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