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/text-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) that can 107 * hold ppc64_stub_insns or stub_insns. Must be 8-byte aligned 108 * with PCREL kernels that use prefix instructions in the stub. 109 */ 110 u32 jump[7]; 111 /* Used by ftrace to identify stubs */ 112 u32 magic; 113 /* Data for the above code */ 114 func_desc_t funcdata; 115 } __aligned(8); 116 117 struct ppc64_got_entry { 118 u64 addr; 119 }; 120 121 /* 122 * PPC64 uses 24 bit jumps, but we need to jump into other modules or 123 * the kernel which may be further. So we jump to a stub. 124 * 125 * Target address and TOC are loaded from function descriptor in the 126 * ppc64_stub_entry. 127 * 128 * r12 is used to generate the target address, which is required for the 129 * ELFv2 global entry point calling convention. 130 * 131 * TOC handling: 132 * - PCREL does not have a TOC. 133 * - ELFv2 non-PCREL just has to save r2, the callee is responsible for 134 * setting its own TOC pointer at the global entry address. 135 * - ELFv1 must load the new TOC pointer from the function descriptor. 136 */ 137 static u32 ppc64_stub_insns[] = { 138 #ifdef CONFIG_PPC_KERNEL_PCREL 139 /* pld r12,addr */ 140 PPC_PREFIX_8LS | __PPC_PRFX_R(1), 141 PPC_INST_PLD | ___PPC_RT(_R12), 142 #else 143 PPC_RAW_ADDIS(_R11, _R2, 0), 144 PPC_RAW_ADDI(_R11, _R11, 0), 145 /* Save current r2 value in magic place on the stack. */ 146 PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET), 147 PPC_RAW_LD(_R12, _R11, 32), 148 #ifdef CONFIG_PPC64_ELF_ABI_V1 149 /* Set up new r2 from function descriptor */ 150 PPC_RAW_LD(_R2, _R11, 40), 151 #endif 152 #endif 153 PPC_RAW_MTCTR(_R12), 154 PPC_RAW_BCTR(), 155 }; 156 157 /* 158 * Count how many different r_type relocations (different symbol, 159 * different addend). 160 */ 161 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num, 162 unsigned long r_type) 163 { 164 unsigned int i, r_info, r_addend, _count_relocs; 165 166 /* FIXME: Only count external ones --RR */ 167 _count_relocs = 0; 168 r_info = 0; 169 r_addend = 0; 170 for (i = 0; i < num; i++) 171 /* Only count r_type relocs, others don't need stubs */ 172 if (ELF64_R_TYPE(rela[i].r_info) == r_type && 173 (r_info != ELF64_R_SYM(rela[i].r_info) || 174 r_addend != rela[i].r_addend)) { 175 _count_relocs++; 176 r_info = ELF64_R_SYM(rela[i].r_info); 177 r_addend = rela[i].r_addend; 178 } 179 180 return _count_relocs; 181 } 182 183 static int relacmp(const void *_x, const void *_y) 184 { 185 const Elf64_Rela *x, *y; 186 187 y = (Elf64_Rela *)_x; 188 x = (Elf64_Rela *)_y; 189 190 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to 191 * make the comparison cheaper/faster. It won't affect the sorting or 192 * the counting algorithms' performance 193 */ 194 if (x->r_info < y->r_info) 195 return -1; 196 else if (x->r_info > y->r_info) 197 return 1; 198 else if (x->r_addend < y->r_addend) 199 return -1; 200 else if (x->r_addend > y->r_addend) 201 return 1; 202 else 203 return 0; 204 } 205 206 /* Get size of potential trampolines required. */ 207 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, 208 const Elf64_Shdr *sechdrs, 209 char *secstrings, 210 struct module *me) 211 { 212 /* One extra reloc so it's always 0-addr terminated */ 213 unsigned long relocs = 1; 214 unsigned i; 215 216 /* Every relocated section... */ 217 for (i = 1; i < hdr->e_shnum; i++) { 218 if (sechdrs[i].sh_type == SHT_RELA) { 219 pr_debug("Found relocations in section %u\n", i); 220 pr_debug("Ptr: %p. Number: %Lu\n", 221 (void *)sechdrs[i].sh_addr, 222 sechdrs[i].sh_size / sizeof(Elf64_Rela)); 223 224 /* Sort the relocation information based on a symbol and 225 * addend key. This is a stable O(n*log n) complexity 226 * algorithm but it will reduce the complexity of 227 * count_relocs() to linear complexity O(n) 228 */ 229 sort((void *)sechdrs[i].sh_addr, 230 sechdrs[i].sh_size / sizeof(Elf64_Rela), 231 sizeof(Elf64_Rela), relacmp, NULL); 232 233 relocs += count_relocs((void *)sechdrs[i].sh_addr, 234 sechdrs[i].sh_size 235 / sizeof(Elf64_Rela), 236 R_PPC_REL24); 237 #ifdef CONFIG_PPC_KERNEL_PCREL 238 relocs += count_relocs((void *)sechdrs[i].sh_addr, 239 sechdrs[i].sh_size 240 / sizeof(Elf64_Rela), 241 R_PPC64_REL24_NOTOC); 242 #endif 243 } 244 } 245 246 /* stubs for ftrace_caller and ftrace_regs_caller */ 247 relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS); 248 249 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE 250 /* stubs for the function tracer */ 251 for (i = 1; i < hdr->e_shnum; i++) { 252 if (!strcmp(secstrings + sechdrs[i].sh_name, "__patchable_function_entries")) { 253 me->arch.ool_stub_count = sechdrs[i].sh_size / sizeof(unsigned long); 254 me->arch.ool_stub_index = 0; 255 relocs += roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), 256 sizeof(struct ppc64_stub_entry)) / 257 sizeof(struct ppc64_stub_entry); 258 break; 259 } 260 } 261 #endif 262 263 pr_debug("Looks like a total of %lu stubs, max\n", relocs); 264 return relocs * sizeof(struct ppc64_stub_entry); 265 } 266 267 #ifdef CONFIG_PPC_KERNEL_PCREL 268 static int count_pcpu_relocs(const Elf64_Shdr *sechdrs, 269 const Elf64_Rela *rela, unsigned int num, 270 unsigned int symindex, unsigned int pcpu) 271 { 272 unsigned int i, r_info, r_addend, _count_relocs; 273 274 _count_relocs = 0; 275 r_info = 0; 276 r_addend = 0; 277 278 for (i = 0; i < num; i++) { 279 Elf64_Sym *sym; 280 281 /* This is the symbol it is referring to */ 282 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 283 + ELF64_R_SYM(rela[i].r_info); 284 285 if (sym->st_shndx == pcpu && 286 (r_info != ELF64_R_SYM(rela[i].r_info) || 287 r_addend != rela[i].r_addend)) { 288 _count_relocs++; 289 r_info = ELF64_R_SYM(rela[i].r_info); 290 r_addend = rela[i].r_addend; 291 } 292 } 293 294 return _count_relocs; 295 } 296 297 /* Get size of potential GOT required. */ 298 static unsigned long get_got_size(const Elf64_Ehdr *hdr, 299 const Elf64_Shdr *sechdrs, 300 struct module *me) 301 { 302 /* One extra reloc so it's always 0-addr terminated */ 303 unsigned long relocs = 1; 304 unsigned int i, symindex = 0; 305 306 for (i = 1; i < hdr->e_shnum; i++) { 307 if (sechdrs[i].sh_type == SHT_SYMTAB) { 308 symindex = i; 309 break; 310 } 311 } 312 WARN_ON_ONCE(!symindex); 313 314 /* Every relocated section... */ 315 for (i = 1; i < hdr->e_shnum; i++) { 316 if (sechdrs[i].sh_type == SHT_RELA) { 317 pr_debug("Found relocations in section %u\n", i); 318 pr_debug("Ptr: %p. Number: %llu\n", (void *)sechdrs[i].sh_addr, 319 sechdrs[i].sh_size / sizeof(Elf64_Rela)); 320 321 /* 322 * Sort the relocation information based on a symbol and 323 * addend key. This is a stable O(n*log n) complexity 324 * algorithm but it will reduce the complexity of 325 * count_relocs() to linear complexity O(n) 326 */ 327 sort((void *)sechdrs[i].sh_addr, 328 sechdrs[i].sh_size / sizeof(Elf64_Rela), 329 sizeof(Elf64_Rela), relacmp, NULL); 330 331 relocs += count_relocs((void *)sechdrs[i].sh_addr, 332 sechdrs[i].sh_size 333 / sizeof(Elf64_Rela), 334 R_PPC64_GOT_PCREL34); 335 336 /* 337 * Percpu data access typically gets linked with 338 * REL34 relocations, but the percpu section gets 339 * moved at load time and requires that to be 340 * converted to GOT linkage. 341 */ 342 if (IS_ENABLED(CONFIG_SMP) && symindex) 343 relocs += count_pcpu_relocs(sechdrs, 344 (void *)sechdrs[i].sh_addr, 345 sechdrs[i].sh_size 346 / sizeof(Elf64_Rela), 347 symindex, me->arch.pcpu_section); 348 } 349 } 350 351 pr_debug("Looks like a total of %lu GOT entries, max\n", relocs); 352 return relocs * sizeof(struct ppc64_got_entry); 353 } 354 #else /* CONFIG_PPC_KERNEL_PCREL */ 355 356 /* Still needed for ELFv2, for .TOC. */ 357 static void dedotify_versions(struct modversion_info *vers, 358 unsigned long size) 359 { 360 struct modversion_info *end; 361 362 for (end = (void *)vers + size; vers < end; vers++) 363 if (vers->name[0] == '.') { 364 memmove(vers->name, vers->name+1, strlen(vers->name)); 365 } 366 } 367 368 /* Same as normal versions, remove a leading dot if present. */ 369 static void dedotify_ext_version_names(char *str_seq, unsigned long size) 370 { 371 unsigned long out = 0; 372 unsigned long in; 373 char last = '\0'; 374 375 for (in = 0; in < size; in++) { 376 /* Skip one leading dot */ 377 if (last == '\0' && str_seq[in] == '.') 378 in++; 379 last = str_seq[in]; 380 str_seq[out++] = last; 381 } 382 /* Zero the trailing portion of the names table for robustness */ 383 memset(&str_seq[out], 0, size - out); 384 } 385 386 /* 387 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. 388 * seem to be defined (value set later). 389 */ 390 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) 391 { 392 unsigned int i; 393 394 for (i = 1; i < numsyms; i++) { 395 if (syms[i].st_shndx == SHN_UNDEF) { 396 char *name = strtab + syms[i].st_name; 397 if (name[0] == '.') { 398 if (strcmp(name+1, "TOC.") == 0) 399 syms[i].st_shndx = SHN_ABS; 400 syms[i].st_name++; 401 } 402 } 403 } 404 } 405 406 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, 407 const char *strtab, 408 unsigned int symindex) 409 { 410 unsigned int i, numsyms; 411 Elf64_Sym *syms; 412 413 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; 414 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); 415 416 for (i = 1; i < numsyms; i++) { 417 if (syms[i].st_shndx == SHN_ABS 418 && strcmp(strtab + syms[i].st_name, "TOC.") == 0) 419 return &syms[i]; 420 } 421 return NULL; 422 } 423 #endif /* CONFIG_PPC_KERNEL_PCREL */ 424 425 bool module_init_section(const char *name) 426 { 427 /* We don't handle .init for the moment: always return false. */ 428 return false; 429 } 430 431 int module_frob_arch_sections(Elf64_Ehdr *hdr, 432 Elf64_Shdr *sechdrs, 433 char *secstrings, 434 struct module *me) 435 { 436 unsigned int i; 437 438 /* Find .toc and .stubs sections, symtab and strtab */ 439 for (i = 1; i < hdr->e_shnum; i++) { 440 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) 441 me->arch.stubs_section = i; 442 #ifdef CONFIG_PPC_KERNEL_PCREL 443 else if (strcmp(secstrings + sechdrs[i].sh_name, ".data..percpu") == 0) 444 me->arch.pcpu_section = i; 445 else if (strcmp(secstrings + sechdrs[i].sh_name, ".mygot") == 0) { 446 me->arch.got_section = i; 447 if (sechdrs[i].sh_addralign < 8) 448 sechdrs[i].sh_addralign = 8; 449 } 450 #else 451 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) { 452 me->arch.toc_section = i; 453 if (sechdrs[i].sh_addralign < 8) 454 sechdrs[i].sh_addralign = 8; 455 } else if (strcmp(secstrings + sechdrs[i].sh_name, "__versions") == 0) 456 dedotify_versions((void *)hdr + sechdrs[i].sh_offset, 457 sechdrs[i].sh_size); 458 else if (strcmp(secstrings + sechdrs[i].sh_name, "__version_ext_names") == 0) 459 dedotify_ext_version_names((void *)hdr + sechdrs[i].sh_offset, 460 sechdrs[i].sh_size); 461 462 if (sechdrs[i].sh_type == SHT_SYMTAB) 463 dedotify((void *)hdr + sechdrs[i].sh_offset, 464 sechdrs[i].sh_size / sizeof(Elf64_Sym), 465 (void *)hdr 466 + sechdrs[sechdrs[i].sh_link].sh_offset); 467 #endif 468 } 469 470 if (!me->arch.stubs_section) { 471 pr_err("%s: doesn't contain .stubs.\n", me->name); 472 return -ENOEXEC; 473 } 474 475 #ifdef CONFIG_PPC_KERNEL_PCREL 476 if (!me->arch.got_section) { 477 pr_err("%s: doesn't contain .mygot.\n", me->name); 478 return -ENOEXEC; 479 } 480 481 /* Override the got size */ 482 sechdrs[me->arch.got_section].sh_size = get_got_size(hdr, sechdrs, me); 483 #else 484 /* If we don't have a .toc, just use .stubs. We need to set r2 485 to some reasonable value in case the module calls out to 486 other functions via a stub, or if a function pointer escapes 487 the module by some means. */ 488 if (!me->arch.toc_section) 489 me->arch.toc_section = me->arch.stubs_section; 490 #endif 491 492 /* Override the stubs size */ 493 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs, secstrings, me); 494 495 return 0; 496 } 497 498 #if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) 499 500 static u32 stub_insns[] = { 501 #ifdef CONFIG_PPC_KERNEL_PCREL 502 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)), 503 PPC_RAW_NOP(), /* align the prefix insn */ 504 /* paddi r12,r12,addr */ 505 PPC_PREFIX_MLS | __PPC_PRFX_R(0), 506 PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12), 507 PPC_RAW_MTCTR(_R12), 508 PPC_RAW_BCTR(), 509 #else 510 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), 511 PPC_RAW_ADDIS(_R12, _R12, 0), 512 PPC_RAW_ADDI(_R12, _R12, 0), 513 PPC_RAW_MTCTR(_R12), 514 PPC_RAW_BCTR(), 515 #endif 516 }; 517 518 /* 519 * For mprofile-kernel we use a special stub for ftrace_caller() because we 520 * can't rely on r2 containing this module's TOC when we enter the stub. 521 * 522 * That can happen if the function calling us didn't need to use the toc. In 523 * that case it won't have setup r2, and the r2 value will be either the 524 * kernel's toc, or possibly another modules toc. 525 * 526 * To deal with that this stub uses the kernel toc, which is always accessible 527 * via the paca (in r13). The target (ftrace_caller()) is responsible for 528 * saving and restoring the toc before returning. 529 */ 530 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 531 unsigned long addr, 532 struct module *me) 533 { 534 long reladdr; 535 536 if ((unsigned long)entry->jump % 8 != 0) { 537 pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name); 538 return 0; 539 } 540 541 BUILD_BUG_ON(sizeof(stub_insns) > sizeof(entry->jump)); 542 memcpy(entry->jump, stub_insns, sizeof(stub_insns)); 543 544 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { 545 /* Stub uses address relative to kernel base (from the paca) */ 546 reladdr = addr - local_paca->kernelbase; 547 if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) { 548 pr_err("%s: Address of %ps out of range of 34-bit relative address.\n", 549 me->name, (void *)addr); 550 return 0; 551 } 552 553 entry->jump[2] |= IMM_H18(reladdr); 554 entry->jump[3] |= IMM_L(reladdr); 555 } else { 556 /* Stub uses address relative to kernel toc (from the paca) */ 557 reladdr = addr - kernel_toc_addr(); 558 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 559 pr_err("%s: Address of %ps out of range of kernel_toc.\n", 560 me->name, (void *)addr); 561 return 0; 562 } 563 564 entry->jump[1] |= PPC_HA(reladdr); 565 entry->jump[2] |= PPC_LO(reladdr); 566 } 567 568 /* Even though we don't use funcdata in the stub, it's needed elsewhere. */ 569 entry->funcdata = func_desc(addr); 570 entry->magic = STUB_MAGIC; 571 572 return 1; 573 } 574 575 static bool is_mprofile_ftrace_call(const char *name) 576 { 577 if (!strcmp("_mcount", name)) 578 return true; 579 #ifdef CONFIG_DYNAMIC_FTRACE 580 if (!strcmp("ftrace_caller", name)) 581 return true; 582 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 583 if (!strcmp("ftrace_regs_caller", name)) 584 return true; 585 #endif 586 #endif 587 588 return false; 589 } 590 #else 591 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 592 unsigned long addr, 593 struct module *me) 594 { 595 return 0; 596 } 597 598 static bool is_mprofile_ftrace_call(const char *name) 599 { 600 return false; 601 } 602 #endif 603 604 /* 605 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the 606 * value maximum span in an instruction which uses a signed offset). Round down 607 * to a 256 byte boundary for the odd case where we are setting up r2 without a 608 * .toc section. 609 */ 610 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) 611 { 612 #ifndef CONFIG_PPC_KERNEL_PCREL 613 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; 614 #else 615 return -1; 616 #endif 617 } 618 619 /* Patch stub to reference function and correct r2 value. */ 620 static inline int create_stub(const Elf64_Shdr *sechdrs, 621 struct ppc64_stub_entry *entry, 622 unsigned long addr, 623 struct module *me, 624 const char *name) 625 { 626 long reladdr; 627 func_desc_t desc; 628 int i; 629 630 if (is_mprofile_ftrace_call(name)) 631 return create_ftrace_stub(entry, addr, me); 632 633 if ((unsigned long)entry->jump % 8 != 0) { 634 pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name); 635 return 0; 636 } 637 638 BUILD_BUG_ON(sizeof(ppc64_stub_insns) > sizeof(entry->jump)); 639 for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) { 640 if (patch_instruction(&entry->jump[i], 641 ppc_inst(ppc64_stub_insns[i]))) 642 return 0; 643 } 644 645 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { 646 /* Stub uses address relative to itself! */ 647 reladdr = 0 + offsetof(struct ppc64_stub_entry, funcdata); 648 BUILD_BUG_ON(reladdr != 32); 649 if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) { 650 pr_err("%s: Address of %p out of range of 34-bit relative address.\n", 651 me->name, (void *)reladdr); 652 return 0; 653 } 654 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); 655 656 /* May not even need this if we're relative to 0 */ 657 if (patch_instruction(&entry->jump[0], 658 ppc_inst_prefix(entry->jump[0] | IMM_H18(reladdr), 659 entry->jump[1] | IMM_L(reladdr)))) 660 return 0; 661 662 } else { 663 /* Stub uses address relative to r2. */ 664 reladdr = (unsigned long)entry - my_r2(sechdrs, me); 665 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 666 pr_err("%s: Address %p of stub out of range of %p.\n", 667 me->name, (void *)reladdr, (void *)my_r2); 668 return 0; 669 } 670 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); 671 672 if (patch_instruction(&entry->jump[0], 673 ppc_inst(entry->jump[0] | PPC_HA(reladdr)))) 674 return 0; 675 676 if (patch_instruction(&entry->jump[1], 677 ppc_inst(entry->jump[1] | PPC_LO(reladdr)))) 678 return 0; 679 } 680 681 // func_desc_t is 8 bytes if ABIv2, else 16 bytes 682 desc = func_desc(addr); 683 for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) { 684 if (patch_u32(((u32 *)&entry->funcdata) + i, ((u32 *)&desc)[i])) 685 return 0; 686 } 687 688 if (patch_u32(&entry->magic, STUB_MAGIC)) 689 return 0; 690 691 return 1; 692 } 693 694 /* Create stub to jump to function described in this OPD/ptr: we need the 695 stub to set up the TOC ptr (r2) for the function. */ 696 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, 697 unsigned long addr, 698 struct module *me, 699 const char *name) 700 { 701 struct ppc64_stub_entry *stubs; 702 unsigned int i, num_stubs; 703 704 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); 705 706 /* Find this stub, or if that fails, the next avail. entry */ 707 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; 708 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { 709 if (WARN_ON(i >= num_stubs)) 710 return 0; 711 712 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) 713 return (unsigned long)&stubs[i]; 714 } 715 716 if (!create_stub(sechdrs, &stubs[i], addr, me, name)) 717 return 0; 718 719 return (unsigned long)&stubs[i]; 720 } 721 722 #ifdef CONFIG_PPC_KERNEL_PCREL 723 /* Create GOT to load the location described in this ptr */ 724 static unsigned long got_for_addr(const Elf64_Shdr *sechdrs, 725 unsigned long addr, 726 struct module *me, 727 const char *name) 728 { 729 struct ppc64_got_entry *got; 730 unsigned int i, num_got; 731 732 if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) 733 return addr; 734 735 num_got = sechdrs[me->arch.got_section].sh_size / sizeof(*got); 736 737 /* Find this stub, or if that fails, the next avail. entry */ 738 got = (void *)sechdrs[me->arch.got_section].sh_addr; 739 for (i = 0; got[i].addr; i++) { 740 if (WARN_ON(i >= num_got)) 741 return 0; 742 743 if (got[i].addr == addr) 744 return (unsigned long)&got[i]; 745 } 746 747 got[i].addr = addr; 748 749 return (unsigned long)&got[i]; 750 } 751 #endif 752 753 /* We expect a noop next: if it is, replace it with instruction to 754 restore r2. */ 755 static int restore_r2(const char *name, u32 *instruction, struct module *me) 756 { 757 u32 *prev_insn = instruction - 1; 758 u32 insn_val = *instruction; 759 760 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) 761 return 0; 762 763 if (is_mprofile_ftrace_call(name)) 764 return 0; 765 766 /* 767 * Make sure the branch isn't a sibling call. Sibling calls aren't 768 * "link" branches and they don't return, so they don't need the r2 769 * restore afterwards. 770 */ 771 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn))) 772 return 0; 773 774 /* 775 * For livepatch, the restore r2 instruction might have already been 776 * written previously, if the referenced symbol is in a previously 777 * unloaded module which is now being loaded again. In that case, skip 778 * the warning and the instruction write. 779 */ 780 if (insn_val == PPC_INST_LD_TOC) 781 return 0; 782 783 if (insn_val != PPC_RAW_NOP()) { 784 pr_err("%s: Expected nop after call, got %08x at %pS\n", 785 me->name, insn_val, instruction); 786 return -ENOEXEC; 787 } 788 789 /* ld r2,R2_STACK_OFFSET(r1) */ 790 return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC)); 791 } 792 793 int apply_relocate_add(Elf64_Shdr *sechdrs, 794 const char *strtab, 795 unsigned int symindex, 796 unsigned int relsec, 797 struct module *me) 798 { 799 unsigned int i; 800 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; 801 Elf64_Sym *sym; 802 unsigned long *location; 803 unsigned long value; 804 805 pr_debug("Applying ADD relocate section %u to %u\n", relsec, 806 sechdrs[relsec].sh_info); 807 808 #ifndef CONFIG_PPC_KERNEL_PCREL 809 /* First time we're called, we can fix up .TOC. */ 810 if (!me->arch.toc_fixed) { 811 sym = find_dot_toc(sechdrs, strtab, symindex); 812 /* It's theoretically possible that a module doesn't want a 813 * .TOC. so don't fail it just for that. */ 814 if (sym) 815 sym->st_value = my_r2(sechdrs, me); 816 me->arch.toc_fixed = true; 817 } 818 #endif 819 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 820 /* This is where to make the change */ 821 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 822 + rela[i].r_offset; 823 /* This is the symbol it is referring to */ 824 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 825 + ELF64_R_SYM(rela[i].r_info); 826 827 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", 828 location, (long)ELF64_R_TYPE(rela[i].r_info), 829 strtab + sym->st_name, (unsigned long)sym->st_value, 830 (long)rela[i].r_addend); 831 832 /* `Everything is relative'. */ 833 value = sym->st_value + rela[i].r_addend; 834 835 switch (ELF64_R_TYPE(rela[i].r_info)) { 836 case R_PPC64_ADDR32: 837 /* Simply set it */ 838 *(u32 *)location = value; 839 break; 840 841 case R_PPC64_ADDR64: 842 /* Simply set it */ 843 *(unsigned long *)location = value; 844 break; 845 846 #ifndef CONFIG_PPC_KERNEL_PCREL 847 case R_PPC64_TOC: 848 *(unsigned long *)location = my_r2(sechdrs, me); 849 break; 850 851 case R_PPC64_TOC16: 852 /* Subtract TOC pointer */ 853 value -= my_r2(sechdrs, me); 854 if (value + 0x8000 > 0xffff) { 855 pr_err("%s: bad TOC16 relocation (0x%lx)\n", 856 me->name, value); 857 return -ENOEXEC; 858 } 859 *((uint16_t *) location) 860 = (*((uint16_t *) location) & ~0xffff) 861 | (value & 0xffff); 862 break; 863 864 case R_PPC64_TOC16_LO: 865 /* Subtract TOC pointer */ 866 value -= my_r2(sechdrs, me); 867 *((uint16_t *) location) 868 = (*((uint16_t *) location) & ~0xffff) 869 | (value & 0xffff); 870 break; 871 872 case R_PPC64_TOC16_DS: 873 /* Subtract TOC pointer */ 874 value -= my_r2(sechdrs, me); 875 if ((value & 3) != 0 || value + 0x8000 > 0xffff) { 876 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n", 877 me->name, value); 878 return -ENOEXEC; 879 } 880 *((uint16_t *) location) 881 = (*((uint16_t *) location) & ~0xfffc) 882 | (value & 0xfffc); 883 break; 884 885 case R_PPC64_TOC16_LO_DS: 886 /* Subtract TOC pointer */ 887 value -= my_r2(sechdrs, me); 888 if ((value & 3) != 0) { 889 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n", 890 me->name, value); 891 return -ENOEXEC; 892 } 893 *((uint16_t *) location) 894 = (*((uint16_t *) location) & ~0xfffc) 895 | (value & 0xfffc); 896 break; 897 898 case R_PPC64_TOC16_HA: 899 /* Subtract TOC pointer */ 900 value -= my_r2(sechdrs, me); 901 value = ((value + 0x8000) >> 16); 902 *((uint16_t *) location) 903 = (*((uint16_t *) location) & ~0xffff) 904 | (value & 0xffff); 905 break; 906 #endif 907 908 case R_PPC_REL24: 909 #ifdef CONFIG_PPC_KERNEL_PCREL 910 /* PCREL still generates REL24 for mcount */ 911 case R_PPC64_REL24_NOTOC: 912 #endif 913 /* FIXME: Handle weak symbols here --RR */ 914 if (sym->st_shndx == SHN_UNDEF || 915 sym->st_shndx == SHN_LIVEPATCH) { 916 /* External: go via stub */ 917 value = stub_for_addr(sechdrs, value, me, 918 strtab + sym->st_name); 919 if (!value) 920 return -ENOENT; 921 if (restore_r2(strtab + sym->st_name, 922 (u32 *)location + 1, me)) 923 return -ENOEXEC; 924 } else 925 value += local_entry_offset(sym); 926 927 /* Convert value to relative */ 928 value -= (unsigned long)location; 929 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ 930 pr_err("%s: REL24 %li out of range!\n", 931 me->name, (long int)value); 932 return -ENOEXEC; 933 } 934 935 /* Only replace bits 2 through 26 */ 936 value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value); 937 938 if (patch_instruction((u32 *)location, ppc_inst(value))) 939 return -EFAULT; 940 941 break; 942 943 case R_PPC64_REL64: 944 /* 64 bits relative (used by features fixups) */ 945 *location = value - (unsigned long)location; 946 break; 947 948 case R_PPC64_REL32: 949 /* 32 bits relative (used by relative exception tables) */ 950 /* Convert value to relative */ 951 value -= (unsigned long)location; 952 if (value + 0x80000000 > 0xffffffff) { 953 pr_err("%s: REL32 %li out of range!\n", 954 me->name, (long int)value); 955 return -ENOEXEC; 956 } 957 *(u32 *)location = value; 958 break; 959 960 #ifdef CONFIG_PPC_KERNEL_PCREL 961 case R_PPC64_PCREL34: { 962 unsigned long absvalue = value; 963 964 /* Convert value to relative */ 965 value -= (unsigned long)location; 966 967 if (value + 0x200000000 > 0x3ffffffff) { 968 if (sym->st_shndx != me->arch.pcpu_section) { 969 pr_err("%s: REL34 %li out of range!\n", 970 me->name, (long)value); 971 return -ENOEXEC; 972 } 973 974 /* 975 * per-cpu section is special cased because 976 * it is moved during loading, so has to be 977 * converted to use GOT. 978 */ 979 value = got_for_addr(sechdrs, absvalue, me, 980 strtab + sym->st_name); 981 if (!value) 982 return -ENOENT; 983 value -= (unsigned long)location; 984 985 /* Turn pla into pld */ 986 if (patch_instruction((u32 *)location, 987 ppc_inst_prefix((*(u32 *)location & ~0x02000000), 988 (*((u32 *)location + 1) & ~0xf8000000) | 0xe4000000))) 989 return -EFAULT; 990 } 991 992 if (patch_instruction((u32 *)location, 993 ppc_inst_prefix((*(u32 *)location & ~0x3ffff) | IMM_H18(value), 994 (*((u32 *)location + 1) & ~0xffff) | IMM_L(value)))) 995 return -EFAULT; 996 997 break; 998 } 999 1000 #else 1001 case R_PPC64_TOCSAVE: 1002 /* 1003 * Marker reloc indicates we don't have to save r2. 1004 * That would only save us one instruction, so ignore 1005 * it. 1006 */ 1007 break; 1008 #endif 1009 1010 case R_PPC64_ENTRY: 1011 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) 1012 break; 1013 1014 /* 1015 * Optimize ELFv2 large code model entry point if 1016 * the TOC is within 2GB range of current location. 1017 */ 1018 value = my_r2(sechdrs, me) - (unsigned long)location; 1019 if (value + 0x80008000 > 0xffffffff) 1020 break; 1021 /* 1022 * Check for the large code model prolog sequence: 1023 * ld r2, ...(r12) 1024 * add r2, r2, r12 1025 */ 1026 if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0)) 1027 break; 1028 if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12)) 1029 break; 1030 /* 1031 * If found, replace it with: 1032 * addis r2, r12, (.TOC.-func)@ha 1033 * addi r2, r2, (.TOC.-func)@l 1034 */ 1035 ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value)); 1036 ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value)); 1037 break; 1038 1039 case R_PPC64_REL16_HA: 1040 /* Subtract location pointer */ 1041 value -= (unsigned long)location; 1042 value = ((value + 0x8000) >> 16); 1043 *((uint16_t *) location) 1044 = (*((uint16_t *) location) & ~0xffff) 1045 | (value & 0xffff); 1046 break; 1047 1048 case R_PPC64_REL16_LO: 1049 /* Subtract location pointer */ 1050 value -= (unsigned long)location; 1051 *((uint16_t *) location) 1052 = (*((uint16_t *) location) & ~0xffff) 1053 | (value & 0xffff); 1054 break; 1055 1056 #ifdef CONFIG_PPC_KERNEL_PCREL 1057 case R_PPC64_GOT_PCREL34: 1058 value = got_for_addr(sechdrs, value, me, 1059 strtab + sym->st_name); 1060 if (!value) 1061 return -ENOENT; 1062 value -= (unsigned long)location; 1063 ((uint32_t *)location)[0] = (((uint32_t *)location)[0] & ~0x3ffff) | 1064 ((value >> 16) & 0x3ffff); 1065 ((uint32_t *)location)[1] = (((uint32_t *)location)[1] & ~0xffff) | 1066 (value & 0xffff); 1067 break; 1068 #endif 1069 1070 default: 1071 pr_err("%s: Unknown ADD relocation: %lu\n", 1072 me->name, 1073 (unsigned long)ELF64_R_TYPE(rela[i].r_info)); 1074 return -ENOEXEC; 1075 } 1076 } 1077 1078 return 0; 1079 } 1080 1081 #ifdef CONFIG_DYNAMIC_FTRACE 1082 int module_trampoline_target(struct module *mod, unsigned long addr, 1083 unsigned long *target) 1084 { 1085 struct ppc64_stub_entry *stub; 1086 func_desc_t funcdata; 1087 u32 magic; 1088 1089 if (!within_module_core(addr, mod)) { 1090 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); 1091 return -EFAULT; 1092 } 1093 1094 stub = (struct ppc64_stub_entry *)addr; 1095 1096 if (copy_from_kernel_nofault(&magic, &stub->magic, 1097 sizeof(magic))) { 1098 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); 1099 return -EFAULT; 1100 } 1101 1102 if (magic != STUB_MAGIC) { 1103 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); 1104 return -EFAULT; 1105 } 1106 1107 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata, 1108 sizeof(funcdata))) { 1109 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); 1110 return -EFAULT; 1111 } 1112 1113 *target = stub_func_addr(funcdata); 1114 1115 return 0; 1116 } 1117 1118 static int setup_ftrace_ool_stubs(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me) 1119 { 1120 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE 1121 unsigned int i, total_stubs, num_stubs; 1122 struct ppc64_stub_entry *stub; 1123 1124 total_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stub); 1125 num_stubs = roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), 1126 sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry); 1127 1128 /* Find the next available entry */ 1129 stub = (void *)sechdrs[me->arch.stubs_section].sh_addr; 1130 for (i = 0; stub_func_addr(stub[i].funcdata); i++) 1131 if (WARN_ON(i >= total_stubs)) 1132 return -1; 1133 1134 if (WARN_ON(i + num_stubs > total_stubs)) 1135 return -1; 1136 1137 stub += i; 1138 me->arch.ool_stubs = (struct ftrace_ool_stub *)stub; 1139 1140 /* reserve stubs */ 1141 for (i = 0; i < num_stubs; i++) 1142 if (patch_u32((void *)&stub->funcdata, PPC_RAW_NOP())) 1143 return -1; 1144 #endif 1145 1146 return 0; 1147 } 1148 1149 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) 1150 { 1151 mod->arch.tramp = stub_for_addr(sechdrs, 1152 (unsigned long)ftrace_caller, 1153 mod, 1154 "ftrace_caller"); 1155 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 1156 mod->arch.tramp_regs = stub_for_addr(sechdrs, 1157 (unsigned long)ftrace_regs_caller, 1158 mod, 1159 "ftrace_regs_caller"); 1160 if (!mod->arch.tramp_regs) 1161 return -ENOENT; 1162 #endif 1163 1164 if (!mod->arch.tramp) 1165 return -ENOENT; 1166 1167 if (setup_ftrace_ool_stubs(sechdrs, mod->arch.tramp, mod)) 1168 return -ENOENT; 1169 1170 return 0; 1171 } 1172 #endif 1173