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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_METAG
37
38#define EM_METAG 174
39#define R_METAG_ADDR32 2
40#define R_METAG_NONE 3
41#endif
42
43#ifndef EM_AARCH64
44#define EM_AARCH64 183
45#define R_AARCH64_NONE 0
46#define R_AARCH64_ABS64 257
47#endif
48
49static int fd_map;
50static int mmap_failed;
51static char gpfx;
52static struct stat sb;
53static jmp_buf jmpenv;
54static const char *altmcount;
55static int warn_on_notrace_sect;
56static void *file_map;
57static void *file_end;
58static int file_updated;
59static void *file_ptr;
60static void *file_append;
61static size_t file_append_size;
62
63
64enum {
65 SJ_SETJMP = 0,
66 SJ_FAIL,
67 SJ_SUCCEED
68};
69
70
71static void
72cleanup(void)
73{
74 if (!mmap_failed)
75 munmap(file_map, sb.st_size);
76 else
77 free(file_map);
78 file_map = NULL;
79 free(file_append);
80 file_append = NULL;
81 file_append_size = 0;
82 file_updated = 0;
83}
84
85static void __attribute__((noreturn))
86fail_file(void)
87{
88 cleanup();
89 longjmp(jmpenv, SJ_FAIL);
90}
91
92static void __attribute__((noreturn))
93succeed_file(void)
94{
95 cleanup();
96 longjmp(jmpenv, SJ_SUCCEED);
97}
98
99
100
101static off_t
102ulseek(int const fd, off_t const offset, int const whence)
103{
104 switch (whence) {
105 case SEEK_SET:
106 file_ptr = file_map + offset;
107 break;
108 case SEEK_CUR:
109 file_ptr += offset;
110 break;
111 case SEEK_END:
112 file_ptr = file_map + (sb.st_size - offset);
113 break;
114 }
115 if (file_ptr < file_map) {
116 fprintf(stderr, "lseek: seek before file\n");
117 fail_file();
118 }
119 return file_ptr - file_map;
120}
121
122static size_t
123uread(int const fd, void *const buf, size_t const count)
124{
125 size_t const n = read(fd, buf, count);
126 if (n != count) {
127 perror("read");
128 fail_file();
129 }
130 return n;
131}
132
133static size_t
134uwrite(int const fd, void const *const buf, size_t const count)
135{
136 size_t cnt = count;
137 off_t idx = 0;
138
139 file_updated = 1;
140
141 if (file_ptr + count >= file_end) {
142 off_t aoffset = (file_ptr + count) - file_end;
143
144 if (aoffset > file_append_size) {
145 file_append = realloc(file_append, aoffset);
146 file_append_size = aoffset;
147 }
148 if (!file_append) {
149 perror("write");
150 fail_file();
151 }
152 if (file_ptr < file_end) {
153 cnt = file_end - file_ptr;
154 } else {
155 cnt = 0;
156 idx = aoffset - count;
157 }
158 }
159
160 if (cnt)
161 memcpy(file_ptr, buf, cnt);
162
163 if (cnt < count)
164 memcpy(file_append + idx, buf + cnt, count - cnt);
165
166 file_ptr += count;
167 return count;
168}
169
170static void *
171umalloc(size_t size)
172{
173 void *const addr = malloc(size);
174 if (addr == 0) {
175 fprintf(stderr, "malloc failed: %zu bytes\n", size);
176 fail_file();
177 }
178 return addr;
179}
180
181static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
182static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
183static unsigned char *ideal_nop;
184
185static char rel_type_nop;
186
187static int (*make_nop)(void *map, size_t const offset);
188
189static int make_nop_x86(void *map, size_t const offset)
190{
191 uint32_t *ptr;
192 unsigned char *op;
193
194
195 ptr = map + offset;
196 if (*ptr != 0)
197 return -1;
198
199 op = map + offset - 1;
200 if (*op != 0xe8)
201 return -1;
202
203
204 ulseek(fd_map, offset - 1, SEEK_SET);
205 uwrite(fd_map, ideal_nop, 5);
206 return 0;
207}
208
209static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
210static int make_nop_arm64(void *map, size_t const offset)
211{
212 uint32_t *ptr;
213
214 ptr = map + offset;
215
216 if (*ptr != 0x94000000)
217 return -1;
218
219
220 ulseek(fd_map, offset, SEEK_SET);
221 uwrite(fd_map, ideal_nop, 4);
222 return 0;
223}
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238static void *mmap_file(char const *fname)
239{
240 fd_map = open(fname, O_RDONLY);
241 if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
242 perror(fname);
243 fail_file();
244 }
245 if (!S_ISREG(sb.st_mode)) {
246 fprintf(stderr, "not a regular file: %s\n", fname);
247 fail_file();
248 }
249 file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
250 fd_map, 0);
251 mmap_failed = 0;
252 if (file_map == MAP_FAILED) {
253 mmap_failed = 1;
254 file_map = umalloc(sb.st_size);
255 uread(fd_map, file_map, sb.st_size);
256 }
257 close(fd_map);
258
259 file_end = file_map + sb.st_size;
260
261 return file_map;
262}
263
264static void write_file(const char *fname)
265{
266 char tmp_file[strlen(fname) + 4];
267 size_t n;
268
269 if (!file_updated)
270 return;
271
272 sprintf(tmp_file, "%s.rc", fname);
273
274
275
276
277
278
279 fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
280 if (fd_map < 0) {
281 perror(fname);
282 fail_file();
283 }
284 n = write(fd_map, file_map, sb.st_size);
285 if (n != sb.st_size) {
286 perror("write");
287 fail_file();
288 }
289 if (file_append_size) {
290 n = write(fd_map, file_append, file_append_size);
291 if (n != file_append_size) {
292 perror("write");
293 fail_file();
294 }
295 }
296 close(fd_map);
297 if (rename(tmp_file, fname) < 0) {
298 perror(fname);
299 fail_file();
300 }
301}
302
303
304
305static uint64_t w8rev(uint64_t const x)
306{
307 return ((0xff & (x >> (0 * 8))) << (7 * 8))
308 | ((0xff & (x >> (1 * 8))) << (6 * 8))
309 | ((0xff & (x >> (2 * 8))) << (5 * 8))
310 | ((0xff & (x >> (3 * 8))) << (4 * 8))
311 | ((0xff & (x >> (4 * 8))) << (3 * 8))
312 | ((0xff & (x >> (5 * 8))) << (2 * 8))
313 | ((0xff & (x >> (6 * 8))) << (1 * 8))
314 | ((0xff & (x >> (7 * 8))) << (0 * 8));
315}
316
317static uint32_t w4rev(uint32_t const x)
318{
319 return ((0xff & (x >> (0 * 8))) << (3 * 8))
320 | ((0xff & (x >> (1 * 8))) << (2 * 8))
321 | ((0xff & (x >> (2 * 8))) << (1 * 8))
322 | ((0xff & (x >> (3 * 8))) << (0 * 8));
323}
324
325static uint32_t w2rev(uint16_t const x)
326{
327 return ((0xff & (x >> (0 * 8))) << (1 * 8))
328 | ((0xff & (x >> (1 * 8))) << (0 * 8));
329}
330
331static uint64_t w8nat(uint64_t const x)
332{
333 return x;
334}
335
336static uint32_t w4nat(uint32_t const x)
337{
338 return x;
339}
340
341static uint32_t w2nat(uint16_t const x)
342{
343 return x;
344}
345
346static uint64_t (*w8)(uint64_t);
347static uint32_t (*w)(uint32_t);
348static uint32_t (*w2)(uint16_t);
349
350
351static int
352is_mcounted_section_name(char const *const txtname)
353{
354 return strcmp(".text", txtname) == 0 ||
355 strcmp(".ref.text", txtname) == 0 ||
356 strcmp(".sched.text", txtname) == 0 ||
357 strcmp(".spinlock.text", txtname) == 0 ||
358 strcmp(".irqentry.text", txtname) == 0 ||
359 strcmp(".kprobes.text", txtname) == 0 ||
360 strcmp(".text.unlikely", txtname) == 0;
361}
362
363
364#include "recordmcount.h"
365#define RECORD_MCOUNT_64
366#include "recordmcount.h"
367
368
369
370
371
372
373
374
375
376typedef uint8_t myElf64_Byte;
377
378union mips_r_info {
379 Elf64_Xword r_info;
380 struct {
381 Elf64_Word r_sym;
382 myElf64_Byte r_ssym;
383 myElf64_Byte r_type3;
384 myElf64_Byte r_type2;
385 myElf64_Byte r_type;
386 } r_mips;
387};
388
389static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
390{
391 return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
392}
393
394static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
395{
396 rp->r_info = ((union mips_r_info){
397 .r_mips = { .r_sym = w(sym), .r_type = type }
398 }).r_info;
399}
400
401static void
402do_file(char const *const fname)
403{
404 Elf32_Ehdr *const ehdr = mmap_file(fname);
405 unsigned int reltype = 0;
406
407 w = w4nat;
408 w2 = w2nat;
409 w8 = w8nat;
410 switch (ehdr->e_ident[EI_DATA]) {
411 static unsigned int const endian = 1;
412 default:
413 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
414 ehdr->e_ident[EI_DATA], fname);
415 fail_file();
416 break;
417 case ELFDATA2LSB:
418 if (*(unsigned char const *)&endian != 1) {
419
420 w = w4rev;
421 w2 = w2rev;
422 w8 = w8rev;
423 }
424 break;
425 case ELFDATA2MSB:
426 if (*(unsigned char const *)&endian != 0) {
427
428 w = w4rev;
429 w2 = w2rev;
430 w8 = w8rev;
431 }
432 break;
433 }
434 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
435 || w2(ehdr->e_type) != ET_REL
436 || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
437 fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
438 fail_file();
439 }
440
441 gpfx = 0;
442 switch (w2(ehdr->e_machine)) {
443 default:
444 fprintf(stderr, "unrecognized e_machine %d %s\n",
445 w2(ehdr->e_machine), fname);
446 fail_file();
447 break;
448 case EM_386:
449 reltype = R_386_32;
450 rel_type_nop = R_386_NONE;
451 make_nop = make_nop_x86;
452 ideal_nop = ideal_nop5_x86_32;
453 mcount_adjust_32 = -1;
454 break;
455 case EM_ARM: reltype = R_ARM_ABS32;
456 altmcount = "__gnu_mcount_nc";
457 break;
458 case EM_AARCH64:
459 reltype = R_AARCH64_ABS64;
460 make_nop = make_nop_arm64;
461 rel_type_nop = R_AARCH64_NONE;
462 ideal_nop = ideal_nop4_arm64;
463 gpfx = '_';
464 break;
465 case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
466 case EM_METAG: reltype = R_METAG_ADDR32;
467 altmcount = "_mcount_wrapper";
468 rel_type_nop = R_METAG_NONE;
469
470 is_fake_mcount32 = MIPS32_is_fake_mcount;
471 break;
472 case EM_MIPS: gpfx = '_'; break;
473 case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
474 case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
475 case EM_S390: gpfx = '_'; break;
476 case EM_SH: reltype = R_SH_DIR32; break;
477 case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break;
478 case EM_X86_64:
479 make_nop = make_nop_x86;
480 ideal_nop = ideal_nop5_x86_64;
481 reltype = R_X86_64_64;
482 rel_type_nop = R_X86_64_NONE;
483 mcount_adjust_64 = -1;
484 break;
485 }
486
487 switch (ehdr->e_ident[EI_CLASS]) {
488 default:
489 fprintf(stderr, "unrecognized ELF class %d %s\n",
490 ehdr->e_ident[EI_CLASS], fname);
491 fail_file();
492 break;
493 case ELFCLASS32:
494 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
495 || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
496 fprintf(stderr,
497 "unrecognized ET_REL file: %s\n", fname);
498 fail_file();
499 }
500 if (w2(ehdr->e_machine) == EM_MIPS) {
501 reltype = R_MIPS_32;
502 is_fake_mcount32 = MIPS32_is_fake_mcount;
503 }
504 do32(ehdr, fname, reltype);
505 break;
506 case ELFCLASS64: {
507 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
508 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
509 || w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
510 fprintf(stderr,
511 "unrecognized ET_REL file: %s\n", fname);
512 fail_file();
513 }
514 if (w2(ghdr->e_machine) == EM_S390) {
515 reltype = R_390_64;
516 mcount_adjust_64 = -14;
517 }
518 if (w2(ghdr->e_machine) == EM_MIPS) {
519 reltype = R_MIPS_64;
520 Elf64_r_sym = MIPS64_r_sym;
521 Elf64_r_info = MIPS64_r_info;
522 is_fake_mcount64 = MIPS64_is_fake_mcount;
523 }
524 do64(ghdr, fname, reltype);
525 break;
526 }
527 }
528
529 write_file(fname);
530 cleanup();
531}
532
533int
534main(int argc, char *argv[])
535{
536 const char ftrace[] = "/ftrace.o";
537 int ftrace_size = sizeof(ftrace) - 1;
538 int n_error = 0;
539 int c;
540 int i;
541
542 while ((c = getopt(argc, argv, "w")) >= 0) {
543 switch (c) {
544 case 'w':
545 warn_on_notrace_sect = 1;
546 break;
547 default:
548 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
549 return 0;
550 }
551 }
552
553 if ((argc - optind) < 1) {
554 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
555 return 0;
556 }
557
558
559 for (i = optind; i < argc; i++) {
560 char *file = argv[i];
561 int const sjval = setjmp(jmpenv);
562 int len;
563
564
565
566
567
568
569 len = strlen(file);
570 if (len >= ftrace_size &&
571 strcmp(file + (len - ftrace_size), ftrace) == 0)
572 continue;
573
574 switch (sjval) {
575 default:
576 fprintf(stderr, "internal error: %s\n", file);
577 exit(1);
578 break;
579 case SJ_SETJMP:
580
581 fd_map = -1;
582 mmap_failed = 1;
583 file_map = NULL;
584 file_ptr = NULL;
585 file_updated = 0;
586 do_file(file);
587 break;
588 case SJ_FAIL:
589 fprintf(stderr, "%s: failed\n", file);
590 ++n_error;
591 break;
592 case SJ_SUCCEED:
593
594 break;
595 }
596 }
597 return !!n_error;
598}
599