[PATCH RESEND] Add a "-m" option to "perf buildid-list".

[PATCH RESEND] Add a "-m" option to "perf buildid-list".

[Blake Jones]

This new option displays all of the information needed to do external
BuildID-based symbolization of kernel stack traces, such as those collected
by bpf_get_stackid(). For each kernel module plus the main kernel, it
displays the BuildID, the start and end virtual addresses of that module's
text range (rounded out to page boundaries), and the pathname of the
module.

When run as a non-privileged user, the actual addresses of the modules'
text ranges are not available, so the tools displays "0, <text length>" for
kernel modules and "0, ffffffffffffffff" for the kernel itself.

This patch has been rebased as of this afternoon, but is otherwise
identical to the version I sent out last month.

Sample output:

root# perf buildid-list -m
cf6df852fd4da122d616153353cc8f560fd12fe0 ffffffffa5400000 ffffffffa6001e27 [kernel.kallsyms]
1aa7209aa2acb067d66ed6cf7676d65066384d61 ffffffffc0087000 ffffffffc008b000 /lib/modules/5.15.15-1rodete2-amd64/kernel/crypto/sha512_generic.ko
3857815b5bf0183697b68f8fe0ea06121644041e ffffffffc008c000 ffffffffc0098000 /lib/modules/5.15.15-1rodete2-amd64/kernel/arch/x86/crypto/sha512-ssse3.ko
4081fde0bca2bc097cb3e9d1efcb836047d485f1 ffffffffc0099000 ffffffffc009f000 /lib/modules/5.15.15-1rodete2-amd64/kernel/drivers/acpi/button.ko
1ef81ba4890552ea6b0314f9635fc43fc8cef568 ffffffffc00a4000 ffffffffc00aa000 /lib/modules/5.15.15-1rodete2-amd64/kernel/crypto/cryptd.ko
cc5c985506cb240d7d082b55ed260cbb851f983e ffffffffc00af000 ffffffffc00b6000 /lib/modules/5.15.15-1rodete2-amd64/kernel/drivers/i2c/busses/i2c-piix4.ko
[...]

Signed-off-by: Blake Jones <blakejones@google.com>
---
 .../perf/Documentation/perf-buildid-list.txt  |  3 ++
 tools/perf/builtin-buildid-list.c             | 33 ++++++++++++++++++-
 tools/perf/util/dso.c                         | 23 +++++++++++++
 tools/perf/util/dso.h                         |  2 ++
 tools/perf/util/machine.c                     | 13 ++++++++
 tools/perf/util/machine.h                     |  5 +++
 6 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-buildid-list.txt b/tools/perf/Documentation/perf-buildid-list.txt
index 25c52efcc7f0..a82e92c2667d 100644
--- a/tools/perf/Documentation/perf-buildid-list.txt
+++ b/tools/perf/Documentation/perf-buildid-list.txt
@@ -33,6 +33,9 @@ OPTIONS
 -k::
 --kernel::
 	Show running kernel build id.
+-m::
+--modules::
+	Show buildid, start/end text address, and path of kernel and modules.
 -v::
 --verbose::
 	Be more verbose.
diff --git a/tools/perf/builtin-buildid-list.c b/tools/perf/builtin-buildid-list.c
index cebadd632234..9a5587de8fd0 100644
--- a/tools/perf/builtin-buildid-list.c
+++ b/tools/perf/builtin-buildid-list.c
@@ -12,6 +12,7 @@
 #include "util/build-id.h"
 #include "util/debug.h"
 #include "util/dso.h"
+#include "util/map.h"
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
 #include "util/session.h"
@@ -20,6 +21,29 @@
 #include <errno.h>
 #include <linux/err.h>
 
+static int buildid__map_cb(struct map *map, void *arg __maybe_unused)
+{
+	struct build_id build_id;
+	char bid_buf[SBUILD_ID_SIZE];
+	char modpath[255];
+
+	dso__get_build_id(map->dso, &build_id);
+	build_id__sprintf(&build_id, bid_buf);
+	dso__get_long_name(map->dso, modpath, sizeof(modpath));
+	printf("%s %16lx %16lx %s\n", bid_buf, map->start, map->end, modpath);
+
+	return 0;
+}
+
+static void buildid__show_kernel_modules(void)
+{
+	struct machine *machine;
+
+	machine = machine__new_host();
+	machine__for_each_kernel_map(machine, buildid__map_cb, NULL);
+	machine__delete(machine);
+}
+
 static int sysfs__fprintf_build_id(FILE *fp)
 {
 	char sbuild_id[SBUILD_ID_SIZE];
@@ -99,6 +123,7 @@ static int perf_session__list_build_ids(bool force, bool with_hits)
 int cmd_buildid_list(int argc, const char **argv)
 {
 	bool show_kernel = false;
+	bool show_modules = false;
 	bool with_hits = false;
 	bool force = false;
 	const struct option options[] = {
@@ -106,6 +131,8 @@ int cmd_buildid_list(int argc, const char **argv)
 	OPT_STRING('i', "input", &input_name, "file", "input file name"),
 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
 	OPT_BOOLEAN('k', "kernel", &show_kernel, "Show current kernel build id"),
+	OPT_BOOLEAN('m', "modules", &show_modules,
+	    "Show build id of current kernel + modules"),
 	OPT_INCR('v', "verbose", &verbose, "be more verbose"),
 	OPT_END()
 	};
@@ -117,8 +144,12 @@ int cmd_buildid_list(int argc, const char **argv)
 	argc = parse_options(argc, argv, options, buildid_list_usage, 0);
 	setup_pager();
 
-	if (show_kernel)
+	if (show_kernel) {
 		return !(sysfs__fprintf_build_id(stdout) > 0);
+	} else if (show_modules) {
+		buildid__show_kernel_modules();
+		return 0;
+	}
 
 	return perf_session__list_build_ids(force, with_hits);
 }
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 5ac13958d1bd..7c490b5ce449 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1227,6 +1227,19 @@ void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
 	dso__set_long_name_id(dso, name, NULL, name_allocated);
 }
 
+void dso__get_long_name(const struct dso *dso, char *name, size_t len)
+{
+	if (len == 0)
+		return;
+	if (dso->long_name == NULL) {
+		name[0] = '\0';
+		return;
+	}
+
+	strncpy(name, dso->long_name, len);
+	name[len - 1] = '\0';
+}
+
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
 {
 	if (name == NULL)
@@ -1359,6 +1372,16 @@ void dso__set_build_id(struct dso *dso, struct build_id *bid)
 	dso->has_build_id = 1;
 }
 
+void dso__get_build_id(struct dso *dso, struct build_id *bid)
+{
+	if (dso->has_build_id) {
+		*bid = dso->bid;
+	} else {
+		bid->size = 0;
+		memset(bid->data, 0, sizeof(*bid->data));
+	}
+}
+
 bool dso__build_id_equal(const struct dso *dso, struct build_id *bid)
 {
 	if (dso->bid.size > bid->size && dso->bid.size == BUILD_ID_SIZE) {
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 97047a11282b..e531f9d0818d 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -239,6 +239,7 @@ void dso__delete(struct dso *dso);
 int dso__cmp_id(struct dso *a, struct dso *b);
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated);
 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated);
+void dso__get_long_name(const struct dso *dso, char *name, size_t len);
 
 int dso__name_len(const struct dso *dso);
 
@@ -265,6 +266,7 @@ void dso__set_sorted_by_name(struct dso *dso);
 void dso__sort_by_name(struct dso *dso);
 
 void dso__set_build_id(struct dso *dso, struct build_id *bid);
+void dso__get_build_id(struct dso *dso, struct build_id *bid);
 bool dso__build_id_equal(const struct dso *dso, struct build_id *bid);
 void dso__read_running_kernel_build_id(struct dso *dso,
 				       struct machine *machine);
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 009061852808..28fff9a02ab0 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -3327,3 +3327,16 @@ int machine__for_each_dso(struct machine *machine, machine__dso_t fn, void *priv
 	}
 	return err;
 }
+
+int machine__for_each_kernel_map(struct machine *machine, machine__map_t fn, void *priv)
+{
+	struct maps *maps = machine__kernel_maps(machine);
+	struct map *map;
+	int err = 0;
+
+	for (map = maps__first(maps); map != NULL; map = map__next(map)) {
+		if (fn(map, priv))
+			err = -1;
+	}
+	return err;
+}
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 5d7daf7cb7bc..e1476343cbb2 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -262,6 +262,11 @@ typedef int (*machine__dso_t)(struct dso *dso, struct machine *machine, void *pr
 
 int machine__for_each_dso(struct machine *machine, machine__dso_t fn,
 			  void *priv);
+
+typedef int (*machine__map_t)(struct map *map, void *priv);
+int machine__for_each_kernel_map(struct machine *machine, machine__map_t fn,
+				 void *priv);
+
 int machine__for_each_thread(struct machine *machine,
 			     int (*fn)(struct thread *thread, void *p),
 			     void *priv);

base-commit: 1bcca2b1bd67f3c0e5c3a88ed16c6389f01a5b31
-- 
2.36.1.476.g0c4daa206d-goog

Re: [PATCH RESEND] Add a "-m" option to "perf buildid-list".

[Jiri Olsa]

On Tue, Jun 07, 2022 at 12:15:50PM -0700, Blake Jones wrote:
> This new option displays all of the information needed to do external
> BuildID-based symbolization of kernel stack traces, such as those collected
> by bpf_get_stackid(). For each kernel module plus the main kernel, it
> displays the BuildID, the start and end virtual addresses of that module's
> text range (rounded out to page boundaries), and the pathname of the
> module.
> 
> When run as a non-privileged user, the actual addresses of the modules'
> text ranges are not available, so the tools displays "0, <text length>" for
> kernel modules and "0, ffffffffffffffff" for the kernel itself.
> 
> This patch has been rebased as of this afternoon, but is otherwise
> identical to the version I sent out last month.
> 
> Sample output:
> 
> root# perf buildid-list -m
> cf6df852fd4da122d616153353cc8f560fd12fe0 ffffffffa5400000 ffffffffa6001e27 [kernel.kallsyms]
> 1aa7209aa2acb067d66ed6cf7676d65066384d61 ffffffffc0087000 ffffffffc008b000 /lib/modules/5.15.15-1rodete2-amd64/kernel/crypto/sha512_generic.ko
> 3857815b5bf0183697b68f8fe0ea06121644041e ffffffffc008c000 ffffffffc0098000 /lib/modules/5.15.15-1rodete2-amd64/kernel/arch/x86/crypto/sha512-ssse3.ko
> 4081fde0bca2bc097cb3e9d1efcb836047d485f1 ffffffffc0099000 ffffffffc009f000 /lib/modules/5.15.15-1rodete2-amd64/kernel/drivers/acpi/button.ko
> 1ef81ba4890552ea6b0314f9635fc43fc8cef568 ffffffffc00a4000 ffffffffc00aa000 /lib/modules/5.15.15-1rodete2-amd64/kernel/crypto/cryptd.ko
> cc5c985506cb240d7d082b55ed260cbb851f983e ffffffffc00af000 ffffffffc00b6000 /lib/modules/5.15.15-1rodete2-amd64/kernel/drivers/i2c/busses/i2c-piix4.ko
> [...]
> 
> Signed-off-by: Blake Jones <blakejones@google.com>
> ---
>  .../perf/Documentation/perf-buildid-list.txt  |  3 ++
>  tools/perf/builtin-buildid-list.c             | 33 ++++++++++++++++++-
>  tools/perf/util/dso.c                         | 23 +++++++++++++
>  tools/perf/util/dso.h                         |  2 ++
>  tools/perf/util/machine.c                     | 13 ++++++++
>  tools/perf/util/machine.h                     |  5 +++
>  6 files changed, 78 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/Documentation/perf-buildid-list.txt b/tools/perf/Documentation/perf-buildid-list.txt
> index 25c52efcc7f0..a82e92c2667d 100644
> --- a/tools/perf/Documentation/perf-buildid-list.txt
> +++ b/tools/perf/Documentation/perf-buildid-list.txt
> @@ -33,6 +33,9 @@ OPTIONS
>  -k::
>  --kernel::
>  	Show running kernel build id.
> +-m::
> +--modules::
> +	Show buildid, start/end text address, and path of kernel and modules.

why 'modules' ? it shows all maps (including kernel)
so perhaps -m/--maps would be better?

also please state that it's from running kernel

SNIP

> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index 5ac13958d1bd..7c490b5ce449 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -1227,6 +1227,19 @@ void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
>  	dso__set_long_name_id(dso, name, NULL, name_allocated);
>  }
>  
> +void dso__get_long_name(const struct dso *dso, char *name, size_t len)
> +{
> +	if (len == 0)
> +		return;
> +	if (dso->long_name == NULL) {
> +		name[0] = '\0';
> +		return;
> +	}
> +
> +	strncpy(name, dso->long_name, len);
> +	name[len - 1] = '\0';
> +}
> +
>  void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
>  {
>  	if (name == NULL)
> @@ -1359,6 +1372,16 @@ void dso__set_build_id(struct dso *dso, struct build_id *bid)
>  	dso->has_build_id = 1;
>  }
>  
> +void dso__get_build_id(struct dso *dso, struct build_id *bid)
> +{
> +	if (dso->has_build_id) {
> +		*bid = dso->bid;
> +	} else {
> +		bid->size = 0;
> +		memset(bid->data, 0, sizeof(*bid->data));
> +	}
> +}

any reason why not use the dso fields directly?

thanks,
jirka

Re: [PATCH RESEND] Add a "-m" option to "perf buildid-list".

[Blake Jones]

Thanks for taking a look at this!

On Sun, Jun 12, 2022 at 3:18 PM Jiri Olsa <olsajiri@gmail.com> wrote:
> why 'modules' ? it shows all maps (including kernel)
> so perhaps -m/--maps would be better?

 I called it "modules" because it only operates on the kernel. Calling it
"maps" would suggest to me that it might also be able to show
information about the maps in perf.data files, which it can't (just as the
"-k" option only operates on the kernel). Given that, does it still seem
like "maps" would be more appropriate?

> also please state that it's from running kernel

Happy to make this change.

> any reason why not use the dso fields directly?

I was just following my general software engineering instincts to
encapsulate implementation details, so that e.g. the caller doesn't need to
know about details such as the "has_build_id" boolean. I haven't made
changes to perf before, so if that's not the preferred style, I can do it
a different way.

Blake

Re: [PATCH RESEND] Add a "-m" option to "perf buildid-list".

[Jiri Olsa]

On Mon, Jun 13, 2022 at 03:02:39PM -0700, Blake Jones wrote:
> Thanks for taking a look at this!
> 
> On Sun, Jun 12, 2022 at 3:18 PM Jiri Olsa <olsajiri@gmail.com> wrote:
> > why 'modules' ? it shows all maps (including kernel)
> > so perhaps -m/--maps would be better?
> 
>  I called it "modules" because it only operates on the kernel. Calling it
> "maps" would suggest to me that it might also be able to show
> information about the maps in perf.data files, which it can't (just as the
> "-k" option only operates on the kernel). Given that, does it still seem
> like "maps" would be more appropriate?

still there's kernel map included, so it's strange to me call it modules

  --m/--kernel-maps ?

> 
> > also please state that it's from running kernel
> 
> Happy to make this change.
> 
> > any reason why not use the dso fields directly?
> 
> I was just following my general software engineering instincts to
> encapsulate implementation details, so that e.g. the caller doesn't need to
> know about details such as the "has_build_id" boolean. I haven't made
> changes to perf before, so if that's not the preferred style, I can do it
> a different way.

we have some helpers for dso fields, but AFAICS long_name and has_build_id
are used directly all over the place

jirka

Re: [PATCH RESEND] Add a "-m" option to "perf buildid-list".

[Blake Jones]

On Tue, Jun 14, 2022 at 5:29 AM Jiri Olsa <olsajiri@gmail.com> wrote:
> still there's kernel map included, so it's strange to me call it modules
>
>   --m/--kernel-maps ?

Sure, I'll go with that.

> > > also please state that it's from running kernel
> >
> > Happy to make this change.
> >
> > > any reason why not use the dso fields directly?
> >
> > I was just following my general software engineering instincts to
> > encapsulate implementation details, so that e.g. the caller doesn't need to
> > know about details such as the "has_build_id" boolean. I haven't made
> > changes to perf before, so if that's not the preferred style, I can do it
> > a different way.
>
> we have some helpers for dso fields, but AFAICS long_name and has_build_id
> are used directly all over the place

Okay, I've switched the code over to use those fields directly.

New patch coming shortly.

Blake