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
 55static int fd_map;	/* File descriptor for file being modified. */
 56static int mmap_failed; /* Boolean flag. */
 
 57static char gpfx;	/* prefix for global symbol name (sometimes '_') */
 58static struct stat sb;	/* Remember .st_size, etc. */
 
 59static const char *altmcount;	/* alternate mcount symbol name */
 60static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
 61static void *file_map;	/* pointer of the mapped file */
 62static void *file_end;	/* pointer to the end of the mapped file */
 63static int file_updated; /* flag to state file was changed */
 64static void *file_ptr;	/* current file pointer location */
 65
 66static void *file_append; /* added to the end of the file */
 67static size_t file_append_size; /* how much is added to end of file */
 
 
 
 
 68
 69/* Per-file resource cleanup when multiple files. */
 70static 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
 78static 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
 89static 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
109static ssize_t uwrite(void const *const buf, size_t const count)
 
110{
111	size_t cnt = count;
112	off_t idx = 0;
113
114	file_updated = 1;
115
116	if (file_ptr + count >= file_end) {
117		off_t aoffset = (file_ptr + count) - file_end;
118
119		if (aoffset > file_append_size) {
120			file_append = realloc(file_append, aoffset);
121			file_append_size = aoffset;
122		}
123		if (!file_append) {
124			perror("write");
125			file_append_cleanup();
126			mmap_cleanup();
127			return -1;
128		}
129		if (file_ptr < file_end) {
130			cnt = file_end - file_ptr;
131		} else {
132			cnt = 0;
133			idx = aoffset - count;
134		}
135	}
 
 
136
137	if (cnt)
138		memcpy(file_ptr, buf, cnt);
139
140	if (cnt < count)
141		memcpy(file_append + idx, buf + cnt, count - cnt);
 
 
 
 
 
142
143	file_ptr += count;
144	return count;
 
 
 
 
 
 
 
145}
146
147static void * umalloc(size_t size)
 
148{
149	void *const addr = malloc(size);
150	if (addr == 0) {
151		fprintf(stderr, "malloc failed: %zu bytes\n", size);
152		file_append_cleanup();
153		mmap_cleanup();
154		return NULL;
155	}
156	return addr;
157}
158
159/*
160 * Get the whole file as a programming convenience in order to avoid
161 * malloc+lseek+read+free of many pieces.  If successful, then mmap
162 * avoids copying unused pieces; else just read the whole file.
163 * Open for both read and write; new info will be appended to the file.
164 * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
165 * do not propagate to the file until an explicit overwrite at the last.
166 * This preserves most aspects of consistency (all except .st_size)
167 * for simultaneous readers of the file while we are appending to it.
168 * However, multiple writers still are bad.  We choose not to use
169 * locking because it is expensive and the use case of kernel build
170 * makes multiple writers unlikely.
171 */
172static void *mmap_file(char const *fname)
173{
174	/* Avoid problems if early cleanup() */
175	fd_map = -1;
176	mmap_failed = 1;
177	file_map = NULL;
178	file_ptr = NULL;
179	file_updated = 0;
180	sb.st_size = 0;
181
182	fd_map = open(fname, O_RDONLY);
183	if (fd_map < 0) {
184		perror(fname);
185		return NULL;
186	}
187	if (fstat(fd_map, &sb) < 0) {
188		perror(fname);
189		goto out;
190	}
191	if (!S_ISREG(sb.st_mode)) {
192		fprintf(stderr, "not a regular file: %s\n", fname);
193		goto out;
194	}
195	file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
196			fd_map, 0);
197	if (file_map == MAP_FAILED) {
198		mmap_failed = 1;
199		file_map = umalloc(sb.st_size);
200		if (!file_map) {
201			perror(fname);
202			goto out;
203		}
204		if (read(fd_map, file_map, sb.st_size) != sb.st_size) {
205			perror(fname);
206			free(file_map);
207			file_map = NULL;
208			goto out;
209		}
210	} else
211		mmap_failed = 0;
212out:
213	close(fd_map);
214	fd_map = -1;
215
216	file_end = file_map + sb.st_size;
217
218	return file_map;
219}
220
221
222static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
223static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
224static unsigned char *ideal_nop;
225
226static char rel_type_nop;
227
228static int (*make_nop)(void *map, size_t const offset);
229
230static int make_nop_x86(void *map, size_t const offset)
231{
232	uint32_t *ptr;
233	unsigned char *op;
234
235	/* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
236	ptr = map + offset;
237	if (*ptr != 0)
238		return -1;
239
240	op = map + offset - 1;
241	if (*op != 0xe8)
242		return -1;
243
244	/* convert to nop */
245	if (ulseek(offset - 1, SEEK_SET) < 0)
246		return -1;
247	if (uwrite(ideal_nop, 5) < 0)
248		return -1;
249	return 0;
250}
251
252static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */
253static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */
254static unsigned char *ideal_nop4_arm;
255
256static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */
257static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */
258static unsigned char *bl_mcount_arm;
259
260static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */
261static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */
262static unsigned char *push_arm;
263
264static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */
265static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */
266static unsigned char *ideal_nop2_thumb;
267
268static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */
269static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */
270static unsigned char *push_bl_mcount_thumb;
271
272static int make_nop_arm(void *map, size_t const offset)
273{
274	char *ptr;
275	int cnt = 1;
276	int nop_size;
277	size_t off = offset;
278
279	ptr = map + offset;
280	if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
281		if (memcmp(ptr - 4, push_arm, 4) == 0) {
282			off -= 4;
283			cnt = 2;
284		}
285		ideal_nop = ideal_nop4_arm;
286		nop_size = 4;
287	} else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
288		cnt = 3;
289		nop_size = 2;
290		off -= 2;
291		ideal_nop = ideal_nop2_thumb;
292	} else
293		return -1;
294
295	/* Convert to nop */
296	if (ulseek(off, SEEK_SET) < 0)
297		return -1;
298
299	do {
300		if (uwrite(ideal_nop, nop_size) < 0)
301			return -1;
302	} while (--cnt > 0);
303
304	return 0;
305}
306
307static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
308static int make_nop_arm64(void *map, size_t const offset)
309{
310	uint32_t *ptr;
311
312	ptr = map + offset;
313	/* bl <_mcount> is 0x94000000 before relocation */
314	if (*ptr != 0x94000000)
315		return -1;
316
317	/* Convert to nop */
318	if (ulseek(offset, SEEK_SET) < 0)
319		return -1;
320	if (uwrite(ideal_nop, 4) < 0)
321		return -1;
322	return 0;
323}
324
325static int write_file(const char *fname)
326{
327	char tmp_file[strlen(fname) + 4];
328	size_t n;
329
330	if (!file_updated)
331		return 0;
332
333	sprintf(tmp_file, "%s.rc", fname);
334
335	/*
336	 * After reading the entire file into memory, delete it
337	 * and write it back, to prevent weird side effects of modifying
338	 * an object file in place.
339	 */
340	fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
341	if (fd_map < 0) {
342		perror(fname);
343		return -1;
344	}
345	n = write(fd_map, file_map, sb.st_size);
346	if (n != sb.st_size) {
347		perror("write");
348		close(fd_map);
349		return -1;
350	}
351	if (file_append_size) {
352		n = write(fd_map, file_append, file_append_size);
353		if (n != file_append_size) {
354			perror("write");
355			close(fd_map);
356			return -1;
357		}
358	}
359	close(fd_map);
360	if (rename(tmp_file, fname) < 0) {
361		perror(fname);
362		return -1;
 
 
 
363	}
364	return 0;
365}
366
367/* w8rev, w8nat, ...: Handle endianness. */
368
369static uint64_t w8rev(uint64_t const x)
370{
371	return   ((0xff & (x >> (0 * 8))) << (7 * 8))
372	       | ((0xff & (x >> (1 * 8))) << (6 * 8))
373	       | ((0xff & (x >> (2 * 8))) << (5 * 8))
374	       | ((0xff & (x >> (3 * 8))) << (4 * 8))
375	       | ((0xff & (x >> (4 * 8))) << (3 * 8))
376	       | ((0xff & (x >> (5 * 8))) << (2 * 8))
377	       | ((0xff & (x >> (6 * 8))) << (1 * 8))
378	       | ((0xff & (x >> (7 * 8))) << (0 * 8));
379}
380
381static uint32_t w4rev(uint32_t const x)
382{
383	return   ((0xff & (x >> (0 * 8))) << (3 * 8))
384	       | ((0xff & (x >> (1 * 8))) << (2 * 8))
385	       | ((0xff & (x >> (2 * 8))) << (1 * 8))
386	       | ((0xff & (x >> (3 * 8))) << (0 * 8));
387}
388
389static uint32_t w2rev(uint16_t const x)
390{
391	return   ((0xff & (x >> (0 * 8))) << (1 * 8))
392	       | ((0xff & (x >> (1 * 8))) << (0 * 8));
393}
394
395static uint64_t w8nat(uint64_t const x)
396{
397	return x;
398}
399
400static uint32_t w4nat(uint32_t const x)
401{
402	return x;
403}
404
405static uint32_t w2nat(uint16_t const x)
406{
407	return x;
408}
409
410static uint64_t (*w8)(uint64_t);
411static uint32_t (*w)(uint32_t);
412static uint32_t (*w2)(uint16_t);
413
414/* Names of the sections that could contain calls to mcount. */
415static int is_mcounted_section_name(char const *const txtname)
 
416{
417	return strncmp(".text",          txtname, 5) == 0 ||
418		strcmp(".init.text",     txtname) == 0 ||
419		strcmp(".ref.text",      txtname) == 0 ||
420		strcmp(".sched.text",    txtname) == 0 ||
421		strcmp(".spinlock.text", txtname) == 0 ||
422		strcmp(".irqentry.text", txtname) == 0 ||
423		strcmp(".softirqentry.text", txtname) == 0 ||
424		strcmp(".kprobes.text", txtname) == 0 ||
425		strcmp(".cpuidle.text", txtname) == 0;
426}
427
428static char const *already_has_rel_mcount = "success"; /* our work here is done! */
429
430/* 32 bit and 64 bit are very similar */
431#include "recordmcount.h"
432#define RECORD_MCOUNT_64
433#include "recordmcount.h"
434
435static int arm_is_fake_mcount(Elf32_Rel const *rp)
436{
437	switch (ELF32_R_TYPE(w(rp->r_info))) {
438	case R_ARM_THM_CALL:
439	case R_ARM_CALL:
440	case R_ARM_PC24:
441		return 0;
442	}
443
444	return 1;
445}
446
447static int arm64_is_fake_mcount(Elf64_Rel const *rp)
448{
449	return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26;
450}
451
452static int LARCH32_is_fake_mcount(Elf32_Rel const *rp)
453{
454	switch (ELF64_R_TYPE(w(rp->r_info))) {
455	case R_LARCH_MARK_LA:
456	case R_LARCH_SOP_PUSH_PLT_PCREL:
457		return 0;
458	}
459
460	return 1;
461}
462
463static int LARCH64_is_fake_mcount(Elf64_Rel const *rp)
464{
465	switch (ELF64_R_TYPE(w(rp->r_info))) {
466	case R_LARCH_MARK_LA:
467	case R_LARCH_SOP_PUSH_PLT_PCREL:
468		return 0;
469	}
470
471	return 1;
472}
473
474/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
475 * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
476 * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
477 * to imply the order of the members; the spec does not say so.
478 *	typedef unsigned char Elf64_Byte;
479 * fails on MIPS64 because their <elf.h> already has it!
480 */
481
482typedef uint8_t myElf64_Byte;		/* Type for a 8-bit quantity.  */
483
484union mips_r_info {
485	Elf64_Xword r_info;
486	struct {
487		Elf64_Word r_sym;		/* Symbol index.  */
488		myElf64_Byte r_ssym;		/* Special symbol.  */
489		myElf64_Byte r_type3;		/* Third relocation.  */
490		myElf64_Byte r_type2;		/* Second relocation.  */
491		myElf64_Byte r_type;		/* First relocation.  */
492	} r_mips;
493};
494
495static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
496{
497	return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
498}
499
500static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
501{
502	rp->r_info = ((union mips_r_info){
503		.r_mips = { .r_sym = w(sym), .r_type = type }
504	}).r_info;
505}
506
507static int do_file(char const *const fname)
 
508{
 
509	unsigned int reltype = 0;
510	Elf32_Ehdr *ehdr;
511	int rc = -1;
512
513	ehdr = mmap_file(fname);
514	if (!ehdr)
515		goto out;
516
 
517	w = w4nat;
518	w2 = w2nat;
519	w8 = w8nat;
520	switch (ehdr->e_ident[EI_DATA]) {
521		static unsigned int const endian = 1;
522	default:
523		fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
524			ehdr->e_ident[EI_DATA], fname);
525		goto out;
 
526	case ELFDATA2LSB:
527		if (*(unsigned char const *)&endian != 1) {
528			/* main() is big endian, file.o is little endian. */
529			w = w4rev;
530			w2 = w2rev;
531			w8 = w8rev;
532		}
533		ideal_nop4_arm = ideal_nop4_arm_le;
534		bl_mcount_arm = bl_mcount_arm_le;
535		push_arm = push_arm_le;
536		ideal_nop2_thumb = ideal_nop2_thumb_le;
537		push_bl_mcount_thumb = push_bl_mcount_thumb_le;
538		break;
539	case ELFDATA2MSB:
540		if (*(unsigned char const *)&endian != 0) {
541			/* main() is little endian, file.o is big endian. */
542			w = w4rev;
543			w2 = w2rev;
544			w8 = w8rev;
545		}
546		ideal_nop4_arm = ideal_nop4_arm_be;
547		bl_mcount_arm = bl_mcount_arm_be;
548		push_arm = push_arm_be;
549		ideal_nop2_thumb = ideal_nop2_thumb_be;
550		push_bl_mcount_thumb = push_bl_mcount_thumb_be;
551		break;
552	}  /* end switch */
553	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 ||
554	    w2(ehdr->e_type) != ET_REL ||
555	    ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
556		fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
557		goto out;
558	}
559
560	gpfx = '_';
561	switch (w2(ehdr->e_machine)) {
562	default:
563		fprintf(stderr, "unrecognized e_machine %u %s\n",
564			w2(ehdr->e_machine), fname);
565		goto out;
 
566	case EM_386:
567		reltype = R_386_32;
568		rel_type_nop = R_386_NONE;
569		make_nop = make_nop_x86;
570		ideal_nop = ideal_nop5_x86_32;
571		mcount_adjust_32 = -1;
572		gpfx = 0;
573		break;
574	case EM_ARM:
575		reltype = R_ARM_ABS32;
576		altmcount = "__gnu_mcount_nc";
577		make_nop = make_nop_arm;
578		rel_type_nop = R_ARM_NONE;
579		is_fake_mcount32 = arm_is_fake_mcount;
580		gpfx = 0;
581		break;
582	case EM_AARCH64:
583		reltype = R_AARCH64_ABS64;
584		make_nop = make_nop_arm64;
585		rel_type_nop = R_AARCH64_NONE;
586		ideal_nop = ideal_nop4_arm64;
587		is_fake_mcount64 = arm64_is_fake_mcount;
588		break;
589	case EM_IA_64:	reltype = R_IA64_IMM64; break;
590	case EM_MIPS:	/* reltype: e_class    */ break;
591	case EM_LOONGARCH:	/* reltype: e_class    */ break;
592	case EM_PPC:	reltype = R_PPC_ADDR32; break;
593	case EM_PPC64:	reltype = R_PPC64_ADDR64; break;
594	case EM_S390:	/* reltype: e_class    */ break;
595	case EM_SH:	reltype = R_SH_DIR32; gpfx = 0; break;
596	case EM_SPARCV9: reltype = R_SPARC_64; break;
597	case EM_X86_64:
598		make_nop = make_nop_x86;
599		ideal_nop = ideal_nop5_x86_64;
600		reltype = R_X86_64_64;
601		rel_type_nop = R_X86_64_NONE;
602		mcount_adjust_64 = -1;
603		gpfx = 0;
604		break;
605	}  /* end switch */
606
607	switch (ehdr->e_ident[EI_CLASS]) {
608	default:
609		fprintf(stderr, "unrecognized ELF class %d %s\n",
610			ehdr->e_ident[EI_CLASS], fname);
611		goto out;
 
612	case ELFCLASS32:
613		if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
614		||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
615			fprintf(stderr,
616				"unrecognized ET_REL file: %s\n", fname);
617			goto out;
 
 
 
 
618		}
619		if (w2(ehdr->e_machine) == EM_MIPS) {
620			reltype = R_MIPS_32;
621			is_fake_mcount32 = MIPS32_is_fake_mcount;
622		}
623		if (w2(ehdr->e_machine) == EM_LOONGARCH) {
624			reltype = R_LARCH_32;
625			is_fake_mcount32 = LARCH32_is_fake_mcount;
626		}
627		if (do32(ehdr, fname, reltype) < 0)
628			goto out;
629		break;
630	case ELFCLASS64: {
631		Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
632		if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
633		||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
634			fprintf(stderr,
635				"unrecognized ET_REL file: %s\n", fname);
636			goto out;
637		}
638		if (w2(ghdr->e_machine) == EM_S390) {
639			reltype = R_390_64;
640			mcount_adjust_64 = -14;
641		}
642		if (w2(ghdr->e_machine) == EM_MIPS) {
643			reltype = R_MIPS_64;
644			Elf64_r_sym = MIPS64_r_sym;
645			Elf64_r_info = MIPS64_r_info;
646			is_fake_mcount64 = MIPS64_is_fake_mcount;
647		}
648		if (w2(ghdr->e_machine) == EM_LOONGARCH) {
649			reltype = R_LARCH_64;
650			is_fake_mcount64 = LARCH64_is_fake_mcount;
651		}
652		if (do64(ghdr, fname, reltype) < 0)
653			goto out;
654		break;
655	}
656	}  /* end switch */
657
658	rc = write_file(fname);
659out:
660	file_append_cleanup();
661	mmap_cleanup();
662	return rc;
663}
664
665int main(int argc, char *argv[])
 
666{
667	const char ftrace[] = "/ftrace.o";
668	int ftrace_size = sizeof(ftrace) - 1;
669	int n_error = 0;  /* gcc-4.3.0 false positive complaint */
670	int c;
671	int i;
672
673	while ((c = getopt(argc, argv, "w")) >= 0) {
674		switch (c) {
675		case 'w':
676			warn_on_notrace_sect = 1;
677			break;
678		default:
679			fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
680			return 0;
681		}
682	}
683
684	if ((argc - optind) < 1) {
685		fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
686		return 0;
687	}
688
689	/* Process each file in turn, allowing deep failure. */
690	for (i = optind; i < argc; i++) {
691		char *file = argv[i];
 
692		int len;
693
694		/*
695		 * The file kernel/trace/ftrace.o references the mcount
696		 * function but does not call it. Since ftrace.o should
697		 * not be traced anyway, we just skip it.
698		 */
699		len = strlen(file);
700		if (len >= ftrace_size &&
701		    strcmp(file + (len - ftrace_size), ftrace) == 0)
702			continue;
703
704		if (do_file(file)) {
705			fprintf(stderr, "%s: failed\n", file);
 
 
 
 
 
 
 
 
 
 
 
706			++n_error;
707		}
 
 
 
 
708	}
709	return !!n_error;
710}