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 void *p = NULL; 114 115 file_updated = 1; 116 117 if (file_ptr + count >= file_end) { 118 off_t aoffset = (file_ptr + count) - file_end; 119 120 if (aoffset > file_append_size) { 121 p = realloc(file_append, aoffset); 122 if (!p) 123 free(file_append); 124 file_append = p; 125 file_append_size = aoffset; 126 } 127 if (!file_append) { 128 perror("write"); 129 file_append_cleanup(); 130 mmap_cleanup(); 131 return -1; 132 } 133 if (file_ptr < file_end) { 134 cnt = file_end - file_ptr; 135 } else { 136 cnt = 0; 137 idx = aoffset - count; 138 } 139 } 140 141 if (cnt) 142 memcpy(file_ptr, buf, cnt); 143 144 if (cnt < count) 145 memcpy(file_append + idx, buf + cnt, count - cnt); 146 147 file_ptr += count; 148 return count; 149 } 150 151 static void * umalloc(size_t size) 152 { 153 void *const addr = malloc(size); 154 if (addr == 0) { 155 fprintf(stderr, "malloc failed: %zu bytes\n", size); 156 file_append_cleanup(); 157 mmap_cleanup(); 158 return NULL; 159 } 160 return addr; 161 } 162 163 /* 164 * Get the whole file as a programming convenience in order to avoid 165 * malloc+lseek+read+free of many pieces. If successful, then mmap 166 * avoids copying unused pieces; else just read the whole file. 167 * Open for both read and write; new info will be appended to the file. 168 * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr 169 * do not propagate to the file until an explicit overwrite at the last. 170 * This preserves most aspects of consistency (all except .st_size) 171 * for simultaneous readers of the file while we are appending to it. 172 * However, multiple writers still are bad. We choose not to use 173 * locking because it is expensive and the use case of kernel build 174 * makes multiple writers unlikely. 175 */ 176 static void *mmap_file(char const *fname) 177 { 178 /* Avoid problems if early cleanup() */ 179 fd_map = -1; 180 mmap_failed = 1; 181 file_map = NULL; 182 file_ptr = NULL; 183 file_updated = 0; 184 sb.st_size = 0; 185 186 fd_map = open(fname, O_RDONLY); 187 if (fd_map < 0) { 188 perror(fname); 189 return NULL; 190 } 191 if (fstat(fd_map, &sb) < 0) { 192 perror(fname); 193 goto out; 194 } 195 if (!S_ISREG(sb.st_mode)) { 196 fprintf(stderr, "not a regular file: %s\n", fname); 197 goto out; 198 } 199 file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, 200 fd_map, 0); 201 if (file_map == MAP_FAILED) { 202 mmap_failed = 1; 203 file_map = umalloc(sb.st_size); 204 if (!file_map) { 205 perror(fname); 206 goto out; 207 } 208 if (read(fd_map, file_map, sb.st_size) != sb.st_size) { 209 perror(fname); 210 free(file_map); 211 file_map = NULL; 212 goto out; 213 } 214 } else 215 mmap_failed = 0; 216 out: 217 close(fd_map); 218 fd_map = -1; 219 220 file_end = file_map + sb.st_size; 221 222 return file_map; 223 } 224 225 226 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 }; 227 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 }; 228 static unsigned char *ideal_nop; 229 230 static char rel_type_nop; 231 232 static int (*make_nop)(void *map, size_t const offset); 233 234 static int make_nop_x86(void *map, size_t const offset) 235 { 236 uint32_t *ptr; 237 unsigned char *op; 238 239 /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */ 240 ptr = map + offset; 241 if (*ptr != 0) 242 return -1; 243 244 op = map + offset - 1; 245 if (*op != 0xe8) 246 return -1; 247 248 /* convert to nop */ 249 if (ulseek(offset - 1, SEEK_SET) < 0) 250 return -1; 251 if (uwrite(ideal_nop, 5) < 0) 252 return -1; 253 return 0; 254 } 255 256 static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */ 257 static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */ 258 static unsigned char *ideal_nop4_arm; 259 260 static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */ 261 static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */ 262 static unsigned char *bl_mcount_arm; 263 264 static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */ 265 static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */ 266 static unsigned char *push_arm; 267 268 static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */ 269 static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */ 270 static unsigned char *ideal_nop2_thumb; 271 272 static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */ 273 static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */ 274 static unsigned char *push_bl_mcount_thumb; 275 276 static int make_nop_arm(void *map, size_t const offset) 277 { 278 char *ptr; 279 int cnt = 1; 280 int nop_size; 281 size_t off = offset; 282 283 ptr = map + offset; 284 if (memcmp(ptr, bl_mcount_arm, 4) == 0) { 285 if (memcmp(ptr - 4, push_arm, 4) == 0) { 286 off -= 4; 287 cnt = 2; 288 } 289 ideal_nop = ideal_nop4_arm; 290 nop_size = 4; 291 } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) { 292 cnt = 3; 293 nop_size = 2; 294 off -= 2; 295 ideal_nop = ideal_nop2_thumb; 296 } else 297 return -1; 298 299 /* Convert to nop */ 300 if (ulseek(off, SEEK_SET) < 0) 301 return -1; 302 303 do { 304 if (uwrite(ideal_nop, nop_size) < 0) 305 return -1; 306 } while (--cnt > 0); 307 308 return 0; 309 } 310 311 static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5}; 312 static int make_nop_arm64(void *map, size_t const offset) 313 { 314 uint32_t *ptr; 315 316 ptr = map + offset; 317 /* bl <_mcount> is 0x94000000 before relocation */ 318 if (*ptr != 0x94000000) 319 return -1; 320 321 /* Convert to nop */ 322 if (ulseek(offset, SEEK_SET) < 0) 323 return -1; 324 if (uwrite(ideal_nop, 4) < 0) 325 return -1; 326 return 0; 327 } 328 329 static int write_file(const char *fname) 330 { 331 char tmp_file[strlen(fname) + 4]; 332 size_t n; 333 334 if (!file_updated) 335 return 0; 336 337 sprintf(tmp_file, "%s.rc", fname); 338 339 /* 340 * After reading the entire file into memory, delete it 341 * and write it back, to prevent weird side effects of modifying 342 * an object file in place. 343 */ 344 fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode); 345 if (fd_map < 0) { 346 perror(fname); 347 return -1; 348 } 349 n = write(fd_map, file_map, sb.st_size); 350 if (n != sb.st_size) { 351 perror("write"); 352 close(fd_map); 353 return -1; 354 } 355 if (file_append_size) { 356 n = write(fd_map, file_append, file_append_size); 357 if (n != file_append_size) { 358 perror("write"); 359 close(fd_map); 360 return -1; 361 } 362 } 363 close(fd_map); 364 if (rename(tmp_file, fname) < 0) { 365 perror(fname); 366 return -1; 367 } 368 return 0; 369 } 370 371 /* w8rev, w8nat, ...: Handle endianness. */ 372 373 static uint64_t w8rev(uint64_t const x) 374 { 375 return ((0xff & (x >> (0 * 8))) << (7 * 8)) 376 | ((0xff & (x >> (1 * 8))) << (6 * 8)) 377 | ((0xff & (x >> (2 * 8))) << (5 * 8)) 378 | ((0xff & (x >> (3 * 8))) << (4 * 8)) 379 | ((0xff & (x >> (4 * 8))) << (3 * 8)) 380 | ((0xff & (x >> (5 * 8))) << (2 * 8)) 381 | ((0xff & (x >> (6 * 8))) << (1 * 8)) 382 | ((0xff & (x >> (7 * 8))) << (0 * 8)); 383 } 384 385 static uint32_t w4rev(uint32_t const x) 386 { 387 return ((0xff & (x >> (0 * 8))) << (3 * 8)) 388 | ((0xff & (x >> (1 * 8))) << (2 * 8)) 389 | ((0xff & (x >> (2 * 8))) << (1 * 8)) 390 | ((0xff & (x >> (3 * 8))) << (0 * 8)); 391 } 392 393 static uint32_t w2rev(uint16_t const x) 394 { 395 return ((0xff & (x >> (0 * 8))) << (1 * 8)) 396 | ((0xff & (x >> (1 * 8))) << (0 * 8)); 397 } 398 399 static uint64_t w8nat(uint64_t const x) 400 { 401 return x; 402 } 403 404 static uint32_t w4nat(uint32_t const x) 405 { 406 return x; 407 } 408 409 static uint32_t w2nat(uint16_t const x) 410 { 411 return x; 412 } 413 414 static uint64_t (*w8)(uint64_t); 415 static uint32_t (*w)(uint32_t); 416 static uint32_t (*w2)(uint16_t); 417 418 /* Names of the sections that could contain calls to mcount. */ 419 static int is_mcounted_section_name(char const *const txtname) 420 { 421 return strncmp(".text", txtname, 5) == 0 || 422 strcmp(".init.text", txtname) == 0 || 423 strcmp(".ref.text", txtname) == 0 || 424 strcmp(".sched.text", txtname) == 0 || 425 strcmp(".spinlock.text", txtname) == 0 || 426 strcmp(".irqentry.text", txtname) == 0 || 427 strcmp(".softirqentry.text", txtname) == 0 || 428 strcmp(".kprobes.text", txtname) == 0 || 429 strcmp(".cpuidle.text", txtname) == 0; 430 } 431 432 static char const *already_has_rel_mcount = "success"; /* our work here is done! */ 433 434 /* 32 bit and 64 bit are very similar */ 435 #include "recordmcount.h" 436 #define RECORD_MCOUNT_64 437 #include "recordmcount.h" 438 439 static int arm_is_fake_mcount(Elf32_Rel const *rp) 440 { 441 switch (ELF32_R_TYPE(w(rp->r_info))) { 442 case R_ARM_THM_CALL: 443 case R_ARM_CALL: 444 case R_ARM_PC24: 445 return 0; 446 } 447 448 return 1; 449 } 450 451 static int arm64_is_fake_mcount(Elf64_Rel const *rp) 452 { 453 return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26; 454 } 455 456 static int LARCH32_is_fake_mcount(Elf32_Rel const *rp) 457 { 458 switch (ELF64_R_TYPE(w(rp->r_info))) { 459 case R_LARCH_MARK_LA: 460 case R_LARCH_SOP_PUSH_PLT_PCREL: 461 return 0; 462 } 463 464 return 1; 465 } 466 467 static int LARCH64_is_fake_mcount(Elf64_Rel const *rp) 468 { 469 switch (ELF64_R_TYPE(w(rp->r_info))) { 470 case R_LARCH_MARK_LA: 471 case R_LARCH_SOP_PUSH_PLT_PCREL: 472 return 0; 473 } 474 475 return 1; 476 } 477 478 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info. 479 * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf 480 * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40] 481 * to imply the order of the members; the spec does not say so. 482 * typedef unsigned char Elf64_Byte; 483 * fails on MIPS64 because their <elf.h> already has it! 484 */ 485 486 typedef uint8_t myElf64_Byte; /* Type for a 8-bit quantity. */ 487 488 union mips_r_info { 489 Elf64_Xword r_info; 490 struct { 491 Elf64_Word r_sym; /* Symbol index. */ 492 myElf64_Byte r_ssym; /* Special symbol. */ 493 myElf64_Byte r_type3; /* Third relocation. */ 494 myElf64_Byte r_type2; /* Second relocation. */ 495 myElf64_Byte r_type; /* First relocation. */ 496 } r_mips; 497 }; 498 499 static uint64_t MIPS64_r_sym(Elf64_Rel const *rp) 500 { 501 return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym); 502 } 503 504 static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type) 505 { 506 rp->r_info = ((union mips_r_info){ 507 .r_mips = { .r_sym = w(sym), .r_type = type } 508 }).r_info; 509 } 510 511 static int do_file(char const *const fname) 512 { 513 unsigned int reltype = 0; 514 Elf32_Ehdr *ehdr; 515 int rc = -1; 516 517 ehdr = mmap_file(fname); 518 if (!ehdr) 519 goto out; 520 521 w = w4nat; 522 w2 = w2nat; 523 w8 = w8nat; 524 switch (ehdr->e_ident[EI_DATA]) { 525 static unsigned int const endian = 1; 526 default: 527 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", 528 ehdr->e_ident[EI_DATA], fname); 529 goto out; 530 case ELFDATA2LSB: 531 if (*(unsigned char const *)&endian != 1) { 532 /* main() is big endian, file.o is little endian. */ 533 w = w4rev; 534 w2 = w2rev; 535 w8 = w8rev; 536 } 537 ideal_nop4_arm = ideal_nop4_arm_le; 538 bl_mcount_arm = bl_mcount_arm_le; 539 push_arm = push_arm_le; 540 ideal_nop2_thumb = ideal_nop2_thumb_le; 541 push_bl_mcount_thumb = push_bl_mcount_thumb_le; 542 break; 543 case ELFDATA2MSB: 544 if (*(unsigned char const *)&endian != 0) { 545 /* main() is little endian, file.o is big endian. */ 546 w = w4rev; 547 w2 = w2rev; 548 w8 = w8rev; 549 } 550 ideal_nop4_arm = ideal_nop4_arm_be; 551 bl_mcount_arm = bl_mcount_arm_be; 552 push_arm = push_arm_be; 553 ideal_nop2_thumb = ideal_nop2_thumb_be; 554 push_bl_mcount_thumb = push_bl_mcount_thumb_be; 555 break; 556 } /* end switch */ 557 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 || 558 w2(ehdr->e_type) != ET_REL || 559 ehdr->e_ident[EI_VERSION] != EV_CURRENT) { 560 fprintf(stderr, "unrecognized ET_REL file %s\n", fname); 561 goto out; 562 } 563 564 gpfx = '_'; 565 switch (w2(ehdr->e_machine)) { 566 default: 567 fprintf(stderr, "unrecognized e_machine %u %s\n", 568 w2(ehdr->e_machine), fname); 569 goto out; 570 case EM_386: 571 reltype = R_386_32; 572 rel_type_nop = R_386_NONE; 573 make_nop = make_nop_x86; 574 ideal_nop = ideal_nop5_x86_32; 575 mcount_adjust_32 = -1; 576 gpfx = 0; 577 break; 578 case EM_ARM: 579 reltype = R_ARM_ABS32; 580 altmcount = "__gnu_mcount_nc"; 581 make_nop = make_nop_arm; 582 rel_type_nop = R_ARM_NONE; 583 is_fake_mcount32 = arm_is_fake_mcount; 584 gpfx = 0; 585 break; 586 case EM_AARCH64: 587 reltype = R_AARCH64_ABS64; 588 make_nop = make_nop_arm64; 589 rel_type_nop = R_AARCH64_NONE; 590 ideal_nop = ideal_nop4_arm64; 591 is_fake_mcount64 = arm64_is_fake_mcount; 592 break; 593 case EM_IA_64: reltype = R_IA64_IMM64; break; 594 case EM_MIPS: /* reltype: e_class */ break; 595 case EM_LOONGARCH: /* reltype: e_class */ break; 596 case EM_PPC: reltype = R_PPC_ADDR32; break; 597 case EM_PPC64: reltype = R_PPC64_ADDR64; break; 598 case EM_S390: /* reltype: e_class */ break; 599 case EM_SH: reltype = R_SH_DIR32; gpfx = 0; break; 600 case EM_SPARCV9: reltype = R_SPARC_64; break; 601 case EM_X86_64: 602 make_nop = make_nop_x86; 603 ideal_nop = ideal_nop5_x86_64; 604 reltype = R_X86_64_64; 605 rel_type_nop = R_X86_64_NONE; 606 mcount_adjust_64 = -1; 607 gpfx = 0; 608 break; 609 } /* end switch */ 610 611 switch (ehdr->e_ident[EI_CLASS]) { 612 default: 613 fprintf(stderr, "unrecognized ELF class %d %s\n", 614 ehdr->e_ident[EI_CLASS], fname); 615 goto out; 616 case ELFCLASS32: 617 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr) 618 || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { 619 fprintf(stderr, 620 "unrecognized ET_REL file: %s\n", fname); 621 goto out; 622 } 623 if (w2(ehdr->e_machine) == EM_MIPS) { 624 reltype = R_MIPS_32; 625 is_fake_mcount32 = MIPS32_is_fake_mcount; 626 } 627 if (w2(ehdr->e_machine) == EM_LOONGARCH) { 628 reltype = R_LARCH_32; 629 is_fake_mcount32 = LARCH32_is_fake_mcount; 630 } 631 if (do32(ehdr, fname, reltype) < 0) 632 goto out; 633 break; 634 case ELFCLASS64: { 635 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; 636 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr) 637 || w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) { 638 fprintf(stderr, 639 "unrecognized ET_REL file: %s\n", fname); 640 goto out; 641 } 642 if (w2(ghdr->e_machine) == EM_S390) { 643 reltype = R_390_64; 644 mcount_adjust_64 = -14; 645 } 646 if (w2(ghdr->e_machine) == EM_MIPS) { 647 reltype = R_MIPS_64; 648 Elf64_r_sym = MIPS64_r_sym; 649 Elf64_r_info = MIPS64_r_info; 650 is_fake_mcount64 = MIPS64_is_fake_mcount; 651 } 652 if (w2(ghdr->e_machine) == EM_LOONGARCH) { 653 reltype = R_LARCH_64; 654 is_fake_mcount64 = LARCH64_is_fake_mcount; 655 } 656 if (do64(ghdr, fname, reltype) < 0) 657 goto out; 658 break; 659 } 660 } /* end switch */ 661 662 rc = write_file(fname); 663 out: 664 file_append_cleanup(); 665 mmap_cleanup(); 666 return rc; 667 } 668 669 int main(int argc, char *argv[]) 670 { 671 const char ftrace[] = "/ftrace.o"; 672 int ftrace_size = sizeof(ftrace) - 1; 673 int n_error = 0; /* gcc-4.3.0 false positive complaint */ 674 int c; 675 int i; 676 677 while ((c = getopt(argc, argv, "w")) >= 0) { 678 switch (c) { 679 case 'w': 680 warn_on_notrace_sect = 1; 681 break; 682 default: 683 fprintf(stderr, "usage: recordmcount [-w] file.o...\n"); 684 return 0; 685 } 686 } 687 688 if ((argc - optind) < 1) { 689 fprintf(stderr, "usage: recordmcount [-w] file.o...\n"); 690 return 0; 691 } 692 693 /* Process each file in turn, allowing deep failure. */ 694 for (i = optind; i < argc; i++) { 695 char *file = argv[i]; 696 int len; 697 698 /* 699 * The file kernel/trace/ftrace.o references the mcount 700 * function but does not call it. Since ftrace.o should 701 * not be traced anyway, we just skip it. 702 */ 703 len = strlen(file); 704 if (len >= ftrace_size && 705 strcmp(file + (len - ftrace_size), ftrace) == 0) 706 continue; 707 708 if (do_file(file)) { 709 fprintf(stderr, "%s: failed\n", file); 710 ++n_error; 711 } 712 } 713 return !!n_error; 714 } 715