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 28 #ifdef CONFIG_XIP_KERNEL 29 /* 30 * The XIP kernel text is mapped in the module area for modules and 31 * some other stuff to work without any indirect relocations. 32 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 33 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 34 */ 35 #undef MODULES_VADDR 36 #define MODULES_VADDR (((unsigned long)_etext + ~PMD_MASK) & PMD_MASK) 37 #endif 38 39 #ifdef CONFIG_MMU 40 void *module_alloc(unsigned long size) 41 { 42 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 43 GFP_KERNEL, PAGE_KERNEL_EXEC, -1, 44 __builtin_return_address(0)); 45 } 46 #endif 47 48 int 49 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 50 unsigned int relindex, struct module *module) 51 { 52 Elf32_Shdr *symsec = sechdrs + symindex; 53 Elf32_Shdr *relsec = sechdrs + relindex; 54 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 55 Elf32_Rel *rel = (void *)relsec->sh_addr; 56 unsigned int i; 57 58 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 59 unsigned long loc; 60 Elf32_Sym *sym; 61 const char *symname; 62 s32 offset; 63 #ifdef CONFIG_THUMB2_KERNEL 64 u32 upper, lower, sign, j1, j2; 65 #endif 66 67 offset = ELF32_R_SYM(rel->r_info); 68 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 69 pr_err("%s: section %u reloc %u: bad relocation sym offset\n", 70 module->name, relindex, i); 71 return -ENOEXEC; 72 } 73 74 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 75 symname = strtab + sym->st_name; 76 77 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 78 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n", 79 module->name, relindex, i, symname, 80 rel->r_offset, dstsec->sh_size); 81 return -ENOEXEC; 82 } 83 84 loc = dstsec->sh_addr + rel->r_offset; 85 86 switch (ELF32_R_TYPE(rel->r_info)) { 87 case R_ARM_NONE: 88 /* ignore */ 89 break; 90 91 case R_ARM_ABS32: 92 *(u32 *)loc += sym->st_value; 93 break; 94 95 case R_ARM_PC24: 96 case R_ARM_CALL: 97 case R_ARM_JUMP24: 98 offset = (*(u32 *)loc & 0x00ffffff) << 2; 99 if (offset & 0x02000000) 100 offset -= 0x04000000; 101 102 offset += sym->st_value - loc; 103 if (offset & 3 || 104 offset <= (s32)0xfe000000 || 105 offset >= (s32)0x02000000) { 106 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 107 module->name, relindex, i, symname, 108 ELF32_R_TYPE(rel->r_info), loc, 109 sym->st_value); 110 return -ENOEXEC; 111 } 112 113 offset >>= 2; 114 115 *(u32 *)loc &= 0xff000000; 116 *(u32 *)loc |= offset & 0x00ffffff; 117 break; 118 119 case R_ARM_V4BX: 120 /* Preserve Rm and the condition code. Alter 121 * other bits to re-code instruction as 122 * MOV PC,Rm. 123 */ 124 *(u32 *)loc &= 0xf000000f; 125 *(u32 *)loc |= 0x01a0f000; 126 break; 127 128 case R_ARM_PREL31: 129 offset = *(u32 *)loc + sym->st_value - loc; 130 *(u32 *)loc = offset & 0x7fffffff; 131 break; 132 133 case R_ARM_MOVW_ABS_NC: 134 case R_ARM_MOVT_ABS: 135 offset = *(u32 *)loc; 136 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 137 offset = (offset ^ 0x8000) - 0x8000; 138 139 offset += sym->st_value; 140 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 141 offset >>= 16; 142 143 *(u32 *)loc &= 0xfff0f000; 144 *(u32 *)loc |= ((offset & 0xf000) << 4) | 145 (offset & 0x0fff); 146 break; 147 148 #ifdef CONFIG_THUMB2_KERNEL 149 case R_ARM_THM_CALL: 150 case R_ARM_THM_JUMP24: 151 upper = *(u16 *)loc; 152 lower = *(u16 *)(loc + 2); 153 154 /* 155 * 25 bit signed address range (Thumb-2 BL and B.W 156 * instructions): 157 * S:I1:I2:imm10:imm11:0 158 * where: 159 * S = upper[10] = offset[24] 160 * I1 = ~(J1 ^ S) = offset[23] 161 * I2 = ~(J2 ^ S) = offset[22] 162 * imm10 = upper[9:0] = offset[21:12] 163 * imm11 = lower[10:0] = offset[11:1] 164 * J1 = lower[13] 165 * J2 = lower[11] 166 */ 167 sign = (upper >> 10) & 1; 168 j1 = (lower >> 13) & 1; 169 j2 = (lower >> 11) & 1; 170 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 171 ((~(j2 ^ sign) & 1) << 22) | 172 ((upper & 0x03ff) << 12) | 173 ((lower & 0x07ff) << 1); 174 if (offset & 0x01000000) 175 offset -= 0x02000000; 176 offset += sym->st_value - loc; 177 178 /* 179 * For function symbols, only Thumb addresses are 180 * allowed (no interworking). 181 * 182 * For non-function symbols, the destination 183 * has no specific ARM/Thumb disposition, so 184 * the branch is resolved under the assumption 185 * that interworking is not required. 186 */ 187 if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 188 !(offset & 1)) || 189 offset <= (s32)0xff000000 || 190 offset >= (s32)0x01000000) { 191 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 192 module->name, relindex, i, symname, 193 ELF32_R_TYPE(rel->r_info), loc, 194 sym->st_value); 195 return -ENOEXEC; 196 } 197 198 sign = (offset >> 24) & 1; 199 j1 = sign ^ (~(offset >> 23) & 1); 200 j2 = sign ^ (~(offset >> 22) & 1); 201 *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) | 202 ((offset >> 12) & 0x03ff)); 203 *(u16 *)(loc + 2) = (u16)((lower & 0xd000) | 204 (j1 << 13) | (j2 << 11) | 205 ((offset >> 1) & 0x07ff)); 206 break; 207 208 case R_ARM_THM_MOVW_ABS_NC: 209 case R_ARM_THM_MOVT_ABS: 210 upper = *(u16 *)loc; 211 lower = *(u16 *)(loc + 2); 212 213 /* 214 * MOVT/MOVW instructions encoding in Thumb-2: 215 * 216 * i = upper[10] 217 * imm4 = upper[3:0] 218 * imm3 = lower[14:12] 219 * imm8 = lower[7:0] 220 * 221 * imm16 = imm4:i:imm3:imm8 222 */ 223 offset = ((upper & 0x000f) << 12) | 224 ((upper & 0x0400) << 1) | 225 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 226 offset = (offset ^ 0x8000) - 0x8000; 227 offset += sym->st_value; 228 229 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 230 offset >>= 16; 231 232 *(u16 *)loc = (u16)((upper & 0xfbf0) | 233 ((offset & 0xf000) >> 12) | 234 ((offset & 0x0800) >> 1)); 235 *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) | 236 ((offset & 0x0700) << 4) | 237 (offset & 0x00ff)); 238 break; 239 #endif 240 241 default: 242 printk(KERN_ERR "%s: unknown relocation: %u\n", 243 module->name, ELF32_R_TYPE(rel->r_info)); 244 return -ENOEXEC; 245 } 246 } 247 return 0; 248 } 249 250 struct mod_unwind_map { 251 const Elf_Shdr *unw_sec; 252 const Elf_Shdr *txt_sec; 253 }; 254 255 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 256 const Elf_Shdr *sechdrs, const char *name) 257 { 258 const Elf_Shdr *s, *se; 259 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 260 261 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 262 if (strcmp(name, secstrs + s->sh_name) == 0) 263 return s; 264 265 return NULL; 266 } 267 268 extern void fixup_pv_table(const void *, unsigned long); 269 extern void fixup_smp(const void *, unsigned long); 270 271 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 272 struct module *mod) 273 { 274 const Elf_Shdr *s = NULL; 275 #ifdef CONFIG_ARM_UNWIND 276 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 277 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 278 struct mod_unwind_map maps[ARM_SEC_MAX]; 279 int i; 280 281 memset(maps, 0, sizeof(maps)); 282 283 for (s = sechdrs; s < sechdrs_end; s++) { 284 const char *secname = secstrs + s->sh_name; 285 286 if (!(s->sh_flags & SHF_ALLOC)) 287 continue; 288 289 if (strcmp(".ARM.exidx.init.text", secname) == 0) 290 maps[ARM_SEC_INIT].unw_sec = s; 291 else if (strcmp(".ARM.exidx", secname) == 0) 292 maps[ARM_SEC_CORE].unw_sec = s; 293 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 294 maps[ARM_SEC_EXIT].unw_sec = s; 295 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) 296 maps[ARM_SEC_UNLIKELY].unw_sec = s; 297 else if (strcmp(".ARM.exidx.text.hot", secname) == 0) 298 maps[ARM_SEC_HOT].unw_sec = s; 299 else if (strcmp(".init.text", secname) == 0) 300 maps[ARM_SEC_INIT].txt_sec = s; 301 else if (strcmp(".text", secname) == 0) 302 maps[ARM_SEC_CORE].txt_sec = s; 303 else if (strcmp(".exit.text", secname) == 0) 304 maps[ARM_SEC_EXIT].txt_sec = s; 305 else if (strcmp(".text.unlikely", secname) == 0) 306 maps[ARM_SEC_UNLIKELY].txt_sec = s; 307 else if (strcmp(".text.hot", secname) == 0) 308 maps[ARM_SEC_HOT].txt_sec = s; 309 } 310 311 for (i = 0; i < ARM_SEC_MAX; i++) 312 if (maps[i].unw_sec && maps[i].txt_sec) 313 mod->arch.unwind[i] = 314 unwind_table_add(maps[i].unw_sec->sh_addr, 315 maps[i].unw_sec->sh_size, 316 maps[i].txt_sec->sh_addr, 317 maps[i].txt_sec->sh_size); 318 #endif 319 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 320 s = find_mod_section(hdr, sechdrs, ".pv_table"); 321 if (s) 322 fixup_pv_table((void *)s->sh_addr, s->sh_size); 323 #endif 324 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 325 if (s && !is_smp()) 326 #ifdef CONFIG_SMP_ON_UP 327 fixup_smp((void *)s->sh_addr, s->sh_size); 328 #else 329 return -EINVAL; 330 #endif 331 return 0; 332 } 333 334 void 335 module_arch_cleanup(struct module *mod) 336 { 337 #ifdef CONFIG_ARM_UNWIND 338 int i; 339 340 for (i = 0; i < ARM_SEC_MAX; i++) 341 if (mod->arch.unwind[i]) 342 unwind_table_del(mod->arch.unwind[i]); 343 #endif 344 } 345