scripts/recordmcount.h - kernel/msm-4.9 - Gitiles

 /*
  * recordmcount.h
  *
  * This code was taken out of recordmcount.c written by
  * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
  *
  * The original code had the same algorithms for both 32bit
  * and 64bit ELF files, but the code was duplicated to support
  * the difference in structures that were used. This
  * file creates a macro of everything that is different between
  * the 64 and 32 bit code, such that by including this header
  * twice we can create both sets of functions by including this
  * header once with RECORD_MCOUNT_64 undefined, and again with
  * it defined.
  *
  * This conversion to macros was done by:
  * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
  *
  * Licensed under the GNU General Public License, version 2 (GPLv2).
  */
 #undef append_func
 #undef is_fake_mcount
 #undef fn_is_fake_mcount
 #undef MIPS_is_fake_mcount
 #undef sift_rel_mcount
 #undef nop_mcount
 #undef find_secsym_ndx
 #undef __has_rel_mcount
 #undef has_rel_mcount
 #undef tot_relsize
 #undef do_func
 #undef Elf_Addr
 #undef Elf_Ehdr
 #undef Elf_Shdr
 #undef Elf_Rel
 #undef Elf_Rela
 #undef Elf_Sym
 #undef ELF_R_SYM
 #undef Elf_r_sym
 #undef ELF_R_INFO
 #undef Elf_r_info
 #undef ELF_ST_BIND
 #undef fn_ELF_R_SYM
 #undef fn_ELF_R_INFO
 #undef uint_t
 #undef _w
 #undef _align
 #undef _size

 #ifdef RECORD_MCOUNT_64
 # define append_func		append64
 # define sift_rel_mcount	sift64_rel_mcount
 # define nop_mcount		nop_mcount_64
 # define find_secsym_ndx	find64_secsym_ndx
 # define __has_rel_mcount	__has64_rel_mcount
 # define has_rel_mcount		has64_rel_mcount
 # define tot_relsize		tot64_relsize
 # define do_func		do64
 # define is_fake_mcount		is_fake_mcount64
 # define fn_is_fake_mcount	fn_is_fake_mcount64
 # define MIPS_is_fake_mcount	MIPS64_is_fake_mcount
 # define Elf_Addr		Elf64_Addr
 # define Elf_Ehdr		Elf64_Ehdr
 # define Elf_Shdr		Elf64_Shdr
 # define Elf_Rel		Elf64_Rel
 # define Elf_Rela		Elf64_Rela
 # define Elf_Sym		Elf64_Sym
 # define ELF_R_SYM		ELF64_R_SYM
 # define Elf_r_sym		Elf64_r_sym
 # define ELF_R_INFO		ELF64_R_INFO
 # define Elf_r_info		Elf64_r_info
 # define ELF_ST_BIND		ELF64_ST_BIND
 # define fn_ELF_R_SYM		fn_ELF64_R_SYM
 # define fn_ELF_R_INFO		fn_ELF64_R_INFO
 # define uint_t			uint64_t
 # define _w			w8
 # define _align			7u
 # define _size			8
 #else
 # define append_func		append32
 # define sift_rel_mcount	sift32_rel_mcount
 # define nop_mcount		nop_mcount_32
 # define find_secsym_ndx	find32_secsym_ndx
 # define __has_rel_mcount	__has32_rel_mcount
 # define has_rel_mcount		has32_rel_mcount
 # define tot_relsize		tot32_relsize
 # define do_func		do32
 # define is_fake_mcount		is_fake_mcount32
 # define fn_is_fake_mcount	fn_is_fake_mcount32
 # define MIPS_is_fake_mcount	MIPS32_is_fake_mcount
 # define Elf_Addr		Elf32_Addr
 # define Elf_Ehdr		Elf32_Ehdr
 # define Elf_Shdr		Elf32_Shdr
 # define Elf_Rel		Elf32_Rel
 # define Elf_Rela		Elf32_Rela
 # define Elf_Sym		Elf32_Sym
 # define ELF_R_SYM		ELF32_R_SYM
 # define Elf_r_sym		Elf32_r_sym
 # define ELF_R_INFO		ELF32_R_INFO
 # define Elf_r_info		Elf32_r_info
 # define ELF_ST_BIND		ELF32_ST_BIND
 # define fn_ELF_R_SYM		fn_ELF32_R_SYM
 # define fn_ELF_R_INFO		fn_ELF32_R_INFO
 # define uint_t			uint32_t
 # define _w			w
 # define _align			3u
 # define _size			4
 #endif

 /* Functions and pointers that do_file() may override for specific e_machine. */
 static int fn_is_fake_mcount(Elf_Rel const *rp)
 {
 	return 0;
 }
 static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount;

 static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
 {
 	return ELF_R_SYM(_w(rp->r_info));
 }
 static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM;

 static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
 {
 	rp->r_info = _w(ELF_R_INFO(sym, type));
 }
 static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;

 /*
  * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
  * _mcount symbol is needed for dynamic function tracer, with it, to disable
  * tracing(ftrace_make_nop), the instruction in the position is replaced with
  * the "b label" instruction, to enable tracing(ftrace_make_call), replace the
  * instruction back. So, here, we set the 2nd one as fake and filter it.
  *
  * c:	3c030000	lui	v1,0x0		<-->	b	label
  *		c: R_MIPS_HI16	_mcount
  *		c: R_MIPS_NONE	*ABS*
  *		c: R_MIPS_NONE	*ABS*
  * 10:	64630000	daddiu	v1,v1,0
  *		10: R_MIPS_LO16	_mcount
  *		10: R_MIPS_NONE	*ABS*
  *		10: R_MIPS_NONE	*ABS*
  * 14:	03e0082d	move	at,ra
  * 18:	0060f809	jalr	v1
  * label:
  */
 #define MIPS_FAKEMCOUNT_OFFSET	4

 static int MIPS_is_fake_mcount(Elf_Rel const *rp)
 {
 	static Elf_Addr old_r_offset;
 	Elf_Addr current_r_offset = _w(rp->r_offset);
 	int is_fake;

 	is_fake = old_r_offset &&
 		(current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
 	old_r_offset = current_r_offset;

 	return is_fake;
 }

 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
 static void append_func(Elf_Ehdr *const ehdr,
 			Elf_Shdr *const shstr,
 			uint_t const *const mloc0,
 			uint_t const *const mlocp,
 			Elf_Rel const *const mrel0,
 			Elf_Rel const *const mrelp,
 			unsigned int const rel_entsize,
 			unsigned int const symsec_sh_link)
 {
 	/* Begin constructing output file */
 	Elf_Shdr mcsec;
 	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
 		? ".rela__mcount_loc"
 		:  ".rel__mcount_loc";
 	unsigned const old_shnum = w2(ehdr->e_shnum);
 	uint_t const old_shoff = _w(ehdr->e_shoff);
 	uint_t const old_shstr_sh_size   = _w(shstr->sh_size);
 	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
 	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
 	uint_t new_e_shoff;

 	shstr->sh_size = _w(t);
 	shstr->sh_offset = _w(sb.st_size);
 	t += sb.st_size;
 	t += (_align & -t);  /* word-byte align */
 	new_e_shoff = t;

 	/* body for new shstrtab */
 	ulseek(fd_map, sb.st_size, SEEK_SET);
 	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
 	uwrite(fd_map, mc_name, 1 + strlen(mc_name));

 	/* old(modified) Elf_Shdr table, word-byte aligned */
 	ulseek(fd_map, t, SEEK_SET);
 	t += sizeof(Elf_Shdr) * old_shnum;
 	uwrite(fd_map, old_shoff + (void *)ehdr,
 	       sizeof(Elf_Shdr) * old_shnum);

 	/* new sections __mcount_loc and .rel__mcount_loc */
 	t += 2*sizeof(mcsec);
 	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
 		+ old_shstr_sh_size);
 	mcsec.sh_type = w(SHT_PROGBITS);
 	mcsec.sh_flags = _w(SHF_ALLOC);
 	mcsec.sh_addr = 0;
 	mcsec.sh_offset = _w(t);
 	mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
 	mcsec.sh_link = 0;
 	mcsec.sh_info = 0;
 	mcsec.sh_addralign = _w(_size);
 	mcsec.sh_entsize = _w(_size);
 	uwrite(fd_map, &mcsec, sizeof(mcsec));

 	mcsec.sh_name = w(old_shstr_sh_size);
 	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
 		? w(SHT_RELA)
 		: w(SHT_REL);
 	mcsec.sh_flags = 0;
 	mcsec.sh_addr = 0;
 	mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
 	mcsec.sh_size   = _w((void *)mrelp - (void *)mrel0);
 	mcsec.sh_link = w(symsec_sh_link);
 	mcsec.sh_info = w(old_shnum);
 	mcsec.sh_addralign = _w(_size);
 	mcsec.sh_entsize = _w(rel_entsize);
 	uwrite(fd_map, &mcsec, sizeof(mcsec));

 	uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
 	uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);

 	ehdr->e_shoff = _w(new_e_shoff);
 	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum));  /* {.rel,}__mcount_loc */
 	ulseek(fd_map, 0, SEEK_SET);
 	uwrite(fd_map, ehdr, sizeof(*ehdr));
 }

 /*
  * Look at the relocations in order to find the calls to mcount.
  * Accumulate the section offsets that are found, and their relocation info,
  * onto the end of the existing arrays.
  */
 static uint_t *sift_rel_mcount(uint_t *mlocp,
 			       unsigned const offbase,
 			       Elf_Rel **const mrelpp,
 			       Elf_Shdr const *const relhdr,
 			       Elf_Ehdr const *const ehdr,
 			       unsigned const recsym,
 			       uint_t const recval,
 			       unsigned const reltype)
 {
 	uint_t *const mloc0 = mlocp;
 	Elf_Rel *mrelp = *mrelpp;
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
 		+ (void *)ehdr);
 	unsigned const symsec_sh_link = w(relhdr->sh_link);
 	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
 	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
 		+ (void *)ehdr);

 	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
 	char const *const str0 = (char const *)(_w(strsec->sh_offset)
 		+ (void *)ehdr);

 	Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
 		+ (void *)ehdr);
 	unsigned rel_entsize = _w(relhdr->sh_entsize);
 	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
 	Elf_Rel const *relp = rel0;

 	unsigned mcountsym = 0;
 	unsigned t;

 	for (t = nrel; t; --t) {
 		if (!mcountsym) {
 			Elf_Sym const *const symp =
 				&sym0[Elf_r_sym(relp)];
 			char const *symname = &str0[w(symp->st_name)];
 			char const *mcount = gpfx == '_' ? "_mcount" : "mcount";

 			if (symname[0] == '.')
 				++symname;  /* ppc64 hack */
 			if (strcmp(mcount, symname) == 0 ||
 			    (altmcount && strcmp(altmcount, symname) == 0))
 				mcountsym = Elf_r_sym(relp);
 		}

 		if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
 			uint_t const addend = _w(_w(relp->r_offset) - recval);

 			mrelp->r_offset = _w(offbase
 				+ ((void *)mlocp - (void *)mloc0));
 			Elf_r_info(mrelp, recsym, reltype);
 			if (rel_entsize == sizeof(Elf_Rela)) {
 				((Elf_Rela *)mrelp)->r_addend = addend;
 				*mlocp++ = 0;
 			} else
 				*mlocp++ = addend;

 			mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
 		}
 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
 	}
 	*mrelpp = mrelp;
 	return mlocp;
 }

 /*
  * Read the relocation table again, but this time its called on sections
  * that are not going to be traced. The mcount calls here will be converted
  * into nops.
  */
 static void nop_mcount(Elf_Shdr const *const relhdr,
 		       Elf_Ehdr const *const ehdr,
 		       const char *const txtname)
 {
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
 		+ (void *)ehdr);
 	unsigned const symsec_sh_link = w(relhdr->sh_link);
 	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
 	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
 		+ (void *)ehdr);

 	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
 	char const *const str0 = (char const *)(_w(strsec->sh_offset)
 		+ (void *)ehdr);

 	Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
 		+ (void *)ehdr);
 	unsigned rel_entsize = _w(relhdr->sh_entsize);
 	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
 	Elf_Rel const *relp = rel0;

 	Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];

 	unsigned mcountsym = 0;
 	unsigned t;
 	int once = 0;

 	for (t = nrel; t; --t) {
 		int ret = -1;

 		if (!mcountsym) {
 			Elf_Sym const *const symp =
 				&sym0[Elf_r_sym(relp)];
 			char const *symname = &str0[w(symp->st_name)];
 			char const *mcount = gpfx == '_' ? "_mcount" : "mcount";

 			if (symname[0] == '.')
 				++symname;  /* ppc64 hack */
 			if (strcmp(mcount, symname) == 0 ||
 			    (altmcount && strcmp(altmcount, symname) == 0))
 				mcountsym = Elf_r_sym(relp);
 		}

 		if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
 			if (make_nop)
 				ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
 			if (warn_on_notrace_sect && !once) {
 				printf("Section %s has mcount callers being ignored\n",
 				       txtname);
 				once = 1;
 				/* just warn? */
 				if (!make_nop)
 					return;
 			}
 		}

 		/*
 		 * If we successfully removed the mcount, mark the relocation
 		 * as a nop (don't do anything with it).
 		 */
 		if (!ret) {
 			Elf_Rel rel;
 			rel = *(Elf_Rel *)relp;
 			Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
 			ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET);
 			uwrite(fd_map, &rel, sizeof(rel));
 		}
 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
 	}
 }


 /*
  * Find a symbol in the given section, to be used as the base for relocating
  * the table of offsets of calls to mcount.  A local or global symbol suffices,
  * but avoid a Weak symbol because it may be overridden; the change in value
  * would invalidate the relocations of the offsets of the calls to mcount.
  * Often the found symbol will be the unnamed local symbol generated by
  * GNU 'as' for the start of each section.  For example:
  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
  */
 static unsigned find_secsym_ndx(unsigned const txtndx,
 				char const *const txtname,
 				uint_t *const recvalp,
 				Elf_Shdr const *const symhdr,
 				Elf_Ehdr const *const ehdr)
 {
 	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
 		+ (void *)ehdr);
 	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
 	Elf_Sym const *symp;
 	unsigned t;

 	for (symp = sym0, t = nsym; t; --t, ++symp) {
 		unsigned int const st_bind = ELF_ST_BIND(symp->st_info);

 		if (txtndx == w2(symp->st_shndx)
 			/* avoid STB_WEAK */
 		    && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
 			*recvalp = _w(symp->st_value);
 			return symp - sym0;
 		}
 	}
 	fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
 		txtndx, txtname);
 	fail_file();
 }


 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
 static char const *
 __has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
 		 Elf_Shdr const *const shdr0,
 		 char const *const shstrtab,
 		 char const *const fname)
 {
 	/* .sh_info depends on .sh_type == SHT_REL[,A] */
 	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
 	char const *const txtname = &shstrtab[w(txthdr->sh_name)];

 	if (strcmp("__mcount_loc", txtname) == 0) {
 		fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
 			fname);
 		succeed_file();
 	}
 	if (w(txthdr->sh_type) != SHT_PROGBITS ||
 	    !(w(txthdr->sh_flags) & SHF_EXECINSTR))
 		return NULL;
 	return txtname;
 }

 static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
 				  Elf_Shdr const *const shdr0,
 				  char const *const shstrtab,
 				  char const *const fname)
 {
 	if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
 		return NULL;
 	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
 }


 static unsigned tot_relsize(Elf_Shdr const *const shdr0,
 			    unsigned nhdr,
 			    const char *const shstrtab,
 			    const char *const fname)
 {
 	unsigned totrelsz = 0;
 	Elf_Shdr const *shdrp = shdr0;
 	char const *txtname;

 	for (; nhdr; --nhdr, ++shdrp) {
 		txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
 		if (txtname && is_mcounted_section_name(txtname))
 			totrelsz += _w(shdrp->sh_size);
 	}
 	return totrelsz;
 }


 /* Overall supervision for Elf32 ET_REL file. */
 static void
 do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
 {
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
 		+ (void *)ehdr);
 	unsigned const nhdr = w2(ehdr->e_shnum);
 	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
 	char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
 		+ (void *)ehdr);

 	Elf_Shdr const *relhdr;
 	unsigned k;

 	/* Upper bound on space: assume all relevant relocs are for mcount. */
 	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
 	Elf_Rel *const mrel0 = umalloc(totrelsz);
 	Elf_Rel *      mrelp = mrel0;

 	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
 	uint_t *const mloc0 = umalloc(totrelsz>>1);
 	uint_t *      mlocp = mloc0;

 	unsigned rel_entsize = 0;
 	unsigned symsec_sh_link = 0;

 	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
 		char const *const txtname = has_rel_mcount(relhdr, shdr0,
 			shstrtab, fname);
 		if (txtname && is_mcounted_section_name(txtname)) {
 			uint_t recval = 0;
 			unsigned const recsym = find_secsym_ndx(
 				w(relhdr->sh_info), txtname, &recval,
 				&shdr0[symsec_sh_link = w(relhdr->sh_link)],
 				ehdr);

 			rel_entsize = _w(relhdr->sh_entsize);
 			mlocp = sift_rel_mcount(mlocp,
 				(void *)mlocp - (void *)mloc0, &mrelp,
 				relhdr, ehdr, recsym, recval, reltype);
 		} else if (txtname && (warn_on_notrace_sect || make_nop)) {
 			/*
 			 * This section is ignored by ftrace, but still
 			 * has mcount calls. Convert them to nops now.
 			 */
 			nop_mcount(relhdr, ehdr, txtname);
 		}
 	}
 	if (mloc0 != mlocp) {
 		append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
 			    rel_entsize, symsec_sh_link);
 	}
 	free(mrel0);
 	free(mloc0);
 }
	/*
	* recordmcount.h
	*
	* This code was taken out of recordmcount.c written by
	* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
	*
	* The original code had the same algorithms for both 32bit
	* and 64bit ELF files, but the code was duplicated to support
	* the difference in structures that were used. This
	* file creates a macro of everything that is different between
	* the 64 and 32 bit code, such that by including this header
	* twice we can create both sets of functions by including this
	* header once with RECORD_MCOUNT_64 undefined, and again with
	* it defined.
	*
	* This conversion to macros was done by:
	* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
	*
	* Licensed under the GNU General Public License, version 2 (GPLv2).
	*/
	#undef append_func
	#undef is_fake_mcount
	#undef fn_is_fake_mcount
	#undef MIPS_is_fake_mcount
	#undef sift_rel_mcount
	#undef nop_mcount
	#undef find_secsym_ndx
	#undef __has_rel_mcount
	#undef has_rel_mcount
	#undef tot_relsize
	#undef do_func
	#undef Elf_Addr
	#undef Elf_Ehdr
	#undef Elf_Shdr
	#undef Elf_Rel
	#undef Elf_Rela
	#undef Elf_Sym
	#undef ELF_R_SYM
	#undef Elf_r_sym
	#undef ELF_R_INFO
	#undef Elf_r_info
	#undef ELF_ST_BIND
	#undef fn_ELF_R_SYM
	#undef fn_ELF_R_INFO
	#undef uint_t
	#undef _w
	#undef _align
	#undef _size

	#ifdef RECORD_MCOUNT_64
	# define append_func append64
	# define sift_rel_mcount sift64_rel_mcount
	# define nop_mcount nop_mcount_64
	# define find_secsym_ndx find64_secsym_ndx
	# define __has_rel_mcount __has64_rel_mcount
	# define has_rel_mcount has64_rel_mcount
	# define tot_relsize tot64_relsize
	# define do_func do64
	# define is_fake_mcount is_fake_mcount64
	# define fn_is_fake_mcount fn_is_fake_mcount64
	# define MIPS_is_fake_mcount MIPS64_is_fake_mcount
	# define Elf_Addr Elf64_Addr
	# define Elf_Ehdr Elf64_Ehdr
	# define Elf_Shdr Elf64_Shdr
	# define Elf_Rel Elf64_Rel
	# define Elf_Rela Elf64_Rela
	# define Elf_Sym Elf64_Sym
	# define ELF_R_SYM ELF64_R_SYM
	# define Elf_r_sym Elf64_r_sym
	# define ELF_R_INFO ELF64_R_INFO
	# define Elf_r_info Elf64_r_info
	# define ELF_ST_BIND ELF64_ST_BIND
	# define fn_ELF_R_SYM fn_ELF64_R_SYM
	# define fn_ELF_R_INFO fn_ELF64_R_INFO
	# define uint_t uint64_t
	# define _w w8
	# define _align 7u
	# define _size 8
	#else
	# define append_func append32
	# define sift_rel_mcount sift32_rel_mcount
	# define nop_mcount nop_mcount_32
	# define find_secsym_ndx find32_secsym_ndx
	# define __has_rel_mcount __has32_rel_mcount
	# define has_rel_mcount has32_rel_mcount
	# define tot_relsize tot32_relsize
	# define do_func do32
	# define is_fake_mcount is_fake_mcount32
	# define fn_is_fake_mcount fn_is_fake_mcount32
	# define MIPS_is_fake_mcount MIPS32_is_fake_mcount
	# define Elf_Addr Elf32_Addr
	# define Elf_Ehdr Elf32_Ehdr
	# define Elf_Shdr Elf32_Shdr
	# define Elf_Rel Elf32_Rel
	# define Elf_Rela Elf32_Rela
	# define Elf_Sym Elf32_Sym
	# define ELF_R_SYM ELF32_R_SYM
	# define Elf_r_sym Elf32_r_sym
	# define ELF_R_INFO ELF32_R_INFO
	# define Elf_r_info Elf32_r_info
	# define ELF_ST_BIND ELF32_ST_BIND
	# define fn_ELF_R_SYM fn_ELF32_R_SYM
	# define fn_ELF_R_INFO fn_ELF32_R_INFO
	# define uint_t uint32_t
	# define _w w
	# define _align 3u
	# define _size 4
	#endif

	/* Functions and pointers that do_file() may override for specific e_machine. */
	static int fn_is_fake_mcount(Elf_Rel const *rp)
	{
	return 0;
	}
	static int (is_fake_mcount)(Elf_Rel const rp) = fn_is_fake_mcount;

	static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
	{
	return ELF_R_SYM(_w(rp->r_info));
	}
	static uint_t (Elf_r_sym)(Elf_Rel const rp) = fn_ELF_R_SYM;

	static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
	{
	rp->r_info = _w(ELF_R_INFO(sym, type));
	}
	static void (Elf_r_info)(Elf_Rel const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;

	/*
	* MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
	* _mcount symbol is needed for dynamic function tracer, with it, to disable
	* tracing(ftrace_make_nop), the instruction in the position is replaced with
	* the "b label" instruction, to enable tracing(ftrace_make_call), replace the
	* instruction back. So, here, we set the 2nd one as fake and filter it.
	*
	* c: 3c030000 lui v1,0x0 <--> b label
	* c: R_MIPS_HI16 _mcount
	* c: R_MIPS_NONE ABS
	* c: R_MIPS_NONE ABS
	* 10: 64630000 daddiu v1,v1,0
	* 10: R_MIPS_LO16 _mcount
	* 10: R_MIPS_NONE ABS
	* 10: R_MIPS_NONE ABS
	* 14: 03e0082d move at,ra
	* 18: 0060f809 jalr v1
	* label:
	*/
	#define MIPS_FAKEMCOUNT_OFFSET 4

	static int MIPS_is_fake_mcount(Elf_Rel const *rp)
	{
	static Elf_Addr old_r_offset;
	Elf_Addr current_r_offset = _w(rp->r_offset);
	int is_fake;

	is_fake = old_r_offset &&
	(current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
	old_r_offset = current_r_offset;

	return is_fake;
	}

	/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
	static void append_func(Elf_Ehdr *const ehdr,
	Elf_Shdr *const shstr,
	uint_t const *const mloc0,
	uint_t const *const mlocp,
	Elf_Rel const *const mrel0,
	Elf_Rel const *const mrelp,
	unsigned int const rel_entsize,
	unsigned int const symsec_sh_link)
	{
	/* Begin constructing output file */
	Elf_Shdr mcsec;
	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
	? ".rela__mcount_loc"
	: ".rel__mcount_loc";
	unsigned const old_shnum = w2(ehdr->e_shnum);
	uint_t const old_shoff = _w(ehdr->e_shoff);
	uint_t const old_shstr_sh_size = _w(shstr->sh_size);
	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
	uint_t new_e_shoff;

	shstr->sh_size = _w(t);
	shstr->sh_offset = _w(sb.st_size);
	t += sb.st_size;
	t += (_align & -t); /* word-byte align */
	new_e_shoff = t;

	/* body for new shstrtab */
	ulseek(fd_map, sb.st_size, SEEK_SET);
	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
	uwrite(fd_map, mc_name, 1 + strlen(mc_name));

	/* old(modified) Elf_Shdr table, word-byte aligned */
	ulseek(fd_map, t, SEEK_SET);
	t += sizeof(Elf_Shdr) * old_shnum;
	uwrite(fd_map, old_shoff + (void *)ehdr,
	sizeof(Elf_Shdr) * old_shnum);

	/* new sections __mcount_loc and .rel__mcount_loc */
	t += 2*sizeof(mcsec);
	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
	+ old_shstr_sh_size);
	mcsec.sh_type = w(SHT_PROGBITS);
	mcsec.sh_flags = _w(SHF_ALLOC);
	mcsec.sh_addr = 0;
	mcsec.sh_offset = _w(t);
	mcsec.sh_size = _w((void )mlocp - (void )mloc0);
	mcsec.sh_link = 0;
	mcsec.sh_info = 0;
	mcsec.sh_addralign = _w(_size);
	mcsec.sh_entsize = _w(_size);
	uwrite(fd_map, &mcsec, sizeof(mcsec));

	mcsec.sh_name = w(old_shstr_sh_size);
	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
	? w(SHT_RELA)
	: w(SHT_REL);
	mcsec.sh_flags = 0;
	mcsec.sh_addr = 0;
	mcsec.sh_offset = _w((void )mlocp - (void )mloc0 + t);
	mcsec.sh_size = _w((void )mrelp - (void )mrel0);
	mcsec.sh_link = w(symsec_sh_link);
	mcsec.sh_info = w(old_shnum);
	mcsec.sh_addralign = _w(_size);
	mcsec.sh_entsize = _w(rel_entsize);
	uwrite(fd_map, &mcsec, sizeof(mcsec));

	uwrite(fd_map, mloc0, (void )mlocp - (void )mloc0);
	uwrite(fd_map, mrel0, (void )mrelp - (void )mrel0);

	ehdr->e_shoff = _w(new_e_shoff);
	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
	ulseek(fd_map, 0, SEEK_SET);
	uwrite(fd_map, ehdr, sizeof(*ehdr));
	}

	/*
	* Look at the relocations in order to find the calls to mcount.
	* Accumulate the section offsets that are found, and their relocation info,
	* onto the end of the existing arrays.
	*/
	static uint_t sift_rel_mcount(uint_t mlocp,
	unsigned const offbase,
	Elf_Rel **const mrelpp,
	Elf_Shdr const *const relhdr,
	Elf_Ehdr const *const ehdr,
	unsigned const recsym,
	uint_t const recval,
	unsigned const reltype)
	{
	uint_t *const mloc0 = mlocp;
	Elf_Rel mrelp = mrelpp;
	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	+ (void *)ehdr);
	unsigned const symsec_sh_link = w(relhdr->sh_link);
	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symsec->sh_offset)
	+ (void *)ehdr);

	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
	char const const str0 = (char const )(_w(strsec->sh_offset)
	+ (void *)ehdr);

	Elf_Rel const const rel0 = (Elf_Rel const )(_w(relhdr->sh_offset)
	+ (void *)ehdr);
	unsigned rel_entsize = _w(relhdr->sh_entsize);
	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
	Elf_Rel const *relp = rel0;

	unsigned mcountsym = 0;
	unsigned t;

	for (t = nrel; t; --t) {
	if (!mcountsym) {
	Elf_Sym const *const symp =
	&sym0[Elf_r_sym(relp)];
	char const *symname = &str0[w(symp->st_name)];
	char const *mcount = gpfx == '_' ? "_mcount" : "mcount";

	if (symname[0] == '.')
	++symname; /* ppc64 hack */
	if (strcmp(mcount, symname) == 0 \|\|
	(altmcount && strcmp(altmcount, symname) == 0))
	mcountsym = Elf_r_sym(relp);
	}

	if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
	uint_t const addend = _w(_w(relp->r_offset) - recval);

	mrelp->r_offset = _w(offbase
	+ ((void )mlocp - (void )mloc0));
	Elf_r_info(mrelp, recsym, reltype);
	if (rel_entsize == sizeof(Elf_Rela)) {
	((Elf_Rela *)mrelp)->r_addend = addend;
	*mlocp++ = 0;
	} else
	*mlocp++ = addend;

	mrelp = (Elf_Rel )(rel_entsize + (void )mrelp);
	}
	relp = (Elf_Rel const )(rel_entsize + (void )relp);
	}
	*mrelpp = mrelp;
	return mlocp;
	}

	/*
	* Read the relocation table again, but this time its called on sections
	* that are not going to be traced. The mcount calls here will be converted
	* into nops.
	*/
	static void nop_mcount(Elf_Shdr const *const relhdr,
	Elf_Ehdr const *const ehdr,
	const char *const txtname)
	{
	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	+ (void *)ehdr);
	unsigned const symsec_sh_link = w(relhdr->sh_link);
	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symsec->sh_offset)
	+ (void *)ehdr);

	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
	char const const str0 = (char const )(_w(strsec->sh_offset)
	+ (void *)ehdr);

	Elf_Rel const const rel0 = (Elf_Rel const )(_w(relhdr->sh_offset)
	+ (void *)ehdr);
	unsigned rel_entsize = _w(relhdr->sh_entsize);
	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
	Elf_Rel const *relp = rel0;

	Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];

	unsigned mcountsym = 0;
	unsigned t;
	int once = 0;

	for (t = nrel; t; --t) {
	int ret = -1;

	if (!mcountsym) {
	Elf_Sym const *const symp =
	&sym0[Elf_r_sym(relp)];
	char const *symname = &str0[w(symp->st_name)];
	char const *mcount = gpfx == '_' ? "_mcount" : "mcount";

	if (symname[0] == '.')
	++symname; /* ppc64 hack */
	if (strcmp(mcount, symname) == 0 \|\|
	(altmcount && strcmp(altmcount, symname) == 0))
	mcountsym = Elf_r_sym(relp);
	}

	if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
	if (make_nop)
	ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
	if (warn_on_notrace_sect && !once) {
	printf("Section %s has mcount callers being ignored\n",
	txtname);
	once = 1;
	/* just warn? */
	if (!make_nop)
	return;
	}
	}

	/*
	* If we successfully removed the mcount, mark the relocation
	* as a nop (don't do anything with it).
	*/
	if (!ret) {
	Elf_Rel rel;
	rel = (Elf_Rel )relp;
	Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
	ulseek(fd_map, (void )relp - (void )ehdr, SEEK_SET);
	uwrite(fd_map, &rel, sizeof(rel));
	}
	relp = (Elf_Rel const )(rel_entsize + (void )relp);
	}
	}


	/*
	* Find a symbol in the given section, to be used as the base for relocating
	* the table of offsets of calls to mcount. A local or global symbol suffices,
	* but avoid a Weak symbol because it may be overridden; the change in value
	* would invalidate the relocations of the offsets of the calls to mcount.
	* Often the found symbol will be the unnamed local symbol generated by
	* GNU 'as' for the start of each section. For example:
	* Num: Value Size Type Bind Vis Ndx Name
	* 2: 00000000 0 SECTION LOCAL DEFAULT 1
	*/
	static unsigned find_secsym_ndx(unsigned const txtndx,
	char const *const txtname,
	uint_t *const recvalp,
	Elf_Shdr const *const symhdr,
	Elf_Ehdr const *const ehdr)
	{
	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symhdr->sh_offset)
	+ (void *)ehdr);
	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
	Elf_Sym const *symp;
	unsigned t;

	for (symp = sym0, t = nsym; t; --t, ++symp) {
	unsigned int const st_bind = ELF_ST_BIND(symp->st_info);

	if (txtndx == w2(symp->st_shndx)
	/* avoid STB_WEAK */
	&& (STB_LOCAL == st_bind \|\| STB_GLOBAL == st_bind)) {
	*recvalp = _w(symp->st_value);
	return symp - sym0;
	}
	}
	fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
	txtndx, txtname);
	fail_file();
	}


	/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
	static char const *
	__has_rel_mcount(Elf_Shdr const const relhdr, / is SHT_REL or SHT_RELA */
	Elf_Shdr const *const shdr0,
	char const *const shstrtab,
	char const *const fname)
	{
	/* .sh_info depends on .sh_type == SHT_REL[,A] */
	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
	char const *const txtname = &shstrtab[w(txthdr->sh_name)];

	if (strcmp("__mcount_loc", txtname) == 0) {
	fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
	fname);
	succeed_file();
	}
	if (w(txthdr->sh_type) != SHT_PROGBITS \|\|
	!(w(txthdr->sh_flags) & SHF_EXECINSTR))
	return NULL;
	return txtname;
	}

	static char const has_rel_mcount(Elf_Shdr const const relhdr,
	Elf_Shdr const *const shdr0,
	char const *const shstrtab,
	char const *const fname)
	{
	if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
	return NULL;
	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
	}


	static unsigned tot_relsize(Elf_Shdr const *const shdr0,
	unsigned nhdr,
	const char *const shstrtab,
	const char *const fname)
	{
	unsigned totrelsz = 0;
	Elf_Shdr const *shdrp = shdr0;
	char const *txtname;

	for (; nhdr; --nhdr, ++shdrp) {
	txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
	if (txtname && is_mcounted_section_name(txtname))
	totrelsz += _w(shdrp->sh_size);
	}
	return totrelsz;
	}


	/* Overall supervision for Elf32 ET_REL file. */
	static void
	do_func(Elf_Ehdr const ehdr, char const const fname, unsigned const reltype)
	{
	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	+ (void *)ehdr);
	unsigned const nhdr = w2(ehdr->e_shnum);
	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
	char const const shstrtab = (char const )(_w(shstr->sh_offset)
	+ (void *)ehdr);

	Elf_Shdr const *relhdr;
	unsigned k;

	/* Upper bound on space: assume all relevant relocs are for mcount. */
	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
	Elf_Rel *const mrel0 = umalloc(totrelsz);
	Elf_Rel * mrelp = mrel0;

	/* 2sizeof(address) <= sizeof(Elf_Rel) /
	uint_t *const mloc0 = umalloc(totrelsz>>1);
	uint_t * mlocp = mloc0;

	unsigned rel_entsize = 0;
	unsigned symsec_sh_link = 0;

	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
	char const *const txtname = has_rel_mcount(relhdr, shdr0,
	shstrtab, fname);
	if (txtname && is_mcounted_section_name(txtname)) {
	uint_t recval = 0;
	unsigned const recsym = find_secsym_ndx(
	w(relhdr->sh_info), txtname, &recval,
	&shdr0[symsec_sh_link = w(relhdr->sh_link)],
	ehdr);

	rel_entsize = _w(relhdr->sh_entsize);
	mlocp = sift_rel_mcount(mlocp,
	(void )mlocp - (void )mloc0, &mrelp,
	relhdr, ehdr, recsym, recval, reltype);
	} else if (txtname && (warn_on_notrace_sect \|\| make_nop)) {
	/*
	* This section is ignored by ftrace, but still
	* has mcount calls. Convert them to nops now.
	*/
	nop_mcount(relhdr, ehdr, txtname);
	}
	}
	if (mloc0 != mlocp) {
	append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
	rel_entsize, symsec_sh_link);
	}
	free(mrel0);
	free(mloc0);
	}