![Andi Kleen](/assets/img/avatar_default.png)
When profiling the kernel with the 'srcfile' sort key it's common to "get stuck" in include. For example a lot of code uses current or other inlines, so they get accounted to some random include file. This is not very useful as a high level categorization. For example just profiling the idle loop usually shows mostly inlines, so you never see the actual cpuidle file. This patch changes the 'srcfile' sort key to always unwind the inline stack using BFD/DWARF. So we always account to the base function that called the inline. In a few cases include is still shown (for example for MSR accesses), but that is because they get inlining expanded as part of assigning to a global function pointer. For the majority it works fine though. v2: Use simpler while loop. Add maximum iteration count. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1441133239-31254-1-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
332 lines
5.9 KiB
C
332 lines
5.9 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <linux/kernel.h>
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#include "util/dso.h"
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#include "util/util.h"
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#include "util/debug.h"
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#include "symbol.h"
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bool srcline_full_filename;
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#ifdef HAVE_LIBBFD_SUPPORT
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/*
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* Implement addr2line using libbfd.
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*/
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#define PACKAGE "perf"
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#include <bfd.h>
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struct a2l_data {
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const char *input;
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u64 addr;
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bool found;
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const char *filename;
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const char *funcname;
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unsigned line;
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bfd *abfd;
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asymbol **syms;
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};
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static int bfd_error(const char *string)
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{
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const char *errmsg;
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errmsg = bfd_errmsg(bfd_get_error());
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fflush(stdout);
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if (string)
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pr_debug("%s: %s\n", string, errmsg);
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else
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pr_debug("%s\n", errmsg);
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return -1;
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}
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static int slurp_symtab(bfd *abfd, struct a2l_data *a2l)
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{
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long storage;
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long symcount;
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asymbol **syms;
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bfd_boolean dynamic = FALSE;
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if ((bfd_get_file_flags(abfd) & HAS_SYMS) == 0)
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return bfd_error(bfd_get_filename(abfd));
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storage = bfd_get_symtab_upper_bound(abfd);
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if (storage == 0L) {
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storage = bfd_get_dynamic_symtab_upper_bound(abfd);
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dynamic = TRUE;
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}
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if (storage < 0L)
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return bfd_error(bfd_get_filename(abfd));
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syms = malloc(storage);
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if (dynamic)
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symcount = bfd_canonicalize_dynamic_symtab(abfd, syms);
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else
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symcount = bfd_canonicalize_symtab(abfd, syms);
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if (symcount < 0) {
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free(syms);
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return bfd_error(bfd_get_filename(abfd));
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}
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a2l->syms = syms;
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return 0;
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}
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static void find_address_in_section(bfd *abfd, asection *section, void *data)
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{
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bfd_vma pc, vma;
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bfd_size_type size;
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struct a2l_data *a2l = data;
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if (a2l->found)
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return;
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if ((bfd_get_section_flags(abfd, section) & SEC_ALLOC) == 0)
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return;
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pc = a2l->addr;
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vma = bfd_get_section_vma(abfd, section);
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size = bfd_get_section_size(section);
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if (pc < vma || pc >= vma + size)
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return;
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a2l->found = bfd_find_nearest_line(abfd, section, a2l->syms, pc - vma,
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&a2l->filename, &a2l->funcname,
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&a2l->line);
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}
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static struct a2l_data *addr2line_init(const char *path)
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{
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bfd *abfd;
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struct a2l_data *a2l = NULL;
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abfd = bfd_openr(path, NULL);
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if (abfd == NULL)
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return NULL;
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if (!bfd_check_format(abfd, bfd_object))
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goto out;
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a2l = zalloc(sizeof(*a2l));
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if (a2l == NULL)
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goto out;
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a2l->abfd = abfd;
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a2l->input = strdup(path);
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if (a2l->input == NULL)
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goto out;
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if (slurp_symtab(abfd, a2l))
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goto out;
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return a2l;
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out:
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if (a2l) {
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zfree((char **)&a2l->input);
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free(a2l);
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}
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bfd_close(abfd);
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return NULL;
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}
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static void addr2line_cleanup(struct a2l_data *a2l)
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{
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if (a2l->abfd)
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bfd_close(a2l->abfd);
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zfree((char **)&a2l->input);
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zfree(&a2l->syms);
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free(a2l);
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}
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#define MAX_INLINE_NEST 1024
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static int addr2line(const char *dso_name, u64 addr,
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char **file, unsigned int *line, struct dso *dso,
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bool unwind_inlines)
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{
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int ret = 0;
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struct a2l_data *a2l = dso->a2l;
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if (!a2l) {
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dso->a2l = addr2line_init(dso_name);
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a2l = dso->a2l;
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}
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if (a2l == NULL) {
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pr_warning("addr2line_init failed for %s\n", dso_name);
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return 0;
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}
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a2l->addr = addr;
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a2l->found = false;
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bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);
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if (a2l->found && unwind_inlines) {
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int cnt = 0;
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while (bfd_find_inliner_info(a2l->abfd, &a2l->filename,
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&a2l->funcname, &a2l->line) &&
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cnt++ < MAX_INLINE_NEST)
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;
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}
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if (a2l->found && a2l->filename) {
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*file = strdup(a2l->filename);
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*line = a2l->line;
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if (*file)
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ret = 1;
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}
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return ret;
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}
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void dso__free_a2l(struct dso *dso)
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{
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struct a2l_data *a2l = dso->a2l;
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if (!a2l)
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return;
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addr2line_cleanup(a2l);
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dso->a2l = NULL;
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}
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#else /* HAVE_LIBBFD_SUPPORT */
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static int addr2line(const char *dso_name, u64 addr,
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char **file, unsigned int *line_nr,
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struct dso *dso __maybe_unused,
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bool unwind_inlines __maybe_unused)
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{
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FILE *fp;
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char cmd[PATH_MAX];
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char *filename = NULL;
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size_t len;
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char *sep;
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int ret = 0;
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scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
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dso_name, addr);
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fp = popen(cmd, "r");
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if (fp == NULL) {
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pr_warning("popen failed for %s\n", dso_name);
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return 0;
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}
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if (getline(&filename, &len, fp) < 0 || !len) {
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pr_warning("addr2line has no output for %s\n", dso_name);
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goto out;
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}
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sep = strchr(filename, '\n');
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if (sep)
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*sep = '\0';
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if (!strcmp(filename, "??:0")) {
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pr_debug("no debugging info in %s\n", dso_name);
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free(filename);
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goto out;
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}
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sep = strchr(filename, ':');
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if (sep) {
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*sep++ = '\0';
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*file = filename;
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*line_nr = strtoul(sep, NULL, 0);
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ret = 1;
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}
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out:
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pclose(fp);
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return ret;
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}
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void dso__free_a2l(struct dso *dso __maybe_unused)
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{
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}
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#endif /* HAVE_LIBBFD_SUPPORT */
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/*
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* Number of addr2line failures (without success) before disabling it for that
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* dso.
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*/
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#define A2L_FAIL_LIMIT 123
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char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
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bool show_sym, bool unwind_inlines)
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{
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char *file = NULL;
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unsigned line = 0;
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char *srcline;
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const char *dso_name;
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if (!dso->has_srcline)
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goto out;
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if (dso->symsrc_filename)
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dso_name = dso->symsrc_filename;
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else
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dso_name = dso->long_name;
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if (dso_name[0] == '[')
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goto out;
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if (!strncmp(dso_name, "/tmp/perf-", 10))
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goto out;
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if (!addr2line(dso_name, addr, &file, &line, dso, unwind_inlines))
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goto out;
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if (asprintf(&srcline, "%s:%u",
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srcline_full_filename ? file : basename(file),
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line) < 0) {
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free(file);
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goto out;
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}
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dso->a2l_fails = 0;
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free(file);
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return srcline;
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out:
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if (dso->a2l_fails && ++dso->a2l_fails > A2L_FAIL_LIMIT) {
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dso->has_srcline = 0;
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dso__free_a2l(dso);
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}
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if (sym) {
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if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
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addr - sym->start) < 0)
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return SRCLINE_UNKNOWN;
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} else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
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return SRCLINE_UNKNOWN;
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return srcline;
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}
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void free_srcline(char *srcline)
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{
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if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
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free(srcline);
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}
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char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
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bool show_sym)
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{
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return __get_srcline(dso, addr, sym, show_sym, false);
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}
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