arch/powerpc/kernel/module_64.c

   1 /*  Kernel module help for PPC64.
   2     Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/module.h>
  22 #include <linux/elf.h>
  23 #include <linux/moduleloader.h>
  24 #include <linux/err.h>
  25 #include <linux/vmalloc.h>
  26 #include <linux/ftrace.h>
  27 #include <linux/bug.h>
  28 #include <linux/uaccess.h>
  29 #include <asm/module.h>
  30 #include <asm/firmware.h>
  31 #include <asm/code-patching.h>
  32 #include <linux/sort.h>
  33 #include <asm/setup.h>
  34
  35 /* FIXME: We don't do .init separately.  To do this, we'd need to have
  36    a separate r2 value in the init and core section, and stub between
  37    them, too.
  38
  39    Using a magic allocator which places modules within 32MB solves
  40    this, and makes other things simpler.  Anton?
  41    --RR.  */
  42
  43 #if defined(_CALL_ELF) && _CALL_ELF == 2
  44 #define R2_STACK_OFFSET 24
  45
  46 /* An address is simply the address of the function. */
  47 typedef unsigned long func_desc_t;
  48
  49 static func_desc_t func_desc(unsigned long addr)
  50 {
  51         return addr;
  52 }
  53 static unsigned long func_addr(unsigned long addr)
  54 {
  55         return addr;
  56 }
  57 static unsigned long stub_func_addr(func_desc_t func)
  58 {
  59         return func;
  60 }
  61
  62 /* PowerPC64 specific values for the Elf64_Sym st_other field.  */
  63 #define STO_PPC64_LOCAL_BIT     5
  64 #define STO_PPC64_LOCAL_MASK    (7 << STO_PPC64_LOCAL_BIT)
  65 #define PPC64_LOCAL_ENTRY_OFFSET(other)                                 \
  66  (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
  67
  68 static unsigned int local_entry_offset(const Elf64_Sym *sym)
  69 {
  70         /* sym->st_other indicates offset to local entry point
  71          * (otherwise it will assume r12 is the address of the start
  72          * of function and try to derive r2 from it). */
  73         return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
  74 }
  75 #else
  76 #define R2_STACK_OFFSET 40
  77
  78 /* An address is address of the OPD entry, which contains address of fn. */
  79 typedef struct ppc64_opd_entry func_desc_t;
  80
  81 static func_desc_t func_desc(unsigned long addr)
  82 {
  83         return *(struct ppc64_opd_entry *)addr;
  84 }
  85 static unsigned long func_addr(unsigned long addr)
  86 {
  87         return func_desc(addr).funcaddr;
  88 }
  89 static unsigned long stub_func_addr(func_desc_t func)
  90 {
  91         return func.funcaddr;
  92 }
  93 static unsigned int local_entry_offset(const Elf64_Sym *sym)
  94 {
  95         return 0;
  96 }
  97 #endif
  98
  99 /* Like PPC32, we need little trampolines to do > 24-bit jumps (into
 100    the kernel itself).  But on PPC64, these need to be used for every
 101    jump, actually, to reset r2 (TOC+0x8000). */
 102 struct ppc64_stub_entry
 103 {
 104         /* 28 byte jump instruction sequence (7 instructions). We only
 105          * need 6 instructions on ABIv2 but we always allocate 7 so
 106          * so we don't have to modify the trampoline load instruction. */
 107         u32 jump[7];
 108         u32 unused;
 109         /* Data for the above code */
 110         func_desc_t funcdata;
 111 };
 112
 113 /*
 114  * PPC64 uses 24 bit jumps, but we need to jump into other modules or
 115  * the kernel which may be further.  So we jump to a stub.
 116  *
 117  * For ELFv1 we need to use this to set up the new r2 value (aka TOC
 118  * pointer).  For ELFv2 it's the callee's responsibility to set up the
 119  * new r2, but for both we need to save the old r2.
 120  *
 121  * We could simply patch the new r2 value and function pointer into
 122  * the stub, but it's significantly shorter to put these values at the
 123  * end of the stub code, and patch the stub address (32-bits relative
 124  * to the TOC ptr, r2) into the stub.
 125  */
 126
 127 static u32 ppc64_stub_insns[] = {
 128         0x3d620000,                     /* addis   r11,r2, <high> */
 129         0x396b0000,                     /* addi    r11,r11, <low> */
 130         /* Save current r2 value in magic place on the stack. */
 131         0xf8410000|R2_STACK_OFFSET,     /* std     r2,R2_STACK_OFFSET(r1) */
 132         0xe98b0020,                     /* ld      r12,32(r11) */
 133 #if !defined(_CALL_ELF) || _CALL_ELF != 2
 134         /* Set up new r2 from function descriptor */
 135         0xe84b0028,                     /* ld      r2,40(r11) */
 136 #endif
 137         0x7d8903a6,                     /* mtctr   r12 */
 138         0x4e800420                      /* bctr */
 139 };
 140
 141 #ifdef CONFIG_DYNAMIC_FTRACE
 142
 143 static u32 ppc64_stub_mask[] = {
 144         0xffff0000,
 145         0xffff0000,
 146         0xffffffff,
 147         0xffffffff,
 148 #if !defined(_CALL_ELF) || _CALL_ELF != 2
 149         0xffffffff,
 150 #endif
 151         0xffffffff,
 152         0xffffffff
 153 };
 154
 155 bool is_module_trampoline(u32 *p)
 156 {
 157         unsigned int i;
 158         u32 insns[ARRAY_SIZE(ppc64_stub_insns)];
 159
 160         BUILD_BUG_ON(sizeof(ppc64_stub_insns) != sizeof(ppc64_stub_mask));
 161
 162         if (probe_kernel_read(insns, p, sizeof(insns)))
 163                 return -EFAULT;
 164
 165         for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
 166                 u32 insna = insns[i];
 167                 u32 insnb = ppc64_stub_insns[i];
 168                 u32 mask = ppc64_stub_mask[i];
 169
 170                 if ((insna & mask) != (insnb & mask))
 171                         return false;
 172         }
 173
 174         return true;
 175 }
 176
 177 int module_trampoline_target(struct module *mod, u32 *trampoline,
 178                              unsigned long *target)
 179 {
 180         u32 buf[2];
 181         u16 upper, lower;
 182         long offset;
 183         void *toc_entry;
 184
 185         if (probe_kernel_read(buf, trampoline, sizeof(buf)))
 186                 return -EFAULT;
 187
 188         upper = buf[0] & 0xffff;
 189         lower = buf[1] & 0xffff;
 190
 191         /* perform the addis/addi, both signed */
 192         offset = ((short)upper << 16) + (short)lower;
 193
 194         /*
 195          * Now get the address this trampoline jumps to. This
 196          * is always 32 bytes into our trampoline stub.
 197          */
 198         toc_entry = (void *)mod->arch.toc + offset + 32;
 199
 200         if (probe_kernel_read(target, toc_entry, sizeof(*target)))
 201                 return -EFAULT;
 202
 203         return 0;
 204 }
 205
 206 #endif
 207
 208 /* Count how many different 24-bit relocations (different symbol,
 209    different addend) */
 210 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
 211 {
 212         unsigned int i, r_info, r_addend, _count_relocs;
 213
 214         /* FIXME: Only count external ones --RR */
 215         _count_relocs = 0;
 216         r_info = 0;
 217         r_addend = 0;
 218         for (i = 0; i < num; i++)
 219                 /* Only count 24-bit relocs, others don't need stubs */
 220                 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
 221                     (r_info != ELF64_R_SYM(rela[i].r_info) ||
 222                      r_addend != rela[i].r_addend)) {
 223                         _count_relocs++;
 224                         r_info = ELF64_R_SYM(rela[i].r_info);
 225                         r_addend = rela[i].r_addend;
 226                 }
 227
 228         return _count_relocs;
 229 }
 230
 231 static int relacmp(const void *_x, const void *_y)
 232 {
 233         const Elf64_Rela *x, *y;
 234
 235         y = (Elf64_Rela *)_x;
 236         x = (Elf64_Rela *)_y;
 237
 238         /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
 239          * make the comparison cheaper/faster. It won't affect the sorting or
 240          * the counting algorithms' performance
 241          */
 242         if (x->r_info < y->r_info)
 243                 return -1;
 244         else if (x->r_info > y->r_info)
 245                 return 1;
 246         else if (x->r_addend < y->r_addend)
 247                 return -1;
 248         else if (x->r_addend > y->r_addend)
 249                 return 1;
 250         else
 251                 return 0;
 252 }
 253
 254 static void relaswap(void *_x, void *_y, int size)
 255 {
 256         uint64_t *x, *y, tmp;
 257         int i;
 258
 259         y = (uint64_t *)_x;
 260         x = (uint64_t *)_y;
 261
 262         for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
 263                 tmp = x[i];
 264                 x[i] = y[i];
 265                 y[i] = tmp;
 266         }
 267 }
 268
 269 /* Get size of potential trampolines required. */
 270 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 271                                     const Elf64_Shdr *sechdrs)
 272 {
 273         /* One extra reloc so it's always 0-funcaddr terminated */
 274         unsigned long relocs = 1;
 275         unsigned i;
 276
 277         /* Every relocated section... */
 278         for (i = 1; i < hdr->e_shnum; i++) {
 279                 if (sechdrs[i].sh_type == SHT_RELA) {
 280                         pr_debug("Found relocations in section %u\n", i);
 281                         pr_debug("Ptr: %p.  Number: %Lu\n",
 282                                (void *)sechdrs[i].sh_addr,
 283                                sechdrs[i].sh_size / sizeof(Elf64_Rela));
 284
 285                         /* Sort the relocation information based on a symbol and
 286                          * addend key. This is a stable O(n*log n) complexity
 287                          * alogrithm but it will reduce the complexity of
 288                          * count_relocs() to linear complexity O(n)
 289                          */
 290                         sort((void *)sechdrs[i].sh_addr,
 291                              sechdrs[i].sh_size / sizeof(Elf64_Rela),
 292                              sizeof(Elf64_Rela), relacmp, relaswap);
 293
 294                         relocs += count_relocs((void *)sechdrs[i].sh_addr,
 295                                                sechdrs[i].sh_size
 296                                                / sizeof(Elf64_Rela));
 297                 }
 298         }
 299
 300 #ifdef CONFIG_DYNAMIC_FTRACE
 301         /* make the trampoline to the ftrace_caller */
 302         relocs++;
 303 #endif
 304
 305         pr_debug("Looks like a total of %lu stubs, max\n", relocs);
 306         return relocs * sizeof(struct ppc64_stub_entry);
 307 }
 308
 309 /* Still needed for ELFv2, for .TOC. */
 310 static void dedotify_versions(struct modversion_info *vers,
 311                               unsigned long size)
 312 {
 313         struct modversion_info *end;
 314
 315         for (end = (void *)vers + size; vers < end; vers++)
 316                 if (vers->name[0] == '.') {
 317                         memmove(vers->name, vers->name+1, strlen(vers->name));
 318 #ifdef ARCH_RELOCATES_KCRCTAB
 319                         /* The TOC symbol has no CRC computed. To avoid CRC
 320                          * check failing, we must force it to the expected
 321                          * value (see CRC check in module.c).
 322                          */
 323                         if (!strcmp(vers->name, "TOC."))
 324                                 vers->crc = -(unsigned long)reloc_start;
 325 #endif
 326                 }
 327 }
 328
 329 /* Undefined symbols which refer to .funcname, hack to funcname (or .TOC.) */
 330 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
 331 {
 332         unsigned int i;
 333
 334         for (i = 1; i < numsyms; i++) {
 335                 if (syms[i].st_shndx == SHN_UNDEF) {
 336                         char *name = strtab + syms[i].st_name;
 337                         if (name[0] == '.')
 338                                 memmove(name, name+1, strlen(name));
 339                 }
 340         }
 341 }
 342
 343 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
 344                                const char *strtab,
 345                                unsigned int symindex)
 346 {
 347         unsigned int i, numsyms;
 348         Elf64_Sym *syms;
 349
 350         syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
 351         numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
 352
 353         for (i = 1; i < numsyms; i++) {
 354                 if (syms[i].st_shndx == SHN_UNDEF
 355                     && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
 356                         return &syms[i];
 357         }
 358         return NULL;
 359 }
 360
 361 int module_frob_arch_sections(Elf64_Ehdr *hdr,
 362                               Elf64_Shdr *sechdrs,
 363                               char *secstrings,
 364                               struct module *me)
 365 {
 366         unsigned int i;
 367
 368         /* Find .toc and .stubs sections, symtab and strtab */
 369         for (i = 1; i < hdr->e_shnum; i++) {
 370                 char *p;
 371                 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
 372                         me->arch.stubs_section = i;
 373                 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0)
 374                         me->arch.toc_section = i;
 375                 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
 376                         dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
 377                                           sechdrs[i].sh_size);
 378
 379                 /* We don't handle .init for the moment: rename to _init */
 380                 while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
 381                         p[0] = '_';
 382
 383                 if (sechdrs[i].sh_type == SHT_SYMTAB)
 384                         dedotify((void *)hdr + sechdrs[i].sh_offset,
 385                                  sechdrs[i].sh_size / sizeof(Elf64_Sym),
 386                                  (void *)hdr
 387                                  + sechdrs[sechdrs[i].sh_link].sh_offset);
 388         }
 389
 390         if (!me->arch.stubs_section) {
 391                 pr_err("%s: doesn't contain .stubs.\n", me->name);
 392                 return -ENOEXEC;
 393         }
 394
 395         /* If we don't have a .toc, just use .stubs.  We need to set r2
 396            to some reasonable value in case the module calls out to
 397            other functions via a stub, or if a function pointer escapes
 398            the module by some means.  */
 399         if (!me->arch.toc_section)
 400                 me->arch.toc_section = me->arch.stubs_section;
 401
 402         /* Override the stubs size */
 403         sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
 404         return 0;
 405 }
 406
 407 /* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this
 408    gives the value maximum span in an instruction which uses a signed
 409    offset) */
 410 static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me)
 411 {
 412         return sechdrs[me->arch.toc_section].sh_addr + 0x8000;
 413 }
 414
 415 /* Both low and high 16 bits are added as SIGNED additions, so if low
 416    16 bits has high bit set, high 16 bits must be adjusted.  These
 417    macros do that (stolen from binutils). */
 418 #define PPC_LO(v) ((v) & 0xffff)
 419 #define PPC_HI(v) (((v) >> 16) & 0xffff)
 420 #define PPC_HA(v) PPC_HI ((v) + 0x8000)
 421
 422 /* Patch stub to reference function and correct r2 value. */
 423 static inline int create_stub(Elf64_Shdr *sechdrs,
 424                               struct ppc64_stub_entry *entry,
 425                               unsigned long addr,
 426                               struct module *me)
 427 {
 428         long reladdr;
 429
 430         memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
 431
 432         /* Stub uses address relative to r2. */
 433         reladdr = (unsigned long)entry - my_r2(sechdrs, me);
 434         if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
 435                 pr_err("%s: Address %p of stub out of range of %p.\n",
 436                        me->name, (void *)reladdr, (void *)my_r2);
 437                 return 0;
 438         }
 439         pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
 440
 441         entry->jump[0] |= PPC_HA(reladdr);
 442         entry->jump[1] |= PPC_LO(reladdr);
 443         entry->funcdata = func_desc(addr);
 444         return 1;
 445 }
 446
 447 /* Create stub to jump to function described in this OPD/ptr: we need the
 448    stub to set up the TOC ptr (r2) for the function. */
 449 static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
 450                                    unsigned long addr,
 451                                    struct module *me)
 452 {
 453         struct ppc64_stub_entry *stubs;
 454         unsigned int i, num_stubs;
 455
 456         num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
 457
 458         /* Find this stub, or if that fails, the next avail. entry */
 459         stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
 460         for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
 461                 BUG_ON(i >= num_stubs);
 462
 463                 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
 464                         return (unsigned long)&stubs[i];
 465         }
 466
 467         if (!create_stub(sechdrs, &stubs[i], addr, me))
 468                 return 0;
 469
 470         return (unsigned long)&stubs[i];
 471 }
 472
 473 /* We expect a noop next: if it is, replace it with instruction to
 474    restore r2. */
 475 static int restore_r2(u32 *instruction, struct module *me)
 476 {
 477         if (*instruction != PPC_INST_NOP) {
 478                 pr_err("%s: Expect noop after relocate, got %08x\n",
 479                        me->name, *instruction);
 480                 return 0;
 481         }
 482         /* ld r2,R2_STACK_OFFSET(r1) */
 483         *instruction = 0xe8410000 | R2_STACK_OFFSET;
 484         return 1;
 485 }
 486
 487 int apply_relocate_add(Elf64_Shdr *sechdrs,
 488                        const char *strtab,
 489                        unsigned int symindex,
 490                        unsigned int relsec,
 491                        struct module *me)
 492 {
 493         unsigned int i;
 494         Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
 495         Elf64_Sym *sym;
 496         unsigned long *location;
 497         unsigned long value;
 498
 499         pr_debug("Applying ADD relocate section %u to %u\n", relsec,
 500                sechdrs[relsec].sh_info);
 501
 502         /* First time we're called, we can fix up .TOC. */
 503         if (!me->arch.toc_fixed) {
 504                 sym = find_dot_toc(sechdrs, strtab, symindex);
 505                 /* It's theoretically possible that a module doesn't want a
 506                  * .TOC. so don't fail it just for that. */
 507                 if (sym)
 508                         sym->st_value = my_r2(sechdrs, me);
 509                 me->arch.toc_fixed = true;
 510         }
 511
 512         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
 513                 /* This is where to make the change */
 514                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 515                         + rela[i].r_offset;
 516                 /* This is the symbol it is referring to */
 517                 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 518                         + ELF64_R_SYM(rela[i].r_info);
 519
 520                 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
 521                        location, (long)ELF64_R_TYPE(rela[i].r_info),
 522                        strtab + sym->st_name, (unsigned long)sym->st_value,
 523                        (long)rela[i].r_addend);
 524
 525                 /* `Everything is relative'. */
 526                 value = sym->st_value + rela[i].r_addend;
 527
 528                 switch (ELF64_R_TYPE(rela[i].r_info)) {
 529                 case R_PPC64_ADDR32:
 530                         /* Simply set it */
 531                         *(u32 *)location = value;
 532                         break;
 533
 534                 case R_PPC64_ADDR64:
 535                         /* Simply set it */
 536                         *(unsigned long *)location = value;
 537                         break;
 538
 539                 case R_PPC64_TOC:
 540                         *(unsigned long *)location = my_r2(sechdrs, me);
 541                         break;
 542
 543                 case R_PPC64_TOC16:
 544                         /* Subtract TOC pointer */
 545                         value -= my_r2(sechdrs, me);
 546                         if (value + 0x8000 > 0xffff) {
 547                                 pr_err("%s: bad TOC16 relocation (0x%lx)\n",
 548                                        me->name, value);
 549                                 return -ENOEXEC;
 550                         }
 551                         *((uint16_t *) location)
 552                                 = (*((uint16_t *) location) & ~0xffff)
 553                                 | (value & 0xffff);
 554                         break;
 555
 556                 case R_PPC64_TOC16_LO:
 557                         /* Subtract TOC pointer */
 558                         value -= my_r2(sechdrs, me);
 559                         *((uint16_t *) location)
 560                                 = (*((uint16_t *) location) & ~0xffff)
 561                                 | (value & 0xffff);
 562                         break;
 563
 564                 case R_PPC64_TOC16_DS:
 565                         /* Subtract TOC pointer */
 566                         value -= my_r2(sechdrs, me);
 567                         if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
 568                                 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
 569                                        me->name, value);
 570                                 return -ENOEXEC;
 571                         }
 572                         *((uint16_t *) location)
 573                                 = (*((uint16_t *) location) & ~0xfffc)
 574                                 | (value & 0xfffc);
 575                         break;
 576
 577                 case R_PPC64_TOC16_LO_DS:
 578                         /* Subtract TOC pointer */
 579                         value -= my_r2(sechdrs, me);
 580                         if ((value & 3) != 0) {
 581                                 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
 582                                        me->name, value);
 583                                 return -ENOEXEC;
 584                         }
 585                         *((uint16_t *) location)
 586                                 = (*((uint16_t *) location) & ~0xfffc)
 587                                 | (value & 0xfffc);
 588                         break;
 589
 590                 case R_PPC64_TOC16_HA:
 591                         /* Subtract TOC pointer */
 592                         value -= my_r2(sechdrs, me);
 593                         value = ((value + 0x8000) >> 16);
 594                         *((uint16_t *) location)
 595                                 = (*((uint16_t *) location) & ~0xffff)
 596                                 | (value & 0xffff);
 597                         break;
 598
 599                 case R_PPC_REL24:
 600                         /* FIXME: Handle weak symbols here --RR */
 601                         if (sym->st_shndx == SHN_UNDEF) {
 602                                 /* External: go via stub */
 603                                 value = stub_for_addr(sechdrs, value, me);
 604                                 if (!value)
 605                                         return -ENOENT;
 606                                 if (!restore_r2((u32 *)location + 1, me))
 607                                         return -ENOEXEC;
 608                         } else
 609                                 value += local_entry_offset(sym);
 610
 611                         /* Convert value to relative */
 612                         value -= (unsigned long)location;
 613                         if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
 614                                 pr_err("%s: REL24 %li out of range!\n",
 615                                        me->name, (long int)value);
 616                                 return -ENOEXEC;
 617                         }
 618
 619                         /* Only replace bits 2 through 26 */
 620                         *(uint32_t *)location
 621                                 = (*(uint32_t *)location & ~0x03fffffc)
 622                                 | (value & 0x03fffffc);
 623                         break;
 624
 625                 case R_PPC64_REL64:
 626                         /* 64 bits relative (used by features fixups) */
 627                         *location = value - (unsigned long)location;
 628                         break;
 629
 630                 case R_PPC64_TOCSAVE:
 631                         /*
 632                          * Marker reloc indicates we don't have to save r2.
 633                          * That would only save us one instruction, so ignore
 634                          * it.
 635                          */
 636                         break;
 637
 638                 case R_PPC64_REL16_HA:
 639                         /* Subtract location pointer */
 640                         value -= (unsigned long)location;
 641                         value = ((value + 0x8000) >> 16);
 642                         *((uint16_t *) location)
 643                                 = (*((uint16_t *) location) & ~0xffff)
 644                                 | (value & 0xffff);
 645                         break;
 646
 647                 case R_PPC64_REL16_LO:
 648                         /* Subtract location pointer */
 649                         value -= (unsigned long)location;
 650                         *((uint16_t *) location)
 651                                 = (*((uint16_t *) location) & ~0xffff)
 652                                 | (value & 0xffff);
 653                         break;
 654
 655                 default:
 656                         pr_err("%s: Unknown ADD relocation: %lu\n",
 657                                me->name,
 658                                (unsigned long)ELF64_R_TYPE(rela[i].r_info));
 659                         return -ENOEXEC;
 660                 }
 661         }
 662
 663 #ifdef CONFIG_DYNAMIC_FTRACE
 664         me->arch.toc = my_r2(sechdrs, me);
 665         me->arch.tramp = stub_for_addr(sechdrs,
 666                                        (unsigned long)ftrace_caller,
 667                                        me);
 668 #endif
 669
 670         return 0;
 671 }