[GitHub/mt8127/android_kernel_alcatel_ttab.git] / scripts / recordmcount.h

/*
 * 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 mcount_adjust
#undef sift_rel_mcount
#undef nop_mcount
#undef find_secsym_ndx
#undef __has_rel_mcount
#undef has_rel_mcount
#undef tot_relsize
#undef get_mcountsym
#undef get_sym_str_and_relp
#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 ELF_ST_TYPE
#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 get_sym_str_and_relp	get_sym_str_and_relp_64
# define do_func		do64
# define get_mcountsym		get_mcountsym_64
# 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 mcount_adjust		mcount_adjust_64
# 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 ELF_ST_TYPE		ELF64_ST_TYPE
# 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 get_sym_str_and_relp	get_sym_str_and_relp_32
# define do_func		do32
# define get_mcountsym		get_mcountsym_32
# 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 mcount_adjust		mcount_adjust_32
# 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 ELF_ST_TYPE		ELF32_ST_TYPE
# 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;

static int mcount_adjust = 0;

/*
 * 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));
}

static unsigned get_mcountsym(Elf_Sym const *const sym0,
			      Elf_Rel const *relp,
			      char const *const str0)
{
	unsigned mcountsym = 0;

	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);

	return mcountsym;
}

static void get_sym_str_and_relp(Elf_Shdr const *const relhdr,
				 Elf_Ehdr const *const ehdr,
				 Elf_Sym const **sym0,
				 char const **str0,
				 Elf_Rel const **relp)
{
	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_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
	Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
		+ (void *)ehdr);

	*sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
				  + (void *)ehdr);

	*str0 = (char const *)(_w(strsec->sh_offset)
			       + (void *)ehdr);

	*relp = rel0;
}

/*
 * 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_Sym const *sym0;
	char const *str0;
	Elf_Rel const *relp;
	unsigned rel_entsize = _w(relhdr->sh_entsize);
	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
	unsigned mcountsym = 0;
	unsigned t;

	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);

	for (t = nrel; t; --t) {
		if (!mcountsym)
			mcountsym = get_mcountsym(sym0, relp, str0);

		if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
			uint_t const addend =
				_w(_w(relp->r_offset) - recval + mcount_adjust);
			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);
	Elf_Sym const *sym0;
	char const *str0;
	Elf_Rel const *relp;
	Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
	unsigned rel_entsize = _w(relhdr->sh_entsize);
	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
	unsigned mcountsym = 0;
	unsigned t;
	int once = 0;

	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);

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

		if (!mcountsym)
			mcountsym = get_mcountsym(sym0, relp, str0);

		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)) {
			/* function symbols on ARM have quirks, avoid them */
			if (w2(ehdr->e_machine) == EM_ARM
			    && ELF_ST_TYPE(symp->st_info) == STT_FUNC)
				continue;

			*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);
}
Commit	Line	Data
c28d5077 SR	1	/*
	2	* recordmcount.h
	3	*
	4	* This code was taken out of recordmcount.c written by
	5	* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
	6	*
	7	* The original code had the same algorithms for both 32bit
	8	* and 64bit ELF files, but the code was duplicated to support
	9	* the difference in structures that were used. This
	10	* file creates a macro of everything that is different between
	11	* the 64 and 32 bit code, such that by including this header
	12	* twice we can create both sets of functions by including this
	13	* header once with RECORD_MCOUNT_64 undefined, and again with
	14	* it defined.
	15	*
	16	* This conversion to macros was done by:
	17	* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
	18	*
	19	* Licensed under the GNU General Public License, version 2 (GPLv2).
	20	*/
	21	#undef append_func
412910cd WZ	22	#undef is_fake_mcount
	23	#undef fn_is_fake_mcount
	24	#undef MIPS_is_fake_mcount
07d8b595	25	#undef mcount_adjust
c28d5077	26	#undef sift_rel_mcount
ffd618fa	27	#undef nop_mcount
c28d5077 SR	28	#undef find_secsym_ndx
	29	#undef __has_rel_mcount
	30	#undef has_rel_mcount
	31	#undef tot_relsize
37762cb9	32	#undef get_mcountsym
41b402a2	33	#undef get_sym_str_and_relp
c28d5077	34	#undef do_func
412910cd	35	#undef Elf_Addr
c28d5077 SR	36	#undef Elf_Ehdr
	37	#undef Elf_Shdr
	38	#undef Elf_Rel
	39	#undef Elf_Rela
	40	#undef Elf_Sym
	41	#undef ELF_R_SYM
a2d49358	42	#undef Elf_r_sym
c28d5077	43	#undef ELF_R_INFO
a2d49358	44	#undef Elf_r_info
c28d5077	45	#undef ELF_ST_BIND
9905ce8a	46	#undef ELF_ST_TYPE
a2d49358 JR	47	#undef fn_ELF_R_SYM
a2d49358 JR	48	#undef fn_ELF_R_INFO
c28d5077 SR	49	#undef uint_t
	50	#undef _w
	51	#undef _align
	52	#undef _size
	53
	54	#ifdef RECORD_MCOUNT_64
	55	# define append_func append64
	56	# define sift_rel_mcount sift64_rel_mcount
ffd618fa	57	# define nop_mcount nop_mcount_64
c28d5077 SR	58	# define find_secsym_ndx find64_secsym_ndx
	59	# define __has_rel_mcount __has64_rel_mcount
	60	# define has_rel_mcount has64_rel_mcount
	61	# define tot_relsize tot64_relsize
41b402a2	62	# define get_sym_str_and_relp get_sym_str_and_relp_64
c28d5077	63	# define do_func do64
37762cb9	64	# define get_mcountsym get_mcountsym_64
412910cd WZ	65	# define is_fake_mcount is_fake_mcount64
	66	# define fn_is_fake_mcount fn_is_fake_mcount64
	67	# define MIPS_is_fake_mcount MIPS64_is_fake_mcount
07d8b595	68	# define mcount_adjust mcount_adjust_64
412910cd	69	# define Elf_Addr Elf64_Addr
c28d5077 SR	70	# define Elf_Ehdr Elf64_Ehdr
	71	# define Elf_Shdr Elf64_Shdr
	72	# define Elf_Rel Elf64_Rel
	73	# define Elf_Rela Elf64_Rela
	74	# define Elf_Sym Elf64_Sym
	75	# define ELF_R_SYM ELF64_R_SYM
a2d49358	76	# define Elf_r_sym Elf64_r_sym
c28d5077	77	# define ELF_R_INFO ELF64_R_INFO
a2d49358	78	# define Elf_r_info Elf64_r_info
c28d5077	79	# define ELF_ST_BIND ELF64_ST_BIND
9905ce8a	80	# define ELF_ST_TYPE ELF64_ST_TYPE
a2d49358 JR	81	# define fn_ELF_R_SYM fn_ELF64_R_SYM
a2d49358 JR	82	# define fn_ELF_R_INFO fn_ELF64_R_INFO
c28d5077 SR	83	# define uint_t uint64_t
	84	# define _w w8
	85	# define _align 7u
	86	# define _size 8
	87	#else
	88	# define append_func append32
	89	# define sift_rel_mcount sift32_rel_mcount
ffd618fa	90	# define nop_mcount nop_mcount_32
c28d5077 SR	91	# define find_secsym_ndx find32_secsym_ndx
	92	# define __has_rel_mcount __has32_rel_mcount
	93	# define has_rel_mcount has32_rel_mcount
	94	# define tot_relsize tot32_relsize
41b402a2	95	# define get_sym_str_and_relp get_sym_str_and_relp_32
c28d5077	96	# define do_func do32
37762cb9	97	# define get_mcountsym get_mcountsym_32
412910cd WZ	98	# define is_fake_mcount is_fake_mcount32
	99	# define fn_is_fake_mcount fn_is_fake_mcount32
	100	# define MIPS_is_fake_mcount MIPS32_is_fake_mcount
07d8b595	101	# define mcount_adjust mcount_adjust_32
412910cd	102	# define Elf_Addr Elf32_Addr
c28d5077 SR	103	# define Elf_Ehdr Elf32_Ehdr
	104	# define Elf_Shdr Elf32_Shdr
	105	# define Elf_Rel Elf32_Rel
	106	# define Elf_Rela Elf32_Rela
	107	# define Elf_Sym Elf32_Sym
	108	# define ELF_R_SYM ELF32_R_SYM
a2d49358	109	# define Elf_r_sym Elf32_r_sym
c28d5077	110	# define ELF_R_INFO ELF32_R_INFO
a2d49358	111	# define Elf_r_info Elf32_r_info
c28d5077	112	# define ELF_ST_BIND ELF32_ST_BIND
9905ce8a	113	# define ELF_ST_TYPE ELF32_ST_TYPE
a2d49358 JR	114	# define fn_ELF_R_SYM fn_ELF32_R_SYM
a2d49358 JR	115	# define fn_ELF_R_INFO fn_ELF32_R_INFO
c28d5077 SR	116	# define uint_t uint32_t
	117	# define _w w
	118	# define _align 3u
	119	# define _size 4
	120	#endif
	121
412910cd WZ	122	/* Functions and pointers that do_file() may override for specific e_machine. */
	123	static int fn_is_fake_mcount(Elf_Rel const *rp)
	124	{
	125	return 0;
	126	}
	127	static int (is_fake_mcount)(Elf_Rel const rp) = fn_is_fake_mcount;
	128
a2d49358 JR	129	static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
	130	{
	131	return ELF_R_SYM(_w(rp->r_info));
	132	}
	133	static uint_t (Elf_r_sym)(Elf_Rel const rp) = fn_ELF_R_SYM;
	134
	135	static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
	136	{
e63233f7	137	rp->r_info = _w(ELF_R_INFO(sym, type));
a2d49358 JR	138	}
	139	static void (Elf_r_info)(Elf_Rel const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;
	140
07d8b595 MS	141	static int mcount_adjust = 0;
07d8b595 MS	142
412910cd WZ	143	/*
	144	* MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
	145	* _mcount symbol is needed for dynamic function tracer, with it, to disable
	146	* tracing(ftrace_make_nop), the instruction in the position is replaced with
	147	* the "b label" instruction, to enable tracing(ftrace_make_call), replace the
	148	* instruction back. So, here, we set the 2nd one as fake and filter it.
	149	*
	150	* c: 3c030000 lui v1,0x0 <--> b label
	151	* c: R_MIPS_HI16 _mcount
	152	* c: R_MIPS_NONE ABS
	153	* c: R_MIPS_NONE ABS
	154	* 10: 64630000 daddiu v1,v1,0
	155	* 10: R_MIPS_LO16 _mcount
	156	* 10: R_MIPS_NONE ABS
	157	* 10: R_MIPS_NONE ABS
	158	* 14: 03e0082d move at,ra
	159	* 18: 0060f809 jalr v1
	160	* label:
	161	*/
	162	#define MIPS_FAKEMCOUNT_OFFSET 4
	163
	164	static int MIPS_is_fake_mcount(Elf_Rel const *rp)
	165	{
	166	static Elf_Addr old_r_offset;
	167	Elf_Addr current_r_offset = _w(rp->r_offset);
	168	int is_fake;
	169
	170	is_fake = old_r_offset &&
	171	(current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
	172	old_r_offset = current_r_offset;
	173
	174	return is_fake;
	175	}
a2d49358	176
c28d5077 SR	177	/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
	178	static void append_func(Elf_Ehdr *const ehdr,
	179	Elf_Shdr *const shstr,
	180	uint_t const *const mloc0,
	181	uint_t const *const mlocp,
	182	Elf_Rel const *const mrel0,
	183	Elf_Rel const *const mrelp,
	184	unsigned int const rel_entsize,
	185	unsigned int const symsec_sh_link)
	186	{
	187	/* Begin constructing output file */
	188	Elf_Shdr mcsec;
	189	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
	190	? ".rela__mcount_loc"
	191	: ".rel__mcount_loc";
	192	unsigned const old_shnum = w2(ehdr->e_shnum);
	193	uint_t const old_shoff = _w(ehdr->e_shoff);
	194	uint_t const old_shstr_sh_size = _w(shstr->sh_size);
	195	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
	196	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
	197	uint_t new_e_shoff;
	198
	199	shstr->sh_size = _w(t);
	200	shstr->sh_offset = _w(sb.st_size);
	201	t += sb.st_size;
	202	t += (_align & -t); /* word-byte align */
	203	new_e_shoff = t;
	204
	205	/* body for new shstrtab */
	206	ulseek(fd_map, sb.st_size, SEEK_SET);
	207	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
	208	uwrite(fd_map, mc_name, 1 + strlen(mc_name));
	209
	210	/* old(modified) Elf_Shdr table, word-byte aligned */
	211	ulseek(fd_map, t, SEEK_SET);
	212	t += sizeof(Elf_Shdr) * old_shnum;
	213	uwrite(fd_map, old_shoff + (void *)ehdr,
	214	sizeof(Elf_Shdr) * old_shnum);
	215
	216	/* new sections __mcount_loc and .rel__mcount_loc */
	217	t += 2*sizeof(mcsec);
	218	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
	219	+ old_shstr_sh_size);
	220	mcsec.sh_type = w(SHT_PROGBITS);
	221	mcsec.sh_flags = _w(SHF_ALLOC);
	222	mcsec.sh_addr = 0;
	223	mcsec.sh_offset = _w(t);
	224	mcsec.sh_size = _w((void )mlocp - (void )mloc0);
	225	mcsec.sh_link = 0;
	226	mcsec.sh_info = 0;
	227	mcsec.sh_addralign = _w(_size);
	228	mcsec.sh_entsize = _w(_size);
	229	uwrite(fd_map, &mcsec, sizeof(mcsec));
	230
	231	mcsec.sh_name = w(old_shstr_sh_size);
	232	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
	233	? w(SHT_RELA)
	234	: w(SHT_REL);
	235	mcsec.sh_flags = 0;
	236	mcsec.sh_addr = 0;
	237	mcsec.sh_offset = _w((void )mlocp - (void )mloc0 + t);
	238	mcsec.sh_size = _w((void )mrelp - (void )mrel0);
	239	mcsec.sh_link = w(symsec_sh_link);
	240	mcsec.sh_info = w(old_shnum);
241	mcsec.sh_addralign = _w(_size);
242	mcsec.sh_entsize = _w(rel_entsize);
243	uwrite(fd_map, &mcsec, sizeof(mcsec));
244
245	uwrite(fd_map, mloc0, (void )mlocp - (void )mloc0);
246	uwrite(fd_map, mrel0, (void )mrelp - (void )mrel0);
247
248	ehdr->e_shoff = _w(new_e_shoff);
249	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
250	ulseek(fd_map, 0, SEEK_SET);
251	uwrite(fd_map, ehdr, sizeof(*ehdr));
252	}
253
37762cb9 SR	254	static unsigned get_mcountsym(Elf_Sym const *const sym0,
	255	Elf_Rel const *relp,
	256	char const *const str0)
	257	{
	258	unsigned mcountsym = 0;
	259
	260	Elf_Sym const *const symp =
	261	&sym0[Elf_r_sym(relp)];
	262	char const *symname = &str0[w(symp->st_name)];
	263	char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
	264
	265	if (symname[0] == '.')
	266	++symname; /* ppc64 hack */
	267	if (strcmp(mcount, symname) == 0 \|\|
	268	(altmcount && strcmp(altmcount, symname) == 0))
	269	mcountsym = Elf_r_sym(relp);
	270
	271	return mcountsym;
	272	}
	273
41b402a2 SR	274	static void get_sym_str_and_relp(Elf_Shdr const *const relhdr,
	275	Elf_Ehdr const *const ehdr,
	276	Elf_Sym const **sym0,
	277	char const **str0,
	278	Elf_Rel const **relp)
	279	{
	280	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	281	+ (void *)ehdr);
	282	unsigned const symsec_sh_link = w(relhdr->sh_link);
	283	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
	284	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
	285	Elf_Rel const const rel0 = (Elf_Rel const )(_w(relhdr->sh_offset)
	286	+ (void *)ehdr);
	287
	288	sym0 = (Elf_Sym const )(_w(symsec->sh_offset)
	289	+ (void *)ehdr);
	290
	291	str0 = (char const )(_w(strsec->sh_offset)
	292	+ (void *)ehdr);
	293
	294	*relp = rel0;
	295	}
	296
c28d5077 SR	297	/*
	298	* Look at the relocations in order to find the calls to mcount.
	299	* Accumulate the section offsets that are found, and their relocation info,
	300	* onto the end of the existing arrays.
	301	*/
	302	static uint_t sift_rel_mcount(uint_t mlocp,
	303	unsigned const offbase,
	304	Elf_Rel **const mrelpp,
	305	Elf_Shdr const *const relhdr,
	306	Elf_Ehdr const *const ehdr,
	307	unsigned const recsym,
	308	uint_t const recval,
	309	unsigned const reltype)
	310	{
	311	uint_t *const mloc0 = mlocp;
	312	Elf_Rel mrelp = mrelpp;
41b402a2 SR	313	Elf_Sym const *sym0;
	314	char const *str0;
	315	Elf_Rel const *relp;
c28d5077 SR	316	unsigned rel_entsize = _w(relhdr->sh_entsize);
c28d5077 SR	317	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
c28d5077 SR	318	unsigned mcountsym = 0;
	319	unsigned t;
	320
41b402a2 SR	321	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
41b402a2 SR	322
c28d5077	323	for (t = nrel; t; --t) {
37762cb9 SR	324	if (!mcountsym)
37762cb9 SR	325	mcountsym = get_mcountsym(sym0, relp, str0);
c28d5077	326
412910cd	327	if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
07d8b595 MS	328	uint_t const addend =
07d8b595 MS	329	_w(_w(relp->r_offset) - recval + mcount_adjust);
c28d5077 SR	330	mrelp->r_offset = _w(offbase
c28d5077 SR	331	+ ((void )mlocp - (void )mloc0));
a2d49358	332	Elf_r_info(mrelp, recsym, reltype);
dd5477ff	333	if (rel_entsize == sizeof(Elf_Rela)) {
c28d5077 SR	334	((Elf_Rela *)mrelp)->r_addend = addend;
	335	*mlocp++ = 0;
	336	} else
	337	*mlocp++ = addend;
	338
	339	mrelp = (Elf_Rel )(rel_entsize + (void )mrelp);
	340	}
	341	relp = (Elf_Rel const )(rel_entsize + (void )relp);
	342	}
	343	*mrelpp = mrelp;
	344	return mlocp;
	345	}
	346
ffd618fa SR	347	/*
	348	* Read the relocation table again, but this time its called on sections
	349	* that are not going to be traced. The mcount calls here will be converted
	350	* into nops.
	351	*/
	352	static void nop_mcount(Elf_Shdr const *const relhdr,
dfad3d59 SR	353	Elf_Ehdr const *const ehdr,
dfad3d59 SR	354	const char *const txtname)
ffd618fa SR	355	{
	356	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	357	+ (void *)ehdr);
41b402a2 SR	358	Elf_Sym const *sym0;
	359	char const *str0;
	360	Elf_Rel const *relp;
	361	Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
ffd618fa SR	362	unsigned rel_entsize = _w(relhdr->sh_entsize);
ffd618fa SR	363	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
ffd618fa SR	364	unsigned mcountsym = 0;
ffd618fa SR	365	unsigned t;
dfad3d59	366	int once = 0;
ffd618fa	367
41b402a2 SR	368	get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
41b402a2 SR	369
ffd618fa SR	370	for (t = nrel; t; --t) {
	371	int ret = -1;
	372
37762cb9 SR	373	if (!mcountsym)
37762cb9 SR	374	mcountsym = get_mcountsym(sym0, relp, str0);
ffd618fa	375
dfad3d59 SR	376	if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
	377	if (make_nop)
	378	ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
	379	if (warn_on_notrace_sect && !once) {
	380	printf("Section %s has mcount callers being ignored\n",
	381	txtname);
	382	once = 1;
	383	/* just warn? */
	384	if (!make_nop)
	385	return;
	386	}
	387	}
ffd618fa SR	388
	389	/*
	390	* If we successfully removed the mcount, mark the relocation
	391	* as a nop (don't do anything with it).
	392	*/
	393	if (!ret) {
	394	Elf_Rel rel;
	395	rel = (Elf_Rel )relp;
	396	Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
	397	ulseek(fd_map, (void )relp - (void )ehdr, SEEK_SET);
	398	uwrite(fd_map, &rel, sizeof(rel));
	399	}
	400	relp = (Elf_Rel const )(rel_entsize + (void )relp);
	401	}
	402	}
	403
c28d5077 SR	404
	405	/*
	406	* Find a symbol in the given section, to be used as the base for relocating
	407	* the table of offsets of calls to mcount. A local or global symbol suffices,
	408	* but avoid a Weak symbol because it may be overridden; the change in value
	409	* would invalidate the relocations of the offsets of the calls to mcount.
	410	* Often the found symbol will be the unnamed local symbol generated by
	411	* GNU 'as' for the start of each section. For example:
	412	* Num: Value Size Type Bind Vis Ndx Name
	413	* 2: 00000000 0 SECTION LOCAL DEFAULT 1
	414	*/
	415	static unsigned find_secsym_ndx(unsigned const txtndx,
	416	char const *const txtname,
	417	uint_t *const recvalp,
	418	Elf_Shdr const *const symhdr,
	419	Elf_Ehdr const *const ehdr)
	420	{
	421	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symhdr->sh_offset)
	422	+ (void *)ehdr);
	423	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
	424	Elf_Sym const *symp;
	425	unsigned t;
	426
	427	for (symp = sym0, t = nsym; t; --t, ++symp) {
	428	unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
	429
	430	if (txtndx == w2(symp->st_shndx)
	431	/* avoid STB_WEAK */
	432	&& (STB_LOCAL == st_bind \|\| STB_GLOBAL == st_bind)) {
9905ce8a RV	433	/* function symbols on ARM have quirks, avoid them */
	434	if (w2(ehdr->e_machine) == EM_ARM
	435	&& ELF_ST_TYPE(symp->st_info) == STT_FUNC)
	436	continue;
	437
c28d5077 SR	438	*recvalp = _w(symp->st_value);
	439	return symp - sym0;
	440	}
	441	}
	442	fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
	443	txtndx, txtname);
	444	fail_file();
	445	}
	446
	447
	448	/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
	449	static char const *
	450	__has_rel_mcount(Elf_Shdr const const relhdr, / is SHT_REL or SHT_RELA */
	451	Elf_Shdr const *const shdr0,
	452	char const *const shstrtab,
	453	char const *const fname)
	454	{
	455	/* .sh_info depends on .sh_type == SHT_REL[,A] */
	456	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
	457	char const *const txtname = &shstrtab[w(txthdr->sh_name)];
	458
dd5477ff	459	if (strcmp("__mcount_loc", txtname) == 0) {
c28d5077 SR	460	fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
	461	fname);
	462	succeed_file();
	463	}
dd5477ff	464	if (w(txthdr->sh_type) != SHT_PROGBITS \|\|
ffd618fa	465	!(w(txthdr->sh_flags) & SHF_EXECINSTR))
c28d5077 SR	466	return NULL;
	467	return txtname;
	468	}
	469
	470	static char const has_rel_mcount(Elf_Shdr const const relhdr,
	471	Elf_Shdr const *const shdr0,
	472	char const *const shstrtab,
	473	char const *const fname)
	474	{
dd5477ff	475	if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
c28d5077 SR	476	return NULL;
	477	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
	478	}
	479
	480
	481	static unsigned tot_relsize(Elf_Shdr const *const shdr0,
	482	unsigned nhdr,
	483	const char *const shstrtab,
	484	const char *const fname)
	485	{
	486	unsigned totrelsz = 0;
	487	Elf_Shdr const *shdrp = shdr0;
ffd618fa	488	char const *txtname;
c28d5077 SR	489
c28d5077 SR	490	for (; nhdr; --nhdr, ++shdrp) {
ffd618fa SR	491	txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
ffd618fa SR	492	if (txtname && is_mcounted_section_name(txtname))
c28d5077 SR	493	totrelsz += _w(shdrp->sh_size);
	494	}
	495	return totrelsz;
	496	}
	497
	498
	499	/* Overall supervision for Elf32 ET_REL file. */
	500	static void
	501	do_func(Elf_Ehdr const ehdr, char const const fname, unsigned const reltype)
	502	{
	503	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
	504	+ (void *)ehdr);
	505	unsigned const nhdr = w2(ehdr->e_shnum);
	506	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
	507	char const const shstrtab = (char const )(_w(shstr->sh_offset)
	508	+ (void *)ehdr);
	509
	510	Elf_Shdr const *relhdr;
	511	unsigned k;
	512
	513	/* Upper bound on space: assume all relevant relocs are for mcount. */
	514	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
	515	Elf_Rel *const mrel0 = umalloc(totrelsz);
	516	Elf_Rel * mrelp = mrel0;
	517
	518	/* 2sizeof(address) <= sizeof(Elf_Rel) /
	519	uint_t *const mloc0 = umalloc(totrelsz>>1);
	520	uint_t * mlocp = mloc0;
	521
	522	unsigned rel_entsize = 0;
	523	unsigned symsec_sh_link = 0;
	524
	525	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
	526	char const *const txtname = has_rel_mcount(relhdr, shdr0,
	527	shstrtab, fname);
ffd618fa	528	if (txtname && is_mcounted_section_name(txtname)) {
c28d5077 SR	529	uint_t recval = 0;
	530	unsigned const recsym = find_secsym_ndx(
	531	w(relhdr->sh_info), txtname, &recval,
	532	&shdr0[symsec_sh_link = w(relhdr->sh_link)],
	533	ehdr);
	534
	535	rel_entsize = _w(relhdr->sh_entsize);
	536	mlocp = sift_rel_mcount(mlocp,
	537	(void )mlocp - (void )mloc0, &mrelp,
	538	relhdr, ehdr, recsym, recval, reltype);
dfad3d59	539	} else if (txtname && (warn_on_notrace_sect \|\| make_nop)) {
ffd618fa SR	540	/*
	541	* This section is ignored by ftrace, but still
	542	* has mcount calls. Convert them to nops now.
	543	*/
dfad3d59	544	nop_mcount(relhdr, ehdr, txtname);
c28d5077 SR	545	}
	546	}
	547	if (mloc0 != mlocp) {
	548	append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
	549	rel_entsize, symsec_sh_link);
	550	}
	551	free(mrel0);
	552	free(mloc0);
	553	}