[ltt-dev] [PATCH] tracepoints: Generate Module.tracepoints file
Mathieu Desnoyers
compudj at krystal.dyndns.org
Thu Sep 18 12:05:41 EDT 2008
Hrmmm, is there a real need for it ? I mean.. if the information is
available in the kernel headers found in include/trace/*.h, why would we
need another repository created at build time ?
Mathieu
* Jan Blunck (jblunck at suse.de) wrote:
> This adds support to generate the Module.tracepoints file by modpost. This
> can be read by tools like SystemTap very similar to the Module.markers file.
>
> Signed-off-by: Jan Blunck <jblunck at suse.de>
> ---
> Makefile | 6 +
> scripts/Makefile.modpost | 5 +
> scripts/mod/modpost.c | 173 +++++++++++++++++++++++++++++++++++++++++++++--
> scripts/mod/modpost.h | 3
> 4 files changed, 178 insertions(+), 9 deletions(-)
>
> Index: b/Makefile
> ===================================================================
> --- a/Makefile
> +++ b/Makefile
> @@ -1178,7 +1178,8 @@ MRPROPER_FILES += .config .config.old in
> include/linux/autoconf.h include/linux/version.h \
> include/linux/utsrelease.h \
> include/linux/bounds.h include/asm*/asm-offsets.h \
> - Module.symvers Module.markers tags TAGS cscope*
> + Module.symvers Module.markers Module.tracepoints \
> + tags TAGS cscope*
>
> # clean - Delete most, but leave enough to build external modules
> #
> @@ -1197,7 +1198,8 @@ clean: archclean $(clean-dirs)
> \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
> -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
> -o -name '*.symtypes' -o -name 'modules.order' \
> - -o -name 'Module.markers' -o -name '.tmp_*.o.*' \) \
> + -o -name 'Module.markers' -o -name 'Module.tracepoints' \
> + -o -name '.tmp_*.o.*' \) \
> -type f -print | xargs rm -f
>
> # mrproper - Delete all generated files, including .config
> Index: b/scripts/Makefile.modpost
> ===================================================================
> --- a/scripts/Makefile.modpost
> +++ b/scripts/Makefile.modpost
> @@ -61,8 +61,11 @@ kernelsymfile := $(objtree)/Module.symve
> modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
> kernelmarkersfile := $(objtree)/Module.markers
> modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
> +kerneltracepointsfile := $(objtree)/Module.tracepoints
> +moduletracepointsfile := $(firstword $(KBUILD_EXTMOD))/Module.tracepoints
>
> markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
> +tracepointsfile = $(if $(KBUILD_EXTMOD),$(moduletracepointsfile),$(kerneltracepointsfile))
>
> # Step 1), find all modules listed in $(MODVERDIR)/
> __modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
> @@ -87,6 +90,8 @@ modpost = scripts/mod/modpost
> $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
> $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
> $(if $(CONFIG_MARKERS),-M $(markersfile)) \
> + $(if $(CONFIG_TRACEPOINTS),-T $(kerneltracepointsfile)) \
> + $(if $(CONFIG_TRACEPOINTS),-t $(tracepointsfile)) \
> $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
> $(if $(cross_build),-c) \
> -N $(firstword $(wildcard $(dir $(MODVERDIR))/Module.supported \
> Index: b/scripts/mod/modpost.c
> ===================================================================
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -439,6 +439,8 @@ static int parse_elf(struct elf_info *in
> info->export_gpl_future_sec = i;
> else if (strcmp(secname, "__markers_strings") == 0)
> info->markers_strings_sec = i;
> + else if (strcmp(secname, "__tracepoints_strings") == 0)
> + info->tracepoints_strings_sec = i;
>
> if (sechdrs[i].sh_type != SHT_SYMTAB)
> continue;
> @@ -1545,6 +1547,63 @@ static void get_markers(struct elf_info
> }
> }
>
> +static void get_tracepoints(struct elf_info *info, struct module *mod)
> +{
> + const Elf_Shdr *sh = &info->sechdrs[info->tracepoints_strings_sec];
> + const char *strings = (const char *) info->hdr + sh->sh_offset;
> + const Elf_Sym *sym, *first_sym, *last_sym;
> + size_t n;
> +
> + if (!info->tracepoints_strings_sec)
> + return;
> +
> + /*
> + * First count the strings. We look for all the symbols defined
> + * in the __tracepoints_strings section named __tpstrtab_*. For
> + * these local names, the compiler puts a random .NNN suffix on,
> + * so the names don't correspond exactly.
> + */
> + first_sym = last_sym = NULL;
> + n = 0;
> + for (sym = info->symtab_start; sym < info->symtab_stop; sym++)
> + if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT &&
> + sym->st_shndx == info->tracepoints_strings_sec &&
> + !strncmp(info->strtab + sym->st_name,
> + "__tpstrtab_", sizeof "__tpstrtab_" - 1)) {
> + if (first_sym == NULL)
> + first_sym = sym;
> + last_sym = sym;
> + ++n;
> + }
> +
> + if (n == 0)
> + return;
> +
> + /*
> + * Now collect each name and format into a line for the output.
> + * Lines look like:
> + * marker_name vmlinux marker %s format %d
> + * The format string after the second \t can use whitespace.
> + */
> + mod->tracepoints = NOFAIL(malloc(sizeof mod->tracepoints[0] * n));
> + mod->ntracepoints = n;
> +
> + n = 0;
> + for (sym = first_sym; sym <= last_sym; sym++)
> + if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT &&
> + sym->st_shndx == info->tracepoints_strings_sec &&
> + !strncmp(info->strtab + sym->st_name,
> + "__tpstrtab_", sizeof "__tpstrtab_" - 1)) {
> + const char *name = strings + sym->st_value;
> + const char *fmt = strchr(name, ':') + 1;
> + char *line = NULL;
> + asprintf(&line, "%.*s\t%s\t%s\n", fmt - name - 1, name,
> + mod->name, fmt);
> + NOFAIL(line);
> + mod->tracepoints[n++] = line;
> + }
> +}
> +
> void *supported_file;
> unsigned long supported_size;
>
> @@ -1643,6 +1702,7 @@ static void read_symbols(char *modname)
> sizeof(mod->srcversion)-1);
>
> get_markers(&info, mod);
> + get_tracepoints(&info, mod);
>
> parse_elf_finish(&info);
>
> @@ -2091,6 +2151,91 @@ static void write_markers(const char *fn
> write_if_changed(&buf, fname);
> }
>
> +static void add_tracepoint(struct module *mod, const char *name,
> + const char *fmt)
> +{
> + char *line = NULL;
> + asprintf(&line, "%s\t%s\t%s\n", name, mod->name, fmt);
> + NOFAIL(line);
> +
> + mod->tracepoints = NOFAIL(realloc(mod->tracepoints,
> + ((mod->ntracepoints + 1) *
> + sizeof mod->tracepoints[0])));
> + mod->tracepoints[mod->ntracepoints++] = line;
> +}
> +
> +static void read_tracepoints(const char *fname)
> +{
> + unsigned long size, pos = 0;
> + void *file = grab_file(fname, &size);
> + char *line;
> +
> + if (!file) /* No old tracepoints, silently ignore */
> + return;
> +
> + while ((line = get_next_line(&pos, file, size))) {
> + char *tracepoint, *modname, *fmt;
> + struct module *mod;
> +
> + tracepoint = line;
> + modname = strchr(tracepoint, '\t');
> + if (!modname)
> + goto fail;
> + *modname++ = '\0';
> + fmt = strchr(modname, '\t');
> + if (!fmt)
> + goto fail;
> + *fmt++ = '\0';
> + if (*tracepoint == '\0' || *modname == '\0')
> + goto fail;
> +
> + mod = find_module(modname);
> + if (!mod) {
> + if (is_vmlinux(modname))
> + have_vmlinux = 1;
> + mod = new_module(NOFAIL(strdup(modname)));
> + mod->skip = 1;
> + }
> +
> + if (!mod->skip)
> + add_tracepoint(mod, tracepoint, fmt);
> + }
> + return;
> +fail:
> + fatal("parse error in tracepoints list file\n");
> +}
> +
> +static void write_tracepoints(const char *fname)
> +{
> + struct buffer buf = { };
> + struct module *mod;
> + size_t i;
> +
> + for (mod = modules; mod; mod = mod->next)
> + if ((!external_module || !mod->skip) &&
> + mod->tracepoints != NULL) {
> + /*
> + * Sort the strings so we can skip duplicates when
> + * we write them out.
> + */
> + qsort(mod->tracepoints, mod->ntracepoints,
> + sizeof mod->tracepoints[0], &compare_strings);
> + for (i = 0; i < mod->ntracepoints; ++i) {
> + char *line = mod->tracepoints[i];
> + buf_write(&buf, line, strlen(line));
> + while (i + 1 < mod->ntracepoints &&
> + !strcmp(mod->tracepoints[i],
> + mod->tracepoints[i + 1]))
> + free(mod->tracepoints[i++]);
> + free(mod->tracepoints[i]);
> + }
> + free(mod->tracepoints);
> + mod->tracepoints = NULL;
> + }
> +
> + write_if_changed(&buf, fname);
> +}
> +
> struct ext_sym_list {
> struct ext_sym_list *next;
> const char *file;
> @@ -2104,13 +2249,15 @@ int main(int argc, char **argv)
> char *dump_write = NULL;
> char *markers_read = NULL;
> char *markers_write = NULL;
> + char *tracepoints_read = NULL;
> + char *tracepoints_write = NULL;
> const char *supported = NULL;
> int opt;
> int err;
> struct ext_sym_list *extsym_iter;
> struct ext_sym_list *extsym_start = NULL;
>
> - while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:N:")) != -1) {
> + while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:N:t:T:")) != -1) {
> switch (opt) {
> case 'i':
> kernel_read = optarg;
> @@ -2148,12 +2295,18 @@ int main(int argc, char **argv)
> case 'w':
> warn_unresolved = 1;
> break;
> - case 'M':
> - markers_write = optarg;
> - break;
> - case 'K':
> - markers_read = optarg;
> - break;
> + case 'M':
> + markers_write = optarg;
> + break;
> + case 'K':
> + markers_read = optarg;
> + break;
> + case 't':
> + tracepoints_write = optarg;
> + break;
> + case 'T':
> + tracepoints_read = optarg;
> + break;
> case 'N':
> supported = optarg;
> break;
> @@ -2219,5 +2372,11 @@ int main(int argc, char **argv)
> if (markers_write)
> write_markers(markers_write);
>
> + if (tracepoints_read)
> + read_tracepoints(tracepoints_read);
> +
> + if (tracepoints_write)
> + write_tracepoints(tracepoints_write);
> +
> return err;
> }
> Index: b/scripts/mod/modpost.h
> ===================================================================
> --- a/scripts/mod/modpost.h
> +++ b/scripts/mod/modpost.h
> @@ -114,6 +114,8 @@ struct module {
> struct buffer dev_table_buf;
> char **markers;
> size_t nmarkers;
> + char **tracepoints;
> + size_t ntracepoints;
> char srcversion[25];
> };
>
> @@ -129,6 +131,7 @@ struct elf_info {
> Elf_Section export_unused_gpl_sec;
> Elf_Section export_gpl_future_sec;
> Elf_Section markers_strings_sec;
> + Elf_Section tracepoints_strings_sec;
> const char *strtab;
> char *modinfo;
> unsigned int modinfo_len;
>
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>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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