[PATCH v2] perf bpf skels: Make vmlinux.h use bpf.h and perf_event.h in source directory

[Yang Jihong]

Currently, vmlinux.h uses the bpf.h and perf_event.h header files in the
system path. If the header files in compilation environment are old,
compilation may fail. For example:

  /home/yangjihong/linux/tools/perf/util/bpf_skel/.tmp/../vmlinux.h:151:27: error: field has incomplete type 'union perf_sample_weight'
          union perf_sample_weight weight;

Use the bpf.h and perf_event.h files in the source code directory to
avoid compilation compatibility problems.

Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
---

Changes since v1:
 - Use Makefile to specify that header files in tools/include/uapi directory are preferentially used.

 tools/perf/Makefile.perf           | 3 ++-
 tools/perf/util/bpf_skel/vmlinux.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index a42a6a99c2bc..9b92749280b2 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1058,13 +1058,14 @@ $(SKEL_TMP_OUT) $(LIBAPI_OUTPUT) $(LIBBPF_OUTPUT) $(LIBPERF_OUTPUT) $(LIBSUBCMD_
 ifdef BUILD_BPF_SKEL
 BPFTOOL := $(SKEL_TMP_OUT)/bootstrap/bpftool
 BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(LIBBPF_INCLUDE)
+TOOLS_UAPI_INCLUDE := -I$(srctree)/tools/include/uapi
 
 $(BPFTOOL): | $(SKEL_TMP_OUT)
 	$(Q)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 -Wall -Werror $(BPF_INCLUDE) \
+	$(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -Wall -Werror $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
 	  -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@ && $(LLVM_STRIP) -g $@
 
 $(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o | $(BPFTOOL)
diff --git a/tools/perf/util/bpf_skel/vmlinux.h b/tools/perf/util/bpf_skel/vmlinux.h
index 449b1ea91fc4..c7ed51b0c1ef 100644
--- a/tools/perf/util/bpf_skel/vmlinux.h
+++ b/tools/perf/util/bpf_skel/vmlinux.h
@@ -1,6 +1,7 @@
 #ifndef __VMLINUX_H
 #define __VMLINUX_H
 
+#include <linux/stddef.h> // for define __always_inline
 #include <linux/bpf.h>
 #include <linux/types.h>
 #include <linux/perf_event.h>
-- 
2.30.GIT