scripts/recordmcount.c

   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_MIPS:   /* reltype: e_class    */ break;
 594         case EM_LOONGARCH:      /* reltype: e_class    */ break;
 595         case EM_PPC:    reltype = R_PPC_ADDR32; break;
 596         case EM_PPC64:  reltype = R_PPC64_ADDR64; break;
 597         case EM_S390:   /* reltype: e_class    */ break;
 598         case EM_SH:     reltype = R_SH_DIR32; gpfx = 0; break;
 599         case EM_SPARCV9: reltype = R_SPARC_64; break;
 600         case EM_X86_64:
 601                 make_nop = make_nop_x86;
 602                 ideal_nop = ideal_nop5_x86_64;
 603                 reltype = R_X86_64_64;
 604                 rel_type_nop = R_X86_64_NONE;
 605                 mcount_adjust_64 = -1;
 606                 gpfx = 0;
 607                 break;
 608         }  /* end switch */
 609
 610         switch (ehdr->e_ident[EI_CLASS]) {
 611         default:
 612                 fprintf(stderr, "unrecognized ELF class %d %s\n",
 613                         ehdr->e_ident[EI_CLASS], fname);
 614                 goto out;
 615         case ELFCLASS32:
 616                 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
 617                 ||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
 618                         fprintf(stderr,
 619                                 "unrecognized ET_REL file: %s\n", fname);
 620                         goto out;
 621                 }
 622                 if (w2(ehdr->e_machine) == EM_MIPS) {
 623                         reltype = R_MIPS_32;
 624                         is_fake_mcount32 = MIPS32_is_fake_mcount;
 625                 }
 626                 if (w2(ehdr->e_machine) == EM_LOONGARCH) {
 627                         reltype = R_LARCH_32;
 628                         is_fake_mcount32 = LARCH32_is_fake_mcount;
 629                 }
 630                 if (do32(ehdr, fname, reltype) < 0)
 631                         goto out;
 632                 break;
 633         case ELFCLASS64: {
 634                 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
 635                 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
 636                 ||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
 637                         fprintf(stderr,
 638                                 "unrecognized ET_REL file: %s\n", fname);
 639                         goto out;
 640                 }
 641                 if (w2(ghdr->e_machine) == EM_S390) {
 642                         reltype = R_390_64;
 643                         mcount_adjust_64 = -14;
 644                 }
 645                 if (w2(ghdr->e_machine) == EM_MIPS) {
 646                         reltype = R_MIPS_64;
 647                         Elf64_r_sym = MIPS64_r_sym;
 648                         Elf64_r_info = MIPS64_r_info;
 649                         is_fake_mcount64 = MIPS64_is_fake_mcount;
 650                 }
 651                 if (w2(ghdr->e_machine) == EM_LOONGARCH) {
 652                         reltype = R_LARCH_64;
 653                         is_fake_mcount64 = LARCH64_is_fake_mcount;
 654                 }
 655                 if (do64(ghdr, fname, reltype) < 0)
 656                         goto out;
 657                 break;
 658         }
 659         }  /* end switch */
 660
 661         rc = write_file(fname);
 662 out:
 663         file_append_cleanup();
 664         mmap_cleanup();
 665         return rc;
 666 }
 667
 668 int main(int argc, char *argv[])
 669 {
 670         const char ftrace[] = "/ftrace.o";
 671         int ftrace_size = sizeof(ftrace) - 1;
 672         int n_error = 0;  /* gcc-4.3.0 false positive complaint */
 673         int c;
 674         int i;
 675
 676         while ((c = getopt(argc, argv, "w")) >= 0) {
 677                 switch (c) {
 678                 case 'w':
 679                         warn_on_notrace_sect = 1;
 680                         break;
 681                 default:
 682                         fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 683                         return 0;
 684                 }
 685         }
 686
 687         if ((argc - optind) < 1) {
 688                 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 689                 return 0;
 690         }
 691
 692         /* Process each file in turn, allowing deep failure. */
 693         for (i = optind; i < argc; i++) {
 694                 char *file = argv[i];
 695                 int len;
 696
 697                 /*
 698                  * The file kernel/trace/ftrace.o references the mcount
 699                  * function but does not call it. Since ftrace.o should
 700                  * not be traced anyway, we just skip it.
 701                  */
 702                 len = strlen(file);
 703                 if (len >= ftrace_size &&
 704                     strcmp(file + (len - ftrace_size), ftrace) == 0)
 705                         continue;
 706
 707                 if (do_file(file)) {
 708                         fprintf(stderr, "%s: failed\n", file);
 709                         ++n_error;
 710                 }
 711         }
 712         return !!n_error;
 713 }