[PATCH] bpftool: use linux/types.h from source tree for profiler build

[Tobias Klauser <tklauser@xxxxxxxxxx>]

When compiling bpftool on a system where the /usr/include/asm symlink
doesn't exist (e.g. on an Ubuntu system without gcc-multilib installed),
the build fails with:

    CLANG    skeleton/profiler.bpf.o
  In file included from skeleton/profiler.bpf.c:4:
  In file included from /usr/include/linux/bpf.h:11:
  /usr/include/linux/types.h:5:10: fatal error: 'asm/types.h' file not found
  #include <asm/types.h>
           ^~~~~~~~~~~~~
  1 error generated.
  make: *** [Makefile:123: skeleton/profiler.bpf.o] Error 1

This indicates that the build is using linux/types.h from system headers
instead of source tree headers.

To fix this, adjust the clang search path to include the necessary
headers from tools/testing/selftests/bpf/include/uapi and
tools/include/uapi. Also undef __bitwise in skeleton/profiler.h avoid
clashing with the empty definition in
tools/testing/selftests/bpf/include/uapi/linux/types.h.

Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx>
---
 tools/bpf/bpftool/Makefile            | 5 ++++-
 tools/bpf/bpftool/skeleton/profiler.h | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 20a90d8450f8..f294f6c1e795 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -120,7 +120,10 @@ $(OUTPUT)_bpftool: $(_OBJS) $(LIBBPF)
 	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(_OBJS) $(LIBS)
 
 skeleton/profiler.bpf.o: skeleton/profiler.bpf.c
-	$(QUIET_CLANG)$(CLANG) -I$(srctree)/tools/lib -g -O2 -target bpf -c $< -o $@
+	$(QUIET_CLANG)$(CLANG) \
+		-I$(srctree)/tools/include/uapi/ \
+		-I$(srctree)/tools/testing/selftests/bpf/include/uapi \
+		-I$(srctree)/tools/lib -g -O2 -target bpf -c $< -o $@
 
 profiler.skel.h: $(OUTPUT)_bpftool skeleton/profiler.bpf.o
 	$(QUIET_GEN)$(OUTPUT)./_bpftool gen skeleton skeleton/profiler.bpf.o > $@
diff --git a/tools/bpf/bpftool/skeleton/profiler.h b/tools/bpf/bpftool/skeleton/profiler.h
index e03b53eae767..95358c0df5ef 100644
--- a/tools/bpf/bpftool/skeleton/profiler.h
+++ b/tools/bpf/bpftool/skeleton/profiler.h
@@ -27,6 +27,7 @@ enum {
 	true = 1,
 };
 
+#undef __bitwise
 #ifdef __CHECKER__
 #define __bitwise__ __attribute__((bitwise))
 #else
-- 
2.25.1