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/unwind.h> 26 27 #ifdef CONFIG_XIP_KERNEL 28 /* 29 * The XIP kernel text is mapped in the module area for modules and 30 * some other stuff to work without any indirect relocations. 31 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 32 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 33 */ 34 #undef MODULES_VADDR 35 #define MODULES_VADDR (((unsigned long)_etext + ~PGDIR_MASK) & PGDIR_MASK) 36 #endif 37 38 #ifdef CONFIG_MMU 39 void *module_alloc(unsigned long size) 40 { 41 struct vm_struct *area; 42 43 size = PAGE_ALIGN(size); 44 if (!size) 45 return NULL; 46 47 area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END); 48 if (!area) 49 return NULL; 50 51 return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC); 52 } 53 #else /* CONFIG_MMU */ 54 void *module_alloc(unsigned long size) 55 { 56 return size == 0 ? NULL : vmalloc(size); 57 } 58 #endif /* !CONFIG_MMU */ 59 60 void module_free(struct module *module, void *region) 61 { 62 vfree(region); 63 } 64 65 int module_frob_arch_sections(Elf_Ehdr *hdr, 66 Elf_Shdr *sechdrs, 67 char *secstrings, 68 struct module *mod) 69 { 70 #ifdef CONFIG_ARM_UNWIND 71 Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum; 72 73 for (s = sechdrs; s < sechdrs_end; s++) { 74 if (strcmp(".ARM.exidx.init.text", secstrings + s->sh_name) == 0) 75 mod->arch.unw_sec_init = s; 76 else if (strcmp(".ARM.exidx.devinit.text", secstrings + s->sh_name) == 0) 77 mod->arch.unw_sec_devinit = s; 78 else if (strcmp(".ARM.exidx", secstrings + s->sh_name) == 0) 79 mod->arch.unw_sec_core = s; 80 else if (strcmp(".init.text", secstrings + s->sh_name) == 0) 81 mod->arch.sec_init_text = s; 82 else if (strcmp(".devinit.text", secstrings + s->sh_name) == 0) 83 mod->arch.sec_devinit_text = s; 84 else if (strcmp(".text", secstrings + s->sh_name) == 0) 85 mod->arch.sec_core_text = s; 86 } 87 #endif 88 return 0; 89 } 90 91 int 92 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 93 unsigned int relindex, struct module *module) 94 { 95 Elf32_Shdr *symsec = sechdrs + symindex; 96 Elf32_Shdr *relsec = sechdrs + relindex; 97 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 98 Elf32_Rel *rel = (void *)relsec->sh_addr; 99 unsigned int i; 100 101 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 102 unsigned long loc; 103 Elf32_Sym *sym; 104 s32 offset; 105 #ifdef CONFIG_THUMB2_KERNEL 106 u32 upper, lower, sign, j1, j2; 107 #endif 108 109 offset = ELF32_R_SYM(rel->r_info); 110 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 111 printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n", 112 module->name, relindex, i); 113 return -ENOEXEC; 114 } 115 116 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 117 118 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 119 printk(KERN_ERR "%s: out of bounds relocation, " 120 "section %d reloc %d offset %d size %d\n", 121 module->name, relindex, i, rel->r_offset, 122 dstsec->sh_size); 123 return -ENOEXEC; 124 } 125 126 loc = dstsec->sh_addr + rel->r_offset; 127 128 switch (ELF32_R_TYPE(rel->r_info)) { 129 case R_ARM_NONE: 130 /* ignore */ 131 break; 132 133 case R_ARM_ABS32: 134 *(u32 *)loc += sym->st_value; 135 break; 136 137 case R_ARM_PC24: 138 case R_ARM_CALL: 139 case R_ARM_JUMP24: 140 offset = (*(u32 *)loc & 0x00ffffff) << 2; 141 if (offset & 0x02000000) 142 offset -= 0x04000000; 143 144 offset += sym->st_value - loc; 145 if (offset & 3 || 146 offset <= (s32)0xfe000000 || 147 offset >= (s32)0x02000000) { 148 printk(KERN_ERR 149 "%s: relocation out of range, section " 150 "%d reloc %d sym '%s'\n", module->name, 151 relindex, i, strtab + sym->st_name); 152 return -ENOEXEC; 153 } 154 155 offset >>= 2; 156 157 *(u32 *)loc &= 0xff000000; 158 *(u32 *)loc |= offset & 0x00ffffff; 159 break; 160 161 case R_ARM_V4BX: 162 /* Preserve Rm and the condition code. Alter 163 * other bits to re-code instruction as 164 * MOV PC,Rm. 165 */ 166 *(u32 *)loc &= 0xf000000f; 167 *(u32 *)loc |= 0x01a0f000; 168 break; 169 170 case R_ARM_PREL31: 171 offset = *(u32 *)loc + sym->st_value - loc; 172 *(u32 *)loc = offset & 0x7fffffff; 173 break; 174 175 case R_ARM_MOVW_ABS_NC: 176 case R_ARM_MOVT_ABS: 177 offset = *(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 *(u32 *)loc &= 0xfff0f000; 186 *(u32 *)loc |= ((offset & 0xf000) << 4) | 187 (offset & 0x0fff); 188 break; 189 190 #ifdef CONFIG_THUMB2_KERNEL 191 case R_ARM_THM_CALL: 192 case R_ARM_THM_JUMP24: 193 upper = *(u16 *)loc; 194 lower = *(u16 *)(loc + 2); 195 196 /* 197 * 25 bit signed address range (Thumb-2 BL and B.W 198 * instructions): 199 * S:I1:I2:imm10:imm11:0 200 * where: 201 * S = upper[10] = offset[24] 202 * I1 = ~(J1 ^ S) = offset[23] 203 * I2 = ~(J2 ^ S) = offset[22] 204 * imm10 = upper[9:0] = offset[21:12] 205 * imm11 = lower[10:0] = offset[11:1] 206 * J1 = lower[13] 207 * J2 = lower[11] 208 */ 209 sign = (upper >> 10) & 1; 210 j1 = (lower >> 13) & 1; 211 j2 = (lower >> 11) & 1; 212 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 213 ((~(j2 ^ sign) & 1) << 22) | 214 ((upper & 0x03ff) << 12) | 215 ((lower & 0x07ff) << 1); 216 if (offset & 0x01000000) 217 offset -= 0x02000000; 218 offset += sym->st_value - loc; 219 220 /* only Thumb addresses allowed (no interworking) */ 221 if (!(offset & 1) || 222 offset <= (s32)0xff000000 || 223 offset >= (s32)0x01000000) { 224 printk(KERN_ERR 225 "%s: relocation out of range, section " 226 "%d reloc %d sym '%s'\n", module->name, 227 relindex, i, strtab + sym->st_name); 228 return -ENOEXEC; 229 } 230 231 sign = (offset >> 24) & 1; 232 j1 = sign ^ (~(offset >> 23) & 1); 233 j2 = sign ^ (~(offset >> 22) & 1); 234 *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) | 235 ((offset >> 12) & 0x03ff)); 236 *(u16 *)(loc + 2) = (u16)((lower & 0xd000) | 237 (j1 << 13) | (j2 << 11) | 238 ((offset >> 1) & 0x07ff)); 239 break; 240 241 case R_ARM_THM_MOVW_ABS_NC: 242 case R_ARM_THM_MOVT_ABS: 243 upper = *(u16 *)loc; 244 lower = *(u16 *)(loc + 2); 245 246 /* 247 * MOVT/MOVW instructions encoding in Thumb-2: 248 * 249 * i = upper[10] 250 * imm4 = upper[3:0] 251 * imm3 = lower[14:12] 252 * imm8 = lower[7:0] 253 * 254 * imm16 = imm4:i:imm3:imm8 255 */ 256 offset = ((upper & 0x000f) << 12) | 257 ((upper & 0x0400) << 1) | 258 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 259 offset = (offset ^ 0x8000) - 0x8000; 260 offset += sym->st_value; 261 262 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 263 offset >>= 16; 264 265 *(u16 *)loc = (u16)((upper & 0xfbf0) | 266 ((offset & 0xf000) >> 12) | 267 ((offset & 0x0800) >> 1)); 268 *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) | 269 ((offset & 0x0700) << 4) | 270 (offset & 0x00ff)); 271 break; 272 #endif 273 274 default: 275 printk(KERN_ERR "%s: unknown relocation: %u\n", 276 module->name, ELF32_R_TYPE(rel->r_info)); 277 return -ENOEXEC; 278 } 279 } 280 return 0; 281 } 282 283 int 284 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab, 285 unsigned int symindex, unsigned int relsec, struct module *module) 286 { 287 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", 288 module->name); 289 return -ENOEXEC; 290 } 291 292 #ifdef CONFIG_ARM_UNWIND 293 static void register_unwind_tables(struct module *mod) 294 { 295 if (mod->arch.unw_sec_init && mod->arch.sec_init_text) 296 mod->arch.unwind_init = 297 unwind_table_add(mod->arch.unw_sec_init->sh_addr, 298 mod->arch.unw_sec_init->sh_size, 299 mod->arch.sec_init_text->sh_addr, 300 mod->arch.sec_init_text->sh_size); 301 if (mod->arch.unw_sec_devinit && mod->arch.sec_devinit_text) 302 mod->arch.unwind_devinit = 303 unwind_table_add(mod->arch.unw_sec_devinit->sh_addr, 304 mod->arch.unw_sec_devinit->sh_size, 305 mod->arch.sec_devinit_text->sh_addr, 306 mod->arch.sec_devinit_text->sh_size); 307 if (mod->arch.unw_sec_core && mod->arch.sec_core_text) 308 mod->arch.unwind_core = 309 unwind_table_add(mod->arch.unw_sec_core->sh_addr, 310 mod->arch.unw_sec_core->sh_size, 311 mod->arch.sec_core_text->sh_addr, 312 mod->arch.sec_core_text->sh_size); 313 } 314 315 static void unregister_unwind_tables(struct module *mod) 316 { 317 unwind_table_del(mod->arch.unwind_init); 318 unwind_table_del(mod->arch.unwind_devinit); 319 unwind_table_del(mod->arch.unwind_core); 320 } 321 #else 322 static inline void register_unwind_tables(struct module *mod) { } 323 static inline void unregister_unwind_tables(struct module *mod) { } 324 #endif 325 326 int 327 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 328 struct module *module) 329 { 330 register_unwind_tables(module); 331 return 0; 332 } 333 334 void 335 module_arch_cleanup(struct module *mod) 336 { 337 unregister_unwind_tables(mod); 338 } 339