perf build: Support build BPF skeletons with perf

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.

Signed-off-by: Song Liu <songliubraving@fb.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Link: http://lore.kernel.org/lkml/20201229214214.3413833-3-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 97cbfb31b762592a4e9ff5f3558d7c750a5de904..74e255d58d8d04c9cc68544d20d26dc5bfa0034c 100644 (file)
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -99,7 +99,9 @@ FEATURE_TESTS_EXTRA :=                  \
          clang                          \
          libbpf                         \
          libpfm4                        \
-         libdebuginfod
+         libdebuginfod                 \
+         clang-bpf-co-re
+
 
 FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
 

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index ce8516e4de34fa60ee50c3fedc0190c625f8f3ac..d8e59d31399a56a1d4f35b5d7462c4254d430295 100644 (file)
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -621,6 +621,15 @@ ifndef NO_LIBBPF
   endif
 endif
 
+ifdef BUILD_BPF_SKEL
+  $(call feature_check,clang-bpf-co-re)
+  ifeq ($(feature-clang-bpf-co-re), 0)
+    dummy := $(error Error: clang too old. Please install recent clang)
+  endif
+  $(call detected,CONFIG_PERF_BPF_SKEL)
+  CFLAGS += -DHAVE_BPF_SKEL
+endif
+
 dwarf-post-unwind := 1
 dwarf-post-unwind-text := BUG
 

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 62f3deb1d3a8b7bcbef40d58ba01b10673a2c8a9..d182a2dbb9bbd9648313768582c876db1fcd2fc3 100644 (file)
--- 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
+#
 
 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL
@@ -175,6 +177,12 @@ endef
 
 LD += $(EXTRA_LDFLAGS)
 
+HOSTCC  ?= gcc
+HOSTLD  ?= ld
+HOSTAR  ?= ar
+CLANG   ?= clang
+LLVM_STRIP ?= llvm-strip
+
 PKG_CONFIG = $(CROSS_COMPILE)pkg-config
 LLVM_CONFIG ?= llvm-config
 
@@ -731,7 +739,8 @@ prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.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
 
 $(OUTPUT)%.o: %.c prepare FORCE
        $(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(build-dir) $@
@@ -1004,7 +1013,43 @@ config-clean:
 python-clean:
        $(python-clean)
 
-clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBPERF)-clean config-clean fixdep-clean python-clean
+SKEL_OUT := $(abspath $(OUTPUT)util/bpf_skel)
+SKEL_TMP_OUT := $(abspath $(SKEL_OUT)/.tmp)
+SKELETONS :=
+
+ifdef BUILD_BPF_SKEL
+BPFTOOL := $(SKEL_TMP_OUT)/bootstrap/bpftool
+LIBBPF_SRC := $(abspath ../lib/bpf)
+BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(BPF_PATH) -I$(LIBBPF_SRC)/..
+
+$(SKEL_TMP_OUT):
+       $(Q)$(MKDIR) -p $@
+
+$(BPFTOOL): | $(SKEL_TMP_OUT)
+       CFLAGS= $(MAKE) -C ../bpf/bpftool \
+               OUTPUT=$(SKEL_TMP_OUT)/ bootstrap
+
+$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) | $(SKEL_TMP_OUT)
+       $(QUIET_CLANG)$(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 $(LIBSUBCMD)-clean $(LIBPERF)-clean config-clean fixdep-clean python-clean bpf-skel-clean
        $(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archive $(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_skel/.gitignore
new file mode 100644 (file)
index 0000000..5263e9e
--- /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.include
index 1358e89cdf7d698951235b2b6ee61d098a74aee4..62119ce69ad9a97658b8fbdd8ecd0471b3618433 100644 (file)
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -127,6 +127,7 @@ ifneq ($(silent),1)
                         $(MAKE) $(PRINT_DIR) -C $$subdir
        QUIET_FLEX     = @echo '  FLEX     '$@;
        QUIET_BISON    = @echo '  BISON    '$@;
+       QUIET_GENSKEL  = @echo '  GEN-SKEL '$@;
 
        descend = \
                +@echo         '  DESCEND  '$(1); \