perf build: Support build BPF skeletons with perf

mainline inclusion
from mainline-5.12-rc1
commit fbcdaa19
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fbcdaa1908e8f61aa56c71a1db9a9deb72110a9d

-------------------------------------------------

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: NSong Liu <songliubraving@fb.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NNamhyung 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.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
(cherry picked from commit fbcdaa19)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>

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)
 

tools/perf/Makefile.config

@@ -636,6 +636,15 @@ 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
 

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
 
 RM      = rm -f
@@ -730,7 +738,8 @@ 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) $@
@@ -1003,7 +1012,43 @@ 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

tools/perf/util/bpf_skel/.gitignore

+# SPDX-License-Identifier: GPL-2.0-only
+.tmp
+*.skel.h
\ No newline at end of file

tools/scripts/Makefile.include

@@ -152,6 +152,7 @@ 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); \