1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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
37
38
39
40#ifndef EM_METAG
41#define EM_METAG 174
42#endif
43#ifndef R_METAG_ADDR32
44#define R_METAG_ADDR32 2
45#endif
46#ifndef R_METAG_NONE
47#define R_METAG_NONE 3
48#endif
49
50#ifndef EM_AARCH64
51#define EM_AARCH64 183
52#define R_AARCH64_NONE 0
53#define R_AARCH64_ABS64 257
54#endif
55
56static int fd_map;
57static int mmap_failed;
58static char gpfx;
59static struct stat sb;
60static jmp_buf jmpenv;
61static const char *altmcount;
62static int warn_on_notrace_sect;
63static void *file_map;
64static void *file_end;
65static int file_updated;
66static void *file_ptr;
67static void *file_append;
68static size_t file_append_size;
69
70
71enum {
72 SJ_SETJMP = 0,
73 SJ_FAIL,
74 SJ_SUCCEED
75};
76
77
78static void
79cleanup(void)
80{
81 if (!mmap_failed)
82 munmap(file_map, sb.st_size);
83 else
84 free(file_map);
85 file_map = NULL;
86 free(file_append);
87 file_append = NULL;
88 file_append_size = 0;
89 file_updated = 0;
90}
91
92static void __attribute__((noreturn))
93fail_file(void)
94{
95 cleanup();
96 longjmp(jmpenv, SJ_FAIL);
97}
98
99static void __attribute__((noreturn))
100succeed_file(void)
101{
102 cleanup();
103 longjmp(jmpenv, SJ_SUCCEED);
104}
105
106
107
108static off_t
109ulseek(int const fd, off_t const offset, int const whence)
110{
111 switch (whence) {
112 case SEEK_SET:
113 file_ptr = file_map + offset;
114 break;
115 case SEEK_CUR:
116 file_ptr += offset;
117 break;
118 case SEEK_END:
119 file_ptr = file_map + (sb.st_size - offset);
120 break;
121 }
122 if (file_ptr < file_map) {
123 fprintf(stderr, "lseek: seek before file\n");
124 fail_file();
125 }
126 return file_ptr - file_map;
127}
128
129static size_t
130uread(int const fd, void *const buf, size_t const count)
131{
132 size_t const n = read(fd, buf, count);
133 if (n != count) {
134 perror("read");
135 fail_file();
136 }
137 return n;
138}
139
140static size_t
141uwrite(int const fd, void const *const buf, size_t const count)
142{
143 size_t cnt = count;
144 off_t idx = 0;
145
146 file_updated = 1;
147
148 if (file_ptr + count >= file_end) {
149 off_t aoffset = (file_ptr + count) - file_end;
150
151 if (aoffset > file_append_size) {
152 file_append = realloc(file_append, aoffset);
153 file_append_size = aoffset;
154 }
155 if (!file_append) {
156 perror("write");
157 fail_file();
158 }
159 if (file_ptr < file_end) {
160 cnt = file_end - file_ptr;
161 } else {
162 cnt = 0;
163 idx = aoffset - count;
164 }
165 }
166
167 if (cnt)
168 memcpy(file_ptr, buf, cnt);
169
170 if (cnt < count)
171 memcpy(file_append + idx, buf + cnt, count - cnt);
172
173 file_ptr += count;
174 return count;
175}
176
177static void *
178umalloc(size_t size)
179{
180 void *const addr = malloc(size);
181 if (addr == 0) {
182 fprintf(stderr, "malloc failed: %zu bytes\n", size);
183 fail_file();
184 }
185 return addr;
186}
187
188static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
189static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
190static unsigned char *ideal_nop;
191
192static char rel_type_nop;
193
194static int (*make_nop)(void *map, size_t const offset);
195
196static int make_nop_x86(void *map, size_t const offset)
197{
198 uint32_t *ptr;
199 unsigned char *op;
200
201
202 ptr = map + offset;
203 if (*ptr != 0)
204 return -1;
205
206 op = map + offset - 1;
207 if (*op != 0xe8)
208 return -1;
209
210
211 ulseek(fd_map, offset - 1, SEEK_SET);
212 uwrite(fd_map, ideal_nop, 5);
213 return 0;
214}
215
216static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 };
217static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 };
218static unsigned char *ideal_nop4_arm;
219
220static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb };
221static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe };
222static unsigned char *bl_mcount_arm;
223
224static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 };
225static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 };
226static unsigned char *push_arm;
227
228static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf };
229static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 };
230static unsigned char *ideal_nop2_thumb;
231
232static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff };
233static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe };
234static unsigned char *push_bl_mcount_thumb;
235
236static int make_nop_arm(void *map, size_t const offset)
237{
238 char *ptr;
239 int cnt = 1;
240 int nop_size;
241 size_t off = offset;
242
243 ptr = map + offset;
244 if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
245 if (memcmp(ptr - 4, push_arm, 4) == 0) {
246 off -= 4;
247 cnt = 2;
248 }
249 ideal_nop = ideal_nop4_arm;
250 nop_size = 4;
251 } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
252 cnt = 3;
253 nop_size = 2;
254 off -= 2;
255 ideal_nop = ideal_nop2_thumb;
256 } else
257 return -1;
258
259
260 ulseek(fd_map, off, SEEK_SET);
261
262 do {
263 uwrite(fd_map, ideal_nop, nop_size);
264 } while (--cnt > 0);
265
266 return 0;
267}
268
269static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
270static int make_nop_arm64(void *map, size_t const offset)
271{
272 uint32_t *ptr;
273
274 ptr = map + offset;
275
276 if (*ptr != 0x94000000)
277 return -1;
278
279
280 ulseek(fd_map, offset, SEEK_SET);
281 uwrite(fd_map, ideal_nop, 4);
282 return 0;
283}
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298static void *mmap_file(char const *fname)
299{
300 fd_map = open(fname, O_RDONLY);
301 if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
302 perror(fname);
303 fail_file();
304 }
305 if (!S_ISREG(sb.st_mode)) {
306 fprintf(stderr, "not a regular file: %s\n", fname);
307 fail_file();
308 }
309 file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
310 fd_map, 0);
311 mmap_failed = 0;
312 if (file_map == MAP_FAILED) {
313 mmap_failed = 1;
314 file_map = umalloc(sb.st_size);
315 uread(fd_map, file_map, sb.st_size);
316 }
317 close(fd_map);
318
319 file_end = file_map + sb.st_size;
320
321 return file_map;
322}
323
324static void write_file(const char *fname)
325{
326 char tmp_file[strlen(fname) + 4];
327 size_t n;
328
329 if (!file_updated)
330 return;
331
332 sprintf(tmp_file, "%s.rc", fname);
333
334
335
336
337
338
339 fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
340 if (fd_map < 0) {
341 perror(fname);
342 fail_file();
343 }
344 n = write(fd_map, file_map, sb.st_size);
345 if (n != sb.st_size) {
346 perror("write");
347 fail_file();
348 }
349 if (file_append_size) {
350 n = write(fd_map, file_append, file_append_size);
351 if (n != file_append_size) {
352 perror("write");
353 fail_file();
354 }
355 }
356 close(fd_map);
357 if (rename(tmp_file, fname) < 0) {
358 perror(fname);
359 fail_file();
360 }
361}
362
363
364
365static uint64_t w8rev(uint64_t const x)
366{
367 return ((0xff & (x >> (0 * 8))) << (7 * 8))
368 | ((0xff & (x >> (1 * 8))) << (6 * 8))
369 | ((0xff & (x >> (2 * 8))) << (5 * 8))
370 | ((0xff & (x >> (3 * 8))) << (4 * 8))
371 | ((0xff & (x >> (4 * 8))) << (3 * 8))
372 | ((0xff & (x >> (5 * 8))) << (2 * 8))
373 | ((0xff & (x >> (6 * 8))) << (1 * 8))
374 | ((0xff & (x >> (7 * 8))) << (0 * 8));
375}
376
377static uint32_t w4rev(uint32_t const x)
378{
379 return ((0xff & (x >> (0 * 8))) << (3 * 8))
380 | ((0xff & (x >> (1 * 8))) << (2 * 8))
381 | ((0xff & (x >> (2 * 8))) << (1 * 8))
382 | ((0xff & (x >> (3 * 8))) << (0 * 8));
383}
384
385static uint32_t w2rev(uint16_t const x)
386{
387 return ((0xff & (x >> (0 * 8))) << (1 * 8))
388 | ((0xff & (x >> (1 * 8))) << (0 * 8));
389}
390
391static uint64_t w8nat(uint64_t const x)
392{
393 return x;
394}
395
396static uint32_t w4nat(uint32_t const x)
397{
398 return x;
399}
400
401static uint32_t w2nat(uint16_t const x)
402{
403 return x;
404}
405
406static uint64_t (*w8)(uint64_t);
407static uint32_t (*w)(uint32_t);
408static uint32_t (*w2)(uint16_t);
409
410
411static int
412is_mcounted_section_name(char const *const txtname)
413{
414 return strcmp(".text", txtname) == 0 ||
415 strcmp(".init.text", txtname) == 0 ||
416 strcmp(".ref.text", txtname) == 0 ||
417 strcmp(".sched.text", txtname) == 0 ||
418 strcmp(".spinlock.text", txtname) == 0 ||
419 strcmp(".irqentry.text", txtname) == 0 ||
420 strcmp(".softirqentry.text", txtname) == 0 ||
421 strcmp(".kprobes.text", txtname) == 0 ||
422 strcmp(".cpuidle.text", txtname) == 0 ||
423 strcmp(".text.unlikely", txtname) == 0;
424}
425
426
427#include "recordmcount.h"
428#define RECORD_MCOUNT_64
429#include "recordmcount.h"
430
431
432
433
434
435
436
437
438
439typedef uint8_t myElf64_Byte;
440
441union mips_r_info {
442 Elf64_Xword r_info;
443 struct {
444 Elf64_Word r_sym;
445 myElf64_Byte r_ssym;
446 myElf64_Byte r_type3;
447 myElf64_Byte r_type2;
448 myElf64_Byte r_type;
449 } r_mips;
450};
451
452static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
453{
454 return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
455}
456
457static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
458{
459 rp->r_info = ((union mips_r_info){
460 .r_mips = { .r_sym = w(sym), .r_type = type }
461 }).r_info;
462}
463
464static void
465do_file(char const *const fname)
466{
467 Elf32_Ehdr *const ehdr = mmap_file(fname);
468 unsigned int reltype = 0;
469
470 w = w4nat;
471 w2 = w2nat;
472 w8 = w8nat;
473 switch (ehdr->e_ident[EI_DATA]) {
474 static unsigned int const endian = 1;
475 default:
476 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
477 ehdr->e_ident[EI_DATA], fname);
478 fail_file();
479 break;
480 case ELFDATA2LSB:
481 if (*(unsigned char const *)&endian != 1) {
482
483 w = w4rev;
484 w2 = w2rev;
485 w8 = w8rev;
486 }
487 ideal_nop4_arm = ideal_nop4_arm_le;
488 bl_mcount_arm = bl_mcount_arm_le;
489 push_arm = push_arm_le;
490 ideal_nop2_thumb = ideal_nop2_thumb_le;
491 push_bl_mcount_thumb = push_bl_mcount_thumb_le;
492 break;
493 case ELFDATA2MSB:
494 if (*(unsigned char const *)&endian != 0) {
495
496 w = w4rev;
497 w2 = w2rev;
498 w8 = w8rev;
499 }
500 ideal_nop4_arm = ideal_nop4_arm_be;
501 bl_mcount_arm = bl_mcount_arm_be;
502 push_arm = push_arm_be;
503 ideal_nop2_thumb = ideal_nop2_thumb_be;
504 push_bl_mcount_thumb = push_bl_mcount_thumb_be;
505 break;
506 }
507 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
508 || w2(ehdr->e_type) != ET_REL
509 || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
510 fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
511 fail_file();
512 }
513
514 gpfx = 0;
515 switch (w2(ehdr->e_machine)) {
516 default:
517 fprintf(stderr, "unrecognized e_machine %d %s\n",
518 w2(ehdr->e_machine), fname);
519 fail_file();
520 break;
521 case EM_386:
522 reltype = R_386_32;
523 rel_type_nop = R_386_NONE;
524 make_nop = make_nop_x86;
525 ideal_nop = ideal_nop5_x86_32;
526 mcount_adjust_32 = -1;
527 break;
528 case EM_ARM: reltype = R_ARM_ABS32;
529 altmcount = "__gnu_mcount_nc";
530 make_nop = make_nop_arm;
531 rel_type_nop = R_ARM_NONE;
532 break;
533 case EM_AARCH64:
534 reltype = R_AARCH64_ABS64;
535 make_nop = make_nop_arm64;
536 rel_type_nop = R_AARCH64_NONE;
537 ideal_nop = ideal_nop4_arm64;
538 gpfx = '_';
539 break;
540 case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
541 case EM_METAG: reltype = R_METAG_ADDR32;
542 altmcount = "_mcount_wrapper";
543 rel_type_nop = R_METAG_NONE;
544
545 is_fake_mcount32 = MIPS32_is_fake_mcount;
546 break;
547 case EM_MIPS: gpfx = '_'; break;
548 case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
549 case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
550 case EM_S390: gpfx = '_'; break;
551 case EM_SH: reltype = R_SH_DIR32; break;
552 case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break;
553 case EM_X86_64:
554 make_nop = make_nop_x86;
555 ideal_nop = ideal_nop5_x86_64;
556 reltype = R_X86_64_64;
557 rel_type_nop = R_X86_64_NONE;
558 mcount_adjust_64 = -1;
559 break;
560 }
561
562 switch (ehdr->e_ident[EI_CLASS]) {
563 default:
564 fprintf(stderr, "unrecognized ELF class %d %s\n",
565 ehdr->e_ident[EI_CLASS], fname);
566 fail_file();
567 break;
568 case ELFCLASS32:
569 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
570 || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
571 fprintf(stderr,
572 "unrecognized ET_REL file: %s\n", fname);
573 fail_file();
574 }
575 if (w2(ehdr->e_machine) == EM_MIPS) {
576 reltype = R_MIPS_32;
577 is_fake_mcount32 = MIPS32_is_fake_mcount;
578 }
579 do32(ehdr, fname, reltype);
580 break;
581 case ELFCLASS64: {
582 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
583 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
584 || w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
585 fprintf(stderr,
586 "unrecognized ET_REL file: %s\n", fname);
587 fail_file();
588 }
589 if (w2(ghdr->e_machine) == EM_S390) {
590 reltype = R_390_64;
591 mcount_adjust_64 = -14;
592 }
593 if (w2(ghdr->e_machine) == EM_MIPS) {
594 reltype = R_MIPS_64;
595 Elf64_r_sym = MIPS64_r_sym;
596 Elf64_r_info = MIPS64_r_info;
597 is_fake_mcount64 = MIPS64_is_fake_mcount;
598 }
599 do64(ghdr, fname, reltype);
600 break;
601 }
602 }
603
604 write_file(fname);
605 cleanup();
606}
607
608int
609main(int argc, char *argv[])
610{
611 const char ftrace[] = "/ftrace.o";
612 int ftrace_size = sizeof(ftrace) - 1;
613 int n_error = 0;
614 int c;
615 int i;
616
617 while ((c = getopt(argc, argv, "w")) >= 0) {
618 switch (c) {
619 case 'w':
620 warn_on_notrace_sect = 1;
621 break;
622 default:
623 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
624 return 0;
625 }
626 }
627
628 if ((argc - optind) < 1) {
629 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
630 return 0;
631 }
632
633
634 for (i = optind; i < argc; i++) {
635 char *file = argv[i];
636 int const sjval = setjmp(jmpenv);
637 int len;
638
639
640
641
642
643
644 len = strlen(file);
645 if (len >= ftrace_size &&
646 strcmp(file + (len - ftrace_size), ftrace) == 0)
647 continue;
648
649 switch (sjval) {
650 default:
651 fprintf(stderr, "internal error: %s\n", file);
652 exit(1);
653 break;
654 case SJ_SETJMP:
655
656 fd_map = -1;
657 mmap_failed = 1;
658 file_map = NULL;
659 file_ptr = NULL;
660 file_updated = 0;
661 do_file(file);
662 break;
663 case SJ_FAIL:
664 fprintf(stderr, "%s: failed\n", file);
665 ++n_error;
666 break;
667 case SJ_SUCCEED:
668
669 break;
670 }
671 }
672 return !!n_error;
673}
674