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