On 10/08/2013 05:09 PM, Masami Hiramatsu wrote:
(2013/10/07 15:47), Hemant Kumar wrote:@@ -325,6 +326,7 @@ 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', "markers", ¶ms.sdt, "Show probe-able sdt notes"),BTW, "-S" for short of "--markers" option is a bit odd. Would we better use -M ? :)
I thought of -S as SDT. :) Anyways, on second thought, will change that to -M.
[...]@@ -355,6 +357,26 @@ 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 --markers with --lines.\n"); + usage_with_options(probe_usage, options); + } + if (params.show_vars) { + pr_err("Error: Don't use --markers with --vars.\n"); + usage_with_options(probe_usage, options); + } + if (params.show_funcs) { + pr_err("Error: Don't use --markers with --funcs.\n"); + usage_with_options(probe_usage, options); + } + ret = show_sdt_notes(params.target);You have to ensure params.target is set before use it.
Yes, will do that.
+ if (ret < 0) { + pr_err(" Error : Failed to find SDT 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");[...]diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 4b12bf8..6b17260 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -846,6 +846,182 @@ out_elf_end: return err; }+/*+ * Populate the name, type, offset in the SDT note structure and + * ignore the argument fields (for now) + */ +static struct sdt_note *populate_sdt_note(Elf **elf, const char *data, + size_t len, int type) +{ + const char *provider, *name; + struct sdt_note *note; + + /* + * Three addresses need to be obtained : + * Marker location, address of base section and semaphore location + */ + union { + Elf64_Addr a64[3]; + Elf32_Addr a32[3]; + } buf; + + /* + * dst and src 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 + }; + + /* Check the type of each of the notes */ + if (type != SDT_NOTE_TYPE) + goto out_ret; + + note = (struct sdt_note *)zalloc(sizeof(struct sdt_note)); + if (note == NULL) { + pr_err("Memory allocation error\n");No need to state out of memory for each place... If you hit an out of memory for such small piece, you'd better abort execution. For that purpose, I recommend you to return errno from each function, and caller must check it.
Yeah this will be better... will return errno from each function.
+ goto out_ret; + } + INIT_LIST_HEAD(¬e->note_list); + + if (len < dst.d_size + 3) + goto out_free; + + /* Translation from file representation to memory representation */ + 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_free; + note->provider = strdup(provider); + note->name = strdup(name); + + /* Obtain the addresses and ignore notes with semaphores set*/ + if (gelf_getclass(*elf) == ELFCLASS32) { + note->addr.a32[0] = buf.a32[0]; + note->addr.a32[1] = buf.a32[1]; + note->addr.a32[2] = buf.a32[2]; + note->bit32 = true; + if (buf.a32[2] != 0) + goto out_free; + } else { + note->addr.a64[0] = buf.a64[0]; + note->addr.a64[1] = buf.a64[1]; + note->addr.a64[2] = buf.a64[2]; + note->bit32 = false; + if (buf.a64[2] != 0) + goto out_free; + } + return note; + +out_free: + free(note); +out_ret: + return NULL; +} + +static struct list_head *construct_sdt_notes_list(Elf *elf)This also would better return errno.
Ok.
+{ + GElf_Ehdr ehdr; + Elf_Scn *scn = NULL; + Elf_Data *data; + GElf_Shdr shdr; + size_t shstrndx; + size_t next; + GElf_Nhdr nhdr; + size_t name_off, desc_off, offset; + struct sdt_note *tmp = NULL, *note = NULL; + + if (gelf_getehdr(elf, &ehdr) == NULL) { + pr_debug("%s: Can't get elf header.\n", __func__); + goto out_err; + } + if (elf_getshdrstrndx(elf, &shstrndx) != 0) { + pr_debug("getshdrstrndx failed\n"); + goto out_err; + } + + /* + * 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) { + printf("SDT markers not present!\n");Why you don't use pr_err() here ? :)
Because, I thought it isn't an error that SDT markers are not present. It won't make much of a difference though. :)
And also, as I commented, I'd like to know which binary doesn't have SDT markers, at least with -v (verbose) option.
Yes, I guess it would be better to show the binary name even without -v option. Will make the changes.
-- Thanks Hemant -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
