1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Kernel module help for PPC64. 3 Copyright (C) 2001, 2003 Rusty Russell IBM Corporation. 4 5 */ 6 7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 8 9 #include <linux/module.h> 10 #include <linux/elf.h> 11 #include <linux/moduleloader.h> 12 #include <linux/err.h> 13 #include <linux/vmalloc.h> 14 #include <linux/ftrace.h> 15 #include <linux/bug.h> 16 #include <linux/uaccess.h> 17 #include <linux/kernel.h> 18 #include <asm/module.h> 19 #include <asm/firmware.h> 20 #include <asm/code-patching.h> 21 #include <linux/sort.h> 22 #include <asm/setup.h> 23 #include <asm/sections.h> 24 #include <asm/inst.h> 25 26 /* FIXME: We don't do .init separately. To do this, we'd need to have 27 a separate r2 value in the init and core section, and stub between 28 them, too. 29 30 Using a magic allocator which places modules within 32MB solves 31 this, and makes other things simpler. Anton? 32 --RR. */ 33 34 bool module_elf_check_arch(Elf_Ehdr *hdr) 35 { 36 unsigned long abi_level = hdr->e_flags & 0x3; 37 38 if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) 39 return abi_level == 2; 40 else 41 return abi_level < 2; 42 } 43 44 #ifdef CONFIG_PPC64_ELF_ABI_V2 45 46 static func_desc_t func_desc(unsigned long addr) 47 { 48 func_desc_t desc = { 49 .addr = addr, 50 }; 51 52 return desc; 53 } 54 55 /* PowerPC64 specific values for the Elf64_Sym st_other field. */ 56 #define STO_PPC64_LOCAL_BIT 5 57 #define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT) 58 #define PPC64_LOCAL_ENTRY_OFFSET(other) \ 59 (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2) 60 61 static unsigned int local_entry_offset(const Elf64_Sym *sym) 62 { 63 /* sym->st_other indicates offset to local entry point 64 * (otherwise it will assume r12 is the address of the start 65 * of function and try to derive r2 from it). */ 66 return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other); 67 } 68 #else 69 70 static func_desc_t func_desc(unsigned long addr) 71 { 72 return *(struct func_desc *)addr; 73 } 74 static unsigned int local_entry_offset(const Elf64_Sym *sym) 75 { 76 return 0; 77 } 78 79 void *dereference_module_function_descriptor(struct module *mod, void *ptr) 80 { 81 if (ptr < (void *)mod->arch.start_opd || 82 ptr >= (void *)mod->arch.end_opd) 83 return ptr; 84 85 return dereference_function_descriptor(ptr); 86 } 87 #endif 88 89 static unsigned long func_addr(unsigned long addr) 90 { 91 return func_desc(addr).addr; 92 } 93 94 static unsigned long stub_func_addr(func_desc_t func) 95 { 96 return func.addr; 97 } 98 99 #define STUB_MAGIC 0x73747562 /* stub */ 100 101 /* Like PPC32, we need little trampolines to do > 24-bit jumps (into 102 the kernel itself). But on PPC64, these need to be used for every 103 jump, actually, to reset r2 (TOC+0x8000). */ 104 struct ppc64_stub_entry 105 { 106 /* 28 byte jump instruction sequence (7 instructions). We only 107 * need 6 instructions on ABIv2 but we always allocate 7 so 108 * so we don't have to modify the trampoline load instruction. */ 109 u32 jump[7]; 110 /* Used by ftrace to identify stubs */ 111 u32 magic; 112 /* Data for the above code */ 113 func_desc_t funcdata; 114 }; 115 116 /* 117 * PPC64 uses 24 bit jumps, but we need to jump into other modules or 118 * the kernel which may be further. So we jump to a stub. 119 * 120 * For ELFv1 we need to use this to set up the new r2 value (aka TOC 121 * pointer). For ELFv2 it's the callee's responsibility to set up the 122 * new r2, but for both we need to save the old r2. 123 * 124 * We could simply patch the new r2 value and function pointer into 125 * the stub, but it's significantly shorter to put these values at the 126 * end of the stub code, and patch the stub address (32-bits relative 127 * to the TOC ptr, r2) into the stub. 128 */ 129 static u32 ppc64_stub_insns[] = { 130 PPC_RAW_ADDIS(_R11, _R2, 0), 131 PPC_RAW_ADDI(_R11, _R11, 0), 132 /* Save current r2 value in magic place on the stack. */ 133 PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET), 134 PPC_RAW_LD(_R12, _R11, 32), 135 #ifdef CONFIG_PPC64_ELF_ABI_V1 136 /* Set up new r2 from function descriptor */ 137 PPC_RAW_LD(_R2, _R11, 40), 138 #endif 139 PPC_RAW_MTCTR(_R12), 140 PPC_RAW_BCTR(), 141 }; 142 143 /* Count how many different 24-bit relocations (different symbol, 144 different addend) */ 145 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) 146 { 147 unsigned int i, r_info, r_addend, _count_relocs; 148 149 /* FIXME: Only count external ones --RR */ 150 _count_relocs = 0; 151 r_info = 0; 152 r_addend = 0; 153 for (i = 0; i < num; i++) 154 /* Only count 24-bit relocs, others don't need stubs */ 155 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && 156 (r_info != ELF64_R_SYM(rela[i].r_info) || 157 r_addend != rela[i].r_addend)) { 158 _count_relocs++; 159 r_info = ELF64_R_SYM(rela[i].r_info); 160 r_addend = rela[i].r_addend; 161 } 162 163 return _count_relocs; 164 } 165 166 static int relacmp(const void *_x, const void *_y) 167 { 168 const Elf64_Rela *x, *y; 169 170 y = (Elf64_Rela *)_x; 171 x = (Elf64_Rela *)_y; 172 173 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to 174 * make the comparison cheaper/faster. It won't affect the sorting or 175 * the counting algorithms' performance 176 */ 177 if (x->r_info < y->r_info) 178 return -1; 179 else if (x->r_info > y->r_info) 180 return 1; 181 else if (x->r_addend < y->r_addend) 182 return -1; 183 else if (x->r_addend > y->r_addend) 184 return 1; 185 else 186 return 0; 187 } 188 189 /* Get size of potential trampolines required. */ 190 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, 191 const Elf64_Shdr *sechdrs) 192 { 193 /* One extra reloc so it's always 0-addr terminated */ 194 unsigned long relocs = 1; 195 unsigned i; 196 197 /* Every relocated section... */ 198 for (i = 1; i < hdr->e_shnum; i++) { 199 if (sechdrs[i].sh_type == SHT_RELA) { 200 pr_debug("Found relocations in section %u\n", i); 201 pr_debug("Ptr: %p. Number: %Lu\n", 202 (void *)sechdrs[i].sh_addr, 203 sechdrs[i].sh_size / sizeof(Elf64_Rela)); 204 205 /* Sort the relocation information based on a symbol and 206 * addend key. This is a stable O(n*log n) complexity 207 * algorithm but it will reduce the complexity of 208 * count_relocs() to linear complexity O(n) 209 */ 210 sort((void *)sechdrs[i].sh_addr, 211 sechdrs[i].sh_size / sizeof(Elf64_Rela), 212 sizeof(Elf64_Rela), relacmp, NULL); 213 214 relocs += count_relocs((void *)sechdrs[i].sh_addr, 215 sechdrs[i].sh_size 216 / sizeof(Elf64_Rela)); 217 } 218 } 219 220 #ifdef CONFIG_DYNAMIC_FTRACE 221 /* make the trampoline to the ftrace_caller */ 222 relocs++; 223 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 224 /* an additional one for ftrace_regs_caller */ 225 relocs++; 226 #endif 227 #endif 228 229 pr_debug("Looks like a total of %lu stubs, max\n", relocs); 230 return relocs * sizeof(struct ppc64_stub_entry); 231 } 232 233 /* Still needed for ELFv2, for .TOC. */ 234 static void dedotify_versions(struct modversion_info *vers, 235 unsigned long size) 236 { 237 struct modversion_info *end; 238 239 for (end = (void *)vers + size; vers < end; vers++) 240 if (vers->name[0] == '.') { 241 memmove(vers->name, vers->name+1, strlen(vers->name)); 242 } 243 } 244 245 /* 246 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. 247 * seem to be defined (value set later). 248 */ 249 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) 250 { 251 unsigned int i; 252 253 for (i = 1; i < numsyms; i++) { 254 if (syms[i].st_shndx == SHN_UNDEF) { 255 char *name = strtab + syms[i].st_name; 256 if (name[0] == '.') { 257 if (strcmp(name+1, "TOC.") == 0) 258 syms[i].st_shndx = SHN_ABS; 259 syms[i].st_name++; 260 } 261 } 262 } 263 } 264 265 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, 266 const char *strtab, 267 unsigned int symindex) 268 { 269 unsigned int i, numsyms; 270 Elf64_Sym *syms; 271 272 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; 273 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); 274 275 for (i = 1; i < numsyms; i++) { 276 if (syms[i].st_shndx == SHN_ABS 277 && strcmp(strtab + syms[i].st_name, "TOC.") == 0) 278 return &syms[i]; 279 } 280 return NULL; 281 } 282 283 bool module_init_section(const char *name) 284 { 285 /* We don't handle .init for the moment: always return false. */ 286 return false; 287 } 288 289 int module_frob_arch_sections(Elf64_Ehdr *hdr, 290 Elf64_Shdr *sechdrs, 291 char *secstrings, 292 struct module *me) 293 { 294 unsigned int i; 295 296 /* Find .toc and .stubs sections, symtab and strtab */ 297 for (i = 1; i < hdr->e_shnum; i++) { 298 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) 299 me->arch.stubs_section = i; 300 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) { 301 me->arch.toc_section = i; 302 if (sechdrs[i].sh_addralign < 8) 303 sechdrs[i].sh_addralign = 8; 304 } 305 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0) 306 dedotify_versions((void *)hdr + sechdrs[i].sh_offset, 307 sechdrs[i].sh_size); 308 309 if (sechdrs[i].sh_type == SHT_SYMTAB) 310 dedotify((void *)hdr + sechdrs[i].sh_offset, 311 sechdrs[i].sh_size / sizeof(Elf64_Sym), 312 (void *)hdr 313 + sechdrs[sechdrs[i].sh_link].sh_offset); 314 } 315 316 if (!me->arch.stubs_section) { 317 pr_err("%s: doesn't contain .stubs.\n", me->name); 318 return -ENOEXEC; 319 } 320 321 /* If we don't have a .toc, just use .stubs. We need to set r2 322 to some reasonable value in case the module calls out to 323 other functions via a stub, or if a function pointer escapes 324 the module by some means. */ 325 if (!me->arch.toc_section) 326 me->arch.toc_section = me->arch.stubs_section; 327 328 /* Override the stubs size */ 329 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); 330 return 0; 331 } 332 333 #ifdef CONFIG_MPROFILE_KERNEL 334 335 static u32 stub_insns[] = { 336 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), 337 PPC_RAW_ADDIS(_R12, _R12, 0), 338 PPC_RAW_ADDI(_R12, _R12, 0), 339 PPC_RAW_MTCTR(_R12), 340 PPC_RAW_BCTR(), 341 }; 342 343 /* 344 * For mprofile-kernel we use a special stub for ftrace_caller() because we 345 * can't rely on r2 containing this module's TOC when we enter the stub. 346 * 347 * That can happen if the function calling us didn't need to use the toc. In 348 * that case it won't have setup r2, and the r2 value will be either the 349 * kernel's toc, or possibly another modules toc. 350 * 351 * To deal with that this stub uses the kernel toc, which is always accessible 352 * via the paca (in r13). The target (ftrace_caller()) is responsible for 353 * saving and restoring the toc before returning. 354 */ 355 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 356 unsigned long addr, 357 struct module *me) 358 { 359 long reladdr; 360 361 memcpy(entry->jump, stub_insns, sizeof(stub_insns)); 362 363 /* Stub uses address relative to kernel toc (from the paca) */ 364 reladdr = addr - kernel_toc_addr(); 365 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 366 pr_err("%s: Address of %ps out of range of kernel_toc.\n", 367 me->name, (void *)addr); 368 return 0; 369 } 370 371 entry->jump[1] |= PPC_HA(reladdr); 372 entry->jump[2] |= PPC_LO(reladdr); 373 374 /* Even though we don't use funcdata in the stub, it's needed elsewhere. */ 375 entry->funcdata = func_desc(addr); 376 entry->magic = STUB_MAGIC; 377 378 return 1; 379 } 380 381 static bool is_mprofile_ftrace_call(const char *name) 382 { 383 if (!strcmp("_mcount", name)) 384 return true; 385 #ifdef CONFIG_DYNAMIC_FTRACE 386 if (!strcmp("ftrace_caller", name)) 387 return true; 388 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 389 if (!strcmp("ftrace_regs_caller", name)) 390 return true; 391 #endif 392 #endif 393 394 return false; 395 } 396 #else 397 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 398 unsigned long addr, 399 struct module *me) 400 { 401 return 0; 402 } 403 404 static bool is_mprofile_ftrace_call(const char *name) 405 { 406 return false; 407 } 408 #endif 409 410 /* 411 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the 412 * value maximum span in an instruction which uses a signed offset). Round down 413 * to a 256 byte boundary for the odd case where we are setting up r2 without a 414 * .toc section. 415 */ 416 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) 417 { 418 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; 419 } 420 421 /* Patch stub to reference function and correct r2 value. */ 422 static inline int create_stub(const Elf64_Shdr *sechdrs, 423 struct ppc64_stub_entry *entry, 424 unsigned long addr, 425 struct module *me, 426 const char *name) 427 { 428 long reladdr; 429 func_desc_t desc; 430 int i; 431 432 if (is_mprofile_ftrace_call(name)) 433 return create_ftrace_stub(entry, addr, me); 434 435 for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) { 436 if (patch_instruction(&entry->jump[i], 437 ppc_inst(ppc64_stub_insns[i]))) 438 return 0; 439 } 440 441 /* Stub uses address relative to r2. */ 442 reladdr = (unsigned long)entry - my_r2(sechdrs, me); 443 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 444 pr_err("%s: Address %p of stub out of range of %p.\n", 445 me->name, (void *)reladdr, (void *)my_r2); 446 return 0; 447 } 448 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); 449 450 if (patch_instruction(&entry->jump[0], 451 ppc_inst(entry->jump[0] | PPC_HA(reladdr)))) 452 return 0; 453 454 if (patch_instruction(&entry->jump[1], 455 ppc_inst(entry->jump[1] | PPC_LO(reladdr)))) 456 return 0; 457 458 // func_desc_t is 8 bytes if ABIv2, else 16 bytes 459 desc = func_desc(addr); 460 for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) { 461 if (patch_instruction(((u32 *)&entry->funcdata) + i, 462 ppc_inst(((u32 *)(&desc))[i]))) 463 return 0; 464 } 465 466 if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC))) 467 return 0; 468 469 return 1; 470 } 471 472 /* Create stub to jump to function described in this OPD/ptr: we need the 473 stub to set up the TOC ptr (r2) for the function. */ 474 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, 475 unsigned long addr, 476 struct module *me, 477 const char *name) 478 { 479 struct ppc64_stub_entry *stubs; 480 unsigned int i, num_stubs; 481 482 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); 483 484 /* Find this stub, or if that fails, the next avail. entry */ 485 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; 486 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { 487 if (WARN_ON(i >= num_stubs)) 488 return 0; 489 490 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) 491 return (unsigned long)&stubs[i]; 492 } 493 494 if (!create_stub(sechdrs, &stubs[i], addr, me, name)) 495 return 0; 496 497 return (unsigned long)&stubs[i]; 498 } 499 500 /* We expect a noop next: if it is, replace it with instruction to 501 restore r2. */ 502 static int restore_r2(const char *name, u32 *instruction, struct module *me) 503 { 504 u32 *prev_insn = instruction - 1; 505 506 if (is_mprofile_ftrace_call(name)) 507 return 1; 508 509 /* 510 * Make sure the branch isn't a sibling call. Sibling calls aren't 511 * "link" branches and they don't return, so they don't need the r2 512 * restore afterwards. 513 */ 514 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn))) 515 return 1; 516 517 if (*instruction != PPC_RAW_NOP()) { 518 pr_err("%s: Expected nop after call, got %08x at %pS\n", 519 me->name, *instruction, instruction); 520 return 0; 521 } 522 523 /* ld r2,R2_STACK_OFFSET(r1) */ 524 if (patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC))) 525 return 0; 526 527 return 1; 528 } 529 530 int apply_relocate_add(Elf64_Shdr *sechdrs, 531 const char *strtab, 532 unsigned int symindex, 533 unsigned int relsec, 534 struct module *me) 535 { 536 unsigned int i; 537 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; 538 Elf64_Sym *sym; 539 unsigned long *location; 540 unsigned long value; 541 542 pr_debug("Applying ADD relocate section %u to %u\n", relsec, 543 sechdrs[relsec].sh_info); 544 545 /* First time we're called, we can fix up .TOC. */ 546 if (!me->arch.toc_fixed) { 547 sym = find_dot_toc(sechdrs, strtab, symindex); 548 /* It's theoretically possible that a module doesn't want a 549 * .TOC. so don't fail it just for that. */ 550 if (sym) 551 sym->st_value = my_r2(sechdrs, me); 552 me->arch.toc_fixed = true; 553 } 554 555 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 556 /* This is where to make the change */ 557 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 558 + rela[i].r_offset; 559 /* This is the symbol it is referring to */ 560 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 561 + ELF64_R_SYM(rela[i].r_info); 562 563 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", 564 location, (long)ELF64_R_TYPE(rela[i].r_info), 565 strtab + sym->st_name, (unsigned long)sym->st_value, 566 (long)rela[i].r_addend); 567 568 /* `Everything is relative'. */ 569 value = sym->st_value + rela[i].r_addend; 570 571 switch (ELF64_R_TYPE(rela[i].r_info)) { 572 case R_PPC64_ADDR32: 573 /* Simply set it */ 574 *(u32 *)location = value; 575 break; 576 577 case R_PPC64_ADDR64: 578 /* Simply set it */ 579 *(unsigned long *)location = value; 580 break; 581 582 case R_PPC64_TOC: 583 *(unsigned long *)location = my_r2(sechdrs, me); 584 break; 585 586 case R_PPC64_TOC16: 587 /* Subtract TOC pointer */ 588 value -= my_r2(sechdrs, me); 589 if (value + 0x8000 > 0xffff) { 590 pr_err("%s: bad TOC16 relocation (0x%lx)\n", 591 me->name, value); 592 return -ENOEXEC; 593 } 594 *((uint16_t *) location) 595 = (*((uint16_t *) location) & ~0xffff) 596 | (value & 0xffff); 597 break; 598 599 case R_PPC64_TOC16_LO: 600 /* Subtract TOC pointer */ 601 value -= my_r2(sechdrs, me); 602 *((uint16_t *) location) 603 = (*((uint16_t *) location) & ~0xffff) 604 | (value & 0xffff); 605 break; 606 607 case R_PPC64_TOC16_DS: 608 /* Subtract TOC pointer */ 609 value -= my_r2(sechdrs, me); 610 if ((value & 3) != 0 || value + 0x8000 > 0xffff) { 611 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n", 612 me->name, value); 613 return -ENOEXEC; 614 } 615 *((uint16_t *) location) 616 = (*((uint16_t *) location) & ~0xfffc) 617 | (value & 0xfffc); 618 break; 619 620 case R_PPC64_TOC16_LO_DS: 621 /* Subtract TOC pointer */ 622 value -= my_r2(sechdrs, me); 623 if ((value & 3) != 0) { 624 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n", 625 me->name, value); 626 return -ENOEXEC; 627 } 628 *((uint16_t *) location) 629 = (*((uint16_t *) location) & ~0xfffc) 630 | (value & 0xfffc); 631 break; 632 633 case R_PPC64_TOC16_HA: 634 /* Subtract TOC pointer */ 635 value -= my_r2(sechdrs, me); 636 value = ((value + 0x8000) >> 16); 637 *((uint16_t *) location) 638 = (*((uint16_t *) location) & ~0xffff) 639 | (value & 0xffff); 640 break; 641 642 case R_PPC_REL24: 643 /* FIXME: Handle weak symbols here --RR */ 644 if (sym->st_shndx == SHN_UNDEF || 645 sym->st_shndx == SHN_LIVEPATCH) { 646 /* External: go via stub */ 647 value = stub_for_addr(sechdrs, value, me, 648 strtab + sym->st_name); 649 if (!value) 650 return -ENOENT; 651 if (!restore_r2(strtab + sym->st_name, 652 (u32 *)location + 1, me)) 653 return -ENOEXEC; 654 } else 655 value += local_entry_offset(sym); 656 657 /* Convert value to relative */ 658 value -= (unsigned long)location; 659 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ 660 pr_err("%s: REL24 %li out of range!\n", 661 me->name, (long int)value); 662 return -ENOEXEC; 663 } 664 665 /* Only replace bits 2 through 26 */ 666 value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value); 667 668 if (patch_instruction((u32 *)location, ppc_inst(value))) 669 return -EFAULT; 670 671 break; 672 673 case R_PPC64_REL64: 674 /* 64 bits relative (used by features fixups) */ 675 *location = value - (unsigned long)location; 676 break; 677 678 case R_PPC64_REL32: 679 /* 32 bits relative (used by relative exception tables) */ 680 /* Convert value to relative */ 681 value -= (unsigned long)location; 682 if (value + 0x80000000 > 0xffffffff) { 683 pr_err("%s: REL32 %li out of range!\n", 684 me->name, (long int)value); 685 return -ENOEXEC; 686 } 687 *(u32 *)location = value; 688 break; 689 690 case R_PPC64_TOCSAVE: 691 /* 692 * Marker reloc indicates we don't have to save r2. 693 * That would only save us one instruction, so ignore 694 * it. 695 */ 696 break; 697 698 case R_PPC64_ENTRY: 699 /* 700 * Optimize ELFv2 large code model entry point if 701 * the TOC is within 2GB range of current location. 702 */ 703 value = my_r2(sechdrs, me) - (unsigned long)location; 704 if (value + 0x80008000 > 0xffffffff) 705 break; 706 /* 707 * Check for the large code model prolog sequence: 708 * ld r2, ...(r12) 709 * add r2, r2, r12 710 */ 711 if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0)) 712 break; 713 if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12)) 714 break; 715 /* 716 * If found, replace it with: 717 * addis r2, r12, (.TOC.-func)@ha 718 * addi r2, r2, (.TOC.-func)@l 719 */ 720 ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value)); 721 ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value)); 722 break; 723 724 case R_PPC64_REL16_HA: 725 /* Subtract location pointer */ 726 value -= (unsigned long)location; 727 value = ((value + 0x8000) >> 16); 728 *((uint16_t *) location) 729 = (*((uint16_t *) location) & ~0xffff) 730 | (value & 0xffff); 731 break; 732 733 case R_PPC64_REL16_LO: 734 /* Subtract location pointer */ 735 value -= (unsigned long)location; 736 *((uint16_t *) location) 737 = (*((uint16_t *) location) & ~0xffff) 738 | (value & 0xffff); 739 break; 740 741 default: 742 pr_err("%s: Unknown ADD relocation: %lu\n", 743 me->name, 744 (unsigned long)ELF64_R_TYPE(rela[i].r_info)); 745 return -ENOEXEC; 746 } 747 } 748 749 return 0; 750 } 751 752 #ifdef CONFIG_DYNAMIC_FTRACE 753 int module_trampoline_target(struct module *mod, unsigned long addr, 754 unsigned long *target) 755 { 756 struct ppc64_stub_entry *stub; 757 func_desc_t funcdata; 758 u32 magic; 759 760 if (!within_module_core(addr, mod)) { 761 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); 762 return -EFAULT; 763 } 764 765 stub = (struct ppc64_stub_entry *)addr; 766 767 if (copy_from_kernel_nofault(&magic, &stub->magic, 768 sizeof(magic))) { 769 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); 770 return -EFAULT; 771 } 772 773 if (magic != STUB_MAGIC) { 774 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); 775 return -EFAULT; 776 } 777 778 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata, 779 sizeof(funcdata))) { 780 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); 781 return -EFAULT; 782 } 783 784 *target = stub_func_addr(funcdata); 785 786 return 0; 787 } 788 789 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) 790 { 791 mod->arch.tramp = stub_for_addr(sechdrs, 792 (unsigned long)ftrace_caller, 793 mod, 794 "ftrace_caller"); 795 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 796 mod->arch.tramp_regs = stub_for_addr(sechdrs, 797 (unsigned long)ftrace_regs_caller, 798 mod, 799 "ftrace_regs_caller"); 800 if (!mod->arch.tramp_regs) 801 return -ENOENT; 802 #endif 803 804 if (!mod->arch.tramp) 805 return -ENOENT; 806 807 return 0; 808 } 809 #endif 810