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 <asm/module.h> 18 #include <asm/firmware.h> 19 #include <asm/code-patching.h> 20 #include <linux/sort.h> 21 #include <asm/setup.h> 22 #include <asm/sections.h> 23 #include <asm/inst.h> 24 25 /* FIXME: We don't do .init separately. To do this, we'd need to have 26 a separate r2 value in the init and core section, and stub between 27 them, too. 28 29 Using a magic allocator which places modules within 32MB solves 30 this, and makes other things simpler. Anton? 31 --RR. */ 32 33 #ifdef PPC64_ELF_ABI_v2 34 35 /* An address is simply the address of the function. */ 36 typedef unsigned long func_desc_t; 37 38 static func_desc_t func_desc(unsigned long addr) 39 { 40 return addr; 41 } 42 static unsigned long func_addr(unsigned long addr) 43 { 44 return addr; 45 } 46 static unsigned long stub_func_addr(func_desc_t func) 47 { 48 return func; 49 } 50 51 /* PowerPC64 specific values for the Elf64_Sym st_other field. */ 52 #define STO_PPC64_LOCAL_BIT 5 53 #define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT) 54 #define PPC64_LOCAL_ENTRY_OFFSET(other) \ 55 (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2) 56 57 static unsigned int local_entry_offset(const Elf64_Sym *sym) 58 { 59 /* sym->st_other indicates offset to local entry point 60 * (otherwise it will assume r12 is the address of the start 61 * of function and try to derive r2 from it). */ 62 return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other); 63 } 64 #else 65 66 /* An address is address of the OPD entry, which contains address of fn. */ 67 typedef struct ppc64_opd_entry func_desc_t; 68 69 static func_desc_t func_desc(unsigned long addr) 70 { 71 return *(struct ppc64_opd_entry *)addr; 72 } 73 static unsigned long func_addr(unsigned long addr) 74 { 75 return func_desc(addr).funcaddr; 76 } 77 static unsigned long stub_func_addr(func_desc_t func) 78 { 79 return func.funcaddr; 80 } 81 static unsigned int local_entry_offset(const Elf64_Sym *sym) 82 { 83 return 0; 84 } 85 86 void *dereference_module_function_descriptor(struct module *mod, void *ptr) 87 { 88 if (ptr < (void *)mod->arch.start_opd || 89 ptr >= (void *)mod->arch.end_opd) 90 return ptr; 91 92 return dereference_function_descriptor(ptr); 93 } 94 #endif 95 96 #define STUB_MAGIC 0x73747562 /* stub */ 97 98 /* Like PPC32, we need little trampolines to do > 24-bit jumps (into 99 the kernel itself). But on PPC64, these need to be used for every 100 jump, actually, to reset r2 (TOC+0x8000). */ 101 struct ppc64_stub_entry 102 { 103 /* 28 byte jump instruction sequence (7 instructions). We only 104 * need 6 instructions on ABIv2 but we always allocate 7 so 105 * so we don't have to modify the trampoline load instruction. */ 106 u32 jump[7]; 107 /* Used by ftrace to identify stubs */ 108 u32 magic; 109 /* Data for the above code */ 110 func_desc_t funcdata; 111 }; 112 113 /* 114 * PPC64 uses 24 bit jumps, but we need to jump into other modules or 115 * the kernel which may be further. So we jump to a stub. 116 * 117 * For ELFv1 we need to use this to set up the new r2 value (aka TOC 118 * pointer). For ELFv2 it's the callee's responsibility to set up the 119 * new r2, but for both we need to save the old r2. 120 * 121 * We could simply patch the new r2 value and function pointer into 122 * the stub, but it's significantly shorter to put these values at the 123 * end of the stub code, and patch the stub address (32-bits relative 124 * to the TOC ptr, r2) into the stub. 125 */ 126 static u32 ppc64_stub_insns[] = { 127 PPC_RAW_ADDIS(_R11, _R2, 0), 128 PPC_RAW_ADDI(_R11, _R11, 0), 129 /* Save current r2 value in magic place on the stack. */ 130 PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET), 131 PPC_RAW_LD(_R12, _R11, 32), 132 #ifdef PPC64_ELF_ABI_v1 133 /* Set up new r2 from function descriptor */ 134 PPC_RAW_LD(_R2, _R11, 40), 135 #endif 136 PPC_RAW_MTCTR(_R12), 137 PPC_RAW_BCTR(), 138 }; 139 140 /* Count how many different 24-bit relocations (different symbol, 141 different addend) */ 142 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) 143 { 144 unsigned int i, r_info, r_addend, _count_relocs; 145 146 /* FIXME: Only count external ones --RR */ 147 _count_relocs = 0; 148 r_info = 0; 149 r_addend = 0; 150 for (i = 0; i < num; i++) 151 /* Only count 24-bit relocs, others don't need stubs */ 152 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && 153 (r_info != ELF64_R_SYM(rela[i].r_info) || 154 r_addend != rela[i].r_addend)) { 155 _count_relocs++; 156 r_info = ELF64_R_SYM(rela[i].r_info); 157 r_addend = rela[i].r_addend; 158 } 159 160 return _count_relocs; 161 } 162 163 static int relacmp(const void *_x, const void *_y) 164 { 165 const Elf64_Rela *x, *y; 166 167 y = (Elf64_Rela *)_x; 168 x = (Elf64_Rela *)_y; 169 170 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to 171 * make the comparison cheaper/faster. It won't affect the sorting or 172 * the counting algorithms' performance 173 */ 174 if (x->r_info < y->r_info) 175 return -1; 176 else if (x->r_info > y->r_info) 177 return 1; 178 else if (x->r_addend < y->r_addend) 179 return -1; 180 else if (x->r_addend > y->r_addend) 181 return 1; 182 else 183 return 0; 184 } 185 186 /* Get size of potential trampolines required. */ 187 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, 188 const Elf64_Shdr *sechdrs) 189 { 190 /* One extra reloc so it's always 0-funcaddr terminated */ 191 unsigned long relocs = 1; 192 unsigned i; 193 194 /* Every relocated section... */ 195 for (i = 1; i < hdr->e_shnum; i++) { 196 if (sechdrs[i].sh_type == SHT_RELA) { 197 pr_debug("Found relocations in section %u\n", i); 198 pr_debug("Ptr: %p. Number: %Lu\n", 199 (void *)sechdrs[i].sh_addr, 200 sechdrs[i].sh_size / sizeof(Elf64_Rela)); 201 202 /* Sort the relocation information based on a symbol and 203 * addend key. This is a stable O(n*log n) complexity 204 * alogrithm but it will reduce the complexity of 205 * count_relocs() to linear complexity O(n) 206 */ 207 sort((void *)sechdrs[i].sh_addr, 208 sechdrs[i].sh_size / sizeof(Elf64_Rela), 209 sizeof(Elf64_Rela), relacmp, NULL); 210 211 relocs += count_relocs((void *)sechdrs[i].sh_addr, 212 sechdrs[i].sh_size 213 / sizeof(Elf64_Rela)); 214 } 215 } 216 217 #ifdef CONFIG_DYNAMIC_FTRACE 218 /* make the trampoline to the ftrace_caller */ 219 relocs++; 220 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 221 /* an additional one for ftrace_regs_caller */ 222 relocs++; 223 #endif 224 #endif 225 226 pr_debug("Looks like a total of %lu stubs, max\n", relocs); 227 return relocs * sizeof(struct ppc64_stub_entry); 228 } 229 230 /* Still needed for ELFv2, for .TOC. */ 231 static void dedotify_versions(struct modversion_info *vers, 232 unsigned long size) 233 { 234 struct modversion_info *end; 235 236 for (end = (void *)vers + size; vers < end; vers++) 237 if (vers->name[0] == '.') { 238 memmove(vers->name, vers->name+1, strlen(vers->name)); 239 } 240 } 241 242 /* 243 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. 244 * seem to be defined (value set later). 245 */ 246 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) 247 { 248 unsigned int i; 249 250 for (i = 1; i < numsyms; i++) { 251 if (syms[i].st_shndx == SHN_UNDEF) { 252 char *name = strtab + syms[i].st_name; 253 if (name[0] == '.') { 254 if (strcmp(name+1, "TOC.") == 0) 255 syms[i].st_shndx = SHN_ABS; 256 syms[i].st_name++; 257 } 258 } 259 } 260 } 261 262 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, 263 const char *strtab, 264 unsigned int symindex) 265 { 266 unsigned int i, numsyms; 267 Elf64_Sym *syms; 268 269 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; 270 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); 271 272 for (i = 1; i < numsyms; i++) { 273 if (syms[i].st_shndx == SHN_ABS 274 && strcmp(strtab + syms[i].st_name, "TOC.") == 0) 275 return &syms[i]; 276 } 277 return NULL; 278 } 279 280 int module_frob_arch_sections(Elf64_Ehdr *hdr, 281 Elf64_Shdr *sechdrs, 282 char *secstrings, 283 struct module *me) 284 { 285 unsigned int i; 286 287 /* Find .toc and .stubs sections, symtab and strtab */ 288 for (i = 1; i < hdr->e_shnum; i++) { 289 char *p; 290 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) 291 me->arch.stubs_section = i; 292 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) { 293 me->arch.toc_section = i; 294 if (sechdrs[i].sh_addralign < 8) 295 sechdrs[i].sh_addralign = 8; 296 } 297 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0) 298 dedotify_versions((void *)hdr + sechdrs[i].sh_offset, 299 sechdrs[i].sh_size); 300 301 /* We don't handle .init for the moment: rename to _init */ 302 while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) 303 p[0] = '_'; 304 305 if (sechdrs[i].sh_type == SHT_SYMTAB) 306 dedotify((void *)hdr + sechdrs[i].sh_offset, 307 sechdrs[i].sh_size / sizeof(Elf64_Sym), 308 (void *)hdr 309 + sechdrs[sechdrs[i].sh_link].sh_offset); 310 } 311 312 if (!me->arch.stubs_section) { 313 pr_err("%s: doesn't contain .stubs.\n", me->name); 314 return -ENOEXEC; 315 } 316 317 /* If we don't have a .toc, just use .stubs. We need to set r2 318 to some reasonable value in case the module calls out to 319 other functions via a stub, or if a function pointer escapes 320 the module by some means. */ 321 if (!me->arch.toc_section) 322 me->arch.toc_section = me->arch.stubs_section; 323 324 /* Override the stubs size */ 325 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); 326 return 0; 327 } 328 329 #ifdef CONFIG_MPROFILE_KERNEL 330 331 static u32 stub_insns[] = { 332 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), 333 PPC_RAW_ADDIS(_R12, _R12, 0), 334 PPC_RAW_ADDI(_R12, _R12, 0), 335 PPC_RAW_MTCTR(_R12), 336 PPC_RAW_BCTR(), 337 }; 338 339 /* 340 * For mprofile-kernel we use a special stub for ftrace_caller() because we 341 * can't rely on r2 containing this module's TOC when we enter the stub. 342 * 343 * That can happen if the function calling us didn't need to use the toc. In 344 * that case it won't have setup r2, and the r2 value will be either the 345 * kernel's toc, or possibly another modules toc. 346 * 347 * To deal with that this stub uses the kernel toc, which is always accessible 348 * via the paca (in r13). The target (ftrace_caller()) is responsible for 349 * saving and restoring the toc before returning. 350 */ 351 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 352 unsigned long addr, 353 struct module *me) 354 { 355 long reladdr; 356 357 memcpy(entry->jump, stub_insns, sizeof(stub_insns)); 358 359 /* Stub uses address relative to kernel toc (from the paca) */ 360 reladdr = addr - kernel_toc_addr(); 361 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 362 pr_err("%s: Address of %ps out of range of kernel_toc.\n", 363 me->name, (void *)addr); 364 return 0; 365 } 366 367 entry->jump[1] |= PPC_HA(reladdr); 368 entry->jump[2] |= PPC_LO(reladdr); 369 370 /* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */ 371 entry->funcdata = func_desc(addr); 372 entry->magic = STUB_MAGIC; 373 374 return 1; 375 } 376 377 static bool is_mprofile_ftrace_call(const char *name) 378 { 379 if (!strcmp("_mcount", name)) 380 return true; 381 #ifdef CONFIG_DYNAMIC_FTRACE 382 if (!strcmp("ftrace_caller", name)) 383 return true; 384 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 385 if (!strcmp("ftrace_regs_caller", name)) 386 return true; 387 #endif 388 #endif 389 390 return false; 391 } 392 #else 393 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 394 unsigned long addr, 395 struct module *me) 396 { 397 return 0; 398 } 399 400 static bool is_mprofile_ftrace_call(const char *name) 401 { 402 return false; 403 } 404 #endif 405 406 /* 407 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the 408 * value maximum span in an instruction which uses a signed offset). Round down 409 * to a 256 byte boundary for the odd case where we are setting up r2 without a 410 * .toc section. 411 */ 412 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) 413 { 414 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; 415 } 416 417 /* Patch stub to reference function and correct r2 value. */ 418 static inline int create_stub(const Elf64_Shdr *sechdrs, 419 struct ppc64_stub_entry *entry, 420 unsigned long addr, 421 struct module *me, 422 const char *name) 423 { 424 long reladdr; 425 426 if (is_mprofile_ftrace_call(name)) 427 return create_ftrace_stub(entry, addr, me); 428 429 memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns)); 430 431 /* Stub uses address relative to r2. */ 432 reladdr = (unsigned long)entry - my_r2(sechdrs, me); 433 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 434 pr_err("%s: Address %p of stub out of range of %p.\n", 435 me->name, (void *)reladdr, (void *)my_r2); 436 return 0; 437 } 438 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); 439 440 entry->jump[0] |= PPC_HA(reladdr); 441 entry->jump[1] |= PPC_LO(reladdr); 442 entry->funcdata = func_desc(addr); 443 entry->magic = STUB_MAGIC; 444 445 return 1; 446 } 447 448 /* Create stub to jump to function described in this OPD/ptr: we need the 449 stub to set up the TOC ptr (r2) for the function. */ 450 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, 451 unsigned long addr, 452 struct module *me, 453 const char *name) 454 { 455 struct ppc64_stub_entry *stubs; 456 unsigned int i, num_stubs; 457 458 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); 459 460 /* Find this stub, or if that fails, the next avail. entry */ 461 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; 462 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { 463 if (WARN_ON(i >= num_stubs)) 464 return 0; 465 466 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) 467 return (unsigned long)&stubs[i]; 468 } 469 470 if (!create_stub(sechdrs, &stubs[i], addr, me, name)) 471 return 0; 472 473 return (unsigned long)&stubs[i]; 474 } 475 476 /* We expect a noop next: if it is, replace it with instruction to 477 restore r2. */ 478 static int restore_r2(const char *name, u32 *instruction, struct module *me) 479 { 480 u32 *prev_insn = instruction - 1; 481 482 if (is_mprofile_ftrace_call(name)) 483 return 1; 484 485 /* 486 * Make sure the branch isn't a sibling call. Sibling calls aren't 487 * "link" branches and they don't return, so they don't need the r2 488 * restore afterwards. 489 */ 490 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn))) 491 return 1; 492 493 if (*instruction != PPC_RAW_NOP()) { 494 pr_err("%s: Expected nop after call, got %08x at %pS\n", 495 me->name, *instruction, instruction); 496 return 0; 497 } 498 /* ld r2,R2_STACK_OFFSET(r1) */ 499 *instruction = PPC_INST_LD_TOC; 500 return 1; 501 } 502 503 int apply_relocate_add(Elf64_Shdr *sechdrs, 504 const char *strtab, 505 unsigned int symindex, 506 unsigned int relsec, 507 struct module *me) 508 { 509 unsigned int i; 510 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; 511 Elf64_Sym *sym; 512 unsigned long *location; 513 unsigned long value; 514 515 pr_debug("Applying ADD relocate section %u to %u\n", relsec, 516 sechdrs[relsec].sh_info); 517 518 /* First time we're called, we can fix up .TOC. */ 519 if (!me->arch.toc_fixed) { 520 sym = find_dot_toc(sechdrs, strtab, symindex); 521 /* It's theoretically possible that a module doesn't want a 522 * .TOC. so don't fail it just for that. */ 523 if (sym) 524 sym->st_value = my_r2(sechdrs, me); 525 me->arch.toc_fixed = true; 526 } 527 528 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 529 /* This is where to make the change */ 530 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 531 + rela[i].r_offset; 532 /* This is the symbol it is referring to */ 533 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 534 + ELF64_R_SYM(rela[i].r_info); 535 536 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", 537 location, (long)ELF64_R_TYPE(rela[i].r_info), 538 strtab + sym->st_name, (unsigned long)sym->st_value, 539 (long)rela[i].r_addend); 540 541 /* `Everything is relative'. */ 542 value = sym->st_value + rela[i].r_addend; 543 544 switch (ELF64_R_TYPE(rela[i].r_info)) { 545 case R_PPC64_ADDR32: 546 /* Simply set it */ 547 *(u32 *)location = value; 548 break; 549 550 case R_PPC64_ADDR64: 551 /* Simply set it */ 552 *(unsigned long *)location = value; 553 break; 554 555 case R_PPC64_TOC: 556 *(unsigned long *)location = my_r2(sechdrs, me); 557 break; 558 559 case R_PPC64_TOC16: 560 /* Subtract TOC pointer */ 561 value -= my_r2(sechdrs, me); 562 if (value + 0x8000 > 0xffff) { 563 pr_err("%s: bad TOC16 relocation (0x%lx)\n", 564 me->name, value); 565 return -ENOEXEC; 566 } 567 *((uint16_t *) location) 568 = (*((uint16_t *) location) & ~0xffff) 569 | (value & 0xffff); 570 break; 571 572 case R_PPC64_TOC16_LO: 573 /* Subtract TOC pointer */ 574 value -= my_r2(sechdrs, me); 575 *((uint16_t *) location) 576 = (*((uint16_t *) location) & ~0xffff) 577 | (value & 0xffff); 578 break; 579 580 case R_PPC64_TOC16_DS: 581 /* Subtract TOC pointer */ 582 value -= my_r2(sechdrs, me); 583 if ((value & 3) != 0 || value + 0x8000 > 0xffff) { 584 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n", 585 me->name, value); 586 return -ENOEXEC; 587 } 588 *((uint16_t *) location) 589 = (*((uint16_t *) location) & ~0xfffc) 590 | (value & 0xfffc); 591 break; 592 593 case R_PPC64_TOC16_LO_DS: 594 /* Subtract TOC pointer */ 595 value -= my_r2(sechdrs, me); 596 if ((value & 3) != 0) { 597 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n", 598 me->name, value); 599 return -ENOEXEC; 600 } 601 *((uint16_t *) location) 602 = (*((uint16_t *) location) & ~0xfffc) 603 | (value & 0xfffc); 604 break; 605 606 case R_PPC64_TOC16_HA: 607 /* Subtract TOC pointer */ 608 value -= my_r2(sechdrs, me); 609 value = ((value + 0x8000) >> 16); 610 *((uint16_t *) location) 611 = (*((uint16_t *) location) & ~0xffff) 612 | (value & 0xffff); 613 break; 614 615 case R_PPC_REL24: 616 /* FIXME: Handle weak symbols here --RR */ 617 if (sym->st_shndx == SHN_UNDEF || 618 sym->st_shndx == SHN_LIVEPATCH) { 619 /* External: go via stub */ 620 value = stub_for_addr(sechdrs, value, me, 621 strtab + sym->st_name); 622 if (!value) 623 return -ENOENT; 624 if (!restore_r2(strtab + sym->st_name, 625 (u32 *)location + 1, me)) 626 return -ENOEXEC; 627 } else 628 value += local_entry_offset(sym); 629 630 /* Convert value to relative */ 631 value -= (unsigned long)location; 632 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ 633 pr_err("%s: REL24 %li out of range!\n", 634 me->name, (long int)value); 635 return -ENOEXEC; 636 } 637 638 /* Only replace bits 2 through 26 */ 639 *(uint32_t *)location 640 = (*(uint32_t *)location & ~0x03fffffc) 641 | (value & 0x03fffffc); 642 break; 643 644 case R_PPC64_REL64: 645 /* 64 bits relative (used by features fixups) */ 646 *location = value - (unsigned long)location; 647 break; 648 649 case R_PPC64_REL32: 650 /* 32 bits relative (used by relative exception tables) */ 651 /* Convert value to relative */ 652 value -= (unsigned long)location; 653 if (value + 0x80000000 > 0xffffffff) { 654 pr_err("%s: REL32 %li out of range!\n", 655 me->name, (long int)value); 656 return -ENOEXEC; 657 } 658 *(u32 *)location = value; 659 break; 660 661 case R_PPC64_TOCSAVE: 662 /* 663 * Marker reloc indicates we don't have to save r2. 664 * That would only save us one instruction, so ignore 665 * it. 666 */ 667 break; 668 669 case R_PPC64_ENTRY: 670 /* 671 * Optimize ELFv2 large code model entry point if 672 * the TOC is within 2GB range of current location. 673 */ 674 value = my_r2(sechdrs, me) - (unsigned long)location; 675 if (value + 0x80008000 > 0xffffffff) 676 break; 677 /* 678 * Check for the large code model prolog sequence: 679 * ld r2, ...(r12) 680 * add r2, r2, r12 681 */ 682 if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0)) 683 break; 684 if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12)) 685 break; 686 /* 687 * If found, replace it with: 688 * addis r2, r12, (.TOC.-func)@ha 689 * addi r2, r2, (.TOC.-func)@l 690 */ 691 ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value)); 692 ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value)); 693 break; 694 695 case R_PPC64_REL16_HA: 696 /* Subtract location pointer */ 697 value -= (unsigned long)location; 698 value = ((value + 0x8000) >> 16); 699 *((uint16_t *) location) 700 = (*((uint16_t *) location) & ~0xffff) 701 | (value & 0xffff); 702 break; 703 704 case R_PPC64_REL16_LO: 705 /* Subtract location pointer */ 706 value -= (unsigned long)location; 707 *((uint16_t *) location) 708 = (*((uint16_t *) location) & ~0xffff) 709 | (value & 0xffff); 710 break; 711 712 default: 713 pr_err("%s: Unknown ADD relocation: %lu\n", 714 me->name, 715 (unsigned long)ELF64_R_TYPE(rela[i].r_info)); 716 return -ENOEXEC; 717 } 718 } 719 720 return 0; 721 } 722 723 #ifdef CONFIG_DYNAMIC_FTRACE 724 int module_trampoline_target(struct module *mod, unsigned long addr, 725 unsigned long *target) 726 { 727 struct ppc64_stub_entry *stub; 728 func_desc_t funcdata; 729 u32 magic; 730 731 if (!within_module_core(addr, mod)) { 732 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); 733 return -EFAULT; 734 } 735 736 stub = (struct ppc64_stub_entry *)addr; 737 738 if (copy_from_kernel_nofault(&magic, &stub->magic, 739 sizeof(magic))) { 740 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); 741 return -EFAULT; 742 } 743 744 if (magic != STUB_MAGIC) { 745 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); 746 return -EFAULT; 747 } 748 749 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata, 750 sizeof(funcdata))) { 751 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); 752 return -EFAULT; 753 } 754 755 *target = stub_func_addr(funcdata); 756 757 return 0; 758 } 759 760 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) 761 { 762 mod->arch.tramp = stub_for_addr(sechdrs, 763 (unsigned long)ftrace_caller, 764 mod, 765 "ftrace_caller"); 766 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 767 mod->arch.tramp_regs = stub_for_addr(sechdrs, 768 (unsigned long)ftrace_regs_caller, 769 mod, 770 "ftrace_regs_caller"); 771 if (!mod->arch.tramp_regs) 772 return -ENOENT; 773 #endif 774 775 if (!mod->arch.tramp) 776 return -ENOENT; 777 778 return 0; 779 } 780 #endif 781