Re: [PATCH v4 bpf-next 01/14] bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object

From: Yonghong Song <yhs@fb.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>, 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 v4 bpf-next 01/14] bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object
Date: Fri, 26 Jun 2020 14:09:53 -0700	[thread overview]
Message-ID: <d521c351-2bcd-2510-7266-0194ade5ca64@fb.com> (raw)
In-Reply-To: <20200625221304.2817194-2-jolsa@kernel.org>

On 6/25/20 3:12 PM, Jiri Olsa wrote:
> The resolve_btfids tool scans elf object for .BTF_ids section
> and resolves its symbols with BTF ID values.
> 
> It will be used to during linking time to resolve arrays of BTF
> ID values used in verifier, so these IDs do not need to be
> resolved in runtime.
> 
> The expected layout of .BTF_ids section is described in btfid.c
> header. Related kernel changes are coming in following changes.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>   tools/bpf/resolve_btfids/Build    |  26 ++
>   tools/bpf/resolve_btfids/Makefile |  76 ++++
>   tools/bpf/resolve_btfids/main.c   | 716 ++++++++++++++++++++++++++++++
>   3 files changed, 818 insertions(+)
>   create mode 100644 tools/bpf/resolve_btfids/Build
>   create mode 100644 tools/bpf/resolve_btfids/Makefile
>   create mode 100644 tools/bpf/resolve_btfids/main.c
> 
> diff --git a/tools/bpf/resolve_btfids/Build b/tools/bpf/resolve_btfids/Build
> new file mode 100644
> index 000000000000..c7318cc55341
> --- /dev/null
> +++ b/tools/bpf/resolve_btfids/Build
> @@ -0,0 +1,26 @@
> +resolve_btfids-y += main.o
> +resolve_btfids-y += rbtree.o
> +resolve_btfids-y += zalloc.o
> +resolve_btfids-y += string.o
> +resolve_btfids-y += ctype.o
> +resolve_btfids-y += str_error_r.o
> +
> +$(OUTPUT)rbtree.o: ../../lib/rbtree.c FORCE
> +	$(call rule_mkdir)
> +	$(call if_changed_dep,cc_o_c)
> +
> +$(OUTPUT)zalloc.o: ../../lib/zalloc.c FORCE
> +	$(call rule_mkdir)
> +	$(call if_changed_dep,cc_o_c)
> +
> +$(OUTPUT)string.o: ../../lib/string.c FORCE
> +	$(call rule_mkdir)
> +	$(call if_changed_dep,cc_o_c)
> +
> +$(OUTPUT)ctype.o: ../../lib/ctype.c FORCE
> +	$(call rule_mkdir)
> +	$(call if_changed_dep,cc_o_c)
> +
> +$(OUTPUT)str_error_r.o: ../../lib/str_error_r.c FORCE
> +	$(call rule_mkdir)
> +	$(call if_changed_dep,cc_o_c)
> diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
> new file mode 100644
> index 000000000000..f6502ff26573
> --- /dev/null
> +++ b/tools/bpf/resolve_btfids/Makefile
> @@ -0,0 +1,76 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +ifeq ($(srctree),)
> +srctree := $(patsubst %/,%,$(dir $(CURDIR)))
> +srctree := $(patsubst %/,%,$(dir $(srctree)))
> +srctree := $(patsubst %/,%,$(dir $(srctree)))
> +endif
> +
> +ifeq ($(V),1)
> +  Q =
> +  msg =
> +else
> +  Q = @
> +  msg = @printf '  %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
> +  MAKEFLAGS=--no-print-directory
> +endif
> +
> +OUTPUT := $(srctree)/tools/bpf/resolve_btfids/
> +
> +LIBBPF_SRC := $(srctree)/tools/lib/bpf/
> +SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
> +
> +BPFOBJ     := $(OUTPUT)/libbpf.a
> +SUBCMDOBJ  := $(OUTPUT)/libsubcmd.a
> +
> +BINARY     := $(OUTPUT)/resolve_btfids
> +BINARY_IN  := $(BINARY)-in.o
> +
> +all: $(BINARY)
> +
> +$(OUTPUT):
> +	$(call msg,MKDIR,,$@)
> +	$(Q)mkdir -p $(OUTPUT)
> +
> +$(SUBCMDOBJ): fixdep FORCE
> +	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT)
> +
> +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
> +	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)  OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
> +
> +CFLAGS := -g \
> +          -I$(srctree)/tools/include \
> +          -I$(srctree)/tools/include/uapi \
> +          -I$(LIBBPF_SRC) \
> +          -I$(SUBCMD_SRC)
> +
> +LIBS = -lelf -lz
> +
> +export srctree OUTPUT CFLAGS Q
> +include $(srctree)/tools/build/Makefile.include
> +
> +$(BINARY_IN): fixdep FORCE
> +	$(Q)$(MAKE) $(build)=resolve_btfids
> +
> +$(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
> +	$(call msg,LINK,$@)
> +	$(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
> +
> +libsubcmd-clean:
> +	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT) clean
> +
> +libbpf-clean:
> +	$(Q)$(MAKE) -C $(LIBBPF_SRC) OUTPUT=$(OUTPUT) clean
> +
> +clean: libsubcmd-clean libbpf-clean fixdep-clean
> +	$(call msg,CLEAN,$(BINARY))
> +	$(Q)$(RM) -f $(BINARY); \
> +	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
> +
> +tags:
> +	$(call msg,GEN,,tags)
> +	$(Q)ctags -R . $(LIBBPF_SRC) $(SUBCMD_SRC)
> +
> +FORCE:
> +
> +.PHONY: all FORCE clean tags

After applying the whole patch set to my bpf-next tree locally, I cannot 
build:

-bash-4.4$ make -j100 && make vmlinux
   GEN     Makefile
   DESCEND  objtool
   DESCEND  bpf/resolve_btfids
make[4]: *** No rule to make target 
`/data/users/yhs/work/net-next/tools/bpf/resolve_btfids/fixdep'.  Stop.
make[3]: *** [fixdep] Error 2
make[2]: *** [bpf/resolve_btfids] Error 2
make[1]: *** [tools/bpf/resolve_btfids] Error 2
make[1]: *** Waiting for unfinished jobs....
make[1]: *** wait: No child processes.  Stop.
make: *** [__sub-make] Error 2
-bash-4.4$

Any clue what is the possible issue here?

> diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
> new file mode 100644
> index 000000000000..d758e2bdbc9d
> --- /dev/null
> +++ b/tools/bpf/resolve_btfids/main.c
> @@ -0,0 +1,716 @@
> +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
> +
> +/*
> + * resolve_btfids scans Elf object for .BTF_ids section and resolves
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