1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Kernel module help for s390. 4 * 5 * S390 version 6 * Copyright IBM Corp. 2002, 2003 7 * Author(s): Arnd Bergmann (arndb@de.ibm.com) 8 * Martin Schwidefsky (schwidefsky@de.ibm.com) 9 * 10 * based on i386 version 11 * Copyright (C) 2001 Rusty Russell. 12 */ 13 #include <linux/module.h> 14 #include <linux/elf.h> 15 #include <linux/vmalloc.h> 16 #include <linux/fs.h> 17 #include <linux/string.h> 18 #include <linux/kernel.h> 19 #include <linux/moduleloader.h> 20 #include <linux/bug.h> 21 #include <asm/alternative.h> 22 23 #if 0 24 #define DEBUGP printk 25 #else 26 #define DEBUGP(fmt , ...) 27 #endif 28 29 #define PLT_ENTRY_SIZE 20 30 31 void *module_alloc(unsigned long size) 32 { 33 if (PAGE_ALIGN(size) > MODULES_LEN) 34 return NULL; 35 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 36 GFP_KERNEL, PAGE_KERNEL_EXEC, 37 0, NUMA_NO_NODE, 38 __builtin_return_address(0)); 39 } 40 41 void module_arch_freeing_init(struct module *mod) 42 { 43 if (is_livepatch_module(mod) && 44 mod->state == MODULE_STATE_LIVE) 45 return; 46 47 vfree(mod->arch.syminfo); 48 mod->arch.syminfo = NULL; 49 } 50 51 static void check_rela(Elf_Rela *rela, struct module *me) 52 { 53 struct mod_arch_syminfo *info; 54 55 info = me->arch.syminfo + ELF_R_SYM (rela->r_info); 56 switch (ELF_R_TYPE (rela->r_info)) { 57 case R_390_GOT12: /* 12 bit GOT offset. */ 58 case R_390_GOT16: /* 16 bit GOT offset. */ 59 case R_390_GOT20: /* 20 bit GOT offset. */ 60 case R_390_GOT32: /* 32 bit GOT offset. */ 61 case R_390_GOT64: /* 64 bit GOT offset. */ 62 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 63 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 64 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 65 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 66 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 67 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 68 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 69 if (info->got_offset == -1UL) { 70 info->got_offset = me->arch.got_size; 71 me->arch.got_size += sizeof(void*); 72 } 73 break; 74 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 75 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 76 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 77 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 78 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 79 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 80 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 81 if (info->plt_offset == -1UL) { 82 info->plt_offset = me->arch.plt_size; 83 me->arch.plt_size += PLT_ENTRY_SIZE; 84 } 85 break; 86 case R_390_COPY: 87 case R_390_GLOB_DAT: 88 case R_390_JMP_SLOT: 89 case R_390_RELATIVE: 90 /* Only needed if we want to support loading of 91 modules linked with -shared. */ 92 break; 93 } 94 } 95 96 /* 97 * Account for GOT and PLT relocations. We can't add sections for 98 * got and plt but we can increase the core module size. 99 */ 100 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 101 char *secstrings, struct module *me) 102 { 103 Elf_Shdr *symtab; 104 Elf_Sym *symbols; 105 Elf_Rela *rela; 106 char *strings; 107 int nrela, i, j; 108 109 /* Find symbol table and string table. */ 110 symtab = NULL; 111 for (i = 0; i < hdr->e_shnum; i++) 112 switch (sechdrs[i].sh_type) { 113 case SHT_SYMTAB: 114 symtab = sechdrs + i; 115 break; 116 } 117 if (!symtab) { 118 printk(KERN_ERR "module %s: no symbol table\n", me->name); 119 return -ENOEXEC; 120 } 121 122 /* Allocate one syminfo structure per symbol. */ 123 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym); 124 me->arch.syminfo = vmalloc(me->arch.nsyms * 125 sizeof(struct mod_arch_syminfo)); 126 if (!me->arch.syminfo) 127 return -ENOMEM; 128 symbols = (void *) hdr + symtab->sh_offset; 129 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset; 130 for (i = 0; i < me->arch.nsyms; i++) { 131 if (symbols[i].st_shndx == SHN_UNDEF && 132 strcmp(strings + symbols[i].st_name, 133 "_GLOBAL_OFFSET_TABLE_") == 0) 134 /* "Define" it as absolute. */ 135 symbols[i].st_shndx = SHN_ABS; 136 me->arch.syminfo[i].got_offset = -1UL; 137 me->arch.syminfo[i].plt_offset = -1UL; 138 me->arch.syminfo[i].got_initialized = 0; 139 me->arch.syminfo[i].plt_initialized = 0; 140 } 141 142 /* Search for got/plt relocations. */ 143 me->arch.got_size = me->arch.plt_size = 0; 144 for (i = 0; i < hdr->e_shnum; i++) { 145 if (sechdrs[i].sh_type != SHT_RELA) 146 continue; 147 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela); 148 rela = (void *) hdr + sechdrs[i].sh_offset; 149 for (j = 0; j < nrela; j++) 150 check_rela(rela + j, me); 151 } 152 153 /* Increase core size by size of got & plt and set start 154 offsets for got and plt. */ 155 me->core_layout.size = ALIGN(me->core_layout.size, 4); 156 me->arch.got_offset = me->core_layout.size; 157 me->core_layout.size += me->arch.got_size; 158 me->arch.plt_offset = me->core_layout.size; 159 me->core_layout.size += me->arch.plt_size; 160 return 0; 161 } 162 163 static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, 164 int sign, int bits, int shift) 165 { 166 unsigned long umax; 167 long min, max; 168 169 if (val & ((1UL << shift) - 1)) 170 return -ENOEXEC; 171 if (sign) { 172 val = (Elf_Addr)(((long) val) >> shift); 173 min = -(1L << (bits - 1)); 174 max = (1L << (bits - 1)) - 1; 175 if ((long) val < min || (long) val > max) 176 return -ENOEXEC; 177 } else { 178 val >>= shift; 179 umax = ((1UL << (bits - 1)) << 1) - 1; 180 if ((unsigned long) val > umax) 181 return -ENOEXEC; 182 } 183 184 if (bits == 8) 185 *(unsigned char *) loc = val; 186 else if (bits == 12) 187 *(unsigned short *) loc = (val & 0xfff) | 188 (*(unsigned short *) loc & 0xf000); 189 else if (bits == 16) 190 *(unsigned short *) loc = val; 191 else if (bits == 20) 192 *(unsigned int *) loc = (val & 0xfff) << 16 | 193 (val & 0xff000) >> 4 | 194 (*(unsigned int *) loc & 0xf00000ff); 195 else if (bits == 32) 196 *(unsigned int *) loc = val; 197 else if (bits == 64) 198 *(unsigned long *) loc = val; 199 return 0; 200 } 201 202 static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, 203 const char *strtab, struct module *me) 204 { 205 struct mod_arch_syminfo *info; 206 Elf_Addr loc, val; 207 int r_type, r_sym; 208 int rc = -ENOEXEC; 209 210 /* This is where to make the change */ 211 loc = base + rela->r_offset; 212 /* This is the symbol it is referring to. Note that all 213 undefined symbols have been resolved. */ 214 r_sym = ELF_R_SYM(rela->r_info); 215 r_type = ELF_R_TYPE(rela->r_info); 216 info = me->arch.syminfo + r_sym; 217 val = symtab[r_sym].st_value; 218 219 switch (r_type) { 220 case R_390_NONE: /* No relocation. */ 221 rc = 0; 222 break; 223 case R_390_8: /* Direct 8 bit. */ 224 case R_390_12: /* Direct 12 bit. */ 225 case R_390_16: /* Direct 16 bit. */ 226 case R_390_20: /* Direct 20 bit. */ 227 case R_390_32: /* Direct 32 bit. */ 228 case R_390_64: /* Direct 64 bit. */ 229 val += rela->r_addend; 230 if (r_type == R_390_8) 231 rc = apply_rela_bits(loc, val, 0, 8, 0); 232 else if (r_type == R_390_12) 233 rc = apply_rela_bits(loc, val, 0, 12, 0); 234 else if (r_type == R_390_16) 235 rc = apply_rela_bits(loc, val, 0, 16, 0); 236 else if (r_type == R_390_20) 237 rc = apply_rela_bits(loc, val, 1, 20, 0); 238 else if (r_type == R_390_32) 239 rc = apply_rela_bits(loc, val, 0, 32, 0); 240 else if (r_type == R_390_64) 241 rc = apply_rela_bits(loc, val, 0, 64, 0); 242 break; 243 case R_390_PC16: /* PC relative 16 bit. */ 244 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ 245 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ 246 case R_390_PC32: /* PC relative 32 bit. */ 247 case R_390_PC64: /* PC relative 64 bit. */ 248 val += rela->r_addend - loc; 249 if (r_type == R_390_PC16) 250 rc = apply_rela_bits(loc, val, 1, 16, 0); 251 else if (r_type == R_390_PC16DBL) 252 rc = apply_rela_bits(loc, val, 1, 16, 1); 253 else if (r_type == R_390_PC32DBL) 254 rc = apply_rela_bits(loc, val, 1, 32, 1); 255 else if (r_type == R_390_PC32) 256 rc = apply_rela_bits(loc, val, 1, 32, 0); 257 else if (r_type == R_390_PC64) 258 rc = apply_rela_bits(loc, val, 1, 64, 0); 259 break; 260 case R_390_GOT12: /* 12 bit GOT offset. */ 261 case R_390_GOT16: /* 16 bit GOT offset. */ 262 case R_390_GOT20: /* 20 bit GOT offset. */ 263 case R_390_GOT32: /* 32 bit GOT offset. */ 264 case R_390_GOT64: /* 64 bit GOT offset. */ 265 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 266 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 267 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 268 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 269 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 270 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 271 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 272 if (info->got_initialized == 0) { 273 Elf_Addr *gotent; 274 275 gotent = me->core_layout.base + me->arch.got_offset + 276 info->got_offset; 277 *gotent = val; 278 info->got_initialized = 1; 279 } 280 val = info->got_offset + rela->r_addend; 281 if (r_type == R_390_GOT12 || 282 r_type == R_390_GOTPLT12) 283 rc = apply_rela_bits(loc, val, 0, 12, 0); 284 else if (r_type == R_390_GOT16 || 285 r_type == R_390_GOTPLT16) 286 rc = apply_rela_bits(loc, val, 0, 16, 0); 287 else if (r_type == R_390_GOT20 || 288 r_type == R_390_GOTPLT20) 289 rc = apply_rela_bits(loc, val, 1, 20, 0); 290 else if (r_type == R_390_GOT32 || 291 r_type == R_390_GOTPLT32) 292 rc = apply_rela_bits(loc, val, 0, 32, 0); 293 else if (r_type == R_390_GOT64 || 294 r_type == R_390_GOTPLT64) 295 rc = apply_rela_bits(loc, val, 0, 64, 0); 296 else if (r_type == R_390_GOTENT || 297 r_type == R_390_GOTPLTENT) { 298 val += (Elf_Addr) me->core_layout.base - loc; 299 rc = apply_rela_bits(loc, val, 1, 32, 1); 300 } 301 break; 302 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 303 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 304 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 305 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 306 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 307 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 308 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 309 if (info->plt_initialized == 0) { 310 unsigned int *ip; 311 ip = me->core_layout.base + me->arch.plt_offset + 312 info->plt_offset; 313 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ 314 ip[1] = 0x100a0004; 315 ip[2] = 0x07f10000; 316 ip[3] = (unsigned int) (val >> 32); 317 ip[4] = (unsigned int) val; 318 info->plt_initialized = 1; 319 } 320 if (r_type == R_390_PLTOFF16 || 321 r_type == R_390_PLTOFF32 || 322 r_type == R_390_PLTOFF64) 323 val = me->arch.plt_offset - me->arch.got_offset + 324 info->plt_offset + rela->r_addend; 325 else { 326 if (!((r_type == R_390_PLT16DBL && 327 val - loc + 0xffffUL < 0x1ffffeUL) || 328 (r_type == R_390_PLT32DBL && 329 val - loc + 0xffffffffULL < 0x1fffffffeULL))) 330 val = (Elf_Addr) me->core_layout.base + 331 me->arch.plt_offset + 332 info->plt_offset; 333 val += rela->r_addend - loc; 334 } 335 if (r_type == R_390_PLT16DBL) 336 rc = apply_rela_bits(loc, val, 1, 16, 1); 337 else if (r_type == R_390_PLTOFF16) 338 rc = apply_rela_bits(loc, val, 0, 16, 0); 339 else if (r_type == R_390_PLT32DBL) 340 rc = apply_rela_bits(loc, val, 1, 32, 1); 341 else if (r_type == R_390_PLT32 || 342 r_type == R_390_PLTOFF32) 343 rc = apply_rela_bits(loc, val, 0, 32, 0); 344 else if (r_type == R_390_PLT64 || 345 r_type == R_390_PLTOFF64) 346 rc = apply_rela_bits(loc, val, 0, 64, 0); 347 break; 348 case R_390_GOTOFF16: /* 16 bit offset to GOT. */ 349 case R_390_GOTOFF32: /* 32 bit offset to GOT. */ 350 case R_390_GOTOFF64: /* 64 bit offset to GOT. */ 351 val = val + rela->r_addend - 352 ((Elf_Addr) me->core_layout.base + me->arch.got_offset); 353 if (r_type == R_390_GOTOFF16) 354 rc = apply_rela_bits(loc, val, 0, 16, 0); 355 else if (r_type == R_390_GOTOFF32) 356 rc = apply_rela_bits(loc, val, 0, 32, 0); 357 else if (r_type == R_390_GOTOFF64) 358 rc = apply_rela_bits(loc, val, 0, 64, 0); 359 break; 360 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ 361 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ 362 val = (Elf_Addr) me->core_layout.base + me->arch.got_offset + 363 rela->r_addend - loc; 364 if (r_type == R_390_GOTPC) 365 rc = apply_rela_bits(loc, val, 1, 32, 0); 366 else if (r_type == R_390_GOTPCDBL) 367 rc = apply_rela_bits(loc, val, 1, 32, 1); 368 break; 369 case R_390_COPY: 370 case R_390_GLOB_DAT: /* Create GOT entry. */ 371 case R_390_JMP_SLOT: /* Create PLT entry. */ 372 case R_390_RELATIVE: /* Adjust by program base. */ 373 /* Only needed if we want to support loading of 374 modules linked with -shared. */ 375 return -ENOEXEC; 376 default: 377 printk(KERN_ERR "module %s: unknown relocation: %u\n", 378 me->name, r_type); 379 return -ENOEXEC; 380 } 381 if (rc) { 382 printk(KERN_ERR "module %s: relocation error for symbol %s " 383 "(r_type %i, value 0x%lx)\n", 384 me->name, strtab + symtab[r_sym].st_name, 385 r_type, (unsigned long) val); 386 return rc; 387 } 388 return 0; 389 } 390 391 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 392 unsigned int symindex, unsigned int relsec, 393 struct module *me) 394 { 395 Elf_Addr base; 396 Elf_Sym *symtab; 397 Elf_Rela *rela; 398 unsigned long i, n; 399 int rc; 400 401 DEBUGP("Applying relocate section %u to %u\n", 402 relsec, sechdrs[relsec].sh_info); 403 base = sechdrs[sechdrs[relsec].sh_info].sh_addr; 404 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; 405 rela = (Elf_Rela *) sechdrs[relsec].sh_addr; 406 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); 407 408 for (i = 0; i < n; i++, rela++) { 409 rc = apply_rela(rela, base, symtab, strtab, me); 410 if (rc) 411 return rc; 412 } 413 return 0; 414 } 415 416 int module_finalize(const Elf_Ehdr *hdr, 417 const Elf_Shdr *sechdrs, 418 struct module *me) 419 { 420 const Elf_Shdr *s; 421 char *secstrings; 422 423 secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 424 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 425 if (!strcmp(".altinstructions", secstrings + s->sh_name)) { 426 /* patch .altinstructions */ 427 void *aseg = (void *)s->sh_addr; 428 429 apply_alternatives(aseg, aseg + s->sh_size); 430 } 431 } 432 433 jump_label_apply_nops(me); 434 return 0; 435 } 436