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