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 */
--
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