1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * recordmcount.c: construct a table of the locations of calls to 'mcount' 4 * so that ftrace can find them quickly. 5 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. 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 <stdio.h> 31 #include <stdlib.h> 32 #include <string.h> 33 #include <unistd.h> 34 35 #ifndef EM_AARCH64 36 #define EM_AARCH64 183 37 #define R_AARCH64_NONE 0 38 #define R_AARCH64_ABS64 257 39 #endif 40 41 #ifndef EM_LOONGARCH 42 #define EM_LOONGARCH 258 43 #define R_LARCH_32 1 44 #define R_LARCH_64 2 45 #define R_LARCH_MARK_LA 20 46 #define R_LARCH_SOP_PUSH_PLT_PCREL 29 47 #endif 48 49 #define R_ARM_PC24 1 50 #define R_ARM_THM_CALL 10 51 #define R_ARM_CALL 28 52 53 #define R_AARCH64_CALL26 283 54 55 static int fd_map; /* File descriptor for file being modified. */ 56 static int mmap_failed; /* Boolean flag. */ 57 static char gpfx; /* prefix for global symbol name (sometimes '_') */ 58 static struct stat sb; /* Remember .st_size, etc. */ 59 static const char *altmcount; /* alternate mcount symbol name */ 60 static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */ 61 static void *file_map; /* pointer of the mapped file */ 62 static void *file_end; /* pointer to the end of the mapped file */ 63 static int file_updated; /* flag to state file was changed */ 64 static void *file_ptr; /* current file pointer location */ 65 66 static void *file_append; /* added to the end of the file */ 67 static size_t file_append_size; /* how much is added to end of file */ 68 69 /* Per-file resource cleanup when multiple files. */ 70 static void file_append_cleanup(void) 71 { 72 free(file_append); 73 file_append = NULL; 74 file_append_size = 0; 75 file_updated = 0; 76 } 77 78 static void mmap_cleanup(void) 79 { 80 if (!mmap_failed) 81 munmap(file_map, sb.st_size); 82 else 83 free(file_map); 84 file_map = NULL; 85 } 86 87 /* ulseek, uwrite, ...: Check return value for errors. */ 88 89 static off_t ulseek(off_t const offset, int const whence) 90 { 91 switch (whence) { 92 case SEEK_SET: 93 file_ptr = file_map + offset; 94 break; 95 case SEEK_CUR: 96 file_ptr += offset; 97 break; 98 case SEEK_END: 99 file_ptr = file_map + (sb.st_size - offset); 100 break; 101 } 102 if (file_ptr < file_map) { 103 fprintf(stderr, "lseek: seek before file\n"); 104 return -1; 105 } 106 return file_ptr - file_map; 107 } 108 109 static ssize_t uwrite(void const *const buf, size_t const count) 110 { 111 size_t cnt = count; 112 off_t idx = 0; 113 114 file_updated = 1; 115 116 if (file_ptr + count >= file_end) { 117 off_t aoffset = (file_ptr + count) - file_end; 118 119 if (aoffset > file_append_size) { 120 file_append = realloc(file_append, aoffset); 121 file_append_size = aoffset; 122 } 123 if (!file_append) { 124 perror("write"); 125 file_append_cleanup(); 126 mmap_cleanup(); 127 return -1; 128 } 129 if (file_ptr < file_end) { 130 cnt = file_end - file_ptr; 131 } else { 132 cnt = 0; 133 idx = aoffset - count; 134 } 135 } 136 137 if (cnt) 138 memcpy(file_ptr, buf, cnt); 139 140 if (cnt < count) 141 memcpy(file_append + idx, buf + cnt, count - cnt); 142 143 file_ptr += count; 144 return count; 145 } 146 147 static void * umalloc(size_t size) 148 { 149 void *const addr = malloc(size); 150 if (addr == 0) { 151 fprintf(stderr, "malloc failed: %zu bytes\n", size); 152 file_append_cleanup(); 153 mmap_cleanup(); 154 return NULL; 155 } 156 return addr; 157 } 158 159 /* 160 * Get the whole file as a programming convenience in order to avoid 161 * malloc+lseek+read+free of many pieces. If successful, then mmap 162 * avoids copying unused pieces; else just read the whole file. 163 * Open for both read and write; new info will be appended to the file. 164 * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr 165 * do not propagate to the file until an explicit overwrite at the last. 166 * This preserves most aspects of consistency (all except .st_size) 167 * for simultaneous readers of the file while we are appending to it. 168 * However, multiple writers still are bad. We choose not to use 169 * locking because it is expensive and the use case of kernel build 170 * makes multiple writers unlikely. 171 */ 172 static void *mmap_file(char const *fname) 173 { 174 /* Avoid problems if early cleanup() */ 175 fd_map = -1; 176 mmap_failed = 1; 177 file_map = NULL; 178 file_ptr = NULL; 179 file_updated = 0; 180 sb.st_size = 0; 181 182 fd_map = open(fname, O_RDONLY); 183 if (fd_map < 0) { 184 perror(fname); 185 return NULL; 186 } 187 if (fstat(fd_map, &sb) < 0) { 188 perror(fname); 189 goto out; 190 } 191 if (!S_ISREG(sb.st_mode)) { 192 fprintf(stderr, "not a regular file: %s\n", fname); 193 goto out; 194 } 195 file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, 196 fd_map, 0); 197 if (file_map == MAP_FAILED) { 198 mmap_failed = 1; 199 file_map = umalloc(sb.st_size); 200 if (!file_map) { 201 perror(fname); 202 goto out; 203 } 204 if (read(fd_map, file_map, sb.st_size) != sb.st_size) { 205 perror(fname); 206 free(file_map); 207 file_map = NULL; 208 goto out; 209 } 210 } else 211 mmap_failed = 0; 212 out: 213 close(fd_map); 214 fd_map = -1; 215 216 file_end = file_map + sb.st_size; 217 218 return file_map; 219 } 220 221 222 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 }; 223 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 }; 224 static unsigned char *ideal_nop; 225 226 static char rel_type_nop; 227 228 static int (*make_nop)(void *map, size_t const offset); 229 230 static int make_nop_x86(void *map, size_t const offset) 231 { 232 uint32_t *ptr; 233 unsigned char *op; 234 235 /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */ 236 ptr = map + offset; 237 if (*ptr != 0) 238 return -1; 239 240 op = map + offset - 1; 241 if (*op != 0xe8) 242 return -1; 243 244 /* convert to nop */ 245 if (ulseek(offset - 1, SEEK_SET) < 0) 246 return -1; 247 if (uwrite(ideal_nop, 5) < 0) 248 return -1; 249 return 0; 250 } 251 252 static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */ 253 static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */ 254 static unsigned char *ideal_nop4_arm; 255 256 static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */ 257 static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */ 258 static unsigned char *bl_mcount_arm; 259 260 static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */ 261 static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */ 262 static unsigned char *push_arm; 263 264 static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */ 265 static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */ 266 static unsigned char *ideal_nop2_thumb; 267 268 static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */ 269 static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */ 270 static unsigned char *push_bl_mcount_thumb; 271 272 static int make_nop_arm(void *map, size_t const offset) 273 { 274 char *ptr; 275 int cnt = 1; 276 int nop_size; 277 size_t off = offset; 278 279 ptr = map + offset; 280 if (memcmp(ptr, bl_mcount_arm, 4) == 0) { 281 if (memcmp(ptr - 4, push_arm, 4) == 0) { 282 off -= 4; 283 cnt = 2; 284 } 285 ideal_nop = ideal_nop4_arm; 286 nop_size = 4; 287 } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) { 288 cnt = 3; 289 nop_size = 2; 290 off -= 2; 291 ideal_nop = ideal_nop2_thumb; 292 } else 293 return -1; 294 295 /* Convert to nop */ 296 if (ulseek(off, SEEK_SET) < 0) 297 return -1; 298 299 do { 300 if (uwrite(ideal_nop, nop_size) < 0) 301 return -1; 302 } while (--cnt > 0); 303 304 return 0; 305 } 306 307 static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5}; 308 static int make_nop_arm64(void *map, size_t const offset) 309 { 310 uint32_t *ptr; 311 312 ptr = map + offset; 313 /* bl <_mcount> is 0x94000000 before relocation */ 314 if (*ptr != 0x94000000) 315 return -1; 316 317 /* Convert to nop */ 318 if (ulseek(offset, SEEK_SET) < 0) 319 return -1; 320 if (uwrite(ideal_nop, 4) < 0) 321 return -1; 322 return 0; 323 } 324 325 static int write_file(const char *fname) 326 { 327 char tmp_file[strlen(fname) + 4]; 328 size_t n; 329 330 if (!file_updated) 331 return 0; 332 333 sprintf(tmp_file, "%s.rc", fname); 334 335 /* 336 * After reading the entire file into memory, delete it 337 * and write it back, to prevent weird side effects of modifying 338 * an object file in place. 339 */ 340 fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode); 341 if (fd_map < 0) { 342 perror(fname); 343 return -1; 344 } 345 n = write(fd_map, file_map, sb.st_size); 346 if (n != sb.st_size) { 347 perror("write"); 348 close(fd_map); 349 return -1; 350 } 351 if (file_append_size) { 352 n = write(fd_map, file_append, file_append_size); 353 if (n != file_append_size) { 354 perror("write"); 355 close(fd_map); 356 return -1; 357 } 358 } 359 close(fd_map); 360 if (rename(tmp_file, fname) < 0) { 361 perror(fname); 362 return -1; 363 } 364 return 0; 365 } 366 367 /* w8rev, w8nat, ...: Handle endianness. */ 368 369 static uint64_t w8rev(uint64_t const x) 370 { 371 return ((0xff & (x >> (0 * 8))) << (7 * 8)) 372 | ((0xff & (x >> (1 * 8))) << (6 * 8)) 373 | ((0xff & (x >> (2 * 8))) << (5 * 8)) 374 | ((0xff & (x >> (3 * 8))) << (4 * 8)) 375 | ((0xff & (x >> (4 * 8))) << (3 * 8)) 376 | ((0xff & (x >> (5 * 8))) << (2 * 8)) 377 | ((0xff & (x >> (6 * 8))) << (1 * 8)) 378 | ((0xff & (x >> (7 * 8))) << (0 * 8)); 379 } 380 381 static uint32_t w4rev(uint32_t const x) 382 { 383 return ((0xff & (x >> (0 * 8))) << (3 * 8)) 384 | ((0xff & (x >> (1 * 8))) << (2 * 8)) 385 | ((0xff & (x >> (2 * 8))) << (1 * 8)) 386 | ((0xff & (x >> (3 * 8))) << (0 * 8)); 387 } 388 389 static uint32_t w2rev(uint16_t const x) 390 { 391 return ((0xff & (x >> (0 * 8))) << (1 * 8)) 392 | ((0xff & (x >> (1 * 8))) << (0 * 8)); 393 } 394 395 static uint64_t w8nat(uint64_t const x) 396 { 397 return x; 398 } 399 400 static uint32_t w4nat(uint32_t const x) 401 { 402 return x; 403 } 404 405 static uint32_t w2nat(uint16_t const x) 406 { 407 return x; 408 } 409 410 static uint64_t (*w8)(uint64_t); 411 static uint32_t (*w)(uint32_t); 412 static uint32_t (*w2)(uint16_t); 413 414 /* Names of the sections that could contain calls to mcount. */ 415 static int is_mcounted_section_name(char const *const txtname) 416 { 417 return strncmp(".text", txtname, 5) == 0 || 418 strcmp(".init.text", txtname) == 0 || 419 strcmp(".ref.text", txtname) == 0 || 420 strcmp(".sched.text", txtname) == 0 || 421 strcmp(".spinlock.text", txtname) == 0 || 422 strcmp(".irqentry.text", txtname) == 0 || 423 strcmp(".softirqentry.text", txtname) == 0 || 424 strcmp(".kprobes.text", txtname) == 0 || 425 strcmp(".cpuidle.text", txtname) == 0; 426 } 427 428 static char const *already_has_rel_mcount = "success"; /* our work here is done! */ 429 430 /* 32 bit and 64 bit are very similar */ 431 #include "recordmcount.h" 432 #define RECORD_MCOUNT_64 433 #include "recordmcount.h" 434 435 static int arm_is_fake_mcount(Elf32_Rel const *rp) 436 { 437 switch (ELF32_R_TYPE(w(rp->r_info))) { 438 case R_ARM_THM_CALL: 439 case R_ARM_CALL: 440 case R_ARM_PC24: 441 return 0; 442 } 443 444 return 1; 445 } 446 447 static int arm64_is_fake_mcount(Elf64_Rel const *rp) 448 { 449 return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26; 450 } 451 452 static int LARCH32_is_fake_mcount(Elf32_Rel const *rp) 453 { 454 switch (ELF64_R_TYPE(w(rp->r_info))) { 455 case R_LARCH_MARK_LA: 456 case R_LARCH_SOP_PUSH_PLT_PCREL: 457 return 0; 458 } 459 460 return 1; 461 } 462 463 static int LARCH64_is_fake_mcount(Elf64_Rel const *rp) 464 { 465 switch (ELF64_R_TYPE(w(rp->r_info))) { 466 case R_LARCH_MARK_LA: 467 case R_LARCH_SOP_PUSH_PLT_PCREL: 468 return 0; 469 } 470 471 return 1; 472 } 473 474 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info. 475 * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf 476 * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40] 477 * to imply the order of the members; the spec does not say so. 478 * typedef unsigned char Elf64_Byte; 479 * fails on MIPS64 because their <elf.h> already has it! 480 */ 481 482 typedef uint8_t myElf64_Byte; /* Type for a 8-bit quantity. */ 483 484 union mips_r_info { 485 Elf64_Xword r_info; 486 struct { 487 Elf64_Word r_sym; /* Symbol index. */ 488 myElf64_Byte r_ssym; /* Special symbol. */ 489 myElf64_Byte r_type3; /* Third relocation. */ 490 myElf64_Byte r_type2; /* Second relocation. */ 491 myElf64_Byte r_type; /* First relocation. */ 492 } r_mips; 493 }; 494 495 static uint64_t MIPS64_r_sym(Elf64_Rel const *rp) 496 { 497 return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym); 498 } 499 500 static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type) 501 { 502 rp->r_info = ((union mips_r_info){ 503 .r_mips = { .r_sym = w(sym), .r_type = type } 504 }).r_info; 505 } 506 507 static int do_file(char const *const fname) 508 { 509 unsigned int reltype = 0; 510 Elf32_Ehdr *ehdr; 511 int rc = -1; 512 513 ehdr = mmap_file(fname); 514 if (!ehdr) 515 goto out; 516 517 w = w4nat; 518 w2 = w2nat; 519 w8 = w8nat; 520 switch (ehdr->e_ident[EI_DATA]) { 521 static unsigned int const endian = 1; 522 default: 523 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", 524 ehdr->e_ident[EI_DATA], fname); 525 goto out; 526 case ELFDATA2LSB: 527 if (*(unsigned char const *)&endian != 1) { 528 /* main() is big endian, file.o is little endian. */ 529 w = w4rev; 530 w2 = w2rev; 531 w8 = w8rev; 532 } 533 ideal_nop4_arm = ideal_nop4_arm_le; 534 bl_mcount_arm = bl_mcount_arm_le; 535 push_arm = push_arm_le; 536 ideal_nop2_thumb = ideal_nop2_thumb_le; 537 push_bl_mcount_thumb = push_bl_mcount_thumb_le; 538 break; 539 case ELFDATA2MSB: 540 if (*(unsigned char const *)&endian != 0) { 541 /* main() is little endian, file.o is big endian. */ 542 w = w4rev; 543 w2 = w2rev; 544 w8 = w8rev; 545 } 546 ideal_nop4_arm = ideal_nop4_arm_be; 547 bl_mcount_arm = bl_mcount_arm_be; 548 push_arm = push_arm_be; 549 ideal_nop2_thumb = ideal_nop2_thumb_be; 550 push_bl_mcount_thumb = push_bl_mcount_thumb_be; 551 break; 552 } /* end switch */ 553 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 || 554 w2(ehdr->e_type) != ET_REL || 555 ehdr->e_ident[EI_VERSION] != EV_CURRENT) { 556 fprintf(stderr, "unrecognized ET_REL file %s\n", fname); 557 goto out; 558 } 559 560 gpfx = '_'; 561 switch (w2(ehdr->e_machine)) { 562 default: 563 fprintf(stderr, "unrecognized e_machine %u %s\n", 564 w2(ehdr->e_machine), fname); 565 goto out; 566 case EM_386: 567 reltype = R_386_32; 568 rel_type_nop = R_386_NONE; 569 make_nop = make_nop_x86; 570 ideal_nop = ideal_nop5_x86_32; 571 mcount_adjust_32 = -1; 572 gpfx = 0; 573 break; 574 case EM_ARM: 575 reltype = R_ARM_ABS32; 576 altmcount = "__gnu_mcount_nc"; 577 make_nop = make_nop_arm; 578 rel_type_nop = R_ARM_NONE; 579 is_fake_mcount32 = arm_is_fake_mcount; 580 gpfx = 0; 581 break; 582 case EM_AARCH64: 583 reltype = R_AARCH64_ABS64; 584 make_nop = make_nop_arm64; 585 rel_type_nop = R_AARCH64_NONE; 586 ideal_nop = ideal_nop4_arm64; 587 is_fake_mcount64 = arm64_is_fake_mcount; 588 break; 589 case EM_IA_64: reltype = R_IA64_IMM64; break; 590 case EM_MIPS: /* reltype: e_class */ break; 591 case EM_LOONGARCH: /* reltype: e_class */ break; 592 case EM_PPC: reltype = R_PPC_ADDR32; break; 593 case EM_PPC64: reltype = R_PPC64_ADDR64; break; 594 case EM_S390: /* reltype: e_class */ break; 595 case EM_SH: reltype = R_SH_DIR32; gpfx = 0; break; 596 case EM_SPARCV9: reltype = R_SPARC_64; break; 597 case EM_X86_64: 598 make_nop = make_nop_x86; 599 ideal_nop = ideal_nop5_x86_64; 600 reltype = R_X86_64_64; 601 rel_type_nop = R_X86_64_NONE; 602 mcount_adjust_64 = -1; 603 gpfx = 0; 604 break; 605 } /* end switch */ 606 607 switch (ehdr->e_ident[EI_CLASS]) { 608 default: 609 fprintf(stderr, "unrecognized ELF class %d %s\n", 610 ehdr->e_ident[EI_CLASS], fname); 611 goto out; 612 case ELFCLASS32: 613 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr) 614 || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { 615 fprintf(stderr, 616 "unrecognized ET_REL file: %s\n", fname); 617 goto out; 618 } 619 if (w2(ehdr->e_machine) == EM_MIPS) { 620 reltype = R_MIPS_32; 621 is_fake_mcount32 = MIPS32_is_fake_mcount; 622 } 623 if (w2(ehdr->e_machine) == EM_LOONGARCH) { 624 reltype = R_LARCH_32; 625 is_fake_mcount32 = LARCH32_is_fake_mcount; 626 } 627 if (do32(ehdr, fname, reltype) < 0) 628 goto out; 629 break; 630 case ELFCLASS64: { 631 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; 632 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr) 633 || w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) { 634 fprintf(stderr, 635 "unrecognized ET_REL file: %s\n", fname); 636 goto out; 637 } 638 if (w2(ghdr->e_machine) == EM_S390) { 639 reltype = R_390_64; 640 mcount_adjust_64 = -14; 641 } 642 if (w2(ghdr->e_machine) == EM_MIPS) { 643 reltype = R_MIPS_64; 644 Elf64_r_sym = MIPS64_r_sym; 645 Elf64_r_info = MIPS64_r_info; 646 is_fake_mcount64 = MIPS64_is_fake_mcount; 647 } 648 if (w2(ghdr->e_machine) == EM_LOONGARCH) { 649 reltype = R_LARCH_64; 650 is_fake_mcount64 = LARCH64_is_fake_mcount; 651 } 652 if (do64(ghdr, fname, reltype) < 0) 653 goto out; 654 break; 655 } 656 } /* end switch */ 657 658 rc = write_file(fname); 659 out: 660 file_append_cleanup(); 661 mmap_cleanup(); 662 return rc; 663 } 664 665 int main(int argc, char *argv[]) 666 { 667 const char ftrace[] = "/ftrace.o"; 668 int ftrace_size = sizeof(ftrace) - 1; 669 int n_error = 0; /* gcc-4.3.0 false positive complaint */ 670 int c; 671 int i; 672 673 while ((c = getopt(argc, argv, "w")) >= 0) { 674 switch (c) { 675 case 'w': 676 warn_on_notrace_sect = 1; 677 break; 678 default: 679 fprintf(stderr, "usage: recordmcount [-w] file.o...\n"); 680 return 0; 681 } 682 } 683 684 if ((argc - optind) < 1) { 685 fprintf(stderr, "usage: recordmcount [-w] file.o...\n"); 686 return 0; 687 } 688 689 /* Process each file in turn, allowing deep failure. */ 690 for (i = optind; i < argc; i++) { 691 char *file = argv[i]; 692 int len; 693 694 /* 695 * The file kernel/trace/ftrace.o references the mcount 696 * function but does not call it. Since ftrace.o should 697 * not be traced anyway, we just skip it. 698 */ 699 len = strlen(file); 700 if (len >= ftrace_size && 701 strcmp(file + (len - ftrace_size), ftrace) == 0) 702 continue; 703 704 if (do_file(file)) { 705 fprintf(stderr, "%s: failed\n", file); 706 ++n_error; 707 } 708 } 709 return !!n_error; 710 } 711