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)_etext + ~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 = *(u32 *)loc + sym->st_value - loc; 159 *(u32 *)loc = offset & 0x7fffffff; 160 break; 161 162 case R_ARM_MOVW_ABS_NC: 163 case R_ARM_MOVT_ABS: 164 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc); 165 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 166 offset = (offset ^ 0x8000) - 0x8000; 167 168 offset += sym->st_value; 169 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 170 offset >>= 16; 171 172 tmp &= 0xfff0f000; 173 tmp |= ((offset & 0xf000) << 4) | 174 (offset & 0x0fff); 175 176 *(u32 *)loc = __opcode_to_mem_arm(tmp); 177 break; 178 179 #ifdef CONFIG_THUMB2_KERNEL 180 case R_ARM_THM_CALL: 181 case R_ARM_THM_JUMP24: 182 /* 183 * For function symbols, only Thumb addresses are 184 * allowed (no interworking). 185 * 186 * For non-function symbols, the destination 187 * has no specific ARM/Thumb disposition, so 188 * the branch is resolved under the assumption 189 * that interworking is not required. 190 */ 191 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 192 !(sym->st_value & 1)) { 193 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n", 194 module->name, relindex, i, symname); 195 return -ENOEXEC; 196 } 197 198 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 199 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 200 201 /* 202 * 25 bit signed address range (Thumb-2 BL and B.W 203 * instructions): 204 * S:I1:I2:imm10:imm11:0 205 * where: 206 * S = upper[10] = offset[24] 207 * I1 = ~(J1 ^ S) = offset[23] 208 * I2 = ~(J2 ^ S) = offset[22] 209 * imm10 = upper[9:0] = offset[21:12] 210 * imm11 = lower[10:0] = offset[11:1] 211 * J1 = lower[13] 212 * J2 = lower[11] 213 */ 214 sign = (upper >> 10) & 1; 215 j1 = (lower >> 13) & 1; 216 j2 = (lower >> 11) & 1; 217 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 218 ((~(j2 ^ sign) & 1) << 22) | 219 ((upper & 0x03ff) << 12) | 220 ((lower & 0x07ff) << 1); 221 if (offset & 0x01000000) 222 offset -= 0x02000000; 223 offset += sym->st_value - loc; 224 225 /* 226 * Route through a PLT entry if 'offset' exceeds the 227 * supported range. 228 */ 229 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) && 230 (offset <= (s32)0xff000000 || 231 offset >= (s32)0x01000000)) 232 offset = get_module_plt(module, loc, 233 offset + loc + 4) 234 - loc - 4; 235 236 if (offset <= (s32)0xff000000 || 237 offset >= (s32)0x01000000) { 238 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 239 module->name, relindex, i, symname, 240 ELF32_R_TYPE(rel->r_info), loc, 241 sym->st_value); 242 return -ENOEXEC; 243 } 244 245 sign = (offset >> 24) & 1; 246 j1 = sign ^ (~(offset >> 23) & 1); 247 j2 = sign ^ (~(offset >> 22) & 1); 248 upper = (u16)((upper & 0xf800) | (sign << 10) | 249 ((offset >> 12) & 0x03ff)); 250 lower = (u16)((lower & 0xd000) | 251 (j1 << 13) | (j2 << 11) | 252 ((offset >> 1) & 0x07ff)); 253 254 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 255 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 256 break; 257 258 case R_ARM_THM_MOVW_ABS_NC: 259 case R_ARM_THM_MOVT_ABS: 260 upper = __mem_to_opcode_thumb16(*(u16 *)loc); 261 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2)); 262 263 /* 264 * MOVT/MOVW instructions encoding in Thumb-2: 265 * 266 * i = upper[10] 267 * imm4 = upper[3:0] 268 * imm3 = lower[14:12] 269 * imm8 = lower[7:0] 270 * 271 * imm16 = imm4:i:imm3:imm8 272 */ 273 offset = ((upper & 0x000f) << 12) | 274 ((upper & 0x0400) << 1) | 275 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 276 offset = (offset ^ 0x8000) - 0x8000; 277 offset += sym->st_value; 278 279 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 280 offset >>= 16; 281 282 upper = (u16)((upper & 0xfbf0) | 283 ((offset & 0xf000) >> 12) | 284 ((offset & 0x0800) >> 1)); 285 lower = (u16)((lower & 0x8f00) | 286 ((offset & 0x0700) << 4) | 287 (offset & 0x00ff)); 288 *(u16 *)loc = __opcode_to_mem_thumb16(upper); 289 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower); 290 break; 291 #endif 292 293 default: 294 pr_err("%s: unknown relocation: %u\n", 295 module->name, ELF32_R_TYPE(rel->r_info)); 296 return -ENOEXEC; 297 } 298 } 299 return 0; 300 } 301 302 struct mod_unwind_map { 303 const Elf_Shdr *unw_sec; 304 const Elf_Shdr *txt_sec; 305 }; 306 307 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 308 const Elf_Shdr *sechdrs, const char *name) 309 { 310 const Elf_Shdr *s, *se; 311 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 312 313 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 314 if (strcmp(name, secstrs + s->sh_name) == 0) 315 return s; 316 317 return NULL; 318 } 319 320 extern void fixup_pv_table(const void *, unsigned long); 321 extern void fixup_smp(const void *, unsigned long); 322 323 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 324 struct module *mod) 325 { 326 const Elf_Shdr *s = NULL; 327 #ifdef CONFIG_ARM_UNWIND 328 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 329 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 330 struct mod_unwind_map maps[ARM_SEC_MAX]; 331 int i; 332 333 memset(maps, 0, sizeof(maps)); 334 335 for (s = sechdrs; s < sechdrs_end; s++) { 336 const char *secname = secstrs + s->sh_name; 337 338 if (!(s->sh_flags & SHF_ALLOC)) 339 continue; 340 341 if (strcmp(".ARM.exidx.init.text", secname) == 0) 342 maps[ARM_SEC_INIT].unw_sec = s; 343 else if (strcmp(".ARM.exidx", secname) == 0) 344 maps[ARM_SEC_CORE].unw_sec = s; 345 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 346 maps[ARM_SEC_EXIT].unw_sec = s; 347 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) 348 maps[ARM_SEC_UNLIKELY].unw_sec = s; 349 else if (strcmp(".ARM.exidx.text.hot", secname) == 0) 350 maps[ARM_SEC_HOT].unw_sec = s; 351 else if (strcmp(".init.text", secname) == 0) 352 maps[ARM_SEC_INIT].txt_sec = s; 353 else if (strcmp(".text", secname) == 0) 354 maps[ARM_SEC_CORE].txt_sec = s; 355 else if (strcmp(".exit.text", secname) == 0) 356 maps[ARM_SEC_EXIT].txt_sec = s; 357 else if (strcmp(".text.unlikely", secname) == 0) 358 maps[ARM_SEC_UNLIKELY].txt_sec = s; 359 else if (strcmp(".text.hot", secname) == 0) 360 maps[ARM_SEC_HOT].txt_sec = s; 361 } 362 363 for (i = 0; i < ARM_SEC_MAX; i++) 364 if (maps[i].unw_sec && maps[i].txt_sec) 365 mod->arch.unwind[i] = 366 unwind_table_add(maps[i].unw_sec->sh_addr, 367 maps[i].unw_sec->sh_size, 368 maps[i].txt_sec->sh_addr, 369 maps[i].txt_sec->sh_size); 370 #endif 371 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 372 s = find_mod_section(hdr, sechdrs, ".pv_table"); 373 if (s) 374 fixup_pv_table((void *)s->sh_addr, s->sh_size); 375 #endif 376 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 377 if (s && !is_smp()) 378 #ifdef CONFIG_SMP_ON_UP 379 fixup_smp((void *)s->sh_addr, s->sh_size); 380 #else 381 return -EINVAL; 382 #endif 383 return 0; 384 } 385 386 void 387 module_arch_cleanup(struct module *mod) 388 { 389 #ifdef CONFIG_ARM_UNWIND 390 int i; 391 392 for (i = 0; i < ARM_SEC_MAX; i++) 393 if (mod->arch.unwind[i]) 394 unwind_table_del(mod->arch.unwind[i]); 395 #endif 396 } 397