 * For non-function symbols, the destination 203 * has no specific ARM/Thumb disposition, so 204 * the branch is resolved under the assumption 205 * that interworking is not required. 206 */ 207 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 208 !(sym->st_value & 1)) { 209 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n", 210 module->name, relindex, i, symname); 211 return -ENOEXEC; 212 } 213 214 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 215 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 216 217 /* 218 * 25 bit signed address range (Thumb-2 BL and B.W 219 * instructions): 220 * S:I1:I2:imm10:imm11:0 221 * where: 222 * S = upper[10] = offset[24] 223 * I1 = ~(J1 ^ S) = offset[23] 224 * I2 = ~(J2 ^ S) = offset[22] 225 * imm10 = upper[9:0] = offset[21:12] 226 * imm11 = lower[10:0] = offset[11:1] 227 * J1 = lower[13] 228 * J2 = lower[11] 229 */ 230 sign = (upper >> 10) & 1; 231 j1 = (lower >> 13) & 1; 232 j2 = (lower >> 11) & 1; 233 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 234 ((~(j2 ^ sign) & 1) << 22) | 235 ((upper & 0x03ff) << 12) | 236 ((lower & 0x07ff) << 1); 237 if (offset & 0x01000000) 238 offset -= 0x02000000; 239 offset += sym->st_value - loc; 240 241 /* 242 * Route through a PLT entry if 'offset' exceeds the 243 * supported range. 244 */ 245 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 246 (offset <= (s32)0xff000000 || 247 offset >= (s32)0x01000000)) 248 offset = get_module_plt(module, loc, 249 offset + loc + 4) 250 - loc - 4; 251 252 if (offset <= (s32)0xff000000 || 253 offset >= (s32)0x01000000) { 254 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 255 module->name, relindex, i, symname, 256 ELF32_R_TYPE(rel->r_info), loc, 257 sym->st_value); 258 return -ENOEXEC; 259 } 260 261 sign = (offset >> 24) & 1; 262 j1 = sign ^ (~(offset >> 23) & 1); 263 j2 = sign ^ (~(offset >> 22) & 1); 264 upper = (u16)((upper & 0xf800) | (sign << 10) | 265 ((offset >> 12) & 0x03ff)); 266 lower = (u16)((lower & 0xd000) | 267 (j1 << 13) | (j2 << 11) | 268 ((offset >> 1) & 0x07ff)); 269 270 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 271 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 272 break; 273 274 case R_ARM_THM_MOVW_ABS_NC: 275 case R_ARM_THM_MOVT_ABS: 276 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 277 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 278 279 /* 280 * MOVT/MOVW instructions encoding in Thumb-2: 281 * 282 * i = upper[10] 283 * imm4 = upper[3:0] 284 * imm3 = lower[14:12] 285 * imm8 = lower[7:0] 286 * 287 * imm16 = imm4:i:imm3:imm8 288 */ 289 offset = ((upper & 0x000f) << 12) | 290 ((upper & 0x0400) << 1) | 291 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 292 offset = (offset ^ 0x8000) - 0x8000; 293 offset += sym->st_value; 294 295 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 296 offset >>= 16; 297 298 upper = (u16)((upper & 0xfbf0) | 299 ((offset & 0xf000) >> 12) | 300 ((offset & 0x0800) >> 1)); 301 lower = (u16)((lower & 0x8f00) | 302 ((offset & 0x0700) << 4) | 303 (offset & 0x00ff)); 304 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 305 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 306 break; 307 #endif 308 309 default: 310 pr_err("%s: unknown relocation: %u\n", 311 module->name, ELF32_R_TYPE(rel->r_info)); 312 return -ENOEXEC; 313 } 314 } 315 return 0; 316 } 317 318 struct mod_unwind_map { 319 const Elf_Shdr *unw_sec; 320 const Elf_Shdr *txt_sec; 321 }; 322 323 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 324 const Elf_Shdr *sechdrs, const char *name) 325 { 326 const Elf_Shdr *s, *se; 327 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 328 329 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 330 if (strcmp(name, secstrs + s->sh_name) == 0) 331 return s; 332 333 return NULL; 334 } 335 336 extern void fixup_pv_table(const void *, unsigned long); 337 extern void fixup_smp(const void *, unsigned long); 338 339 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 340 struct module *mod) 341 { 342 const Elf_Shdr *s = NULL; 343 #ifdef CONFIG_ARM_UNWIND 344 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 345 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 346 struct mod_unwind_map maps[ARM_SEC_MAX]; 347 int i; 348 349 memset(maps, 0, sizeof(maps)); 350 351 for (s = sechdrs; s < sechdrs_end; s++) { 352 const char *secname = secstrs + s->sh_name; 353 354 if (!(s->sh_flags & SHF_ALLOC)) 355 continue; 356 357 if (strcmp(".ARM.exidx.init.text", secname) == 0) 358 maps[ARM_SEC_INIT].unw_sec = s; 359 else if (strcmp(".ARM.exidx", secname) == 0) 360 maps[ARM_SEC_CORE].unw_sec = s; 361 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 362 maps[ARM_SEC_EXIT].unw_sec = s; 363 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) 364 maps[ARM_SEC_UNLIKELY].unw_sec = s; 365 else if (strcmp(".ARM.exidx.text.hot", secname) == 0) 366 maps[ARM_SEC_HOT].unw_sec = s; 367 else if (strcmp(".init.text", secname) == 0) 368 maps[ARM_SEC_INIT].txt_sec = s; 369 else if (strcmp(".text", secname) == 0) 370 maps[ARM_SEC_CORE].txt_sec = s; 371 else if (strcmp(".exit.text", secname) == 0) 372 maps[ARM_SEC_EXIT].txt_sec = s; 373 else if (strcmp(".text.unlikely", secname) == 0) 374 maps[ARM_SEC_UNLIKELY].txt_sec = s; 375 else if (strcmp(".text.hot", secname) == 0) 376 maps[ARM_SEC_HOT].txt_sec = s; 377 } 378 379 for (i = 0; i < ARM_SEC_MAX; i++) 380 if (maps[i].unw_sec && maps[i].txt_sec) 381 mod->arch.unwind[i] = 382 unwind_table_add(maps[i].unw_sec->sh_addr, 383 maps[i].unw_sec->sh_size, 384 maps[i].txt_sec->sh_addr, 385 maps[i].txt_sec->sh_size); 386 #endif 387 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 388 s = find_mod_section(hdr, sechdrs, ".pv_table"); 389 if (s) 390 fixup_pv_table((void *)s->sh_addr, s->sh_size); 391 #endif 392 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 393 if (s && !is_smp()) 394 #ifdef CONFIG_SMP_ON_UP 395 fixup_smp((void *)s->sh_addr, s->sh_size); 396 #else 397 return -EINVAL; 398 #endif 399 return 0; 400 } 401 402 void 403 module_arch_cleanup(struct module *mod) 404 { 405 #ifdef CONFIG_ARM_UNWIND 406 int i; 407 408 for (i = 0; i < ARM_SEC_MAX; i++) 409 if (mod->arch.unwind[i]) 410 unwind_table_del(mod->arch.unwind[i]); 411 #endif 412 } 413