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From:   Song Liu <songliubraving@fb.com>
To:     <linux-kernel@vger.kernel.org>
CC:     <acme@kernel.org>, <peterz@infradead.org>, <mingo@redhat.com>,
        <alexander.shishkin@linux.intel.com>, <namhyung@kernel.org>,
        <mark.rutland@arm.com>, <jolsa@redhat.com>, <kernel-team@fb.com>,
        Song Liu <songliubraving@fb.com>
Subject: [PATCH v7 2/3] perf: support build BPF skeletons with perf
Date:   Tue, 29 Dec 2020 13:42:13 -0800
Message-ID: <20201229214214.3413833-3-songliubraving@fb.com>
In-Reply-To: <20201229214214.3413833-1-songliubraving@fb.com>
References: <20201229214214.3413833-1-songliubraving@fb.com>
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BPF programs are useful in perf to profile BPF programs. BPF skeleton is
by far the easiest way to write BPF tools. Enable building BPF skeletons
in util/bpf_skel. A dummy bpf skeleton is added. More bpf skeletons will
be added for different use cases.

Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
 tools/build/Makefile.feature        |  4 ++-
 tools/perf/Makefile.config          |  9 ++++++
 tools/perf/Makefile.perf            | 49 +++++++++++++++++++++++++++--
 tools/perf/util/bpf_skel/.gitignore |  3 ++
 tools/scripts/Makefile.include      |  1 +
 5 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 tools/perf/util/bpf_skel/.gitignore

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 97cbfb31b7625..74e255d58d8d0 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -99,7 +99,9 @@ FEATURE_TESTS_EXTRA :=3D                  \
          clang                          \
          libbpf                         \
          libpfm4                        \
-         libdebuginfod
+         libdebuginfod			\
+         clang-bpf-co-re
+
=20
 FEATURE_TESTS ?=3D $(FEATURE_TESTS_BASIC)
=20
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index ce8516e4de34f..d8e59d31399a5 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -621,6 +621,15 @@ ifndef NO_LIBBPF
   endif
 endif
=20
+ifdef BUILD_BPF_SKEL
+  $(call feature_check,clang-bpf-co-re)
+  ifeq ($(feature-clang-bpf-co-re), 0)
+    dummy :=3D $(error Error: clang too old. Please install recent clang=
)
+  endif
+  $(call detected,CONFIG_PERF_BPF_SKEL)
+  CFLAGS +=3D -DHAVE_BPF_SKEL
+endif
+
 dwarf-post-unwind :=3D 1
 dwarf-post-unwind-text :=3D BUG
=20
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 62f3deb1d3a8b..d182a2dbb9bbd 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -126,6 +126,8 @@ include ../scripts/utilities.mak
 #
 # Define NO_LIBDEBUGINFOD if you do not want support debuginfod
 #
+# Define BUILD_BPF_SKEL to enable BPF skeletons
+#
=20
 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL
@@ -175,6 +177,12 @@ endef
=20
 LD +=3D $(EXTRA_LDFLAGS)
=20
+HOSTCC  ?=3D gcc
+HOSTLD  ?=3D ld
+HOSTAR  ?=3D ar
+CLANG   ?=3D clang
+LLVM_STRIP ?=3D llvm-strip
+
 PKG_CONFIG =3D $(CROSS_COMPILE)pkg-config
 LLVM_CONFIG ?=3D llvm-config
=20
@@ -731,7 +739,8 @@ prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-c=
mds.h archheaders $(drm_ioc
 	$(x86_arch_prctl_code_array) \
 	$(rename_flags_array) \
 	$(arch_errno_name_array) \
-	$(sync_file_range_arrays)
+	$(sync_file_range_arrays) \
+	bpf-skel
=20
 $(OUTPUT)%.o: %.c prepare FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=3D$(build-dir)=
 $@
@@ -1004,7 +1013,43 @@ config-clean:
 python-clean:
 	$(python-clean)
=20
-clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBC=
MD)-clean $(LIBPERF)-clean config-clean fixdep-clean python-clean
+SKEL_OUT :=3D $(abspath $(OUTPUT)util/bpf_skel)
+SKEL_TMP_OUT :=3D $(abspath $(SKEL_OUT)/.tmp)
+SKELETONS :=3D
+
+ifdef BUILD_BPF_SKEL
+BPFTOOL :=3D $(SKEL_TMP_OUT)/bootstrap/bpftool
+LIBBPF_SRC :=3D $(abspath ../lib/bpf)
+BPF_INCLUDE :=3D -I$(SKEL_TMP_OUT)/.. -I$(BPF_PATH) -I$(LIBBPF_SRC)/..
+
+$(SKEL_TMP_OUT):
+	$(Q)$(MKDIR) -p $@
+
+$(BPFTOOL): | $(SKEL_TMP_OUT)
+	CFLAGS=3D $(MAKE) -C ../bpf/bpftool \
+		OUTPUT=3D$(SKEL_TMP_OUT)/ bootstrap
+
+$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) | $(SKEL_TMP_OU=
T)
+	$(QUIET_CLANG)$(CLANG) -g -O2 -target bpf $(BPF_INCLUDE) \
+	  -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@ && $(LLVM_STRIP) -g $@
+
+$(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o | $(BPFTOOL)
+	$(QUIET_GENSKEL)$(BPFTOOL) gen skeleton $< > $@
+
+bpf-skel: $(SKELETONS)
+
+.PRECIOUS: $(SKEL_TMP_OUT)/%.bpf.o
+
+else # BUILD_BPF_SKEL
+
+bpf-skel:
+
+endif # BUILD_BPF_SKEL
+
+bpf-skel-clean:
+	$(call QUIET_CLEAN, bpf-skel) $(RM) -r $(SKEL_TMP_OUT) $(SKELETONS)
+
+clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBC=
MD)-clean $(LIBPERF)-clean config-clean fixdep-clean python-clean bpf-ske=
l-clean
 	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archiv=
e $(OUTPUT)perf-with-kcore $(LANG_BINDINGS)
 	$(Q)find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.=
cmd' -delete -o -name '\.*.d' -delete
 	$(Q)$(RM) $(OUTPUT).config-detected
diff --git a/tools/perf/util/bpf_skel/.gitignore b/tools/perf/util/bpf_sk=
el/.gitignore
new file mode 100644
index 0000000000000..5263e9e6c5d83
--- /dev/null
+++ b/tools/perf/util/bpf_skel/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+.tmp
+*.skel.h
\ No newline at end of file
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.incl=
ude
index 1358e89cdf7d6..62119ce69ad9a 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -127,6 +127,7 @@ ifneq ($(silent),1)
 			 $(MAKE) $(PRINT_DIR) -C $$subdir
 	QUIET_FLEX     =3D @echo '  FLEX     '$@;
 	QUIET_BISON    =3D @echo '  BISON    '$@;
+	QUIET_GENSKEL  =3D @echo '  GEN-SKEL '$@;
=20
 	descend =3D \
 		+@echo	       '  DESCEND  '$(1); \
--=20
2.24.1