bpftool: Use linux/types.h from source tree for profiler build

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 use __bitwise__ instead of __bitwise in
skeleton/profiler.h to avoid clashing with the definition in
tools/testing/selftests/bpf/include/uapi/linux/types.h.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200312130330.32239-1-tklauser@distanz.ch

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 > $@

tools/bpf/bpftool/skeleton/profiler.h

@@ -32,16 +32,15 @@ enum {
 #else
 #define __bitwise__
 #endif
-#define __bitwise __bitwise__
 
-typedef __u16 __bitwise __le16;
-typedef __u16 __bitwise __be16;
-typedef __u32 __bitwise __le32;
-typedef __u32 __bitwise __be32;
-typedef __u64 __bitwise __le64;
-typedef __u64 __bitwise __be64;
+typedef __u16 __bitwise__ __le16;
+typedef __u16 __bitwise__ __be16;
+typedef __u32 __bitwise__ __le32;
+typedef __u32 __bitwise__ __be32;
+typedef __u64 __bitwise__ __le64;
+typedef __u64 __bitwise__ __be64;
 
-typedef __u16 __bitwise __sum16;
-typedef __u32 __bitwise __wsum;
+typedef __u16 __bitwise__ __sum16;
+typedef __u32 __bitwise__ __wsum;
 
 #endif /* __PROFILER_H */