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 #define R_ARM_PC24              1
  43 #define R_ARM_THM_CALL          10
  44 #define R_ARM_CALL              28
  45
  46 static int fd_map;      /* File descriptor for file being modified. */
  47 static int mmap_failed; /* Boolean flag. */
  48 static char gpfx;       /* prefix for global symbol name (sometimes '_') */
  49 static struct stat sb;  /* Remember .st_size, etc. */
  50 static jmp_buf jmpenv;  /* setjmp/longjmp per-file error escape */
  51 static const char *altmcount;   /* alternate mcount symbol name */
  52 static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
  53 static void *file_map;  /* pointer of the mapped file */
  54 static void *file_end;  /* pointer to the end of the mapped file */
  55 static int file_updated; /* flag to state file was changed */
  56 static void *file_ptr;  /* current file pointer location */
  57 static void *file_append; /* added to the end of the file */
  58 static size_t file_append_size; /* how much is added to end of file */
  59
  60 /* setjmp() return values */
  61 enum {
  62         SJ_SETJMP = 0,  /* hardwired first return */
  63         SJ_FAIL,
  64         SJ_SUCCEED
  65 };
  66
  67 /* Per-file resource cleanup when multiple files. */
  68 static void
  69 cleanup(void)
  70 {
  71         if (!mmap_failed)
  72                 munmap(file_map, sb.st_size);
  73         else
  74                 free(file_map);
  75         file_map = NULL;
  76         free(file_append);
  77         file_append = NULL;
  78         file_append_size = 0;
  79         file_updated = 0;
  80 }
  81
  82 static void __attribute__((noreturn))
  83 fail_file(void)
  84 {
  85         cleanup();
  86         longjmp(jmpenv, SJ_FAIL);
  87 }
  88
  89 static void __attribute__((noreturn))
  90 succeed_file(void)
  91 {
  92         cleanup();
  93         longjmp(jmpenv, SJ_SUCCEED);
  94 }
  95
  96 /* ulseek, uread, ...:  Check return value for errors. */
  97
  98 static off_t
  99 ulseek(int const fd, off_t const offset, int const whence)
 100 {
 101         switch (whence) {
 102         case SEEK_SET:
 103                 file_ptr = file_map + offset;
 104                 break;
 105         case SEEK_CUR:
 106                 file_ptr += offset;
 107                 break;
 108         case SEEK_END:
 109                 file_ptr = file_map + (sb.st_size - offset);
 110                 break;
 111         }
 112         if (file_ptr < file_map) {
 113                 fprintf(stderr, "lseek: seek before file\n");
 114                 fail_file();
 115         }
 116         return file_ptr - file_map;
 117 }
 118
 119 static size_t
 120 uread(int const fd, void *const buf, size_t const count)
 121 {
 122         size_t const n = read(fd, buf, count);
 123         if (n != count) {
 124                 perror("read");
 125                 fail_file();
 126         }
 127         return n;
 128 }
 129
 130 static size_t
 131 uwrite(int const fd, void const *const buf, size_t const count)
 132 {
 133         size_t cnt = count;
 134         off_t idx = 0;
 135
 136         file_updated = 1;
 137
 138         if (file_ptr + count >= file_end) {
 139                 off_t aoffset = (file_ptr + count) - file_end;
 140
 141                 if (aoffset > file_append_size) {
 142                         file_append = realloc(file_append, aoffset);
 143                         file_append_size = aoffset;
 144                 }
 145                 if (!file_append) {
 146                         perror("write");
 147                         fail_file();
 148                 }
 149                 if (file_ptr < file_end) {
 150                         cnt = file_end - file_ptr;
 151                 } else {
 152                         cnt = 0;
 153                         idx = aoffset - count;
 154                 }
 155         }
 156
 157         if (cnt)
 158                 memcpy(file_ptr, buf, cnt);
 159
 160         if (cnt < count)
 161                 memcpy(file_append + idx, buf + cnt, count - cnt);
 162
 163         file_ptr += count;
 164         return count;
 165 }
 166
 167 static void *
 168 umalloc(size_t size)
 169 {
 170         void *const addr = malloc(size);
 171         if (addr == 0) {
 172                 fprintf(stderr, "malloc failed: %zu bytes\n", size);
 173                 fail_file();
 174         }
 175         return addr;
 176 }
 177
 178 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
 179 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
 180 static unsigned char *ideal_nop;
 181
 182 static char rel_type_nop;
 183
 184 static int (*make_nop)(void *map, size_t const offset);
 185
 186 static int make_nop_x86(void *map, size_t const offset)
 187 {
 188         uint32_t *ptr;
 189         unsigned char *op;
 190
 191         /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
 192         ptr = map + offset;
 193         if (*ptr != 0)
 194                 return -1;
 195
 196         op = map + offset - 1;
 197         if (*op != 0xe8)
 198                 return -1;
 199
 200         /* convert to nop */
 201         ulseek(fd_map, offset - 1, SEEK_SET);
 202         uwrite(fd_map, ideal_nop, 5);
 203         return 0;
 204 }
 205
 206 static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */
 207 static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */
 208 static unsigned char *ideal_nop4_arm;
 209
 210 static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */
 211 static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */
 212 static unsigned char *bl_mcount_arm;
 213
 214 static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */
 215 static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */
 216 static unsigned char *push_arm;
 217
 218 static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */
 219 static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */
 220 static unsigned char *ideal_nop2_thumb;
 221
 222 static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */
 223 static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */
 224 static unsigned char *push_bl_mcount_thumb;
 225
 226 static int make_nop_arm(void *map, size_t const offset)
 227 {
 228         char *ptr;
 229         int cnt = 1;
 230         int nop_size;
 231         size_t off = offset;
 232
 233         ptr = map + offset;
 234         if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
 235                 if (memcmp(ptr - 4, push_arm, 4) == 0) {
 236                         off -= 4;
 237                         cnt = 2;
 238                 }
 239                 ideal_nop = ideal_nop4_arm;
 240                 nop_size = 4;
 241         } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
 242                 cnt = 3;
 243                 nop_size = 2;
 244                 off -= 2;
 245                 ideal_nop = ideal_nop2_thumb;
 246         } else
 247                 return -1;
 248
 249         /* Convert to nop */
 250         ulseek(fd_map, off, SEEK_SET);
 251
 252         do {
 253                 uwrite(fd_map, ideal_nop, nop_size);
 254         } while (--cnt > 0);
 255
 256         return 0;
 257 }
 258
 259 static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
 260 static int make_nop_arm64(void *map, size_t const offset)
 261 {
 262         uint32_t *ptr;
 263
 264         ptr = map + offset;
 265         /* bl <_mcount> is 0x94000000 before relocation */
 266         if (*ptr != 0x94000000)
 267                 return -1;
 268
 269         /* Convert to nop */
 270         ulseek(fd_map, offset, SEEK_SET);
 271         uwrite(fd_map, ideal_nop, 4);
 272         return 0;
 273 }
 274
 275 /*
 276  * Get the whole file as a programming convenience in order to avoid
 277  * malloc+lseek+read+free of many pieces.  If successful, then mmap
 278  * avoids copying unused pieces; else just read the whole file.
 279  * Open for both read and write; new info will be appended to the file.
 280  * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
 281  * do not propagate to the file until an explicit overwrite at the last.
 282  * This preserves most aspects of consistency (all except .st_size)
 283  * for simultaneous readers of the file while we are appending to it.
 284  * However, multiple writers still are bad.  We choose not to use
 285  * locking because it is expensive and the use case of kernel build
 286  * makes multiple writers unlikely.
 287  */
 288 static void *mmap_file(char const *fname)
 289 {
 290         fd_map = open(fname, O_RDONLY);
 291         if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
 292                 perror(fname);
 293                 fail_file();
 294         }
 295         if (!S_ISREG(sb.st_mode)) {
 296                 fprintf(stderr, "not a regular file: %s\n", fname);
 297                 fail_file();
 298         }
 299         file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
 300                         fd_map, 0);
 301         mmap_failed = 0;
 302         if (file_map == MAP_FAILED) {
 303                 mmap_failed = 1;
 304                 file_map = umalloc(sb.st_size);
 305                 uread(fd_map, file_map, sb.st_size);
 306         }
 307         close(fd_map);
 308
 309         file_end = file_map + sb.st_size;
 310
 311         return file_map;
 312 }
 313
 314 static void write_file(const char *fname)
 315 {
 316         char tmp_file[strlen(fname) + 4];
 317         size_t n;
 318
 319         if (!file_updated)
 320                 return;
 321
 322         sprintf(tmp_file, "%s.rc", fname);
 323
 324         /*
 325          * After reading the entire file into memory, delete it
 326          * and write it back, to prevent weird side effects of modifying
 327          * an object file in place.
 328          */
 329         fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
 330         if (fd_map < 0) {
 331                 perror(fname);
 332                 fail_file();
 333         }
 334         n = write(fd_map, file_map, sb.st_size);
 335         if (n != sb.st_size) {
 336                 perror("write");
 337                 fail_file();
 338         }
 339         if (file_append_size) {
 340                 n = write(fd_map, file_append, file_append_size);
 341                 if (n != file_append_size) {
 342                         perror("write");
 343                         fail_file();
 344                 }
 345         }
 346         close(fd_map);
 347         if (rename(tmp_file, fname) < 0) {
 348                 perror(fname);
 349                 fail_file();
 350         }
 351 }
 352
 353 /* w8rev, w8nat, ...: Handle endianness. */
 354
 355 static uint64_t w8rev(uint64_t const x)
 356 {
 357         return   ((0xff & (x >> (0 * 8))) << (7 * 8))
 358                | ((0xff & (x >> (1 * 8))) << (6 * 8))
 359                | ((0xff & (x >> (2 * 8))) << (5 * 8))
 360                | ((0xff & (x >> (3 * 8))) << (4 * 8))
 361                | ((0xff & (x >> (4 * 8))) << (3 * 8))
 362                | ((0xff & (x >> (5 * 8))) << (2 * 8))
 363                | ((0xff & (x >> (6 * 8))) << (1 * 8))
 364                | ((0xff & (x >> (7 * 8))) << (0 * 8));
 365 }
 366
 367 static uint32_t w4rev(uint32_t const x)
 368 {
 369         return   ((0xff & (x >> (0 * 8))) << (3 * 8))
 370                | ((0xff & (x >> (1 * 8))) << (2 * 8))
 371                | ((0xff & (x >> (2 * 8))) << (1 * 8))
 372                | ((0xff & (x >> (3 * 8))) << (0 * 8));
 373 }
 374
 375 static uint32_t w2rev(uint16_t const x)
 376 {
 377         return   ((0xff & (x >> (0 * 8))) << (1 * 8))
 378                | ((0xff & (x >> (1 * 8))) << (0 * 8));
 379 }
 380
 381 static uint64_t w8nat(uint64_t const x)
 382 {
 383         return x;
 384 }
 385
 386 static uint32_t w4nat(uint32_t const x)
 387 {
 388         return x;
 389 }
 390
 391 static uint32_t w2nat(uint16_t const x)
 392 {
 393         return x;
 394 }
 395
 396 static uint64_t (*w8)(uint64_t);
 397 static uint32_t (*w)(uint32_t);
 398 static uint32_t (*w2)(uint16_t);
 399
 400 /* Names of the sections that could contain calls to mcount. */
 401 static int
 402 is_mcounted_section_name(char const *const txtname)
 403 {
 404         return strcmp(".text",           txtname) == 0 ||
 405                 strcmp(".init.text",     txtname) == 0 ||
 406                 strcmp(".ref.text",      txtname) == 0 ||
 407                 strcmp(".sched.text",    txtname) == 0 ||
 408                 strcmp(".spinlock.text", txtname) == 0 ||
 409                 strcmp(".irqentry.text", txtname) == 0 ||
 410                 strcmp(".softirqentry.text", txtname) == 0 ||
 411                 strcmp(".kprobes.text", txtname) == 0 ||
 412                 strcmp(".cpuidle.text", txtname) == 0 ||
 413                 strcmp(".text.unlikely", txtname) == 0;
 414 }
 415
 416 /* 32 bit and 64 bit are very similar */
 417 #include "recordmcount.h"
 418 #define RECORD_MCOUNT_64
 419 #include "recordmcount.h"
 420
 421 static int arm_is_fake_mcount(Elf32_Rel const *rp)
 422 {
 423         switch (ELF32_R_TYPE(w(rp->r_info))) {
 424         case R_ARM_THM_CALL:
 425         case R_ARM_CALL:
 426         case R_ARM_PC24:
 427                 return 0;
 428         }
 429
 430         return 1;
 431 }
 432
 433 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
 434  * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
 435  * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
 436  * to imply the order of the members; the spec does not say so.
 437  *      typedef unsigned char Elf64_Byte;
 438  * fails on MIPS64 because their <elf.h> already has it!
 439  */
 440
 441 typedef uint8_t myElf64_Byte;           /* Type for a 8-bit quantity.  */
 442
 443 union mips_r_info {
 444         Elf64_Xword r_info;
 445         struct {
 446                 Elf64_Word r_sym;               /* Symbol index.  */
 447                 myElf64_Byte r_ssym;            /* Special symbol.  */
 448                 myElf64_Byte r_type3;           /* Third relocation.  */
 449                 myElf64_Byte r_type2;           /* Second relocation.  */
 450                 myElf64_Byte r_type;            /* First relocation.  */
 451         } r_mips;
 452 };
 453
 454 static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
 455 {
 456         return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
 457 }
 458
 459 static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
 460 {
 461         rp->r_info = ((union mips_r_info){
 462                 .r_mips = { .r_sym = w(sym), .r_type = type }
 463         }).r_info;
 464 }
 465
 466 static void
 467 do_file(char const *const fname)
 468 {
 469         Elf32_Ehdr *const ehdr = mmap_file(fname);
 470         unsigned int reltype = 0;
 471
 472         w = w4nat;
 473         w2 = w2nat;
 474         w8 = w8nat;
 475         switch (ehdr->e_ident[EI_DATA]) {
 476                 static unsigned int const endian = 1;
 477         default:
 478                 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
 479                         ehdr->e_ident[EI_DATA], fname);
 480                 fail_file();
 481                 break;
 482         case ELFDATA2LSB:
 483                 if (*(unsigned char const *)&endian != 1) {
 484                         /* main() is big endian, file.o is little endian. */
 485                         w = w4rev;
 486                         w2 = w2rev;
 487                         w8 = w8rev;
 488                 }
 489                 ideal_nop4_arm = ideal_nop4_arm_le;
 490                 bl_mcount_arm = bl_mcount_arm_le;
 491                 push_arm = push_arm_le;
 492                 ideal_nop2_thumb = ideal_nop2_thumb_le;
 493                 push_bl_mcount_thumb = push_bl_mcount_thumb_le;
 494                 break;
 495         case ELFDATA2MSB:
 496                 if (*(unsigned char const *)&endian != 0) {
 497                         /* main() is little endian, file.o is big endian. */
 498                         w = w4rev;
 499                         w2 = w2rev;
 500                         w8 = w8rev;
 501                 }
 502                 ideal_nop4_arm = ideal_nop4_arm_be;
 503                 bl_mcount_arm = bl_mcount_arm_be;
 504                 push_arm = push_arm_be;
 505                 ideal_nop2_thumb = ideal_nop2_thumb_be;
 506                 push_bl_mcount_thumb = push_bl_mcount_thumb_be;
 507                 break;
 508         }  /* end switch */
 509         if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
 510         ||  w2(ehdr->e_type) != ET_REL
 511         ||  ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
 512                 fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
 513                 fail_file();
 514         }
 515
 516         gpfx = 0;
 517         switch (w2(ehdr->e_machine)) {
 518         default:
 519                 fprintf(stderr, "unrecognized e_machine %u %s\n",
 520                         w2(ehdr->e_machine), fname);
 521                 fail_file();
 522                 break;
 523         case EM_386:
 524                 reltype = R_386_32;
 525                 rel_type_nop = R_386_NONE;
 526                 make_nop = make_nop_x86;
 527                 ideal_nop = ideal_nop5_x86_32;
 528                 mcount_adjust_32 = -1;
 529                 break;
 530         case EM_ARM:     reltype = R_ARM_ABS32;
 531                          altmcount = "__gnu_mcount_nc";
 532                          make_nop = make_nop_arm;
 533                          rel_type_nop = R_ARM_NONE;
 534                          is_fake_mcount32 = arm_is_fake_mcount;
 535                          break;
 536         case EM_AARCH64:
 537                         reltype = R_AARCH64_ABS64;
 538                         make_nop = make_nop_arm64;
 539                         rel_type_nop = R_AARCH64_NONE;
 540                         ideal_nop = ideal_nop4_arm64;
 541                         gpfx = '_';
 542                         break;
 543         case EM_IA_64:   reltype = R_IA64_IMM64;   gpfx = '_'; break;
 544         case EM_MIPS:    /* reltype: e_class    */ gpfx = '_'; break;
 545         case EM_PPC:     reltype = R_PPC_ADDR32;   gpfx = '_'; break;
 546         case EM_PPC64:   reltype = R_PPC64_ADDR64; gpfx = '_'; break;
 547         case EM_S390:    /* reltype: e_class    */ gpfx = '_'; break;
 548         case EM_SH:      reltype = R_SH_DIR32;                 break;
 549         case EM_SPARCV9: reltype = R_SPARC_64;     gpfx = '_'; break;
 550         case EM_X86_64:
 551                 make_nop = make_nop_x86;
 552                 ideal_nop = ideal_nop5_x86_64;
 553                 reltype = R_X86_64_64;
 554                 rel_type_nop = R_X86_64_NONE;
 555                 mcount_adjust_64 = -1;
 556                 break;
 557         }  /* end switch */
 558
 559         switch (ehdr->e_ident[EI_CLASS]) {
 560         default:
 561                 fprintf(stderr, "unrecognized ELF class %d %s\n",
 562                         ehdr->e_ident[EI_CLASS], fname);
 563                 fail_file();
 564                 break;
 565         case ELFCLASS32:
 566                 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
 567                 ||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
 568                         fprintf(stderr,
 569                                 "unrecognized ET_REL file: %s\n", fname);
 570                         fail_file();
 571                 }
 572                 if (w2(ehdr->e_machine) == EM_MIPS) {
 573                         reltype = R_MIPS_32;
 574                         is_fake_mcount32 = MIPS32_is_fake_mcount;
 575                 }
 576                 do32(ehdr, fname, reltype);
 577                 break;
 578         case ELFCLASS64: {
 579                 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
 580                 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
 581                 ||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
 582                         fprintf(stderr,
 583                                 "unrecognized ET_REL file: %s\n", fname);
 584                         fail_file();
 585                 }
 586                 if (w2(ghdr->e_machine) == EM_S390) {
 587                         reltype = R_390_64;
 588                         mcount_adjust_64 = -14;
 589                 }
 590                 if (w2(ghdr->e_machine) == EM_MIPS) {
 591                         reltype = R_MIPS_64;
 592                         Elf64_r_sym = MIPS64_r_sym;
 593                         Elf64_r_info = MIPS64_r_info;
 594                         is_fake_mcount64 = MIPS64_is_fake_mcount;
 595                 }
 596                 do64(ghdr, fname, reltype);
 597                 break;
 598         }
 599         }  /* end switch */
 600
 601         write_file(fname);
 602         cleanup();
 603 }
 604
 605 int
 606 main(int argc, char *argv[])
 607 {
 608         const char ftrace[] = "/ftrace.o";
 609         int ftrace_size = sizeof(ftrace) - 1;
 610         int n_error = 0;  /* gcc-4.3.0 false positive complaint */
 611         int c;
 612         int i;
 613
 614         while ((c = getopt(argc, argv, "w")) >= 0) {
 615                 switch (c) {
 616                 case 'w':
 617                         warn_on_notrace_sect = 1;
 618                         break;
 619                 default:
 620                         fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 621                         return 0;
 622                 }
 623         }
 624
 625         if ((argc - optind) < 1) {
 626                 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 627                 return 0;
 628         }
 629
 630         /* Process each file in turn, allowing deep failure. */
 631         for (i = optind; i < argc; i++) {
 632                 char *file = argv[i];
 633                 int const sjval = setjmp(jmpenv);
 634                 int len;
 635
 636                 /*
 637                  * The file kernel/trace/ftrace.o references the mcount
 638                  * function but does not call it. Since ftrace.o should
 639                  * not be traced anyway, we just skip it.
 640                  */
 641                 len = strlen(file);
 642                 if (len >= ftrace_size &&
 643                     strcmp(file + (len - ftrace_size), ftrace) == 0)
 644                         continue;
 645
 646                 switch (sjval) {
 647                 default:
 648                         fprintf(stderr, "internal error: %s\n", file);
 649                         exit(1);
 650                         break;
 651                 case SJ_SETJMP:    /* normal sequence */
 652                         /* Avoid problems if early cleanup() */
 653                         fd_map = -1;
 654                         mmap_failed = 1;
 655                         file_map = NULL;
 656                         file_ptr = NULL;
 657                         file_updated = 0;
 658                         do_file(file);
 659                         break;
 660                 case SJ_FAIL:    /* error in do_file or below */
 661                         fprintf(stderr, "%s: failed\n", file);
 662                         ++n_error;
 663                         break;
 664                 case SJ_SUCCEED:    /* premature success */
 665                         /* do nothing */
 666                         break;
 667                 }  /* end switch */
 668         }
 669         return !!n_error;
 670 }