From c7a14fdcb3fa77368273b3daab52ad8e86d358b6 Mon Sep 17 00:00:00 2001
From: "Frank Ch. Eigler" <fche@redhat.com>
Date: Thu, 13 Aug 2020 10:22:04 +0200
Subject: [PATCH] perf build-ids: Fall back to debuginfod query if debuginfo
not found
During a perf-record, use the -ldebuginfod API to query a debuginfod
server, should the debug data not be found in the usual system
locations. If successful, the usual $HOME/.debug dir is populated.
Tested with:
$ find .
.
./ctags-debuginfo-5.8-26.fc31.x86_64.rpm
./usr
./usr/lib
./usr/lib/debug
./usr/lib/debug/.build-id
./usr/lib/debug/.build-id/ca
./usr/lib/debug/.build-id/ca/46f6ae6a0cee57d85abc1d461c49074248908d
./usr/lib/debug/.build-id/ca/46f6ae6a0cee57d85abc1d461c49074248908d.debug
./usr/lib/debug/usr
./usr/lib/debug/usr/bin
./usr/lib/debug/usr/bin/ctags-5.8-26.fc31.x86_64.debug
$ debuginfod -F .
...
$ rm -rf ~/.debug/ ; mkdir ~/.debug
$ perf record make tags
BUILD: Doing 'make -j8' parallel build
GEN tags
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.107 MB perf.data (1483 samples) ]
$ find ~/.debug | grep ctags
/home/jolsa/.debug/usr/bin/ctags
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d/elf
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d/probes
$ rm -rf ~/.debug/ ; mkdir ~/.debug
$ DEBUGINFOD_URLS=http://localhost:8002 perf record make tags
BUILD: Doing 'make -j8' parallel build
GEN tags
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.108 MB perf.data (1531 samples) ]
$ find ~/.debug | grep ctag
/home/jolsa/.debug/usr/bin/ctags
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d/debug
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d/elf
/home/jolsa/.debug/usr/bin/ctags/ca46f6ae6a0cee57d85abc1d461c49074248908d/probes
Note the 'debug' file is created in the last run.
Note that currently the debuginfo data are downloaded only on record path,
we still need add this support to perf build-id/report.. and test ;-)
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/build/Makefile.feature | 3 ++-
tools/build/feature/Makefile | 4 ++++
tools/build/feature/test-libdebuginfod.c | 8 ++++++++
tools/perf/Makefile.config | 8 ++++++++
tools/perf/Makefile.perf | 2 ++
tools/perf/util/build-id.c | 19 +++++++++++++++++++
6 files changed, 43 insertions(+), 1 deletion(-)
create mode 100644 tools/build/feature/test-libdebuginfod.c
diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index e7818b44b48e..c1daf4d57518 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -98,7 +98,8 @@ FEATURE_TESTS_EXTRA := \
llvm-version \
clang \
libbpf \
- libpfm4
+ libpfm4 \
+ libdebuginfod
FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 846ee1341a5c..d220fe952747 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -26,6 +26,7 @@ FILES= \
test-libelf-gelf_getnote.bin \
test-libelf-getshdrstrndx.bin \
test-libelf-mmap.bin \
+ test-libdebuginfod.bin \
test-libnuma.bin \
test-numa_num_possible_cpus.bin \
test-libperl.bin \
@@ -157,6 +158,9 @@ $(OUTPUT)test-libelf-gelf_getnote.bin:
$(OUTPUT)test-libelf-getshdrstrndx.bin:
$(BUILD) -lelf
+$(OUTPUT)test-libdebuginfod.bin:
+ $(BUILD) -ldebuginfod
+
$(OUTPUT)test-libnuma.bin:
$(BUILD) -lnuma
diff --git a/tools/build/feature/test-libdebuginfod.c b/tools/build/feature/test-libdebuginfod.c
new file mode 100644
index 000000000000..da22548b8413
--- /dev/null
+++ b/tools/build/feature/test-libdebuginfod.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <elfutils/debuginfod.h>
+
+int main(void)
+{
+ debuginfod_client* c = debuginfod_begin();
+ return (long)c;
+}
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 513633809c81..190be4fa5c21 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -501,6 +501,14 @@ ifndef NO_LIBELF
CFLAGS += -DHAVE_ELF_GETSHDRSTRNDX_SUPPORT
endif
+ ifndef NO_LIBDEBUGINFOD
+ $(call feature_check,libdebuginfod)
+ ifeq ($(feature-libdebuginfod), 1)
+ CFLAGS += -DHAVE_DEBUGINFOD_SUPPORT
+ EXTLIBS += -ldebuginfod
+ endif
+ endif
+
ifndef NO_DWARF
ifeq ($(origin PERF_HAVE_DWARF_REGS), undefined)
msg := $(warning DWARF register mappings have not been defined for architecture $(SRCARCH), DWARF support disabled);
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index e339e225410c..6031167939ae 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -124,6 +124,8 @@ include ../scripts/utilities.mak
#
# Define LIBPFM4 to enable libpfm4 events extension.
#
+# Define NO_LIBDEBUGINFOD if you do not want support debuginfod
+#
# As per kernel Makefile, avoid funny character set dependencies
unexport LC_ALL
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index c076fc7fe025..31207b6e2066 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -31,6 +31,10 @@
#include "probe-file.h"
#include "strlist.h"
+#ifdef HAVE_DEBUGINFOD_SUPPORT
+#include <elfutils/debuginfod.h>
+#endif
+
#include <linux/ctype.h>
#include <linux/zalloc.h>
@@ -636,6 +640,21 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
if (realname && access(realname, R_OK))
zfree(&realname);
nsinfo__mountns_exit(&nsc);
+
+#ifdef HAVE_DEBUGINFOD_SUPPORT
+ if (realname == NULL) {
+ debuginfod_client* c = debuginfod_begin();
+ if (c != NULL) {
+ int fd = debuginfod_find_debuginfo(c,
+ (const unsigned char*)sbuild_id, 0,
+ &realname);
+ if (fd >= 0)
+ close(fd); /* retaining reference by realname */
+ debuginfod_end(c);
+ }
+ }
+#endif
+
out:
free(debugfile);
return realname;