1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/kernel/module.c 4 * 5 * Copyright (C) 2002 Russell King. 6 * Modified for nommu by Hyok S. Choi 7 * 8 * Module allocation method suggested by Andi Kleen. 9 */ 10 #include <linux/module.h> 11 #include <linux/moduleloader.h> 12 #include <linux/kernel.h> 13 #include <linux/mm.h> 14 #include <linux/elf.h> 15 #include <linux/vmalloc.h> 16 #include <linux/fs.h> 17 #include <linux/string.h> 18 #include <linux/gfp.h> 19 20 #include <asm/pgtable.h> 21 #include <asm/sections.h> 22 #include <asm/smp_plat.h> 23 #include <asm/unwind.h> 24 #include <asm/opcodes.h> 25 26 #ifdef CONFIG_XIP_KERNEL 27 /* 28 * The XIP kernel text is mapped in the module area for modules and 29 * some other stuff to work without any indirect relocations. 30 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 31 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 32 */ 33 #undef MODULES_VADDR 34 #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK) 35 #endif 36 37 #ifdef CONFIG_MMU 38 void *module_alloc(unsigned long size) 39 { 40 gfp_t gfp_mask = GFP_KERNEL; 41 void *p; 42 43 /* Silence the initial allocation */ 44 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS)) 45 gfp_mask |= __GFP_NOWARN; 46 47 p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 48 gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 49 __builtin_return_address(0)); 50 if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p) 51 return p; 52 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, 53 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, 54 __builtin_return_address(0)); 55 } 56 #endif 57 58 bool module_init_section(const char *name) 59 { 60 return strstarts(name, ".init") || 61 strstarts(name, ".ARM.extab.init") || 62 strstarts(name, ".ARM.exidx.init"); 63 } 64 65 bool module_exit_section(const char *name) 66 { 67 return strstarts(name, ".exit") || 68 strstarts(name, ".ARM.extab.exit") || 69 strstarts(name, ".ARM.exidx.exit"); 70 } 71 72 int 73 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 74 unsigned int relindex, struct module *module) 75 { 76 Elf32_Shdr *symsec = sechdrs + symindex; 77 Elf32_Shdr *relsec = sechdrs + relindex; 78 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 79 Elf32_Rel *rel = (void *)relsec->sh_addr; 80 unsigned int i; 81 82 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 83 unsigned long loc; 84 Elf32_Sym *sym; 85 const char *symname; 86 s32 offset; 87 u32 tmp; 88 #ifdef CONFIG_THUMB2_KERNEL 89 u32 upper, lower, sign, j1, j2; 90 #endif 91 92 offset = ELF32_R_SYM(rel->r_info); 93 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 94 pr_err("%s: section %u reloc %u: bad relocation sym offset\n", 95 module->name, relindex, i); 96 return -ENOEXEC; 97 } 98 99 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 100 symname = strtab + sym->st_name; 101 102 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 103 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n", 104 module->name, relindex, i, symname, 105 rel->r_offset, dstsec->sh_size); 106 return -ENOEXEC; 107 } 108 109 loc = dstsec->sh_addr + rel->r_offset; 110 111 switch (ELF32_R_TYPE(rel->r_info)) { 112 case R_ARM_NONE: 113 /* ignore */ 114 break; 115 116 case R_ARM_ABS32: 117 case R_ARM_TARGET1: 118 *(u32 *)loc += sym->st_value; 119 break; 120 121 case R_ARM_PC24: 122 case R_ARM_CALL: 123 case R_ARM_JUMP24: 124 if (sym->st_value & 3) { 125 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n", 126 module->name, relindex, i, symname); 127 return -ENOEXEC; 128 } 129 130 offset = __mem_to_opcode_arm(*(u32 *)loc); 131 offset = (offset & 0x00ffffff) << 2; 132 if (offset & 0x02000000) 133 offset -= 0x04000000; 134 135 offset += sym->st_value - loc; 136 137 /* 138 * Route through a PLT entry if 'offset' exceeds the 139 * supported range. Note that 'offset + loc + 8' 140 * contains the absolute jump target, i.e., 141 * @sym + addend, corrected for the +8 PC bias. 142 */ 143 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 144 (offset <= (s32)0xfe000000 || 145 offset >= (s32)0x02000000)) 146 offset = get_module_plt(module, loc, 147 offset + loc + 8) 148 - loc - 8; 149 150 if (offset <= (s32)0xfe000000 || 151 offset >= (s32)0x02000000) { 152 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 153 module->name, relindex, i, symname, 154 ELF32_R_TYPE(rel->r_info), loc, 155 sym->st_value); 156 return -ENOEXEC; 157 } 158 159 offset >>= 2; 160 offset &= 0x00ffffff; 161 162 *(u32 *)loc &= __opcode_to_mem_arm(0xff000000); 163 *(u32 *)loc |= __opcode_to_mem_arm(offset); 164 break; 165 166 case R_ARM_V4BX: 167 /* Preserve Rm and the condition code. Alter 168 * other bits to re-code instruction as 169 * MOV PC,Rm. 170 */ 171 *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f); 172 *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000); 173 break; 174 175 case R_ARM_PREL31: 176 offset = (*(s32 *)loc << 1) >> 1; /* sign extend */ 177 offset += sym->st_value - loc; 178 if (offset >= 0x40000000 || offset < -0x40000000) { 179 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 180 module->name, relindex, i, symname, 181 ELF32_R_TYPE(rel->r_info), loc, 182 sym->st_value); 183 return -ENOEXEC; 184 } 185 *(u32 *)loc &= 0x80000000; 186 *(u32 *)loc |= offset & 0x7fffffff; 187 break; 188 189 case R_ARM_MOVW_ABS_NC: 190 case R_ARM_MOVT_ABS: 191 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc); 192 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 193 offset = (offset ^ 0x8000) - 0x8000; 194 195 offset += sym->st_value; 196 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 197 offset >>= 16; 198 199 tmp &= 0xfff0f000; 200 tmp |= ((offset & 0xf000) << 4) | 201 (offset & 0x0fff); 202 203 *(u32 *)loc = __opcode_to_mem_arm(tmp); 204 break; 205 206 #ifdef CONFIG_THUMB2_KERNEL 207 case R_ARM_THM_CALL: 208 case R_ARM_THM_JUMP24: 209 /* 210 * For function symbols, only Thumb addresses are 211 * allowed (no interworking). 212 * 213 * For non-function symbols, the destination 214 * has no specific ARM/Thumb disposition, so 215 * the branch is resolved under the assumption 216 * that interworking is not required. 217 */ 218 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 219 !(sym->st_value & 1)) { 220 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n", 221 module->name, relindex, i, symname); 222 return -ENOEXEC; 223 } 224 225 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 226 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 227 228 /* 229 * 25 bit signed address range (Thumb-2 BL and B.W 230 * instructions): 231 * S:I1:I2:imm10:imm11:0 232 * where: 233 * S = upper[10] = offset[24] 234 * I1 = ~(J1 ^ S) = offset[23] 235 * I2 = ~(J2 ^ S) = offset[22] 236 * imm10 = upper[9:0] = offset[21:12] 237 * imm11 = lower[10:0] = offset[11:1] 238 * J1 = lower[13] 239 * J2 = lower[11] 240 */ 241 sign = (upper >> 10) & 1; 242 j1 = (lower >> 13) & 1; 243 j2 = (lower >> 11) & 1; 244 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 245 ((~(j2 ^ sign) & 1) << 22) | 246 ((upper & 0x03ff) << 12) | 247 ((lower & 0x07ff) << 1); 248 if (offset & 0x01000000) 249 offset -= 0x02000000; 250 offset += sym->st_value - loc; 251 252 /* 253 * Route through a PLT entry if 'offset' exceeds the 254 * supported range. 255 */ 256 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 257 (offset <= (s32)0xff000000 || 258 offset >= (s32)0x01000000)) 259 offset = get_module_plt(module, loc, 260 offset + loc + 4) 261 - loc - 4; 262 263 if (offset <= (s32)0xff000000 || 264 offset >= (s32)0x01000000) { 265 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 266 module->name, relindex, i, symname, 267 ELF32_R_TYPE(rel->r_info), loc, 268 sym->st_value); 269 return -ENOEXEC; 270 } 271 272 sign = (offset >> 24) & 1; 273 j1 = sign ^ (~(offset >> 23) & 1); 274 j2 = sign ^ (~(offset >> 22) & 1); 275 upper = (u16)((upper & 0xf800) | (sign << 10) | 276 ((offset >> 12) & 0x03ff)); 277 lower = (u16)((lower & 0xd000) | 278 (j1 << 13) | (j2 << 11) | 279 ((offset >> 1) & 0x07ff)); 280 281 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 282 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 283 break; 284 285 case R_ARM_THM_MOVW_ABS_NC: 286 case R_ARM_THM_MOVT_ABS: 287 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 288 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 289 290 /* 291 * MOVT/MOVW instructions encoding in Thumb-2: 292 * 293 * i = upper[10] 294 * imm4 = upper[3:0] 295 * imm3 = lower[14:12] 296 * imm8 = lower[7:0] 297 * 298 * imm16 = imm4:i:imm3:imm8 299 */ 300 offset = ((upper & 0x000f) << 12) | 301 ((upper & 0x0400) << 1) | 302 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 303 offset = (offset ^ 0x8000) - 0x8000; 304 offset += sym->st_value; 305 306 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 307 offset >>= 16; 308 309 upper = (u16)((upper & 0xfbf0) | 310 ((offset & 0xf000) >> 12) | 311 ((offset & 0x0800) >> 1)); 312 lower = (u16)((lower & 0x8f00) | 313 ((offset & 0x0700) << 4) | 314 (offset & 0x00ff)); 315 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 316 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 317 break; 318 #endif 319 320 default: 321 pr_err("%s: unknown relocation: %u\n", 322 module->name, ELF32_R_TYPE(rel->r_info)); 323 return -ENOEXEC; 324 } 325 } 326 return 0; 327 } 328 329 struct mod_unwind_map { 330 const Elf_Shdr *unw_sec; 331 const Elf_Shdr *txt_sec; 332 }; 333 334 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 335 const Elf_Shdr *sechdrs, const char *name) 336 { 337 const Elf_Shdr *s, *se; 338 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 339 340 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 341 if (strcmp(name, secstrs + s->sh_name) == 0) 342 return s; 343 344 return NULL; 345 } 346 347 extern void fixup_pv_table(const void *, unsigned long); 348 extern void fixup_smp(const void *, unsigned long); 349 350 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 351 struct module *mod) 352 { 353 const Elf_Shdr *s = NULL; 354 #ifdef CONFIG_ARM_UNWIND 355 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 356 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 357 struct mod_unwind_map maps[ARM_SEC_MAX]; 358 int i; 359 360 memset(maps, 0, sizeof(maps)); 361 362 for (s = sechdrs; s < sechdrs_end; s++) { 363 const char *secname = secstrs + s->sh_name; 364 365 if (!(s->sh_flags & SHF_ALLOC)) 366 continue; 367 368 if (strcmp(".ARM.exidx.init.text", secname) == 0) 369 maps[ARM_SEC_INIT].unw_sec = s; 370 else if (strcmp(".ARM.exidx", secname) == 0) 371 maps[ARM_SEC_CORE].unw_sec = s; 372 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 373 maps[ARM_SEC_EXIT].unw_sec = s; 374 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) 375 maps[ARM_SEC_UNLIKELY].unw_sec = s; 376 else if (strcmp(".ARM.exidx.text.hot", secname) == 0) 377 maps[ARM_SEC_HOT].unw_sec = s; 378 else if (strcmp(".init.text", secname) == 0) 379 maps[ARM_SEC_INIT].txt_sec = s; 380 else if (strcmp(".text", secname) == 0) 381 maps[ARM_SEC_CORE].txt_sec = s; 382 else if (strcmp(".exit.text", secname) == 0) 383 maps[ARM_SEC_EXIT].txt_sec = s; 384 else if (strcmp(".text.unlikely", secname) == 0) 385 maps[ARM_SEC_UNLIKELY].txt_sec = s; 386 else if (strcmp(".text.hot", secname) == 0) 387 maps[ARM_SEC_HOT].txt_sec = s; 388 } 389 390 for (i = 0; i < ARM_SEC_MAX; i++) 391 if (maps[i].unw_sec && maps[i].txt_sec) 392 mod->arch.unwind[i] = 393 unwind_table_add(maps[i].unw_sec->sh_addr, 394 maps[i].unw_sec->sh_size, 395 maps[i].txt_sec->sh_addr, 396 maps[i].txt_sec->sh_size); 397 #endif 398 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 399 s = find_mod_section(hdr, sechdrs, ".pv_table"); 400 if (s) 401 fixup_pv_table((void *)s->sh_addr, s->sh_size); 402 #endif 403 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 404 if (s && !is_smp()) 405 #ifdef CONFIG_SMP_ON_UP 406 fixup_smp((void *)s->sh_addr, s->sh_size); 407 #else 408 return -EINVAL; 409 #endif 410 return 0; 411 } 412 413 void 414 module_arch_cleanup(struct module *mod) 415 { 416 #ifdef CONFIG_ARM_UNWIND 417 int i; 418 419 for (i = 0; i < ARM_SEC_MAX; i++) { 420 unwind_table_del(mod->arch.unwind[i]); 421 mod->arch.unwind[i] = NULL; 422 } 423 #endif 424 } 425 426 void __weak module_arch_freeing_init(struct module *mod) 427 { 428 #ifdef CONFIG_ARM_UNWIND 429 unwind_table_del(mod->arch.unwind[ARM_SEC_INIT]); 430 mod->arch.unwind[ARM_SEC_INIT] = NULL; 431 #endif 432 } 433