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 * addis r11,r2, <high> 127 * addi r11,r11, <low> 128 * std r2,R2_STACK_OFFSET(r1) 129 * ld r12,32(r11) 130 * ld r2,40(r11) 131 * mtctr r12 132 * bctr 133 */ 134 static u32 ppc64_stub_insns[] = { 135 PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2), 136 PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11), 137 /* Save current r2 value in magic place on the stack. */ 138 PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET, 139 PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32, 140 #ifdef PPC64_ELF_ABI_v1 141 /* Set up new r2 from function descriptor */ 142 PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40, 143 #endif 144 PPC_INST_MTCTR | __PPC_RS(R12), 145 PPC_INST_BCTR, 146 }; 147 148 /* Count how many different 24-bit relocations (different symbol, 149 different addend) */ 150 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) 151 { 152 unsigned int i, r_info, r_addend, _count_relocs; 153 154 /* FIXME: Only count external ones --RR */ 155 _count_relocs = 0; 156 r_info = 0; 157 r_addend = 0; 158 for (i = 0; i < num; i++) 159 /* Only count 24-bit relocs, others don't need stubs */ 160 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && 161 (r_info != ELF64_R_SYM(rela[i].r_info) || 162 r_addend != rela[i].r_addend)) { 163 _count_relocs++; 164 r_info = ELF64_R_SYM(rela[i].r_info); 165 r_addend = rela[i].r_addend; 166 } 167 168 return _count_relocs; 169 } 170 171 static int relacmp(const void *_x, const void *_y) 172 { 173 const Elf64_Rela *x, *y; 174 175 y = (Elf64_Rela *)_x; 176 x = (Elf64_Rela *)_y; 177 178 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to 179 * make the comparison cheaper/faster. It won't affect the sorting or 180 * the counting algorithms' performance 181 */ 182 if (x->r_info < y->r_info) 183 return -1; 184 else if (x->r_info > y->r_info) 185 return 1; 186 else if (x->r_addend < y->r_addend) 187 return -1; 188 else if (x->r_addend > y->r_addend) 189 return 1; 190 else 191 return 0; 192 } 193 194 /* Get size of potential trampolines required. */ 195 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, 196 const Elf64_Shdr *sechdrs) 197 { 198 /* One extra reloc so it's always 0-funcaddr terminated */ 199 unsigned long relocs = 1; 200 unsigned i; 201 202 /* Every relocated section... */ 203 for (i = 1; i < hdr->e_shnum; i++) { 204 if (sechdrs[i].sh_type == SHT_RELA) { 205 pr_debug("Found relocations in section %u\n", i); 206 pr_debug("Ptr: %p. Number: %Lu\n", 207 (void *)sechdrs[i].sh_addr, 208 sechdrs[i].sh_size / sizeof(Elf64_Rela)); 209 210 /* Sort the relocation information based on a symbol and 211 * addend key. This is a stable O(n*log n) complexity 212 * alogrithm but it will reduce the complexity of 213 * count_relocs() to linear complexity O(n) 214 */ 215 sort((void *)sechdrs[i].sh_addr, 216 sechdrs[i].sh_size / sizeof(Elf64_Rela), 217 sizeof(Elf64_Rela), relacmp, NULL); 218 219 relocs += count_relocs((void *)sechdrs[i].sh_addr, 220 sechdrs[i].sh_size 221 / sizeof(Elf64_Rela)); 222 } 223 } 224 225 #ifdef CONFIG_DYNAMIC_FTRACE 226 /* make the trampoline to the ftrace_caller */ 227 relocs++; 228 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 229 /* an additional one for ftrace_regs_caller */ 230 relocs++; 231 #endif 232 #endif 233 234 pr_debug("Looks like a total of %lu stubs, max\n", relocs); 235 return relocs * sizeof(struct ppc64_stub_entry); 236 } 237 238 /* Still needed for ELFv2, for .TOC. */ 239 static void dedotify_versions(struct modversion_info *vers, 240 unsigned long size) 241 { 242 struct modversion_info *end; 243 244 for (end = (void *)vers + size; vers < end; vers++) 245 if (vers->name[0] == '.') { 246 memmove(vers->name, vers->name+1, strlen(vers->name)); 247 } 248 } 249 250 /* 251 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. 252 * seem to be defined (value set later). 253 */ 254 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) 255 { 256 unsigned int i; 257 258 for (i = 1; i < numsyms; i++) { 259 if (syms[i].st_shndx == SHN_UNDEF) { 260 char *name = strtab + syms[i].st_name; 261 if (name[0] == '.') { 262 if (strcmp(name+1, "TOC.") == 0) 263 syms[i].st_shndx = SHN_ABS; 264 syms[i].st_name++; 265 } 266 } 267 } 268 } 269 270 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, 271 const char *strtab, 272 unsigned int symindex) 273 { 274 unsigned int i, numsyms; 275 Elf64_Sym *syms; 276 277 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; 278 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); 279 280 for (i = 1; i < numsyms; i++) { 281 if (syms[i].st_shndx == SHN_ABS 282 && strcmp(strtab + syms[i].st_name, "TOC.") == 0) 283 return &syms[i]; 284 } 285 return NULL; 286 } 287 288 int module_frob_arch_sections(Elf64_Ehdr *hdr, 289 Elf64_Shdr *sechdrs, 290 char *secstrings, 291 struct module *me) 292 { 293 unsigned int i; 294 295 /* Find .toc and .stubs sections, symtab and strtab */ 296 for (i = 1; i < hdr->e_shnum; i++) { 297 char *p; 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 /* We don't handle .init for the moment: rename to _init */ 310 while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) 311 p[0] = '_'; 312 313 if (sechdrs[i].sh_type == SHT_SYMTAB) 314 dedotify((void *)hdr + sechdrs[i].sh_offset, 315 sechdrs[i].sh_size / sizeof(Elf64_Sym), 316 (void *)hdr 317 + sechdrs[sechdrs[i].sh_link].sh_offset); 318 } 319 320 if (!me->arch.stubs_section) { 321 pr_err("%s: doesn't contain .stubs.\n", me->name); 322 return -ENOEXEC; 323 } 324 325 /* If we don't have a .toc, just use .stubs. We need to set r2 326 to some reasonable value in case the module calls out to 327 other functions via a stub, or if a function pointer escapes 328 the module by some means. */ 329 if (!me->arch.toc_section) 330 me->arch.toc_section = me->arch.stubs_section; 331 332 /* Override the stubs size */ 333 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); 334 return 0; 335 } 336 337 #ifdef CONFIG_MPROFILE_KERNEL 338 339 #define PACATOC offsetof(struct paca_struct, kernel_toc) 340 341 /* 342 * ld r12,PACATOC(r13) 343 * addis r12,r12,<high> 344 * addi r12,r12,<low> 345 * mtctr r12 346 * bctr 347 */ 348 static u32 stub_insns[] = { 349 PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC, 350 PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12), 351 PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12), 352 PPC_INST_MTCTR | __PPC_RS(R12), 353 PPC_INST_BCTR, 354 }; 355 356 /* 357 * For mprofile-kernel we use a special stub for ftrace_caller() because we 358 * can't rely on r2 containing this module's TOC when we enter the stub. 359 * 360 * That can happen if the function calling us didn't need to use the toc. In 361 * that case it won't have setup r2, and the r2 value will be either the 362 * kernel's toc, or possibly another modules toc. 363 * 364 * To deal with that this stub uses the kernel toc, which is always accessible 365 * via the paca (in r13). The target (ftrace_caller()) is responsible for 366 * saving and restoring the toc before returning. 367 */ 368 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 369 unsigned long addr, 370 struct module *me) 371 { 372 long reladdr; 373 374 memcpy(entry->jump, stub_insns, sizeof(stub_insns)); 375 376 /* Stub uses address relative to kernel toc (from the paca) */ 377 reladdr = addr - kernel_toc_addr(); 378 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 379 pr_err("%s: Address of %ps out of range of kernel_toc.\n", 380 me->name, (void *)addr); 381 return 0; 382 } 383 384 entry->jump[1] |= PPC_HA(reladdr); 385 entry->jump[2] |= PPC_LO(reladdr); 386 387 /* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */ 388 entry->funcdata = func_desc(addr); 389 entry->magic = STUB_MAGIC; 390 391 return 1; 392 } 393 394 static bool is_mprofile_ftrace_call(const char *name) 395 { 396 if (!strcmp("_mcount", name)) 397 return true; 398 #ifdef CONFIG_DYNAMIC_FTRACE 399 if (!strcmp("ftrace_caller", name)) 400 return true; 401 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 402 if (!strcmp("ftrace_regs_caller", name)) 403 return true; 404 #endif 405 #endif 406 407 return false; 408 } 409 #else 410 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, 411 unsigned long addr, 412 struct module *me) 413 { 414 return 0; 415 } 416 417 static bool is_mprofile_ftrace_call(const char *name) 418 { 419 return false; 420 } 421 #endif 422 423 /* 424 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the 425 * value maximum span in an instruction which uses a signed offset). Round down 426 * to a 256 byte boundary for the odd case where we are setting up r2 without a 427 * .toc section. 428 */ 429 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) 430 { 431 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; 432 } 433 434 /* Patch stub to reference function and correct r2 value. */ 435 static inline int create_stub(const Elf64_Shdr *sechdrs, 436 struct ppc64_stub_entry *entry, 437 unsigned long addr, 438 struct module *me, 439 const char *name) 440 { 441 long reladdr; 442 443 if (is_mprofile_ftrace_call(name)) 444 return create_ftrace_stub(entry, addr, me); 445 446 memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns)); 447 448 /* Stub uses address relative to r2. */ 449 reladdr = (unsigned long)entry - my_r2(sechdrs, me); 450 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { 451 pr_err("%s: Address %p of stub out of range of %p.\n", 452 me->name, (void *)reladdr, (void *)my_r2); 453 return 0; 454 } 455 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); 456 457 entry->jump[0] |= PPC_HA(reladdr); 458 entry->jump[1] |= PPC_LO(reladdr); 459 entry->funcdata = func_desc(addr); 460 entry->magic = STUB_MAGIC; 461 462 return 1; 463 } 464 465 /* Create stub to jump to function described in this OPD/ptr: we need the 466 stub to set up the TOC ptr (r2) for the function. */ 467 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, 468 unsigned long addr, 469 struct module *me, 470 const char *name) 471 { 472 struct ppc64_stub_entry *stubs; 473 unsigned int i, num_stubs; 474 475 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); 476 477 /* Find this stub, or if that fails, the next avail. entry */ 478 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; 479 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { 480 if (WARN_ON(i >= num_stubs)) 481 return 0; 482 483 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) 484 return (unsigned long)&stubs[i]; 485 } 486 487 if (!create_stub(sechdrs, &stubs[i], addr, me, name)) 488 return 0; 489 490 return (unsigned long)&stubs[i]; 491 } 492 493 /* We expect a noop next: if it is, replace it with instruction to 494 restore r2. */ 495 static int restore_r2(const char *name, u32 *instruction, struct module *me) 496 { 497 u32 *prev_insn = instruction - 1; 498 499 if (is_mprofile_ftrace_call(name)) 500 return 1; 501 502 /* 503 * Make sure the branch isn't a sibling call. Sibling calls aren't 504 * "link" branches and they don't return, so they don't need the r2 505 * restore afterwards. 506 */ 507 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn))) 508 return 1; 509 510 if (*instruction != PPC_INST_NOP) { 511 pr_err("%s: Expected nop after call, got %08x at %pS\n", 512 me->name, *instruction, instruction); 513 return 0; 514 } 515 /* ld r2,R2_STACK_OFFSET(r1) */ 516 *instruction = PPC_INST_LD_TOC; 517 return 1; 518 } 519 520 int apply_relocate_add(Elf64_Shdr *sechdrs, 521 const char *strtab, 522 unsigned int symindex, 523 unsigned int relsec, 524 struct module *me) 525 { 526 unsigned int i; 527 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; 528 Elf64_Sym *sym; 529 unsigned long *location; 530 unsigned long value; 531 532 pr_debug("Applying ADD relocate section %u to %u\n", relsec, 533 sechdrs[relsec].sh_info); 534 535 /* First time we're called, we can fix up .TOC. */ 536 if (!me->arch.toc_fixed) { 537 sym = find_dot_toc(sechdrs, strtab, symindex); 538 /* It's theoretically possible that a module doesn't want a 539 * .TOC. so don't fail it just for that. */ 540 if (sym) 541 sym->st_value = my_r2(sechdrs, me); 542 me->arch.toc_fixed = true; 543 } 544 545 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 546 /* This is where to make the change */ 547 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 548 + rela[i].r_offset; 549 /* This is the symbol it is referring to */ 550 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr 551 + ELF64_R_SYM(rela[i].r_info); 552 553 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", 554 location, (long)ELF64_R_TYPE(rela[i].r_info), 555 strtab + sym->st_name, (unsigned long)sym->st_value, 556 (long)rela[i].r_addend); 557 558 /* `Everything is relative'. */ 559 value = sym->st_value + rela[i].r_addend; 560 561 switch (ELF64_R_TYPE(rela[i].r_info)) { 562 case R_PPC64_ADDR32: 563 /* Simply set it */ 564 *(u32 *)location = value; 565 break; 566 567 case R_PPC64_ADDR64: 568 /* Simply set it */ 569 *(unsigned long *)location = value; 570 break; 571 572 case R_PPC64_TOC: 573 *(unsigned long *)location = my_r2(sechdrs, me); 574 break; 575 576 case R_PPC64_TOC16: 577 /* Subtract TOC pointer */ 578 value -= my_r2(sechdrs, me); 579 if (value + 0x8000 > 0xffff) { 580 pr_err("%s: bad TOC16 relocation (0x%lx)\n", 581 me->name, value); 582 return -ENOEXEC; 583 } 584 *((uint16_t *) location) 585 = (*((uint16_t *) location) & ~0xffff) 586 | (value & 0xffff); 587 break; 588 589 case R_PPC64_TOC16_LO: 590 /* Subtract TOC pointer */ 591 value -= my_r2(sechdrs, me); 592 *((uint16_t *) location) 593 = (*((uint16_t *) location) & ~0xffff) 594 | (value & 0xffff); 595 break; 596 597 case R_PPC64_TOC16_DS: 598 /* Subtract TOC pointer */ 599 value -= my_r2(sechdrs, me); 600 if ((value & 3) != 0 || value + 0x8000 > 0xffff) { 601 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n", 602 me->name, value); 603 return -ENOEXEC; 604 } 605 *((uint16_t *) location) 606 = (*((uint16_t *) location) & ~0xfffc) 607 | (value & 0xfffc); 608 break; 609 610 case R_PPC64_TOC16_LO_DS: 611 /* Subtract TOC pointer */ 612 value -= my_r2(sechdrs, me); 613 if ((value & 3) != 0) { 614 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n", 615 me->name, value); 616 return -ENOEXEC; 617 } 618 *((uint16_t *) location) 619 = (*((uint16_t *) location) & ~0xfffc) 620 | (value & 0xfffc); 621 break; 622 623 case R_PPC64_TOC16_HA: 624 /* Subtract TOC pointer */ 625 value -= my_r2(sechdrs, me); 626 value = ((value + 0x8000) >> 16); 627 *((uint16_t *) location) 628 = (*((uint16_t *) location) & ~0xffff) 629 | (value & 0xffff); 630 break; 631 632 case R_PPC_REL24: 633 /* FIXME: Handle weak symbols here --RR */ 634 if (sym->st_shndx == SHN_UNDEF || 635 sym->st_shndx == SHN_LIVEPATCH) { 636 /* External: go via stub */ 637 value = stub_for_addr(sechdrs, value, me, 638 strtab + sym->st_name); 639 if (!value) 640 return -ENOENT; 641 if (!restore_r2(strtab + sym->st_name, 642 (u32 *)location + 1, me)) 643 return -ENOEXEC; 644 } else 645 value += local_entry_offset(sym); 646 647 /* Convert value to relative */ 648 value -= (unsigned long)location; 649 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ 650 pr_err("%s: REL24 %li out of range!\n", 651 me->name, (long int)value); 652 return -ENOEXEC; 653 } 654 655 /* Only replace bits 2 through 26 */ 656 *(uint32_t *)location 657 = (*(uint32_t *)location & ~0x03fffffc) 658 | (value & 0x03fffffc); 659 break; 660 661 case R_PPC64_REL64: 662 /* 64 bits relative (used by features fixups) */ 663 *location = value - (unsigned long)location; 664 break; 665 666 case R_PPC64_REL32: 667 /* 32 bits relative (used by relative exception tables) */ 668 /* Convert value to relative */ 669 value -= (unsigned long)location; 670 if (value + 0x80000000 > 0xffffffff) { 671 pr_err("%s: REL32 %li out of range!\n", 672 me->name, (long int)value); 673 return -ENOEXEC; 674 } 675 *(u32 *)location = value; 676 break; 677 678 case R_PPC64_TOCSAVE: 679 /* 680 * Marker reloc indicates we don't have to save r2. 681 * That would only save us one instruction, so ignore 682 * it. 683 */ 684 break; 685 686 case R_PPC64_ENTRY: 687 /* 688 * Optimize ELFv2 large code model entry point if 689 * the TOC is within 2GB range of current location. 690 */ 691 value = my_r2(sechdrs, me) - (unsigned long)location; 692 if (value + 0x80008000 > 0xffffffff) 693 break; 694 /* 695 * Check for the large code model prolog sequence: 696 * ld r2, ...(r12) 697 * add r2, r2, r12 698 */ 699 if ((((uint32_t *)location)[0] & ~0xfffc) != 700 (PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R12))) 701 break; 702 if (((uint32_t *)location)[1] != 703 (PPC_INST_ADD | __PPC_RT(R2) | __PPC_RA(R2) | __PPC_RB(R12))) 704 break; 705 /* 706 * If found, replace it with: 707 * addis r2, r12, (.TOC.-func)@ha 708 * addi r2, r2, (.TOC.-func)@l 709 */ 710 ((uint32_t *)location)[0] = PPC_INST_ADDIS | __PPC_RT(R2) | 711 __PPC_RA(R12) | PPC_HA(value); 712 ((uint32_t *)location)[1] = PPC_INST_ADDI | __PPC_RT(R2) | 713 __PPC_RA(R2) | PPC_LO(value); 714 break; 715 716 case R_PPC64_REL16_HA: 717 /* Subtract location pointer */ 718 value -= (unsigned long)location; 719 value = ((value + 0x8000) >> 16); 720 *((uint16_t *) location) 721 = (*((uint16_t *) location) & ~0xffff) 722 | (value & 0xffff); 723 break; 724 725 case R_PPC64_REL16_LO: 726 /* Subtract location pointer */ 727 value -= (unsigned long)location; 728 *((uint16_t *) location) 729 = (*((uint16_t *) location) & ~0xffff) 730 | (value & 0xffff); 731 break; 732 733 default: 734 pr_err("%s: Unknown ADD relocation: %lu\n", 735 me->name, 736 (unsigned long)ELF64_R_TYPE(rela[i].r_info)); 737 return -ENOEXEC; 738 } 739 } 740 741 return 0; 742 } 743 744 #ifdef CONFIG_DYNAMIC_FTRACE 745 int module_trampoline_target(struct module *mod, unsigned long addr, 746 unsigned long *target) 747 { 748 struct ppc64_stub_entry *stub; 749 func_desc_t funcdata; 750 u32 magic; 751 752 if (!within_module_core(addr, mod)) { 753 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); 754 return -EFAULT; 755 } 756 757 stub = (struct ppc64_stub_entry *)addr; 758 759 if (copy_from_kernel_nofault(&magic, &stub->magic, 760 sizeof(magic))) { 761 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); 762 return -EFAULT; 763 } 764 765 if (magic != STUB_MAGIC) { 766 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); 767 return -EFAULT; 768 } 769 770 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata, 771 sizeof(funcdata))) { 772 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); 773 return -EFAULT; 774 } 775 776 *target = stub_func_addr(funcdata); 777 778 return 0; 779 } 780 781 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) 782 { 783 mod->arch.tramp = stub_for_addr(sechdrs, 784 (unsigned long)ftrace_caller, 785 mod, 786 "ftrace_caller"); 787 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 788 mod->arch.tramp_regs = stub_for_addr(sechdrs, 789 (unsigned long)ftrace_regs_caller, 790 mod, 791 "ftrace_regs_caller"); 792 if (!mod->arch.tramp_regs) 793 return -ENOENT; 794 #endif 795 796 if (!mod->arch.tramp) 797 return -ENOENT; 798 799 return 0; 800 } 801 #endif 802