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