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