From: Quentin Monnet <quentin@isovalent.com>
To: Song Liu <songliubraving@fb.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: kernel-team@fb.com, ast@kernel.org, daniel@iogearbox.net,
arnaldo.melo@gmail.com, jolsa@kernel.org
Subject: Re: [PATCH bpf-next 1/2] bpftool: only build bpftool-prog-profile with clang >= v11
Date: Tue, 10 Mar 2020 22:44:57 +0000 [thread overview]
Message-ID: <65be9b45-059a-fc41-fd47-a6b9d7cda418@isovalent.com> (raw)
In-Reply-To: <20200310183624.441788-2-songliubraving@fb.com>
2020-03-10 11:36 UTC-0700 ~ Song Liu <songliubraving@fb.com>
> bpftool-prog-profile requires clang of version 11.0.0 or newer. If
> bpftool is built with older clang, show a hint of to the user.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
> tools/bpf/bpftool/Makefile | 13 +++++++++++--
> tools/bpf/bpftool/prog.c | 2 ++
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index 20a90d8450f8..05a37f0f76a9 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -60,6 +60,15 @@ LIBS = $(LIBBPF) -lelf -lz
> INSTALL ?= install
> RM ?= rm -f
> CLANG ?= clang
> +CLANG_VERS = $(shell $(CLANG) --version | head -n 1 | awk '{print $$3}')
> +CLANG_MAJ = $(shell echo $(CLANG_VERS) | cut -d '.' -f 1)
This will produce error messages on stderr if clang is not installed on
the system.
> +WITHOUT_SKELETONS = -DBPFTOOL_WITHOUT_SKELETONS
> +
> +ifeq ($(shell test $(CLANG_MAJ) -ge 11; echo $$?),0)
Not exactly what I had in mind. I thought about the feature detection
facility we have under tools/build/feature/, as is used for e.g.
detecting libbfd. It would allow to check the feature is available,
instead of tying the build to a numeric version number. But that's more
work to do, so I suppose this version can work, too...
> + PROG_FLAGS =
> +else
> + PROG_FLAGS = $(WITHOUT_SKELETONS)
> +endif
>
> FEATURE_USER = .bpftool
> FEATURE_TESTS = libbfd disassembler-four-args reallocarray zlib
> @@ -114,7 +123,7 @@ OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
> _OBJS = $(filter-out $(OUTPUT)prog.o,$(OBJS)) $(OUTPUT)_prog.o
>
> $(OUTPUT)_prog.o: prog.c
> - $(QUIET_CC)$(COMPILE.c) -MMD -DBPFTOOL_WITHOUT_SKELETONS -o $@ $<
> + $(QUIET_CC)$(COMPILE.c) -MMD $(WITHOUT_SKELETONS) -o $@ $<
>
> $(OUTPUT)_bpftool: $(_OBJS) $(LIBBPF)
> $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(_OBJS) $(LIBS)
> @@ -126,7 +135,7 @@ profiler.skel.h: $(OUTPUT)_bpftool skeleton/profiler.bpf.o
> $(QUIET_GEN)$(OUTPUT)./_bpftool gen skeleton skeleton/profiler.bpf.o > $@
>
> $(OUTPUT)prog.o: prog.c profiler.skel.h
> - $(QUIET_CC)$(COMPILE.c) -MMD -o $@ $<
> + $(QUIET_CC)$(COMPILE.c) -MMD $(PROG_FLAGS) -o $@ $<
Would be nice to find a way to skip the second build if it is not needed?
>
> $(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
> $(QUIET_CC)$(COMPILE.c) -MMD -o $@ $<
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index 576ddd82bc96..5db378d5d970 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1545,6 +1545,8 @@ static int do_loadall(int argc, char **argv)
>
> static int do_profile(int argc, char **argv)
> {
> + fprintf(stdout, "bpftool prog profile command is not supported.\n"
> + "Please recompile bpftool with clang >= 11.0.0\n");
p_err()?
> return 0;
> }
>
>
Thanks a lot for the follow-up!
Quentin
next prev parent reply other threads:[~2020-03-10 22:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-10 18:36 [PATCH bpf-next 0/2] Fixes for bpftool-prog-profile Song Liu
2020-03-10 18:36 ` [PATCH bpf-next 1/2] bpftool: only build bpftool-prog-profile with clang >= v11 Song Liu
2020-03-10 22:44 ` Quentin Monnet [this message]
2020-03-10 22:54 ` Alexei Starovoitov
2020-03-10 18:36 ` [PATCH bpf-next 2/2] bpftool: skeleton should depend on libbpf Song Liu
2020-03-10 22:00 ` [PATCH bpf-next 0/2] Fixes for bpftool-prog-profile John Fastabend
2020-03-11 4:33 ` Andrii Nakryiko
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