arch/powerpc/kernel/module_64.c

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