RE: [PATCH 02/11] bpf: Compile btfid tool at kernel compilation start

From: John Fastabend <john.fastabend@gmail.com>
To: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Martin KaFai Lau <kafai@fb.com>, David Miller <davem@redhat.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Wenbo Zhang <ethercflow@gmail.com>,
	KP Singh <kpsingh@chromium.org>, Andrii Nakryiko <andriin@fb.com>,
	Brendan Gregg <bgregg@netflix.com>,
	Florent Revest <revest@chromium.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: RE: [PATCH 02/11] bpf: Compile btfid tool at kernel compilation start
Date: Thu, 18 Jun 2020 13:40:40 -0700	[thread overview]
Message-ID: <5eebd1486e46b_6d292ad5e7a285b817@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20200616100512.2168860-3-jolsa@kernel.org>

Jiri Olsa wrote:
> The btfid tool will be used during the vmlinux linking,
> so it's necessary it's ready for it.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  Makefile           | 22 ++++++++++++++++++----
>  tools/Makefile     |  3 +++
>  tools/bpf/Makefile |  5 ++++-
>  3 files changed, 25 insertions(+), 5 deletions(-)

This breaks the build for me. I fixed it with this but then I get warnings,

diff --git a/tools/bpf/btfid/btfid.c b/tools/bpf/btfid/btfid.c
index 7cdf39bfb150..3697e8ae9efa 100644
--- a/tools/bpf/btfid/btfid.c
+++ b/tools/bpf/btfid/btfid.c
@@ -48,7 +48,7 @@
 #include <errno.h>
 #include <linux/rbtree.h>
 #include <linux/zalloc.h>
-#include <btf.h>
+#include <linux/btf.h>
 #include <libbpf.h>
 #include <parse-options.h>

Here is the error. Is it something about my setup? bpftool/btf.c uses
<btf.h>. Because this in top-level Makefile we probably don't want to
push extra setup onto folks.

In file included from btfid.c:51:
/home/john/git/bpf-next/tools/lib/bpf/btf.h: In function ‘btf_is_var’:
/home/john/git/bpf-next/tools/lib/bpf/btf.h:254:24: error: ‘BTF_KIND_VAR’ undeclared (first use in this function); did you mean ‘BTF_KIND_PTR’?
  return btf_kind(t) == BTF_KIND_VAR;
                        ^~~~~~~~~~~~
                        BTF_KIND_PTR
/home/john/git/bpf-next/tools/lib/bpf/btf.h:254:24: note: each undeclared identifier is reported only once for each function it appears in
/home/john/git/bpf-next/tools/lib/bpf/btf.h: In function ‘btf_is_datasec’:
/home/john/git/bpf-next/tools/lib/bpf/btf.h:259:24: error: ‘BTF_KIND_DATASEC’ undeclared (first use in this function); did you mean ‘BTF_KIND_PTR’?
  return btf_kind(t) == BTF_KIND_DATASEC;
                        ^~~~~~~~~~~~~~~~
                        BTF_KIND_PTR
mv: cannot stat '/home/john/git/bpf-next/tools/bpf/btfid/.btfid.o.tmp': No such file or directory
make[3]: *** [/home/john/git/bpf-next/tools/build/Makefile.build:97: /home/john/git/bpf-next/tools/bpf/btfid/btfid.o] Error 1
make[2]: *** [Makefile:59: /home/john/git/bpf-next/tools/bpf/btfid/btfid-in.o] Error 2
make[1]: *** [Makefile:71: bpf/btfid] Error 2
make: *** [Makefile:1894: tools/bpf/btfid] Error 2
