Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762028Ab3IDGmb (ORCPT ); Wed, 4 Sep 2013 02:42:31 -0400 Received: from lgeamrelo02.lge.com ([156.147.1.126]:45447 "EHLO LGEAMRELO02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756264Ab3IDGma (ORCPT ); Wed, 4 Sep 2013 02:42:30 -0400 X-AuditID: 9c93017e-b7c76ae000003897-4a-5226d653b967 From: Namhyung Kim To: Hemant Kumar Cc: linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com, peterz@infradead.org, oleg@redhat.com, mingo@redhat.com, anton@redhat.com, systemtap@sourceware.org, masami.hiramatsu.pt@hitachi.com Subject: Re: [PATCH 1/2] SDT markers listing by perf References: <20130903072944.4793.93584.stgit@hemant-fedora> <20130903073655.4793.20013.stgit@hemant-fedora> Date: Wed, 04 Sep 2013 15:42:27 +0900 In-Reply-To: <20130903073655.4793.20013.stgit@hemant-fedora> (Hemant Kumar's message of "Tue, 03 Sep 2013 13:06:55 +0530") Message-ID: <87ioyht7e4.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10068 Lines: 367 On Tue, 03 Sep 2013 13:06:55 +0530, Hemant Kumar wrote: [SNIP] > diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c > index e8a66f9..3d8dcdf 100644 > --- a/tools/perf/builtin-probe.c > +++ b/tools/perf/builtin-probe.c > @@ -55,6 +55,7 @@ static struct { > bool show_funcs; > bool mod_events; > bool uprobes; > + bool sdt; > int nevents; > struct perf_probe_event events[MAX_PROBES]; > struct strlist *dellist; > @@ -325,6 +326,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused) > opt_set_filter), > OPT_CALLBACK('x', "exec", NULL, "executable|path", > "target executable name or path", opt_set_target), > + OPT_BOOLEAN('S', "sdt", ¶ms.sdt, > + "Show and probe on the SDT markers"), You need to add it to Documentation/perf-probe.txt too. In addition if the --sdt option is only able to work with libelf, it should be wrapped into the #ifdef LIBELF_SUPPORT pair. And I'm not sure that it's a good idea to have two behavior on a single option (S) - show and probe (add). Maybe it can be separated into two or the S option can be used as a flag with existing --list and --add option? > OPT_END() > }; > int ret; > @@ -355,6 +358,28 @@ int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused) > */ > symbol_conf.try_vmlinux_path = (symbol_conf.vmlinux_name == NULL); > > + if (params.sdt) { > + if (params.show_lines) { > + pr_err(" Error: Don't use --sdt with --line.\n"); > + usage_with_options(probe_usage, options); > + } > + if (params.show_vars) { > + pr_err(" Error: Don't use --sdt with --vars.\n"); > + usage_with_options(probe_usage, options); > + } > + if (params.show_funcs) { > + pr_err(" Error: Don't use --sdt with --funcs.\n"); > + usage_with_options(probe_usage, options); > + } > + if (params.list_events) { > + ret = show_available_markers(params.target); > + if (ret < 0) > + pr_err(" Error: Failed to show markers." > + " (%d)\n", ret); > + return ret; > + } > + } > + > if (params.list_events) { > if (params.mod_events) { > pr_err(" Error: Don't use --list with --add/--del.\n"); > @@ -382,6 +407,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused) > ret); > return ret; > } > + > if (params.show_funcs) { > if (params.nevents != 0 || params.dellist) { > pr_err(" Error: Don't use --funcs with" > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > index aa04bf9..7f846f9 100644 > --- a/tools/perf/util/probe-event.c > +++ b/tools/perf/util/probe-event.c > @@ -2372,3 +2372,9 @@ out: > free(name); > return ret; > } > + > +int show_available_markers(const char *target) > +{ > + setup_pager(); > + return list_markers(target); > +} Did you build it with NO_LIBELF=1 ? I guess not. At least you need a dummy list_markers() function which just returns -1 for such case. > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 4b12bf8..f3630f2 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -846,6 +846,211 @@ out_elf_end: > return err; > } > > +/* Populate the name, type, offset and argument fields in the note structure */ > +static struct sdt_note *populate_note(Elf **elf, const char *data, size_t len, > + int type) Hmm.. I think the name needs to be changed more specific like populate_sdt_note() or something? > +{ > + const char *provider, *name, *args; > + struct sdt_note *note; > + > + /* > + * There are 3 address values to be obtained: marker offset, base address > + * and semaphore > + */ > + union { > + Elf64_Addr a64[3]; > + Elf32_Addr a32[3]; > + } buf; > + > + /* > + * dst and src (of Elf_Data) are required for translation from file > + * to memory representation > + */ > + Elf_Data dst = { > + .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, > + .d_size = gelf_fsize((*elf), ELF_T_ADDR, 3, EV_CURRENT), > + .d_off = 0, .d_align = 0 > + }; > + > + Elf_Data src = { > + .d_buf = (void *) data, .d_type = ELF_T_ADDR, > + .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, > + .d_align = 0 > + }; > + > + if (type != SDT_NOTE_TYPE) > + goto out_ret; > + > + note = zalloc(sizeof(struct sdt_note)); > + if (note == NULL) { > + pr_err("memory allocation error\n"); > + goto out_ret; > + } > + note->next = NULL; > + > + if (len < dst.d_size + 3) > + goto out_free; > + /* > + * Translating from file representation to memory representation > + * Data now points to the address (offset) > + */ > + if (gelf_xlatetom((*elf), &dst, &src, > + elf_getident((*elf), NULL)[EI_DATA]) == NULL) > + pr_debug("gelf_xlatetom : %s", elf_errmsg(-1)); > + > + /* Populate the fields of sdt_note */ > + provider = data + dst.d_size; > + > + name = (const char *)memchr(provider, '\0', data + len - provider); > + if (name++ == NULL) > + goto out_ret; > + > + args = (const char *)memchr(name, '\0', data + len - name); > + if (args++ == NULL || > + memchr(args, '\0', data + len - name) != data + len - 1) > + goto out_ret; > + note->provider = provider; > + note->name = name; > + > + /* Three addr's for location, base and semaphore addresses */ > + note->addr.a64[0] = (buf.a64[0]); > + note->addr.a64[1] = (buf.a64[1]); > + note->addr.a64[2] = (buf.a64[2]); > + return note; > + > +out_free: > + free(note); > +out_ret: > + return NULL; > +} > + > +/* > + * Traverse the elf of the object, find out the .note.stapsdt section > + * and accordingly initialize the notes' list head > + */ > +static struct sdt_note *get_elf_markers(Elf *elf, bool *exe, bool probe) Ditto. How about get_sdt_markers() or get_sdt_notes()? I can see that there are places those 'marker' and 'note' are used here and there. If they indicate same thing it'd better to unify the term. > +{ > + Elf_Scn *scn = NULL; > + Elf_Data *data; > + GElf_Shdr shdr; > + GElf_Ehdr ehdr; > + size_t shstrndx; > + size_t next; > + GElf_Nhdr nhdr; > + size_t name_off, desc_off, offset; > + struct sdt_note *note = NULL, *tmp, *head = NULL; > + > + if (gelf_getehdr(elf, &ehdr) == NULL) { > + pr_debug("%s: cannot get elf header.\n", __func__); > + goto out_end; > + } > + > + if (elf_getshdrstrndx(elf, &shstrndx) != 0) { > + pr_debug("getshdrstrndx failed\n"); > + goto out_end; > + } > + > + /* library or exec */ > + if (probe) { > + if (ehdr.e_type == ET_EXEC) > + *exe = true; > + } > + > + /* > + * Look for Section type = SHT_NOTE, flags = no SHF_ALLOC > + * and name = .note.stapsdt > + */ > + scn = elf_section_by_name(elf, &ehdr, &shdr, NOTE_SCN, NULL); > + if (scn == NULL) { > + pr_err("%s section not found!\n", NOTE_SCN); > + goto out_end; > + } > + > + if (!(shdr.sh_type == SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) > + goto out_end; > + > + data = elf_getdata(scn, NULL); > + > + /* Get the notes */ > + for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, > + &desc_off)) > 0; offset = next) { > + tmp = populate_note(&elf, (const char *)((long)(data->d_buf) + > + (long)desc_off), > + nhdr.n_descsz, nhdr.n_type); Shouldn't we check the name of note being "stapsdt" as well as version (type) 3? Thanks, Namhyung > + /* For first note */ > + if (!head) { > + note = tmp; > + head = note; > + continue; > + } > + note->next = tmp; > + note = note->next; > + } > + > + if (!head) > + pr_err("No markers found\n"); > + > +out_end: > + return head; > +} > + > +static void print_notes(struct sdt_note *start) > +{ > + struct sdt_note *temp; > + int c; > + > + for (temp = start, c = 0; temp != NULL; temp = temp->next, c++) > + printf("%s:%s\n", temp->provider, temp->name); > + > + printf("\nTotal markers = %d\n", c); > +} > + > +int list_markers(const char *name) > +{ > + int fd, ret = -1; > + Elf *elf; > + struct sdt_note *head = NULL; > + > + fd = open(name, O_RDONLY); > + if (fd < 0) { > + pr_err("Failed to open %s\n", name); > + goto out_ret; > + } > + > + symbol__elf_init(); > + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); > + if (elf == NULL) { > + pr_err("%s: cannot read %s ELF file.\n", __func__, name); > + goto out_close; > + } > + > + head = get_elf_markers(elf, NULL, false); > + if (head) { > + print_notes(head); > + cleanup_notes(head); > + ret = 0; > + } else { > + pr_err("No SDT markers found in %s\n", name); > + } > + elf_end(elf); > + > +out_close: > + close(fd); > +out_ret: > + return ret; > +} > + > +void cleanup_notes(struct sdt_note *start) > +{ > + struct sdt_note *tmp; > + > + while (start) { > + tmp = start->next; > + free(start); > + start = tmp; > + } > +} > + > void symbol__elf_init(void) > { > elf_version(EV_CURRENT); > diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h > index 5f720dc..f2d17b7 100644 > --- a/tools/perf/util/symbol.h > +++ b/tools/perf/util/symbol.h > @@ -197,6 +197,17 @@ struct symsrc { > #endif > }; > > +/* Note structure */ > +struct sdt_note { > + const char *name; > + const char *provider; > + union { > + Elf64_Addr a64[3]; > + Elf32_Addr a32[3]; > + } addr; > + struct sdt_note *next; > +}; > + > void symsrc__destroy(struct symsrc *ss); > int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, > enum dso_binary_type type); > @@ -247,4 +258,12 @@ void symbols__fixup_duplicate(struct rb_root *symbols); > void symbols__fixup_end(struct rb_root *symbols); > void __map_groups__fixup_end(struct map_groups *mg, enum map_type type); > > +/* For SDT markers */ > +int show_available_markers(const char *module); > +int list_markers(const char *name); > +void cleanup_notes(struct sdt_note *start); > + > +#define SDT_NOTE_TYPE 3 > +#define NOTE_SCN ".note.stapsdt" > + > #endif /* __PERF_SYMBOL */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/