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). We only
 107          * need 6 instructions on ABIv2 but we always allocate 7 so
 108          * so we don't have to modify the trampoline load instruction. */
 109         u32 jump[7];
 110         /* Used by ftrace to identify stubs */
 111         u32 magic;
 112         /* Data for the above code */
 113         func_desc_t funcdata;
 114 };
 115
 116 /*
 117  * PPC64 uses 24 bit jumps, but we need to jump into other modules or
 118  * the kernel which may be further.  So we jump to a stub.
 119  *
 120  * For ELFv1 we need to use this to set up the new r2 value (aka TOC
 121  * pointer).  For ELFv2 it's the callee's responsibility to set up the
 122  * new r2, but for both we need to save the old r2.
 123  *
 124  * We could simply patch the new r2 value and function pointer into
 125  * the stub, but it's significantly shorter to put these values at the
 126  * end of the stub code, and patch the stub address (32-bits relative
 127  * to the TOC ptr, r2) into the stub.
 128  */
 129 static u32 ppc64_stub_insns[] = {
 130         PPC_RAW_ADDIS(_R11, _R2, 0),
 131         PPC_RAW_ADDI(_R11, _R11, 0),
 132         /* Save current r2 value in magic place on the stack. */
 133         PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET),
 134         PPC_RAW_LD(_R12, _R11, 32),
 135 #ifdef CONFIG_PPC64_ELF_ABI_V1
 136         /* Set up new r2 from function descriptor */
 137         PPC_RAW_LD(_R2, _R11, 40),
 138 #endif
 139         PPC_RAW_MTCTR(_R12),
 140         PPC_RAW_BCTR(),
 141 };
 142
 143 /* Count how many different 24-bit relocations (different symbol,
 144    different addend) */
 145 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
 146 {
 147         unsigned int i, r_info, r_addend, _count_relocs;
 148
 149         /* FIXME: Only count external ones --RR */
 150         _count_relocs = 0;
 151         r_info = 0;
 152         r_addend = 0;
 153         for (i = 0; i < num; i++)
 154                 /* Only count 24-bit relocs, others don't need stubs */
 155                 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
 156                     (r_info != ELF64_R_SYM(rela[i].r_info) ||
 157                      r_addend != rela[i].r_addend)) {
 158                         _count_relocs++;
 159                         r_info = ELF64_R_SYM(rela[i].r_info);
 160                         r_addend = rela[i].r_addend;
 161                 }
 162
 163         return _count_relocs;
 164 }
 165
 166 static int relacmp(const void *_x, const void *_y)
 167 {
 168         const Elf64_Rela *x, *y;
 169
 170         y = (Elf64_Rela *)_x;
 171         x = (Elf64_Rela *)_y;
 172
 173         /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
 174          * make the comparison cheaper/faster. It won't affect the sorting or
 175          * the counting algorithms' performance
 176          */
 177         if (x->r_info < y->r_info)
 178                 return -1;
 179         else if (x->r_info > y->r_info)
 180                 return 1;
 181         else if (x->r_addend < y->r_addend)
 182                 return -1;
 183         else if (x->r_addend > y->r_addend)
 184                 return 1;
 185         else
 186                 return 0;
 187 }
 188
 189 /* Get size of potential trampolines required. */
 190 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 191                                     const Elf64_Shdr *sechdrs)
 192 {
 193         /* One extra reloc so it's always 0-addr terminated */
 194         unsigned long relocs = 1;
 195         unsigned i;
 196
 197         /* Every relocated section... */
 198         for (i = 1; i < hdr->e_shnum; i++) {
 199                 if (sechdrs[i].sh_type == SHT_RELA) {
 200                         pr_debug("Found relocations in section %u\n", i);
 201                         pr_debug("Ptr: %p.  Number: %Lu\n",
 202                                (void *)sechdrs[i].sh_addr,
 203                                sechdrs[i].sh_size / sizeof(Elf64_Rela));
 204
 205                         /* Sort the relocation information based on a symbol and
 206                          * addend key. This is a stable O(n*log n) complexity
 207                          * algorithm but it will reduce the complexity of
 208                          * count_relocs() to linear complexity O(n)
 209                          */
 210                         sort((void *)sechdrs[i].sh_addr,
 211                              sechdrs[i].sh_size / sizeof(Elf64_Rela),
 212                              sizeof(Elf64_Rela), relacmp, NULL);
 213
 214                         relocs += count_relocs((void *)sechdrs[i].sh_addr,
 215                                                sechdrs[i].sh_size
 216                                                / sizeof(Elf64_Rela));
 217                 }
 218         }
 219
 220 #ifdef CONFIG_DYNAMIC_FTRACE
 221         /* make the trampoline to the ftrace_caller */
 222         relocs++;
 223 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 224         /* an additional one for ftrace_regs_caller */
 225         relocs++;
 226 #endif
 227 #endif
 228
 229         pr_debug("Looks like a total of %lu stubs, max\n", relocs);
 230         return relocs * sizeof(struct ppc64_stub_entry);
 231 }
 232
 233 /* Still needed for ELFv2, for .TOC. */
 234 static void dedotify_versions(struct modversion_info *vers,
 235                               unsigned long size)
 236 {
 237         struct modversion_info *end;
 238
 239         for (end = (void *)vers + size; vers < end; vers++)
 240                 if (vers->name[0] == '.') {
 241                         memmove(vers->name, vers->name+1, strlen(vers->name));
 242                 }
 243 }
 244
 245 /*
 246  * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
 247  * seem to be defined (value set later).
 248  */
 249 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
 250 {
 251         unsigned int i;
 252
 253         for (i = 1; i < numsyms; i++) {
 254                 if (syms[i].st_shndx == SHN_UNDEF) {
 255                         char *name = strtab + syms[i].st_name;
 256                         if (name[0] == '.') {
 257                                 if (strcmp(name+1, "TOC.") == 0)
 258                                         syms[i].st_shndx = SHN_ABS;
 259                                 syms[i].st_name++;
 260                         }
 261                 }
 262         }
 263 }
 264
 265 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
 266                                const char *strtab,
 267                                unsigned int symindex)
 268 {
 269         unsigned int i, numsyms;
 270         Elf64_Sym *syms;
 271
 272         syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
 273         numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
 274
 275         for (i = 1; i < numsyms; i++) {
 276                 if (syms[i].st_shndx == SHN_ABS
 277                     && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
 278                         return &syms[i];
 279         }
 280         return NULL;
 281 }
 282
 283 bool module_init_section(const char *name)
 284 {
 285         /* We don't handle .init for the moment: always return false. */
 286         return false;
 287 }
 288
 289 int module_frob_arch_sections(Elf64_Ehdr *hdr,
 290                               Elf64_Shdr *sechdrs,
 291                               char *secstrings,
 292                               struct module *me)
 293 {
 294         unsigned int i;
 295
 296         /* Find .toc and .stubs sections, symtab and strtab */
 297         for (i = 1; i < hdr->e_shnum; i++) {
 298                 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
 299                         me->arch.stubs_section = i;
 300                 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
 301                         me->arch.toc_section = i;
 302                         if (sechdrs[i].sh_addralign < 8)
 303                                 sechdrs[i].sh_addralign = 8;
 304                 }
 305                 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
 306                         dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
 307                                           sechdrs[i].sh_size);
 308
 309                 if (sechdrs[i].sh_type == SHT_SYMTAB)
 310                         dedotify((void *)hdr + sechdrs[i].sh_offset,
 311                                  sechdrs[i].sh_size / sizeof(Elf64_Sym),
 312                                  (void *)hdr
 313                                  + sechdrs[sechdrs[i].sh_link].sh_offset);
 314         }
 315
 316         if (!me->arch.stubs_section) {
 317                 pr_err("%s: doesn't contain .stubs.\n", me->name);
 318                 return -ENOEXEC;
 319         }
 320
 321         /* If we don't have a .toc, just use .stubs.  We need to set r2
 322            to some reasonable value in case the module calls out to
 323            other functions via a stub, or if a function pointer escapes
 324            the module by some means.  */
 325         if (!me->arch.toc_section)
 326                 me->arch.toc_section = me->arch.stubs_section;
 327
 328         /* Override the stubs size */
 329         sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
 330         return 0;
 331 }
 332
 333 #ifdef CONFIG_MPROFILE_KERNEL
 334
 335 static u32 stub_insns[] = {
 336         PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
 337         PPC_RAW_ADDIS(_R12, _R12, 0),
 338         PPC_RAW_ADDI(_R12, _R12, 0),
 339         PPC_RAW_MTCTR(_R12),
 340         PPC_RAW_BCTR(),
 341 };
 342
 343 /*
 344  * For mprofile-kernel we use a special stub for ftrace_caller() because we
 345  * can't rely on r2 containing this module's TOC when we enter the stub.
 346  *
 347  * That can happen if the function calling us didn't need to use the toc. In
 348  * that case it won't have setup r2, and the r2 value will be either the
 349  * kernel's toc, or possibly another modules toc.
 350  *
 351  * To deal with that this stub uses the kernel toc, which is always accessible
 352  * via the paca (in r13). The target (ftrace_caller()) is responsible for
 353  * saving and restoring the toc before returning.
 354  */
 355 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
 356                                         unsigned long addr,
 357                                         struct module *me)
 358 {
 359         long reladdr;
 360
 361         memcpy(entry->jump, stub_insns, sizeof(stub_insns));
 362
 363         /* Stub uses address relative to kernel toc (from the paca) */
 364         reladdr = addr - kernel_toc_addr();
 365         if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
 366                 pr_err("%s: Address of %ps out of range of kernel_toc.\n",
 367                                                         me->name, (void *)addr);
 368                 return 0;
 369         }
 370
 371         entry->jump[1] |= PPC_HA(reladdr);
 372         entry->jump[2] |= PPC_LO(reladdr);
 373
 374         /* Even though we don't use funcdata in the stub, it's needed elsewhere. */
 375         entry->funcdata = func_desc(addr);
 376         entry->magic = STUB_MAGIC;
 377
 378         return 1;
 379 }
 380
 381 static bool is_mprofile_ftrace_call(const char *name)
 382 {
 383         if (!strcmp("_mcount", name))
 384                 return true;
 385 #ifdef CONFIG_DYNAMIC_FTRACE
 386         if (!strcmp("ftrace_caller", name))
 387                 return true;
 388 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 389         if (!strcmp("ftrace_regs_caller", name))
 390                 return true;
 391 #endif
 392 #endif
 393
 394         return false;
 395 }
 396 #else
 397 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
 398                                         unsigned long addr,
 399                                         struct module *me)
 400 {
 401         return 0;
 402 }
 403
 404 static bool is_mprofile_ftrace_call(const char *name)
 405 {
 406         return false;
 407 }
 408 #endif
 409
 410 /*
 411  * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
 412  * value maximum span in an instruction which uses a signed offset). Round down
 413  * to a 256 byte boundary for the odd case where we are setting up r2 without a
 414  * .toc section.
 415  */
 416 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
 417 {
 418         return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
 419 }
 420
 421 /* Patch stub to reference function and correct r2 value. */
 422 static inline int create_stub(const Elf64_Shdr *sechdrs,
 423                               struct ppc64_stub_entry *entry,
 424                               unsigned long addr,
 425                               struct module *me,
 426                               const char *name)
 427 {
 428         long reladdr;
 429         func_desc_t desc;
 430         int i;
 431
 432         if (is_mprofile_ftrace_call(name))
 433                 return create_ftrace_stub(entry, addr, me);
 434
 435         for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
 436                 if (patch_instruction(&entry->jump[i],
 437                                       ppc_inst(ppc64_stub_insns[i])))
 438                         return 0;
 439         }
 440
 441         /* Stub uses address relative to r2. */
 442         reladdr = (unsigned long)entry - my_r2(sechdrs, me);
 443         if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
 444                 pr_err("%s: Address %p of stub out of range of %p.\n",
 445                        me->name, (void *)reladdr, (void *)my_r2);
 446                 return 0;
 447         }
 448         pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
 449
 450         if (patch_instruction(&entry->jump[0],
 451                               ppc_inst(entry->jump[0] | PPC_HA(reladdr))))
 452                 return 0;
 453
 454         if (patch_instruction(&entry->jump[1],
 455                           ppc_inst(entry->jump[1] | PPC_LO(reladdr))))
 456                 return 0;
 457
 458         // func_desc_t is 8 bytes if ABIv2, else 16 bytes
 459         desc = func_desc(addr);
 460         for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {
 461                 if (patch_instruction(((u32 *)&entry->funcdata) + i,
 462                                       ppc_inst(((u32 *)(&desc))[i])))
 463                         return 0;
 464         }
 465
 466         if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC)))
 467                 return 0;
 468
 469         return 1;
 470 }
 471
 472 /* Create stub to jump to function described in this OPD/ptr: we need the
 473    stub to set up the TOC ptr (r2) for the function. */
 474 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
 475                                    unsigned long addr,
 476                                    struct module *me,
 477                                    const char *name)
 478 {
 479         struct ppc64_stub_entry *stubs;
 480         unsigned int i, num_stubs;
 481
 482         num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
 483
 484         /* Find this stub, or if that fails, the next avail. entry */
 485         stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
 486         for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
 487                 if (WARN_ON(i >= num_stubs))
 488                         return 0;
 489
 490                 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
 491                         return (unsigned long)&stubs[i];
 492         }
 493
 494         if (!create_stub(sechdrs, &stubs[i], addr, me, name))
 495                 return 0;
 496
 497         return (unsigned long)&stubs[i];
 498 }
 499
 500 /* We expect a noop next: if it is, replace it with instruction to
 501    restore r2. */
 502 static int restore_r2(const char *name, u32 *instruction, struct module *me)
 503 {
 504         u32 *prev_insn = instruction - 1;
 505         u32 insn_val = *instruction;
 506
 507         if (is_mprofile_ftrace_call(name))
 508                 return 0;
 509
 510         /*
 511          * Make sure the branch isn't a sibling call.  Sibling calls aren't
 512          * "link" branches and they don't return, so they don't need the r2
 513          * restore afterwards.
 514          */
 515         if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
 516                 return 0;
 517
 518         /*
 519          * For livepatch, the restore r2 instruction might have already been
 520          * written previously, if the referenced symbol is in a previously
 521          * unloaded module which is now being loaded again.  In that case, skip
 522          * the warning and the instruction write.
 523          */
 524         if (insn_val == PPC_INST_LD_TOC)
 525                 return 0;
 526
 527         if (insn_val != PPC_RAW_NOP()) {
 528                 pr_err("%s: Expected nop after call, got %08x at %pS\n",
 529                         me->name, insn_val, instruction);
 530                 return -ENOEXEC;
 531         }
 532
 533         /* ld r2,R2_STACK_OFFSET(r1) */
 534         return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC));
 535 }
 536
 537 int apply_relocate_add(Elf64_Shdr *sechdrs,
 538                        const char *strtab,
 539                        unsigned int symindex,
 540                        unsigned int relsec,
 541                        struct module *me)
 542 {
 543         unsigned int i;
 544         Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
 545         Elf64_Sym *sym;
 546         unsigned long *location;
 547         unsigned long value;
 548
 549         pr_debug("Applying ADD relocate section %u to %u\n", relsec,
 550                sechdrs[relsec].sh_info);
 551
 552         /* First time we're called, we can fix up .TOC. */
 553         if (!me->arch.toc_fixed) {
 554                 sym = find_dot_toc(sechdrs, strtab, symindex);
 555                 /* It's theoretically possible that a module doesn't want a
 556                  * .TOC. so don't fail it just for that. */
 557                 if (sym)
 558                         sym->st_value = my_r2(sechdrs, me);
 559                 me->arch.toc_fixed = true;
 560         }
 561
 562         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
 563                 /* This is where to make the change */
 564                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 565                         + rela[i].r_offset;
 566                 /* This is the symbol it is referring to */
 567                 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 568                         + ELF64_R_SYM(rela[i].r_info);
 569
 570                 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
 571                        location, (long)ELF64_R_TYPE(rela[i].r_info),
 572                        strtab + sym->st_name, (unsigned long)sym->st_value,
 573                        (long)rela[i].r_addend);
 574
 575                 /* `Everything is relative'. */
 576                 value = sym->st_value + rela[i].r_addend;
 577
 578                 switch (ELF64_R_TYPE(rela[i].r_info)) {
 579                 case R_PPC64_ADDR32:
 580                         /* Simply set it */
 581                         *(u32 *)location = value;
 582                         break;
 583
 584                 case R_PPC64_ADDR64:
 585                         /* Simply set it */
 586                         *(unsigned long *)location = value;
 587                         break;
 588
 589                 case R_PPC64_TOC:
 590                         *(unsigned long *)location = my_r2(sechdrs, me);
 591                         break;
 592
 593                 case R_PPC64_TOC16:
 594                         /* Subtract TOC pointer */
 595                         value -= my_r2(sechdrs, me);
 596                         if (value + 0x8000 > 0xffff) {
 597                                 pr_err("%s: bad TOC16 relocation (0x%lx)\n",
 598                                        me->name, value);
 599                                 return -ENOEXEC;
 600                         }
 601                         *((uint16_t *) location)
 602                                 = (*((uint16_t *) location) & ~0xffff)
 603                                 | (value & 0xffff);
 604                         break;
 605
 606                 case R_PPC64_TOC16_LO:
 607                         /* Subtract TOC pointer */
 608                         value -= my_r2(sechdrs, me);
 609                         *((uint16_t *) location)
 610                                 = (*((uint16_t *) location) & ~0xffff)
 611                                 | (value & 0xffff);
 612                         break;
 613
 614                 case R_PPC64_TOC16_DS:
 615                         /* Subtract TOC pointer */
 616                         value -= my_r2(sechdrs, me);
 617                         if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
 618                                 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
 619                                        me->name, value);
 620                                 return -ENOEXEC;
 621                         }
 622                         *((uint16_t *) location)
 623                                 = (*((uint16_t *) location) & ~0xfffc)
 624                                 | (value & 0xfffc);
 625                         break;
 626
 627                 case R_PPC64_TOC16_LO_DS:
 628                         /* Subtract TOC pointer */
 629                         value -= my_r2(sechdrs, me);
 630                         if ((value & 3) != 0) {
 631                                 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
 632                                        me->name, value);
 633                                 return -ENOEXEC;
 634                         }
 635                         *((uint16_t *) location)
 636                                 = (*((uint16_t *) location) & ~0xfffc)
 637                                 | (value & 0xfffc);
 638                         break;
 639
 640                 case R_PPC64_TOC16_HA:
 641                         /* Subtract TOC pointer */
 642                         value -= my_r2(sechdrs, me);
 643                         value = ((value + 0x8000) >> 16);
 644                         *((uint16_t *) location)
 645                                 = (*((uint16_t *) location) & ~0xffff)
 646                                 | (value & 0xffff);
 647                         break;
 648
 649                 case R_PPC_REL24:
 650                         /* FIXME: Handle weak symbols here --RR */
 651                         if (sym->st_shndx == SHN_UNDEF ||
 652                             sym->st_shndx == SHN_LIVEPATCH) {
 653                                 /* External: go via stub */
 654                                 value = stub_for_addr(sechdrs, value, me,
 655                                                 strtab + sym->st_name);
 656                                 if (!value)
 657                                         return -ENOENT;
 658                                 if (restore_r2(strtab + sym->st_name,
 659                                                (u32 *)location + 1, me))
 660                                         return -ENOEXEC;
 661                         } else
 662                                 value += local_entry_offset(sym);
 663
 664                         /* Convert value to relative */
 665                         value -= (unsigned long)location;
 666                         if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
 667                                 pr_err("%s: REL24 %li out of range!\n",
 668                                        me->name, (long int)value);
 669                                 return -ENOEXEC;
 670                         }
 671
 672                         /* Only replace bits 2 through 26 */
 673                         value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value);
 674
 675                         if (patch_instruction((u32 *)location, ppc_inst(value)))
 676                                 return -EFAULT;
 677
 678                         break;
 679
 680                 case R_PPC64_REL64:
 681                         /* 64 bits relative (used by features fixups) */
 682                         *location = value - (unsigned long)location;
 683                         break;
 684
 685                 case R_PPC64_REL32:
 686                         /* 32 bits relative (used by relative exception tables) */
 687                         /* Convert value to relative */
 688                         value -= (unsigned long)location;
 689                         if (value + 0x80000000 > 0xffffffff) {
 690                                 pr_err("%s: REL32 %li out of range!\n",
 691                                        me->name, (long int)value);
 692                                 return -ENOEXEC;
 693                         }
 694                         *(u32 *)location = value;
 695                         break;
 696
 697                 case R_PPC64_TOCSAVE:
 698                         /*
 699                          * Marker reloc indicates we don't have to save r2.
 700                          * That would only save us one instruction, so ignore
 701                          * it.
 702                          */
 703                         break;
 704
 705                 case R_PPC64_ENTRY:
 706                         /*
 707                          * Optimize ELFv2 large code model entry point if
 708                          * the TOC is within 2GB range of current location.
 709                          */
 710                         value = my_r2(sechdrs, me) - (unsigned long)location;
 711                         if (value + 0x80008000 > 0xffffffff)
 712                                 break;
 713                         /*
 714                          * Check for the large code model prolog sequence:
 715                          *      ld r2, ...(r12)
 716                          *      add r2, r2, r12
 717                          */
 718                         if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0))
 719                                 break;
 720                         if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12))
 721                                 break;
 722                         /*
 723                          * If found, replace it with:
 724                          *      addis r2, r12, (.TOC.-func)@ha
 725                          *      addi  r2,  r2, (.TOC.-func)@l
 726                          */
 727                         ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value));
 728                         ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value));
 729                         break;
 730
 731                 case R_PPC64_REL16_HA:
 732                         /* Subtract location pointer */
 733                         value -= (unsigned long)location;
 734                         value = ((value + 0x8000) >> 16);
 735                         *((uint16_t *) location)
 736                                 = (*((uint16_t *) location) & ~0xffff)
 737                                 | (value & 0xffff);
 738                         break;
 739
 740                 case R_PPC64_REL16_LO:
 741                         /* Subtract location pointer */
 742                         value -= (unsigned long)location;
 743                         *((uint16_t *) location)
 744                                 = (*((uint16_t *) location) & ~0xffff)
 745                                 | (value & 0xffff);
 746                         break;
 747
 748                 default:
 749                         pr_err("%s: Unknown ADD relocation: %lu\n",
 750                                me->name,
 751                                (unsigned long)ELF64_R_TYPE(rela[i].r_info));
 752                         return -ENOEXEC;
 753                 }
 754         }
 755
 756         return 0;
 757 }
 758
 759 #ifdef CONFIG_DYNAMIC_FTRACE
 760 int module_trampoline_target(struct module *mod, unsigned long addr,
 761                              unsigned long *target)
 762 {
 763         struct ppc64_stub_entry *stub;
 764         func_desc_t funcdata;
 765         u32 magic;
 766
 767         if (!within_module_core(addr, mod)) {
 768                 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
 769                 return -EFAULT;
 770         }
 771
 772         stub = (struct ppc64_stub_entry *)addr;
 773
 774         if (copy_from_kernel_nofault(&magic, &stub->magic,
 775                         sizeof(magic))) {
 776                 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
 777                 return -EFAULT;
 778         }
 779
 780         if (magic != STUB_MAGIC) {
 781                 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
 782                 return -EFAULT;
 783         }
 784
 785         if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
 786                         sizeof(funcdata))) {
 787                 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
 788                 return -EFAULT;
 789         }
 790
 791         *target = stub_func_addr(funcdata);
 792
 793         return 0;
 794 }
 795
 796 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
 797 {
 798         mod->arch.tramp = stub_for_addr(sechdrs,
 799                                         (unsigned long)ftrace_caller,
 800                                         mod,
 801                                         "ftrace_caller");
 802 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 803         mod->arch.tramp_regs = stub_for_addr(sechdrs,
 804                                         (unsigned long)ftrace_regs_caller,
 805                                         mod,
 806                                         "ftrace_regs_caller");
 807         if (!mod->arch.tramp_regs)
 808                 return -ENOENT;
 809 #endif
 810
 811         if (!mod->arch.tramp)
 812                 return -ENOENT;
 813
 814         return 0;
 815 }
 816 #endif