forked from Minki/linux
perf symbols: Add ability to find kcore in build-id cache
When no vmlinux is found, tools will use kallsyms and, if possible, kcore. Add the ability to find kcore in the build-id cache. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1381747424-3557-7-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter
Arnaldo Carvalho de Melo
parent
9a17d7268d
commit
0544d4225c
@ -1401,6 +1401,105 @@ out:
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return err;
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}
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static int find_matching_kcore(struct map *map, char *dir, size_t dir_sz)
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{
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char kallsyms_filename[PATH_MAX];
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struct dirent *dent;
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int ret = -1;
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DIR *d;
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d = opendir(dir);
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if (!d)
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return -1;
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while (1) {
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dent = readdir(d);
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if (!dent)
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break;
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if (dent->d_type != DT_DIR)
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continue;
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scnprintf(kallsyms_filename, sizeof(kallsyms_filename),
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"%s/%s/kallsyms", dir, dent->d_name);
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if (!validate_kcore_modules(kallsyms_filename, map)) {
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strlcpy(dir, kallsyms_filename, dir_sz);
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ret = 0;
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break;
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}
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}
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closedir(d);
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return ret;
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}
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static char *dso__find_kallsyms(struct dso *dso, struct map *map)
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{
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u8 host_build_id[BUILD_ID_SIZE];
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char sbuild_id[BUILD_ID_SIZE * 2 + 1];
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bool is_host = false;
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char path[PATH_MAX];
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if (!dso->has_build_id) {
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/*
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* Last resort, if we don't have a build-id and couldn't find
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* any vmlinux file, try the running kernel kallsyms table.
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*/
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goto proc_kallsyms;
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}
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if (sysfs__read_build_id("/sys/kernel/notes", host_build_id,
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sizeof(host_build_id)) == 0)
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is_host = dso__build_id_equal(dso, host_build_id);
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build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
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/* Use /proc/kallsyms if possible */
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if (is_host) {
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DIR *d;
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int fd;
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/* If no cached kcore go with /proc/kallsyms */
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scnprintf(path, sizeof(path), "%s/[kernel.kcore]/%s",
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buildid_dir, sbuild_id);
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d = opendir(path);
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if (!d)
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goto proc_kallsyms;
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closedir(d);
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/*
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* Do not check the build-id cache, until we know we cannot use
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* /proc/kcore.
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*/
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fd = open("/proc/kcore", O_RDONLY);
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if (fd != -1) {
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close(fd);
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/* If module maps match go with /proc/kallsyms */
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if (!validate_kcore_modules("/proc/kallsyms", map))
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goto proc_kallsyms;
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}
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/* Find kallsyms in build-id cache with kcore */
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if (!find_matching_kcore(map, path, sizeof(path)))
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return strdup(path);
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goto proc_kallsyms;
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}
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scnprintf(path, sizeof(path), "%s/[kernel.kallsyms]/%s",
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buildid_dir, sbuild_id);
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if (access(path, F_OK)) {
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pr_err("No kallsyms or vmlinux with build-id %s was found\n",
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sbuild_id);
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return NULL;
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}
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return strdup(path);
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proc_kallsyms:
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return strdup("/proc/kallsyms");
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}
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static int dso__load_kernel_sym(struct dso *dso, struct map *map,
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symbol_filter_t filter)
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{
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@ -1449,51 +1548,11 @@ static int dso__load_kernel_sym(struct dso *dso, struct map *map,
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if (symbol_conf.symfs[0] != 0)
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return -1;
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/*
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* Say the kernel DSO was created when processing the build-id header table,
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* we have a build-id, so check if it is the same as the running kernel,
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* using it if it is.
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*/
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if (dso->has_build_id) {
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u8 kallsyms_build_id[BUILD_ID_SIZE];
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char sbuild_id[BUILD_ID_SIZE * 2 + 1];
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kallsyms_allocated_filename = dso__find_kallsyms(dso, map);
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if (!kallsyms_allocated_filename)
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return -1;
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if (sysfs__read_build_id("/sys/kernel/notes", kallsyms_build_id,
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sizeof(kallsyms_build_id)) == 0) {
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if (dso__build_id_equal(dso, kallsyms_build_id)) {
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kallsyms_filename = "/proc/kallsyms";
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goto do_kallsyms;
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}
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}
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/*
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* Now look if we have it on the build-id cache in
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* $HOME/.debug/[kernel.kallsyms].
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*/
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build_id__sprintf(dso->build_id, sizeof(dso->build_id),
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sbuild_id);
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if (asprintf(&kallsyms_allocated_filename,
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"%s/.debug/[kernel.kallsyms]/%s",
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getenv("HOME"), sbuild_id) == -1) {
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pr_err("Not enough memory for kallsyms file lookup\n");
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return -1;
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}
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kallsyms_filename = kallsyms_allocated_filename;
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if (access(kallsyms_filename, F_OK)) {
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pr_err("No kallsyms or vmlinux with build-id %s "
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"was found\n", sbuild_id);
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free(kallsyms_allocated_filename);
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return -1;
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}
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} else {
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/*
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* Last resort, if we don't have a build-id and couldn't find
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* any vmlinux file, try the running kernel kallsyms table.
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*/
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kallsyms_filename = "/proc/kallsyms";
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}
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kallsyms_filename = kallsyms_allocated_filename;
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do_kallsyms:
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err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
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