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 #ifdef CONFIG_PPC64_ELF_ABI_V2
  35
  36 static func_desc_t func_desc(unsigned long addr)
  37 {
  38         func_desc_t desc = {
  39                 .addr = addr,
  40         };
  41
  42         return desc;
  43 }
  44
  45 /* PowerPC64 specific values for the Elf64_Sym st_other field.  */
  46 #define STO_PPC64_LOCAL_BIT     5
  47 #define STO_PPC64_LOCAL_MASK    (7 << STO_PPC64_LOCAL_BIT)
  48 #define PPC64_LOCAL_ENTRY_OFFSET(other)                                 \
  49  (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
  50
  51 static unsigned int local_entry_offset(const Elf64_Sym *sym)
  52 {
  53         /* sym->st_other indicates offset to local entry point
  54          * (otherwise it will assume r12 is the address of the start
  55          * of function and try to derive r2 from it). */
  56         return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
  57 }
  58 #else
  59
  60 static func_desc_t func_desc(unsigned long addr)
  61 {
  62         return *(struct func_desc *)addr;
  63 }
  64 static unsigned int local_entry_offset(const Elf64_Sym *sym)
  65 {
  66         return 0;
  67 }
  68
  69 void *dereference_module_function_descriptor(struct module *mod, void *ptr)
  70 {
  71         if (ptr < (void *)mod->arch.start_opd ||
  72                         ptr >= (void *)mod->arch.end_opd)
  73                 return ptr;
  74
  75         return dereference_function_descriptor(ptr);
  76 }
  77 #endif
  78
  79 static unsigned long func_addr(unsigned long addr)
  80 {
  81         return func_desc(addr).addr;
  82 }
  83
  84 static unsigned long stub_func_addr(func_desc_t func)
  85 {
  86         return func.addr;
  87 }
  88
  89 #define STUB_MAGIC 0x73747562 /* stub */
  90
  91 /* Like PPC32, we need little trampolines to do > 24-bit jumps (into
  92    the kernel itself).  But on PPC64, these need to be used for every
  93    jump, actually, to reset r2 (TOC+0x8000). */
  94 struct ppc64_stub_entry
  95 {
  96         /* 28 byte jump instruction sequence (7 instructions). We only
  97          * need 6 instructions on ABIv2 but we always allocate 7 so
  98          * so we don't have to modify the trampoline load instruction. */
  99         u32 jump[7];
 100         /* Used by ftrace to identify stubs */
 101         u32 magic;
 102         /* Data for the above code */
 103         func_desc_t funcdata;
 104 };
 105
 106 /*
 107  * PPC64 uses 24 bit jumps, but we need to jump into other modules or
 108  * the kernel which may be further.  So we jump to a stub.
 109  *
 110  * For ELFv1 we need to use this to set up the new r2 value (aka TOC
 111  * pointer).  For ELFv2 it's the callee's responsibility to set up the
 112  * new r2, but for both we need to save the old r2.
 113  *
 114  * We could simply patch the new r2 value and function pointer into
 115  * the stub, but it's significantly shorter to put these values at the
 116  * end of the stub code, and patch the stub address (32-bits relative
 117  * to the TOC ptr, r2) into the stub.
 118  */
 119 static u32 ppc64_stub_insns[] = {
 120         PPC_RAW_ADDIS(_R11, _R2, 0),
 121         PPC_RAW_ADDI(_R11, _R11, 0),
 122         /* Save current r2 value in magic place on the stack. */
 123         PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET),
 124         PPC_RAW_LD(_R12, _R11, 32),
 125 #ifdef CONFIG_PPC64_ELF_ABI_V1
 126         /* Set up new r2 from function descriptor */
 127         PPC_RAW_LD(_R2, _R11, 40),
 128 #endif
 129         PPC_RAW_MTCTR(_R12),
 130         PPC_RAW_BCTR(),
 131 };
 132
 133 /* Count how many different 24-bit relocations (different symbol,
 134    different addend) */
 135 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
 136 {
 137         unsigned int i, r_info, r_addend, _count_relocs;
 138
 139         /* FIXME: Only count external ones --RR */
 140         _count_relocs = 0;
 141         r_info = 0;
 142         r_addend = 0;
 143         for (i = 0; i < num; i++)
 144                 /* Only count 24-bit relocs, others don't need stubs */
 145                 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
 146                     (r_info != ELF64_R_SYM(rela[i].r_info) ||
 147                      r_addend != rela[i].r_addend)) {
 148                         _count_relocs++;
 149                         r_info = ELF64_R_SYM(rela[i].r_info);
 150                         r_addend = rela[i].r_addend;
 151                 }
 152
 153         return _count_relocs;
 154 }
 155
 156 static int relacmp(const void *_x, const void *_y)
 157 {
 158         const Elf64_Rela *x, *y;
 159
 160         y = (Elf64_Rela *)_x;
 161         x = (Elf64_Rela *)_y;
 162
 163         /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
 164          * make the comparison cheaper/faster. It won't affect the sorting or
 165          * the counting algorithms' performance
 166          */
 167         if (x->r_info < y->r_info)
 168                 return -1;
 169         else if (x->r_info > y->r_info)
 170                 return 1;
 171         else if (x->r_addend < y->r_addend)
 172                 return -1;
 173         else if (x->r_addend > y->r_addend)
 174                 return 1;
 175         else
 176                 return 0;
 177 }
 178
 179 /* Get size of potential trampolines required. */
 180 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 181                                     const Elf64_Shdr *sechdrs)
 182 {
 183         /* One extra reloc so it's always 0-addr terminated */
 184         unsigned long relocs = 1;
 185         unsigned i;
 186
 187         /* Every relocated section... */
 188         for (i = 1; i < hdr->e_shnum; i++) {
 189                 if (sechdrs[i].sh_type == SHT_RELA) {
 190                         pr_debug("Found relocations in section %u\n", i);
 191                         pr_debug("Ptr: %p.  Number: %Lu\n",
 192                                (void *)sechdrs[i].sh_addr,
 193                                sechdrs[i].sh_size / sizeof(Elf64_Rela));
 194
 195                         /* Sort the relocation information based on a symbol and
 196                          * addend key. This is a stable O(n*log n) complexity
 197                          * algorithm but it will reduce the complexity of
 198                          * count_relocs() to linear complexity O(n)
 199                          */
 200                         sort((void *)sechdrs[i].sh_addr,
 201                              sechdrs[i].sh_size / sizeof(Elf64_Rela),
 202                              sizeof(Elf64_Rela), relacmp, NULL);
 203
 204                         relocs += count_relocs((void *)sechdrs[i].sh_addr,
 205                                                sechdrs[i].sh_size
 206                                                / sizeof(Elf64_Rela));
 207                 }
 208         }
 209
 210 #ifdef CONFIG_DYNAMIC_FTRACE
 211         /* make the trampoline to the ftrace_caller */
 212         relocs++;
 213 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 214         /* an additional one for ftrace_regs_caller */
 215         relocs++;
 216 #endif
 217 #endif
 218
 219         pr_debug("Looks like a total of %lu stubs, max\n", relocs);
 220         return relocs * sizeof(struct ppc64_stub_entry);
 221 }
 222
 223 /* Still needed for ELFv2, for .TOC. */
 224 static void dedotify_versions(struct modversion_info *vers,
 225                               unsigned long size)
 226 {
 227         struct modversion_info *end;
 228
 229         for (end = (void *)vers + size; vers < end; vers++)
 230                 if (vers->name[0] == '.') {
 231                         memmove(vers->name, vers->name+1, strlen(vers->name));
 232                 }
 233 }
 234
 235 /*
 236  * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
 237  * seem to be defined (value set later).
 238  */
 239 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
 240 {
 241         unsigned int i;
 242
 243         for (i = 1; i < numsyms; i++) {
 244                 if (syms[i].st_shndx == SHN_UNDEF) {
 245                         char *name = strtab + syms[i].st_name;
 246                         if (name[0] == '.') {
 247                                 if (strcmp(name+1, "TOC.") == 0)
 248                                         syms[i].st_shndx = SHN_ABS;
 249                                 syms[i].st_name++;
 250                         }
 251                 }
 252         }
 253 }
 254
 255 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
 256                                const char *strtab,
 257                                unsigned int symindex)
 258 {
 259         unsigned int i, numsyms;
 260         Elf64_Sym *syms;
 261
 262         syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
 263         numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
 264
 265         for (i = 1; i < numsyms; i++) {
 266                 if (syms[i].st_shndx == SHN_ABS
 267                     && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
 268                         return &syms[i];
 269         }
 270         return NULL;
 271 }
 272
 273 bool module_init_section(const char *name)
 274 {
 275         /* We don't handle .init for the moment: always return false. */
 276         return false;
 277 }
 278
 279 int module_frob_arch_sections(Elf64_Ehdr *hdr,
 280                               Elf64_Shdr *sechdrs,
 281                               char *secstrings,
 282                               struct module *me)
 283 {
 284         unsigned int i;
 285
 286         /* Find .toc and .stubs sections, symtab and strtab */
 287         for (i = 1; i < hdr->e_shnum; i++) {
 288                 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
 289                         me->arch.stubs_section = i;
 290                 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
 291                         me->arch.toc_section = i;
 292                         if (sechdrs[i].sh_addralign < 8)
 293                                 sechdrs[i].sh_addralign = 8;
 294                 }
 295                 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
 296                         dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
 297                                           sechdrs[i].sh_size);
 298
 299                 if (sechdrs[i].sh_type == SHT_SYMTAB)
 300                         dedotify((void *)hdr + sechdrs[i].sh_offset,
 301                                  sechdrs[i].sh_size / sizeof(Elf64_Sym),
 302                                  (void *)hdr
 303                                  + sechdrs[sechdrs[i].sh_link].sh_offset);
 304         }
 305
 306         if (!me->arch.stubs_section) {
 307                 pr_err("%s: doesn't contain .stubs.\n", me->name);
 308                 return -ENOEXEC;
 309         }
 310
 311         /* If we don't have a .toc, just use .stubs.  We need to set r2
 312            to some reasonable value in case the module calls out to
 313            other functions via a stub, or if a function pointer escapes
 314            the module by some means.  */
 315         if (!me->arch.toc_section)
 316                 me->arch.toc_section = me->arch.stubs_section;
 317
 318         /* Override the stubs size */
 319         sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
 320         return 0;
 321 }
 322
 323 #ifdef CONFIG_MPROFILE_KERNEL
 324
 325 static u32 stub_insns[] = {
 326         PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
 327         PPC_RAW_ADDIS(_R12, _R12, 0),
 328         PPC_RAW_ADDI(_R12, _R12, 0),
 329         PPC_RAW_MTCTR(_R12),
 330         PPC_RAW_BCTR(),
 331 };
 332
 333 /*
 334  * For mprofile-kernel we use a special stub for ftrace_caller() because we
 335  * can't rely on r2 containing this module's TOC when we enter the stub.
 336  *
 337  * That can happen if the function calling us didn't need to use the toc. In
 338  * that case it won't have setup r2, and the r2 value will be either the
 339  * kernel's toc, or possibly another modules toc.
 340  *
 341  * To deal with that this stub uses the kernel toc, which is always accessible
 342  * via the paca (in r13). The target (ftrace_caller()) is responsible for
 343  * saving and restoring the toc before returning.
 344  */
 345 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
 346                                         unsigned long addr,
 347                                         struct module *me)
 348 {
 349         long reladdr;
 350
 351         memcpy(entry->jump, stub_insns, sizeof(stub_insns));
 352
 353         /* Stub uses address relative to kernel toc (from the paca) */
 354         reladdr = addr - kernel_toc_addr();
 355         if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
 356                 pr_err("%s: Address of %ps out of range of kernel_toc.\n",
 357                                                         me->name, (void *)addr);
 358                 return 0;
 359         }
 360
 361         entry->jump[1] |= PPC_HA(reladdr);
 362         entry->jump[2] |= PPC_LO(reladdr);
 363
 364         /* Even though we don't use funcdata in the stub, it's needed elsewhere. */
 365         entry->funcdata = func_desc(addr);
 366         entry->magic = STUB_MAGIC;
 367
 368         return 1;
 369 }
 370
 371 static bool is_mprofile_ftrace_call(const char *name)
 372 {
 373         if (!strcmp("_mcount", name))
 374                 return true;
 375 #ifdef CONFIG_DYNAMIC_FTRACE
 376         if (!strcmp("ftrace_caller", name))
 377                 return true;
 378 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 379         if (!strcmp("ftrace_regs_caller", name))
 380                 return true;
 381 #endif
 382 #endif
 383
 384         return false;
 385 }
 386 #else
 387 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
 388                                         unsigned long addr,
 389                                         struct module *me)
 390 {
 391         return 0;
 392 }
 393
 394 static bool is_mprofile_ftrace_call(const char *name)
 395 {
 396         return false;
 397 }
 398 #endif
 399
 400 /*
 401  * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
 402  * value maximum span in an instruction which uses a signed offset). Round down
 403  * to a 256 byte boundary for the odd case where we are setting up r2 without a
 404  * .toc section.
 405  */
 406 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
 407 {
 408         return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
 409 }
 410
 411 /* Patch stub to reference function and correct r2 value. */
 412 static inline int create_stub(const Elf64_Shdr *sechdrs,
 413                               struct ppc64_stub_entry *entry,
 414                               unsigned long addr,
 415                               struct module *me,
 416                               const char *name)
 417 {
 418         long reladdr;
 419         func_desc_t desc;
 420         int i;
 421
 422         if (is_mprofile_ftrace_call(name))
 423                 return create_ftrace_stub(entry, addr, me);
 424
 425         for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
 426                 if (patch_instruction(&entry->jump[i],
 427                                       ppc_inst(ppc64_stub_insns[i])))
 428                         return 0;
 429         }
 430
 431         /* Stub uses address relative to r2. */
 432         reladdr = (unsigned long)entry - my_r2(sechdrs, me);
 433         if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
 434                 pr_err("%s: Address %p of stub out of range of %p.\n",
 435                        me->name, (void *)reladdr, (void *)my_r2);
 436                 return 0;
 437         }
 438         pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
 439
 440         if (patch_instruction(&entry->jump[0],
 441                               ppc_inst(entry->jump[0] | PPC_HA(reladdr))))
 442                 return 0;
 443
 444         if (patch_instruction(&entry->jump[1],
 445                           ppc_inst(entry->jump[1] | PPC_LO(reladdr))))
 446                 return 0;
 447
 448         // func_desc_t is 8 bytes if ABIv2, else 16 bytes
 449         desc = func_desc(addr);
 450         for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {
 451                 if (patch_instruction(((u32 *)&entry->funcdata) + i,
 452                                       ppc_inst(((u32 *)(&desc))[i])))
 453                         return 0;
 454         }
 455
 456         if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC)))
 457                 return 0;
 458
 459         return 1;
 460 }
 461
 462 /* Create stub to jump to function described in this OPD/ptr: we need the
 463    stub to set up the TOC ptr (r2) for the function. */
 464 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
 465                                    unsigned long addr,
 466                                    struct module *me,
 467                                    const char *name)
 468 {
 469         struct ppc64_stub_entry *stubs;
 470         unsigned int i, num_stubs;
 471
 472         num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
 473
 474         /* Find this stub, or if that fails, the next avail. entry */
 475         stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
 476         for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
 477                 if (WARN_ON(i >= num_stubs))
 478                         return 0;
 479
 480                 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
 481                         return (unsigned long)&stubs[i];
 482         }
 483
 484         if (!create_stub(sechdrs, &stubs[i], addr, me, name))
 485                 return 0;
 486
 487         return (unsigned long)&stubs[i];
 488 }
 489
 490 /* We expect a noop next: if it is, replace it with instruction to
 491    restore r2. */
 492 static int restore_r2(const char *name, u32 *instruction, struct module *me)
 493 {
 494         u32 *prev_insn = instruction - 1;
 495
 496         if (is_mprofile_ftrace_call(name))
 497                 return 1;
 498
 499         /*
 500          * Make sure the branch isn't a sibling call.  Sibling calls aren't
 501          * "link" branches and they don't return, so they don't need the r2
 502          * restore afterwards.
 503          */
 504         if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
 505                 return 1;
 506
 507         if (*instruction != PPC_RAW_NOP()) {
 508                 pr_err("%s: Expected nop after call, got %08x at %pS\n",
 509                         me->name, *instruction, instruction);
 510                 return 0;
 511         }
 512
 513         /* ld r2,R2_STACK_OFFSET(r1) */
 514         if (patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC)))
 515                 return 0;
 516
 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                         value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value);
 657
 658                         if (patch_instruction((u32 *)location, ppc_inst(value)))
 659                                 return -EFAULT;
 660
 661                         break;
 662
 663                 case R_PPC64_REL64:
 664                         /* 64 bits relative (used by features fixups) */
 665                         *location = value - (unsigned long)location;
 666                         break;
 667
 668                 case R_PPC64_REL32:
 669                         /* 32 bits relative (used by relative exception tables) */
 670                         /* Convert value to relative */
 671                         value -= (unsigned long)location;
 672                         if (value + 0x80000000 > 0xffffffff) {
 673                                 pr_err("%s: REL32 %li out of range!\n",
 674                                        me->name, (long int)value);
 675                                 return -ENOEXEC;
 676                         }
 677                         *(u32 *)location = value;
 678                         break;
 679
 680                 case R_PPC64_TOCSAVE:
 681                         /*
 682                          * Marker reloc indicates we don't have to save r2.
 683                          * That would only save us one instruction, so ignore
 684                          * it.
 685                          */
 686                         break;
 687
 688                 case R_PPC64_ENTRY:
 689                         /*
 690                          * Optimize ELFv2 large code model entry point if
 691                          * the TOC is within 2GB range of current location.
 692                          */
 693                         value = my_r2(sechdrs, me) - (unsigned long)location;
 694                         if (value + 0x80008000 > 0xffffffff)
 695                                 break;
 696                         /*
 697                          * Check for the large code model prolog sequence:
 698                          *      ld r2, ...(r12)
 699                          *      add r2, r2, r12
 700                          */
 701                         if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0))
 702                                 break;
 703                         if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _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_RAW_ADDIS(_R2, _R12, PPC_HA(value));
 711                         ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value));
 712                         break;
 713
 714                 case R_PPC64_REL16_HA:
 715                         /* Subtract location pointer */
 716                         value -= (unsigned long)location;
 717                         value = ((value + 0x8000) >> 16);
 718                         *((uint16_t *) location)
 719                                 = (*((uint16_t *) location) & ~0xffff)
 720                                 | (value & 0xffff);
 721                         break;
 722
 723                 case R_PPC64_REL16_LO:
 724                         /* Subtract location pointer */
 725                         value -= (unsigned long)location;
 726                         *((uint16_t *) location)
 727                                 = (*((uint16_t *) location) & ~0xffff)
 728                                 | (value & 0xffff);
 729                         break;
 730
 731                 default:
 732                         pr_err("%s: Unknown ADD relocation: %lu\n",
 733                                me->name,
 734                                (unsigned long)ELF64_R_TYPE(rela[i].r_info));
 735                         return -ENOEXEC;
 736                 }
 737         }
 738
 739         return 0;
 740 }
 741
 742 #ifdef CONFIG_DYNAMIC_FTRACE
 743 int module_trampoline_target(struct module *mod, unsigned long addr,
 744                              unsigned long *target)
 745 {
 746         struct ppc64_stub_entry *stub;
 747         func_desc_t funcdata;
 748         u32 magic;
 749
 750         if (!within_module_core(addr, mod)) {
 751                 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
 752                 return -EFAULT;
 753         }
 754
 755         stub = (struct ppc64_stub_entry *)addr;
 756
 757         if (copy_from_kernel_nofault(&magic, &stub->magic,
 758                         sizeof(magic))) {
 759                 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
 760                 return -EFAULT;
 761         }
 762
 763         if (magic != STUB_MAGIC) {
 764                 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
 765                 return -EFAULT;
 766         }
 767
 768         if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
 769                         sizeof(funcdata))) {
 770                 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
 771                 return -EFAULT;
 772         }
 773
 774         *target = stub_func_addr(funcdata);
 775
 776         return 0;
 777 }
 778
 779 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
 780 {
 781         mod->arch.tramp = stub_for_addr(sechdrs,
 782                                         (unsigned long)ftrace_caller,
 783                                         mod,
 784                                         "ftrace_caller");
 785 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 786         mod->arch.tramp_regs = stub_for_addr(sechdrs,
 787                                         (unsigned long)ftrace_regs_caller,
 788                                         mod,
 789                                         "ftrace_regs_caller");
 790         if (!mod->arch.tramp_regs)
 791                 return -ENOENT;
 792 #endif
 793
 794         if (!mod->arch.tramp)
 795                 return -ENOENT;
 796
 797         return 0;
 798 }
 799 #endif