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Commit 62eb9390 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by Ingo Molnar
Browse files

perf_counter: Implement dso__load using libelf 



Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent fd4242bb

Documentation/perf_counter/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -160,7 +160,7 @@ uname_V := $(shell sh -c 'uname -v 2>/dev/null || echo not') 
# CFLAGS and LDFLAGS are for the users to override from the command line.



CFLAGS = -g -O2 -Wall

LDFLAGS = -lpthread -lrt

LDFLAGS = -lpthread -lrt -lelf

ALL_CFLAGS = $(CFLAGS)

ALL_LDFLAGS = $(LDFLAGS)

STRIP ?= strip

Documentation/perf_counter/builtin-report.c

+120 −2
Original line number Diff line number Diff line
@@ -8,6 +8,9 @@ 
#include <stdlib.h>

#include <string.h>

#include <limits.h>

#include <gelf.h>

#include <elf.h>

#include <libelf.h>

#include <fcntl.h>

#include <stdio.h>

#include <errno.h>
@@ -195,10 +198,123 @@ static struct symbol *dso__find_symbol(struct dso *self, uint64_t ip) 
	return NULL;

}



/**

 * elf_symtab__for_each_symbol - iterate thru all the symbols

 *

 * @self: struct elf_symtab instance to iterate

 * @index: uint32_t index

 * @sym: GElf_Sym iterator

 */

#define elf_symtab__for_each_symbol(syms, nr_syms, index, sym) \

	for (index = 0, gelf_getsym(syms, index, &sym);\

	     index < nr_syms; \

	     index++, gelf_getsym(syms, index, &sym))



static inline uint8_t elf_sym__type(const GElf_Sym *sym)

{

	return GELF_ST_TYPE(sym->st_info);

}



static inline bool elf_sym__is_function(const GElf_Sym *sym)

{

	return elf_sym__type(sym) == STT_FUNC &&

	       sym->st_name != 0 &&

	       sym->st_shndx != SHN_UNDEF;

}



static inline const char *elf_sym__name(const GElf_Sym *sym,

					const Elf_Data *symstrs)

{

	return symstrs->d_buf + sym->st_name;

}



static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,

				    GElf_Shdr *shp, const char *name,

				    size_t *index)

{

	Elf_Scn *sec = NULL;

	size_t cnt = 1;



	while ((sec = elf_nextscn(elf, sec)) != NULL) {

		char *str;



		gelf_getshdr(sec, shp);

		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);

		if (!strcmp(name, str)) {

			if (index)

				*index = cnt;

			break;

		}

		++cnt;

	}



	return sec;

}



static int dso__load(struct dso *self)

{

	/* FIXME */

	return 0;

	int fd = open(self->name, O_RDONLY), err = -1;



	if (fd == -1)

		return -1;



	Elf *elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);

	if (elf == NULL) {

		fprintf(stderr, "%s: cannot read %s ELF file.\n",

			__func__, self->name);

		goto out_close;

	}



	GElf_Ehdr ehdr;

	if (gelf_getehdr(elf, &ehdr) == NULL) {

		fprintf(stderr, "%s: cannot get elf header.\n", __func__);

		goto out_elf_end;

	}



	GElf_Shdr shdr;

	Elf_Scn *sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);

	if (sec == NULL)

		sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL);



	if (sec == NULL)

		goto out_elf_end;



	if (gelf_getshdr(sec, &shdr) == NULL)

		goto out_elf_end;



	Elf_Data *syms = elf_getdata(sec, NULL);

	if (syms == NULL)

		goto out_elf_end;



	sec = elf_getscn(elf, shdr.sh_link);

	if (sec == NULL)

		goto out_elf_end;



	Elf_Data *symstrs = elf_getdata(sec, NULL);

	if (symstrs == NULL)

		goto out_elf_end;



	const uint32_t nr_syms = shdr.sh_size / shdr.sh_entsize;



	GElf_Sym sym;

	uint32_t index;

	elf_symtab__for_each_symbol(syms, nr_syms, index, sym) {

		if (!elf_sym__is_function(&sym))

			continue;

		struct symbol *f = symbol__new(sym.st_value, sym.st_size,

					       elf_sym__name(&sym, symstrs));

		if (f == NULL)

			goto out_elf_end;



		dso__insert_symbol(self, f);

	}



	err = 0;

out_elf_end:

	elf_end(elf);

out_close:

	close(fd);

	return err;

}



static size_t dso__fprintf(struct dso *self, FILE *fp)
@@ -614,6 +730,8 @@ int cmd_report(int argc, char **argv) 
	int ret, rc = EXIT_FAILURE;

	unsigned long total = 0;



	elf_version(EV_CURRENT);



	page_size = getpagesize();



	process_options(argc, argv);