scripts/recordmcount.c

   1 /*
   2  * recordmcount.c: construct a table of the locations of calls to 'mcount'
   3  * so that ftrace can find them quickly.
   4  * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
   5  * Licensed under the GNU General Public License, version 2 (GPLv2).
   6  *
   7  * Restructured to fit Linux format, as well as other updates:
   8  *  Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
   9  */
  10
  11 /*
  12  * Strategy: alter the .o file in-place.
  13  *
  14  * Append a new STRTAB that has the new section names, followed by a new array
  15  * ElfXX_Shdr[] that has the new section headers, followed by the section
  16  * contents for __mcount_loc and its relocations.  The old shstrtab strings,
  17  * and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
  18  * kilobytes.)  Subsequent processing by /bin/ld (or the kernel module loader)
  19  * will ignore the garbage regions, because they are not designated by the
  20  * new .e_shoff nor the new ElfXX_Shdr[].  [In order to remove the garbage,
  21  * then use "ld -r" to create a new file that omits the garbage.]
  22  */
  23
  24 #include <sys/types.h>
  25 #include <sys/mman.h>
  26 #include <sys/stat.h>
  27 #include <getopt.h>
  28 #include <elf.h>
  29 #include <fcntl.h>
  30 #include <setjmp.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35
  36 #ifndef EM_AARCH64
  37 #define EM_AARCH64      183
  38 #define R_AARCH64_NONE          0
  39 #define R_AARCH64_ABS64 257
  40 #endif
  41
  42 static int fd_map;      /* File descriptor for file being modified. */
  43 static int mmap_failed; /* Boolean flag. */
  44 static char gpfx;       /* prefix for global symbol name (sometimes '_') */
  45 static struct stat sb;  /* Remember .st_size, etc. */
  46 static jmp_buf jmpenv;  /* setjmp/longjmp per-file error escape */
  47 static const char *altmcount;   /* alternate mcount symbol name */
  48 static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
  49 static void *file_map;  /* pointer of the mapped file */
  50 static void *file_end;  /* pointer to the end of the mapped file */
  51 static int file_updated; /* flag to state file was changed */
  52 static void *file_ptr;  /* current file pointer location */
  53 static void *file_append; /* added to the end of the file */
  54 static size_t file_append_size; /* how much is added to end of file */
  55
  56 /* setjmp() return values */
  57 enum {
  58         SJ_SETJMP = 0,  /* hardwired first return */
  59         SJ_FAIL,
  60         SJ_SUCCEED
  61 };
  62
  63 /* Per-file resource cleanup when multiple files. */
  64 static void
  65 cleanup(void)
  66 {
  67         if (!mmap_failed)
  68                 munmap(file_map, sb.st_size);
  69         else
  70                 free(file_map);
  71         file_map = NULL;
  72         free(file_append);
  73         file_append = NULL;
  74         file_append_size = 0;
  75         file_updated = 0;
  76 }
  77
  78 static void __attribute__((noreturn))
  79 fail_file(void)
  80 {
  81         cleanup();
  82         longjmp(jmpenv, SJ_FAIL);
  83 }
  84
  85 static void __attribute__((noreturn))
  86 succeed_file(void)
  87 {
  88         cleanup();
  89         longjmp(jmpenv, SJ_SUCCEED);
  90 }
  91
  92 /* ulseek, uread, ...:  Check return value for errors. */
  93
  94 static off_t
  95 ulseek(int const fd, off_t const offset, int const whence)
  96 {
  97         switch (whence) {
  98         case SEEK_SET:
  99                 file_ptr = file_map + offset;
 100                 break;
 101         case SEEK_CUR:
 102                 file_ptr += offset;
 103                 break;
 104         case SEEK_END:
 105                 file_ptr = file_map + (sb.st_size - offset);
 106                 break;
 107         }
 108         if (file_ptr < file_map) {
 109                 fprintf(stderr, "lseek: seek before file\n");
 110                 fail_file();
 111         }
 112         return file_ptr - file_map;
 113 }
 114
 115 static size_t
 116 uread(int const fd, void *const buf, size_t const count)
 117 {
 118         size_t const n = read(fd, buf, count);
 119         if (n != count) {
 120                 perror("read");
 121                 fail_file();
 122         }
 123         return n;
 124 }
 125
 126 static size_t
 127 uwrite(int const fd, void const *const buf, size_t const count)
 128 {
 129         size_t cnt = count;
 130         off_t idx = 0;
 131
 132         file_updated = 1;
 133
 134         if (file_ptr + count >= file_end) {
 135                 off_t aoffset = (file_ptr + count) - file_end;
 136
 137                 if (aoffset > file_append_size) {
 138                         file_append = realloc(file_append, aoffset);
 139                         file_append_size = aoffset;
 140                 }
 141                 if (!file_append) {
 142                         perror("write");
 143                         fail_file();
 144                 }
 145                 if (file_ptr < file_end) {
 146                         cnt = file_end - file_ptr;
 147                 } else {
 148                         cnt = 0;
 149                         idx = aoffset - count;
 150                 }
 151         }
 152
 153         if (cnt)
 154                 memcpy(file_ptr, buf, cnt);
 155
 156         if (cnt < count)
 157                 memcpy(file_append + idx, buf + cnt, count - cnt);
 158
 159         file_ptr += count;
 160         return count;
 161 }
 162
 163 static void *
 164 umalloc(size_t size)
 165 {
 166         void *const addr = malloc(size);
 167         if (addr == 0) {
 168                 fprintf(stderr, "malloc failed: %zu bytes\n", size);
 169                 fail_file();
 170         }
 171         return addr;
 172 }
 173
 174 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
 175 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
 176 static unsigned char *ideal_nop;
 177
 178 static char rel_type_nop;
 179
 180 static int (*make_nop)(void *map, size_t const offset);
 181
 182 static int make_nop_x86(void *map, size_t const offset)
 183 {
 184         uint32_t *ptr;
 185         unsigned char *op;
 186
 187         /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
 188         ptr = map + offset;
 189         if (*ptr != 0)
 190                 return -1;
 191
 192         op = map + offset - 1;
 193         if (*op != 0xe8)
 194                 return -1;
 195
 196         /* convert to nop */
 197         ulseek(fd_map, offset - 1, SEEK_SET);
 198         uwrite(fd_map, ideal_nop, 5);
 199         return 0;
 200 }
 201
 202 static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */
 203 static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */
 204 static unsigned char *ideal_nop4_arm;
 205
 206 static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */
 207 static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */
 208 static unsigned char *bl_mcount_arm;
 209
 210 static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */
 211 static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */
 212 static unsigned char *push_arm;
 213
 214 static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */
 215 static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */
 216 static unsigned char *ideal_nop2_thumb;
 217
 218 static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */
 219 static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */
 220 static unsigned char *push_bl_mcount_thumb;
 221
 222 static int make_nop_arm(void *map, size_t const offset)
 223 {
 224         char *ptr;
 225         int cnt = 1;
 226         int nop_size;
 227         size_t off = offset;
 228
 229         ptr = map + offset;
 230         if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
 231                 if (memcmp(ptr - 4, push_arm, 4) == 0) {
 232                         off -= 4;
 233                         cnt = 2;
 234                 }
 235                 ideal_nop = ideal_nop4_arm;
 236                 nop_size = 4;
 237         } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
 238                 cnt = 3;
 239                 nop_size = 2;
 240                 off -= 2;
 241                 ideal_nop = ideal_nop2_thumb;
 242         } else
 243                 return -1;
 244
 245         /* Convert to nop */
 246         ulseek(fd_map, off, SEEK_SET);
 247
 248         do {
 249                 uwrite(fd_map, ideal_nop, nop_size);
 250         } while (--cnt > 0);
 251
 252         return 0;
 253 }
 254
 255 static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
 256 static int make_nop_arm64(void *map, size_t const offset)
 257 {
 258         uint32_t *ptr;
 259
 260         ptr = map + offset;
 261         /* bl <_mcount> is 0x94000000 before relocation */
 262         if (*ptr != 0x94000000)
 263                 return -1;
 264
 265         /* Convert to nop */
 266         ulseek(fd_map, offset, SEEK_SET);
 267         uwrite(fd_map, ideal_nop, 4);
 268         return 0;
 269 }
 270
 271 /*
 272  * Get the whole file as a programming convenience in order to avoid
 273  * malloc+lseek+read+free of many pieces.  If successful, then mmap
 274  * avoids copying unused pieces; else just read the whole file.
 275  * Open for both read and write; new info will be appended to the file.
 276  * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
 277  * do not propagate to the file until an explicit overwrite at the last.
 278  * This preserves most aspects of consistency (all except .st_size)
 279  * for simultaneous readers of the file while we are appending to it.
 280  * However, multiple writers still are bad.  We choose not to use
 281  * locking because it is expensive and the use case of kernel build
 282  * makes multiple writers unlikely.
 283  */
 284 static void *mmap_file(char const *fname)
 285 {
 286         fd_map = open(fname, O_RDONLY);
 287         if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
 288                 perror(fname);
 289                 fail_file();
 290         }
 291         if (!S_ISREG(sb.st_mode)) {
 292                 fprintf(stderr, "not a regular file: %s\n", fname);
 293                 fail_file();
 294         }
 295         file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
 296                         fd_map, 0);
 297         mmap_failed = 0;
 298         if (file_map == MAP_FAILED) {
 299                 mmap_failed = 1;
 300                 file_map = umalloc(sb.st_size);
 301                 uread(fd_map, file_map, sb.st_size);
 302         }
 303         close(fd_map);
 304
 305         file_end = file_map + sb.st_size;
 306
 307         return file_map;
 308 }
 309
 310 static void write_file(const char *fname)
 311 {
 312         char tmp_file[strlen(fname) + 4];
 313         size_t n;
 314
 315         if (!file_updated)
 316                 return;
 317
 318         sprintf(tmp_file, "%s.rc", fname);
 319
 320         /*
 321          * After reading the entire file into memory, delete it
 322          * and write it back, to prevent weird side effects of modifying
 323          * an object file in place.
 324          */
 325         fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
 326         if (fd_map < 0) {
 327                 perror(fname);
 328                 fail_file();
 329         }
 330         n = write(fd_map, file_map, sb.st_size);
 331         if (n != sb.st_size) {
 332                 perror("write");
 333                 fail_file();
 334         }
 335         if (file_append_size) {
 336                 n = write(fd_map, file_append, file_append_size);
 337                 if (n != file_append_size) {
 338                         perror("write");
 339                         fail_file();
 340                 }
 341         }
 342         close(fd_map);
 343         if (rename(tmp_file, fname) < 0) {
 344                 perror(fname);
 345                 fail_file();
 346         }
 347 }
 348
 349 /* w8rev, w8nat, ...: Handle endianness. */
 350
 351 static uint64_t w8rev(uint64_t const x)
 352 {
 353         return   ((0xff & (x >> (0 * 8))) << (7 * 8))
 354                | ((0xff & (x >> (1 * 8))) << (6 * 8))
 355                | ((0xff & (x >> (2 * 8))) << (5 * 8))
 356                | ((0xff & (x >> (3 * 8))) << (4 * 8))
 357                | ((0xff & (x >> (4 * 8))) << (3 * 8))
 358                | ((0xff & (x >> (5 * 8))) << (2 * 8))
 359                | ((0xff & (x >> (6 * 8))) << (1 * 8))
 360                | ((0xff & (x >> (7 * 8))) << (0 * 8));
 361 }
 362
 363 static uint32_t w4rev(uint32_t const x)
 364 {
 365         return   ((0xff & (x >> (0 * 8))) << (3 * 8))
 366                | ((0xff & (x >> (1 * 8))) << (2 * 8))
 367                | ((0xff & (x >> (2 * 8))) << (1 * 8))
 368                | ((0xff & (x >> (3 * 8))) << (0 * 8));
 369 }
 370
 371 static uint32_t w2rev(uint16_t const x)
 372 {
 373         return   ((0xff & (x >> (0 * 8))) << (1 * 8))
 374                | ((0xff & (x >> (1 * 8))) << (0 * 8));
 375 }
 376
 377 static uint64_t w8nat(uint64_t const x)
 378 {
 379         return x;
 380 }
 381
 382 static uint32_t w4nat(uint32_t const x)
 383 {
 384         return x;
 385 }
 386
 387 static uint32_t w2nat(uint16_t const x)
 388 {
 389         return x;
 390 }
 391
 392 static uint64_t (*w8)(uint64_t);
 393 static uint32_t (*w)(uint32_t);
 394 static uint32_t (*w2)(uint16_t);
 395
 396 /* Names of the sections that could contain calls to mcount. */
 397 static int
 398 is_mcounted_section_name(char const *const txtname)
 399 {
 400         return strncmp(".text",          txtname, 5) == 0 ||
 401                 strcmp(".init.text",     txtname) == 0 ||
 402                 strcmp(".ref.text",      txtname) == 0 ||
 403                 strcmp(".sched.text",    txtname) == 0 ||
 404                 strcmp(".spinlock.text", txtname) == 0 ||
 405                 strcmp(".irqentry.text", txtname) == 0 ||
 406                 strcmp(".softirqentry.text", txtname) == 0 ||
 407                 strcmp(".kprobes.text", txtname) == 0 ||
 408                 strcmp(".cpuidle.text", txtname) == 0 ||
 409                 strcmp(".text.unlikely", txtname) == 0;
 410 }
 411
 412 /* 32 bit and 64 bit are very similar */
 413 #include "recordmcount.h"
 414 #define RECORD_MCOUNT_64
 415 #include "recordmcount.h"
 416
 417 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
 418  * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
 419  * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
 420  * to imply the order of the members; the spec does not say so.
 421  *      typedef unsigned char Elf64_Byte;
 422  * fails on MIPS64 because their <elf.h> already has it!
 423  */
 424
 425 typedef uint8_t myElf64_Byte;           /* Type for a 8-bit quantity.  */
 426
 427 union mips_r_info {
 428         Elf64_Xword r_info;
 429         struct {
 430                 Elf64_Word r_sym;               /* Symbol index.  */
 431                 myElf64_Byte r_ssym;            /* Special symbol.  */
 432                 myElf64_Byte r_type3;           /* Third relocation.  */
 433                 myElf64_Byte r_type2;           /* Second relocation.  */
 434                 myElf64_Byte r_type;            /* First relocation.  */
 435         } r_mips;
 436 };
 437
 438 static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
 439 {
 440         return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
 441 }
 442
 443 static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
 444 {
 445         rp->r_info = ((union mips_r_info){
 446                 .r_mips = { .r_sym = w(sym), .r_type = type }
 447         }).r_info;
 448 }
 449
 450 static void
 451 do_file(char const *const fname)
 452 {
 453         Elf32_Ehdr *const ehdr = mmap_file(fname);
 454         unsigned int reltype = 0;
 455
 456         w = w4nat;
 457         w2 = w2nat;
 458         w8 = w8nat;
 459         switch (ehdr->e_ident[EI_DATA]) {
 460                 static unsigned int const endian = 1;
 461         default:
 462                 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
 463                         ehdr->e_ident[EI_DATA], fname);
 464                 fail_file();
 465                 break;
 466         case ELFDATA2LSB:
 467                 if (*(unsigned char const *)&endian != 1) {
 468                         /* main() is big endian, file.o is little endian. */
 469                         w = w4rev;
 470                         w2 = w2rev;
 471                         w8 = w8rev;
 472                 }
 473                 ideal_nop4_arm = ideal_nop4_arm_le;
 474                 bl_mcount_arm = bl_mcount_arm_le;
 475                 push_arm = push_arm_le;
 476                 ideal_nop2_thumb = ideal_nop2_thumb_le;
 477                 push_bl_mcount_thumb = push_bl_mcount_thumb_le;
 478                 break;
 479         case ELFDATA2MSB:
 480                 if (*(unsigned char const *)&endian != 0) {
 481                         /* main() is little endian, file.o is big endian. */
 482                         w = w4rev;
 483                         w2 = w2rev;
 484                         w8 = w8rev;
 485                 }
 486                 ideal_nop4_arm = ideal_nop4_arm_be;
 487                 bl_mcount_arm = bl_mcount_arm_be;
 488                 push_arm = push_arm_be;
 489                 ideal_nop2_thumb = ideal_nop2_thumb_be;
 490                 push_bl_mcount_thumb = push_bl_mcount_thumb_be;
 491                 break;
 492         }  /* end switch */
 493         if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
 494         ||  w2(ehdr->e_type) != ET_REL
 495         ||  ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
 496                 fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
 497                 fail_file();
 498         }
 499
 500         gpfx = 0;
 501         switch (w2(ehdr->e_machine)) {
 502         default:
 503                 fprintf(stderr, "unrecognized e_machine %u %s\n",
 504                         w2(ehdr->e_machine), fname);
 505                 fail_file();
 506                 break;
 507         case EM_386:
 508                 reltype = R_386_32;
 509                 rel_type_nop = R_386_NONE;
 510                 make_nop = make_nop_x86;
 511                 ideal_nop = ideal_nop5_x86_32;
 512                 mcount_adjust_32 = -1;
 513                 break;
 514         case EM_ARM:     reltype = R_ARM_ABS32;
 515                          altmcount = "__gnu_mcount_nc";
 516                          make_nop = make_nop_arm;
 517                          rel_type_nop = R_ARM_NONE;
 518                          break;
 519         case EM_AARCH64:
 520                         reltype = R_AARCH64_ABS64;
 521                         make_nop = make_nop_arm64;
 522                         rel_type_nop = R_AARCH64_NONE;
 523                         ideal_nop = ideal_nop4_arm64;
 524                         gpfx = '_';
 525                         break;
 526         case EM_IA_64:   reltype = R_IA64_IMM64;   gpfx = '_'; break;
 527         case EM_MIPS:    /* reltype: e_class    */ gpfx = '_'; break;
 528         case EM_PPC:     reltype = R_PPC_ADDR32;   gpfx = '_'; break;
 529         case EM_PPC64:   reltype = R_PPC64_ADDR64; gpfx = '_'; break;
 530         case EM_S390:    /* reltype: e_class    */ gpfx = '_'; break;
 531         case EM_SH:      reltype = R_SH_DIR32;                 break;
 532         case EM_SPARCV9: reltype = R_SPARC_64;     gpfx = '_'; break;
 533         case EM_X86_64:
 534                 make_nop = make_nop_x86;
 535                 ideal_nop = ideal_nop5_x86_64;
 536                 reltype = R_X86_64_64;
 537                 rel_type_nop = R_X86_64_NONE;
 538                 mcount_adjust_64 = -1;
 539                 break;
 540         }  /* end switch */
 541
 542         switch (ehdr->e_ident[EI_CLASS]) {
 543         default:
 544                 fprintf(stderr, "unrecognized ELF class %d %s\n",
 545                         ehdr->e_ident[EI_CLASS], fname);
 546                 fail_file();
 547                 break;
 548         case ELFCLASS32:
 549                 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
 550                 ||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
 551                         fprintf(stderr,
 552                                 "unrecognized ET_REL file: %s\n", fname);
 553                         fail_file();
 554                 }
 555                 if (w2(ehdr->e_machine) == EM_MIPS) {
 556                         reltype = R_MIPS_32;
 557                         is_fake_mcount32 = MIPS32_is_fake_mcount;
 558                 }
 559                 do32(ehdr, fname, reltype);
 560                 break;
 561         case ELFCLASS64: {
 562                 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
 563                 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
 564                 ||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
 565                         fprintf(stderr,
 566                                 "unrecognized ET_REL file: %s\n", fname);
 567                         fail_file();
 568                 }
 569                 if (w2(ghdr->e_machine) == EM_S390) {
 570                         reltype = R_390_64;
 571                         mcount_adjust_64 = -14;
 572                 }
 573                 if (w2(ghdr->e_machine) == EM_MIPS) {
 574                         reltype = R_MIPS_64;
 575                         Elf64_r_sym = MIPS64_r_sym;
 576                         Elf64_r_info = MIPS64_r_info;
 577                         is_fake_mcount64 = MIPS64_is_fake_mcount;
 578                 }
 579                 do64(ghdr, fname, reltype);
 580                 break;
 581         }
 582         }  /* end switch */
 583
 584         write_file(fname);
 585         cleanup();
 586 }
 587
 588 int
 589 main(int argc, char *argv[])
 590 {
 591         const char ftrace[] = "/ftrace.o";
 592         int ftrace_size = sizeof(ftrace) - 1;
 593         int n_error = 0;  /* gcc-4.3.0 false positive complaint */
 594         int c;
 595         int i;
 596
 597         while ((c = getopt(argc, argv, "w")) >= 0) {
 598                 switch (c) {
 599                 case 'w':
 600                         warn_on_notrace_sect = 1;
 601                         break;
 602                 default:
 603                         fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 604                         return 0;
 605                 }
 606         }
 607
 608         if ((argc - optind) < 1) {
 609                 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 610                 return 0;
 611         }
 612
 613         /* Process each file in turn, allowing deep failure. */
 614         for (i = optind; i < argc; i++) {
 615                 char *file = argv[i];
 616                 int const sjval = setjmp(jmpenv);
 617                 int len;
 618
 619                 /*
 620                  * The file kernel/trace/ftrace.o references the mcount
 621                  * function but does not call it. Since ftrace.o should
 622                  * not be traced anyway, we just skip it.
 623                  */
 624                 len = strlen(file);
 625                 if (len >= ftrace_size &&
 626                     strcmp(file + (len - ftrace_size), ftrace) == 0)
 627                         continue;
 628
 629                 switch (sjval) {
 630                 default:
 631                         fprintf(stderr, "internal error: %s\n", file);
 632                         exit(1);
 633                         break;
 634                 case SJ_SETJMP:    /* normal sequence */
 635                         /* Avoid problems if early cleanup() */
 636                         fd_map = -1;
 637                         mmap_failed = 1;
 638                         file_map = NULL;
 639                         file_ptr = NULL;
 640                         file_updated = 0;
 641                         do_file(file);
 642                         break;
 643                 case SJ_FAIL:    /* error in do_file or below */
 644                         fprintf(stderr, "%s: failed\n", file);
 645                         ++n_error;
 646                         break;
 647                 case SJ_SUCCEED:    /* premature success */
 648                         /* do nothing */
 649                         break;
 650                 }  /* end switch */
 651         }
 652         return !!n_error;
 653 }