xref: /openbmc/linux/scripts/recordmcount.h (revision 941e1d36)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * recordmcount.h
4  *
5  * This code was taken out of recordmcount.c written by
6  * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
7  *
8  * The original code had the same algorithms for both 32bit
9  * and 64bit ELF files, but the code was duplicated to support
10  * the difference in structures that were used. This
11  * file creates a macro of everything that is different between
12  * the 64 and 32 bit code, such that by including this header
13  * twice we can create both sets of functions by including this
14  * header once with RECORD_MCOUNT_64 undefined, and again with
15  * it defined.
16  *
17  * This conversion to macros was done by:
18  * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
19  */
20 #undef append_func
21 #undef is_fake_mcount
22 #undef fn_is_fake_mcount
23 #undef MIPS_is_fake_mcount
24 #undef mcount_adjust
25 #undef sift_rel_mcount
26 #undef nop_mcount
27 #undef find_secsym_ndx
28 #undef __has_rel_mcount
29 #undef has_rel_mcount
30 #undef tot_relsize
31 #undef get_mcountsym
32 #undef get_sym_str_and_relp
33 #undef do_func
34 #undef Elf_Addr
35 #undef Elf_Ehdr
36 #undef Elf_Shdr
37 #undef Elf_Rel
38 #undef Elf_Rela
39 #undef Elf_Sym
40 #undef ELF_R_SYM
41 #undef Elf_r_sym
42 #undef ELF_R_INFO
43 #undef Elf_r_info
44 #undef ELF_ST_BIND
45 #undef ELF_ST_TYPE
46 #undef fn_ELF_R_SYM
47 #undef fn_ELF_R_INFO
48 #undef uint_t
49 #undef _w
50 #undef _align
51 #undef _size
52 
53 #ifdef RECORD_MCOUNT_64
54 # define append_func		append64
55 # define sift_rel_mcount	sift64_rel_mcount
56 # define nop_mcount		nop_mcount_64
57 # define find_secsym_ndx	find64_secsym_ndx
58 # define __has_rel_mcount	__has64_rel_mcount
59 # define has_rel_mcount		has64_rel_mcount
60 # define tot_relsize		tot64_relsize
61 # define get_sym_str_and_relp	get_sym_str_and_relp_64
62 # define do_func		do64
63 # define get_mcountsym		get_mcountsym_64
64 # define is_fake_mcount		is_fake_mcount64
65 # define fn_is_fake_mcount	fn_is_fake_mcount64
66 # define MIPS_is_fake_mcount	MIPS64_is_fake_mcount
67 # define mcount_adjust		mcount_adjust_64
68 # define Elf_Addr		Elf64_Addr
69 # define Elf_Ehdr		Elf64_Ehdr
70 # define Elf_Shdr		Elf64_Shdr
71 # define Elf_Rel		Elf64_Rel
72 # define Elf_Rela		Elf64_Rela
73 # define Elf_Sym		Elf64_Sym
74 # define ELF_R_SYM		ELF64_R_SYM
75 # define Elf_r_sym		Elf64_r_sym
76 # define ELF_R_INFO		ELF64_R_INFO
77 # define Elf_r_info		Elf64_r_info
78 # define ELF_ST_BIND		ELF64_ST_BIND
79 # define ELF_ST_TYPE		ELF64_ST_TYPE
80 # define fn_ELF_R_SYM		fn_ELF64_R_SYM
81 # define fn_ELF_R_INFO		fn_ELF64_R_INFO
82 # define uint_t			uint64_t
83 # define _w			w8
84 # define _align			7u
85 # define _size			8
86 #else
87 # define append_func		append32
88 # define sift_rel_mcount	sift32_rel_mcount
89 # define nop_mcount		nop_mcount_32
90 # define find_secsym_ndx	find32_secsym_ndx
91 # define __has_rel_mcount	__has32_rel_mcount
92 # define has_rel_mcount		has32_rel_mcount
93 # define tot_relsize		tot32_relsize
94 # define get_sym_str_and_relp	get_sym_str_and_relp_32
95 # define do_func		do32
96 # define get_mcountsym		get_mcountsym_32
97 # define is_fake_mcount		is_fake_mcount32
98 # define fn_is_fake_mcount	fn_is_fake_mcount32
99 # define MIPS_is_fake_mcount	MIPS32_is_fake_mcount
100 # define mcount_adjust		mcount_adjust_32
101 # define Elf_Addr		Elf32_Addr
102 # define Elf_Ehdr		Elf32_Ehdr
103 # define Elf_Shdr		Elf32_Shdr
104 # define Elf_Rel		Elf32_Rel
105 # define Elf_Rela		Elf32_Rela
106 # define Elf_Sym		Elf32_Sym
107 # define ELF_R_SYM		ELF32_R_SYM
108 # define Elf_r_sym		Elf32_r_sym
109 # define ELF_R_INFO		ELF32_R_INFO
110 # define Elf_r_info		Elf32_r_info
111 # define ELF_ST_BIND		ELF32_ST_BIND
112 # define ELF_ST_TYPE		ELF32_ST_TYPE
113 # define fn_ELF_R_SYM		fn_ELF32_R_SYM
114 # define fn_ELF_R_INFO		fn_ELF32_R_INFO
115 # define uint_t			uint32_t
116 # define _w			w
117 # define _align			3u
118 # define _size			4
119 #endif
120 
121 /* Functions and pointers that do_file() may override for specific e_machine. */
122 static int fn_is_fake_mcount(Elf_Rel const *rp)
123 {
124 	return 0;
125 }
126 static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount;
127 
128 static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
129 {
130 	return ELF_R_SYM(_w(rp->r_info));
131 }
132 static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM;
133 
134 static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
135 {
136 	rp->r_info = _w(ELF_R_INFO(sym, type));
137 }
138 static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;
139 
140 static int mcount_adjust = 0;
141 
142 /*
143  * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
144  * _mcount symbol is needed for dynamic function tracer, with it, to disable
145  * tracing(ftrace_make_nop), the instruction in the position is replaced with
146  * the "b label" instruction, to enable tracing(ftrace_make_call), replace the
147  * instruction back. So, here, we set the 2nd one as fake and filter it.
148  *
149  * c:	3c030000	lui	v1,0x0		<-->	b	label
150  *		c: R_MIPS_HI16	_mcount
151  *		c: R_MIPS_NONE	*ABS*
152  *		c: R_MIPS_NONE	*ABS*
153  * 10:	64630000	daddiu	v1,v1,0
154  *		10: R_MIPS_LO16	_mcount
155  *		10: R_MIPS_NONE	*ABS*
156  *		10: R_MIPS_NONE	*ABS*
157  * 14:	03e0082d	move	at,ra
158  * 18:	0060f809	jalr	v1
159  * label:
160  */
161 #define MIPS_FAKEMCOUNT_OFFSET	4
162 
163 static int MIPS_is_fake_mcount(Elf_Rel const *rp)
164 {
165 	static Elf_Addr old_r_offset = ~(Elf_Addr)0;
166 	Elf_Addr current_r_offset = _w(rp->r_offset);
167 	int is_fake;
168 
169 	is_fake = (old_r_offset != ~(Elf_Addr)0) &&
170 		(current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
171 	old_r_offset = current_r_offset;
172 
173 	return is_fake;
174 }
175 
176 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
177 static int append_func(Elf_Ehdr *const ehdr,
178 			Elf_Shdr *const shstr,
179 			uint_t const *const mloc0,
180 			uint_t const *const mlocp,
181 			Elf_Rel const *const mrel0,
182 			Elf_Rel const *const mrelp,
183 			unsigned int const rel_entsize,
184 			unsigned int const symsec_sh_link)
185 {
186 	/* Begin constructing output file */
187 	Elf_Shdr mcsec;
188 	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
189 		? ".rela__mcount_loc"
190 		:  ".rel__mcount_loc";
191 	unsigned const old_shnum = w2(ehdr->e_shnum);
192 	uint_t const old_shoff = _w(ehdr->e_shoff);
193 	uint_t const old_shstr_sh_size   = _w(shstr->sh_size);
194 	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
195 	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
196 	uint_t new_e_shoff;
197 
198 	shstr->sh_size = _w(t);
199 	shstr->sh_offset = _w(sb.st_size);
200 	t += sb.st_size;
201 	t += (_align & -t);  /* word-byte align */
202 	new_e_shoff = t;
203 
204 	/* body for new shstrtab */
205 	if (ulseek(sb.st_size, SEEK_SET) < 0)
206 		return -1;
207 	if (uwrite(old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size) < 0)
208 		return -1;
209 	if (uwrite(mc_name, 1 + strlen(mc_name)) < 0)
210 		return -1;
211 
212 	/* old(modified) Elf_Shdr table, word-byte aligned */
213 	if (ulseek(t, SEEK_SET) < 0)
214 		return -1;
215 	t += sizeof(Elf_Shdr) * old_shnum;
216 	if (uwrite(old_shoff + (void *)ehdr,
217 	       sizeof(Elf_Shdr) * old_shnum) < 0)
218 		return -1;
219 
220 	/* new sections __mcount_loc and .rel__mcount_loc */
221 	t += 2*sizeof(mcsec);
222 	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
223 		+ old_shstr_sh_size);
224 	mcsec.sh_type = w(SHT_PROGBITS);
225 	mcsec.sh_flags = _w(SHF_ALLOC);
226 	mcsec.sh_addr = 0;
227 	mcsec.sh_offset = _w(t);
228 	mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
229 	mcsec.sh_link = 0;
230 	mcsec.sh_info = 0;
231 	mcsec.sh_addralign = _w(_size);
232 	mcsec.sh_entsize = _w(_size);
233 	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
234 		return -1;
235 
236 	mcsec.sh_name = w(old_shstr_sh_size);
237 	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
238 		? w(SHT_RELA)
239 		: w(SHT_REL);
240 	mcsec.sh_flags = 0;
241 	mcsec.sh_addr = 0;
242 	mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
243 	mcsec.sh_size   = _w((void *)mrelp - (void *)mrel0);
244 	mcsec.sh_link = w(symsec_sh_link);
245 	mcsec.sh_info = w(old_shnum);
246 	mcsec.sh_addralign = _w(_size);
247 	mcsec.sh_entsize = _w(rel_entsize);
248 
249 	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
250 		return -1;
251 
252 	if (uwrite(mloc0, (void *)mlocp - (void *)mloc0) < 0)
253 		return -1;
254 	if (uwrite(mrel0, (void *)mrelp - (void *)mrel0) < 0)
255 		return -1;
256 
257 	ehdr->e_shoff = _w(new_e_shoff);
258 	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum));  /* {.rel,}__mcount_loc */
259 	if (ulseek(0, SEEK_SET) < 0)
260 		return -1;
261 	if (uwrite(ehdr, sizeof(*ehdr)) < 0)
262 		return -1;
263 	return 0;
264 }
265 
266 static unsigned get_mcountsym(Elf_Sym const *const sym0,
267 			      Elf_Rel const *relp,
268 			      char const *const str0)
269 {
270 	unsigned mcountsym = 0;
271 
272 	Elf_Sym const *const symp =
273 		&sym0[Elf_r_sym(relp)];
274 	char const *symname = &str0[w(symp->st_name)];
275 	char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
276 	char const *fentry = "__fentry__";
277 
278 	if (symname[0] == '.')
279 		++symname;  /* ppc64 hack */
280 	if (strcmp(mcount, symname) == 0 ||
281 	    (altmcount && strcmp(altmcount, symname) == 0) ||
282 	    (strcmp(fentry, symname) == 0))
283 		mcountsym = Elf_r_sym(relp);
284 
285 	return mcountsym;
286 }
287 
288 static void get_sym_str_and_relp(Elf_Shdr const *const relhdr,
289 				 Elf_Ehdr const *const ehdr,
290 				 Elf_Sym const **sym0,
291 				 char const **str0,
292 				 Elf_Rel const **relp)
293 {
294 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
295 		+ (void *)ehdr);
296 	unsigned const symsec_sh_link = w(relhdr->sh_link);
297 	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
298 	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
299 	Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
300 		+ (void *)ehdr);
301 
302 	*sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
303 				  + (void *)ehdr);
304 
305 	*str0 = (char const *)(_w(strsec->sh_offset)
306 			       + (void *)ehdr);
307 
308 	*relp = rel0;
309 }
310 
311 /*
312  * Look at the relocations in order to find the calls to mcount.
313  * Accumulate the section offsets that are found, and their relocation info,
314  * onto the end of the existing arrays.
315  */
316 static uint_t *sift_rel_mcount(uint_t *mlocp,
317 			       unsigned const offbase,
318 			       Elf_Rel **const mrelpp,
319 			       Elf_Shdr const *const relhdr,
320 			       Elf_Ehdr const *const ehdr,
321 			       unsigned const recsym,
322 			       uint_t const recval,
323 			       unsigned const reltype)
324 {
325 	uint_t *const mloc0 = mlocp;
326 	Elf_Rel *mrelp = *mrelpp;
327 	Elf_Sym const *sym0;
328 	char const *str0;
329 	Elf_Rel const *relp;
330 	unsigned rel_entsize = _w(relhdr->sh_entsize);
331 	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
332 	unsigned mcountsym = 0;
333 	unsigned t;
334 
335 	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
336 
337 	for (t = nrel; t; --t) {
338 		if (!mcountsym)
339 			mcountsym = get_mcountsym(sym0, relp, str0);
340 
341 		if (mcountsym && mcountsym == Elf_r_sym(relp) &&
342 				!is_fake_mcount(relp)) {
343 			uint_t const addend =
344 				_w(_w(relp->r_offset) - recval + mcount_adjust);
345 			mrelp->r_offset = _w(offbase
346 				+ ((void *)mlocp - (void *)mloc0));
347 			Elf_r_info(mrelp, recsym, reltype);
348 			if (rel_entsize == sizeof(Elf_Rela)) {
349 				((Elf_Rela *)mrelp)->r_addend = addend;
350 				*mlocp++ = 0;
351 			} else
352 				*mlocp++ = addend;
353 
354 			mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
355 		}
356 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
357 	}
358 	*mrelpp = mrelp;
359 	return mlocp;
360 }
361 
362 /*
363  * Read the relocation table again, but this time its called on sections
364  * that are not going to be traced. The mcount calls here will be converted
365  * into nops.
366  */
367 static int nop_mcount(Elf_Shdr const *const relhdr,
368 		      Elf_Ehdr const *const ehdr,
369 		      const char *const txtname)
370 {
371 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
372 		+ (void *)ehdr);
373 	Elf_Sym const *sym0;
374 	char const *str0;
375 	Elf_Rel const *relp;
376 	Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
377 	unsigned rel_entsize = _w(relhdr->sh_entsize);
378 	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
379 	unsigned mcountsym = 0;
380 	unsigned t;
381 	int once = 0;
382 
383 	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
384 
385 	for (t = nrel; t; --t) {
386 		int ret = -1;
387 
388 		if (!mcountsym)
389 			mcountsym = get_mcountsym(sym0, relp, str0);
390 
391 		if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
392 			if (make_nop) {
393 				ret = make_nop((void *)ehdr, _w(shdr->sh_offset) + _w(relp->r_offset));
394 				if (ret < 0)
395 					return -1;
396 			}
397 			if (warn_on_notrace_sect && !once) {
398 				printf("Section %s has mcount callers being ignored\n",
399 				       txtname);
400 				once = 1;
401 				/* just warn? */
402 				if (!make_nop)
403 					return 0;
404 			}
405 		}
406 
407 		/*
408 		 * If we successfully removed the mcount, mark the relocation
409 		 * as a nop (don't do anything with it).
410 		 */
411 		if (!ret) {
412 			Elf_Rel rel;
413 			rel = *(Elf_Rel *)relp;
414 			Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
415 			if (ulseek((void *)relp - (void *)ehdr, SEEK_SET) < 0)
416 				return -1;
417 			if (uwrite(&rel, sizeof(rel)) < 0)
418 				return -1;
419 		}
420 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
421 	}
422 	return 0;
423 }
424 
425 /*
426  * Find a symbol in the given section, to be used as the base for relocating
427  * the table of offsets of calls to mcount.  A local or global symbol suffices,
428  * but avoid a Weak symbol because it may be overridden; the change in value
429  * would invalidate the relocations of the offsets of the calls to mcount.
430  * Often the found symbol will be the unnamed local symbol generated by
431  * GNU 'as' for the start of each section.  For example:
432  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
433  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
434  */
435 static int find_secsym_ndx(unsigned const txtndx,
436 				char const *const txtname,
437 				uint_t *const recvalp,
438 				unsigned int *sym_index,
439 				Elf_Shdr const *const symhdr,
440 				Elf_Ehdr const *const ehdr)
441 {
442 	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
443 		+ (void *)ehdr);
444 	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
445 	Elf_Sym const *symp;
446 	unsigned t;
447 
448 	for (symp = sym0, t = nsym; t; --t, ++symp) {
449 		unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
450 
451 		if (txtndx == w2(symp->st_shndx)
452 			/* avoid STB_WEAK */
453 		    && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
454 			/* function symbols on ARM have quirks, avoid them */
455 			if (w2(ehdr->e_machine) == EM_ARM
456 			    && ELF_ST_TYPE(symp->st_info) == STT_FUNC)
457 				continue;
458 
459 			*recvalp = _w(symp->st_value);
460 			*sym_index = symp - sym0;
461 			return 0;
462 		}
463 	}
464 	fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
465 		txtndx, txtname);
466 	return -1;
467 }
468 
469 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
470 static char const * __has_rel_mcount(Elf_Shdr const *const relhdr, /* reltype */
471 				     Elf_Shdr const *const shdr0,
472 				     char const *const shstrtab,
473 				     char const *const fname)
474 {
475 	/* .sh_info depends on .sh_type == SHT_REL[,A] */
476 	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
477 	char const *const txtname = &shstrtab[w(txthdr->sh_name)];
478 
479 	if (strcmp("__mcount_loc", txtname) == 0) {
480 		fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
481 			fname);
482 		return already_has_rel_mcount;
483 	}
484 	if (w(txthdr->sh_type) != SHT_PROGBITS ||
485 	    !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
486 		return NULL;
487 	return txtname;
488 }
489 
490 static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
491 				  Elf_Shdr const *const shdr0,
492 				  char const *const shstrtab,
493 				  char const *const fname)
494 {
495 	if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
496 		return NULL;
497 	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
498 }
499 
500 
501 static unsigned tot_relsize(Elf_Shdr const *const shdr0,
502 			    unsigned nhdr,
503 			    const char *const shstrtab,
504 			    const char *const fname)
505 {
506 	unsigned totrelsz = 0;
507 	Elf_Shdr const *shdrp = shdr0;
508 	char const *txtname;
509 
510 	for (; nhdr; --nhdr, ++shdrp) {
511 		txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
512 		if (txtname == already_has_rel_mcount) {
513 			totrelsz = 0;
514 			break;
515 		}
516 		if (txtname && is_mcounted_section_name(txtname))
517 			totrelsz += _w(shdrp->sh_size);
518 	}
519 	return totrelsz;
520 }
521 
522 
523 /* Overall supervision for Elf32 ET_REL file. */
524 static int do_func(Elf_Ehdr *const ehdr, char const *const fname,
525 		   unsigned const reltype)
526 {
527 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
528 		+ (void *)ehdr);
529 	unsigned const nhdr = w2(ehdr->e_shnum);
530 	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
531 	char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
532 		+ (void *)ehdr);
533 
534 	Elf_Shdr const *relhdr;
535 	unsigned k;
536 
537 	/* Upper bound on space: assume all relevant relocs are for mcount. */
538 	unsigned       totrelsz;
539 
540 	Elf_Rel *      mrel0;
541 	Elf_Rel *      mrelp;
542 
543 	uint_t *      mloc0;
544 	uint_t *      mlocp;
545 
546 	unsigned rel_entsize = 0;
547 	unsigned symsec_sh_link = 0;
548 
549 	int result = 0;
550 
551 	totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
552 	if (totrelsz == 0)
553 		return 0;
554 	mrel0 = umalloc(totrelsz);
555 	mrelp = mrel0;
556 	if (!mrel0)
557 		return -1;
558 
559 	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
560 	mloc0 = umalloc(totrelsz>>1);
561 	mlocp = mloc0;
562 	if (!mloc0) {
563 		free(mrel0);
564 		return -1;
565 	}
566 
567 	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
568 		char const *const txtname = has_rel_mcount(relhdr, shdr0,
569 			shstrtab, fname);
570 		if (txtname == already_has_rel_mcount) {
571 			result = 0;
572 			file_updated = 0;
573 			goto out; /* Nothing to be done; don't append! */
574 		}
575 		if (txtname && is_mcounted_section_name(txtname)) {
576 			unsigned int recsym;
577 			uint_t recval = 0;
578 
579 			symsec_sh_link = w(relhdr->sh_link);
580 			result = find_secsym_ndx(w(relhdr->sh_info), txtname,
581 						&recval, &recsym,
582 						&shdr0[symsec_sh_link],
583 						ehdr);
584 			if (result)
585 				goto out;
586 
587 			rel_entsize = _w(relhdr->sh_entsize);
588 			mlocp = sift_rel_mcount(mlocp,
589 				(void *)mlocp - (void *)mloc0, &mrelp,
590 				relhdr, ehdr, recsym, recval, reltype);
591 		} else if (txtname && (warn_on_notrace_sect || make_nop)) {
592 			/*
593 			 * This section is ignored by ftrace, but still
594 			 * has mcount calls. Convert them to nops now.
595 			 */
596 			if (nop_mcount(relhdr, ehdr, txtname) < 0) {
597 				result = -1;
598 				goto out;
599 			}
600 		}
601 	}
602 	if (!result && mloc0 != mlocp)
603 		result = append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
604 				     rel_entsize, symsec_sh_link);
605 out:
606 	free(mrel0);
607 	free(mloc0);
608 	return result;
609 }
610