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