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From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Yonghong Song <yhs@fb.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	john fastabend <john.fastabend@gmail.com>,
	open list <linux-kernel@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	clang-built-linux@googlegroups.com,
	sergei.shtylyov@cogentembedded.com
Subject: Re: [PATCH v3 bpf-next 07/14] samples: bpf: add makefile.target for separate CC target build
Date: Wed, 18 Sep 2019 13:12:17 +0300
Message-ID: <20190918101216.GA2908@khorivan> (raw)
In-Reply-To: <CAEf4Bzaidog3n0YP6F5dL2rCrHtKCOBXS0as7usymk8Twdro4w@mail.gmail.com>

On Tue, Sep 17, 2019 at 04:19:40PM -0700, Andrii Nakryiko wrote:
>On Mon, Sep 16, 2019 at 3:58 AM Ivan Khoronzhuk
><ivan.khoronzhuk@linaro.org> wrote:
>>
>> The makefile.target is added only and will be used in
>
>typo: Makefile
>
>> sample/bpf/Makefile later in order to switch cross-compiling on CC
>
>on -> to
>
>> from HOSTCC environment.
>>
>> The HOSTCC is supposed to build binaries and tools running on the host
>> afterwards, in order to simplify build or so, like "fixdep" or else.
>> In case of cross compiling "fixdep" is executed on host when the rest
>> samples should run on target arch. In order to build binaries for
>> target arch with CC and tools running on host with HOSTCC, lets add
>> Makefile.target for simplicity, having definition and routines similar
>> to ones, used in script/Makefile.host. This allows later add
>> cross-compilation to samples/bpf with minimum changes.
>>
>> The tprog stands for target programs built with CC.
>
>Why tprog? Could we just use prog: hostprog vs prog.
Prev. version was with prog, but Yonghong Song found it ambiguous.
As prog can be bpf also. So, decision was made to follow logic:
* target prog - non bpf progs
* bpf prog = bpf prog, that can be later smth similar, providing build options
  for each bpf object separately.

Details here:
https://lkml.org/lkml/2019/9/13/1037

>
>>
>> Makefile.target contains only stuff needed for samples/bpf, potentially
>> can be reused later and now needed only for unblocking tricky
>> samples/bpf cross compilation.
>>
>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
>> ---
>>  samples/bpf/Makefile.target | 75 +++++++++++++++++++++++++++++++++++++
>>  1 file changed, 75 insertions(+)
>>  create mode 100644 samples/bpf/Makefile.target
>>
>> diff --git a/samples/bpf/Makefile.target b/samples/bpf/Makefile.target
>> new file mode 100644
>> index 000000000000..fb6de63f7d2f
>> --- /dev/null
>> +++ b/samples/bpf/Makefile.target
>> @@ -0,0 +1,75 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +# ==========================================================================
>> +# Building binaries on the host system
>> +# Binaries are not used during the compilation of the kernel, and intendent
>
>typo: intended
>
>> +# to be build for target board, target board can be host ofc. Added to build
>
>What's ofc, is it "of course"?
yes, ofc )

>
>> +# binaries to run not on host system.
>> +#
>> +# Sample syntax (see Documentation/kbuild/makefiles.rst for reference)
>> +# tprogs-y := xsk_example
>> +# Will compile xdpsock_example.c and create an executable named xsk_example
>
>You mix references to xsk_example and xdpsock_example, which is very
>confusing. I'm guessing you meant to use xdpsock_example consistently.
Oh, yes. Thanks.

>
>> +#
>> +# tprogs-y    := xdpsock
>> +# xdpsock-objs := xdpsock_1.o xdpsock_2.o
>> +# Will compile xdpsock_1.c and xdpsock_2.c, and then link the executable
>> +# xdpsock, based on xdpsock_1.o and xdpsock_2.o
>> +#
>> +# Inherited from scripts/Makefile.host
>
>"Inspired by" or "Derived from" would be probably more appropriate term :)
I will replace with "Derived from", looks better.

>
>> +#
>> +__tprogs := $(sort $(tprogs-y))
>> +
>> +# C code
>> +# Executables compiled from a single .c file
>> +tprog-csingle  := $(foreach m,$(__tprogs), \
>> +                       $(if $($(m)-objs),,$(m)))
>> +
>> +# C executables linked based on several .o files
>> +tprog-cmulti   := $(foreach m,$(__tprogs),\
>> +                       $(if $($(m)-objs),$(m)))
>> +
>> +# Object (.o) files compiled from .c files
>> +tprog-cobjs    := $(sort $(foreach m,$(__tprogs),$($(m)-objs)))
>> +
>> +tprog-csingle  := $(addprefix $(obj)/,$(tprog-csingle))
>> +tprog-cmulti   := $(addprefix $(obj)/,$(tprog-cmulti))
>> +tprog-cobjs    := $(addprefix $(obj)/,$(tprog-cobjs))
>> +
>> +#####
>> +# Handle options to gcc. Support building with separate output directory
>> +
>> +_tprogc_flags   = $(TPROGS_CFLAGS) \
>> +                 $(TPROGCFLAGS_$(basetarget).o)
>> +
>> +# $(objtree)/$(obj) for including generated headers from checkin source files
>> +ifeq ($(KBUILD_EXTMOD),)
>> +ifdef building_out_of_srctree
>> +_tprogc_flags   += -I $(objtree)/$(obj)
>> +endif
>> +endif
>> +
>> +tprogc_flags    = -Wp,-MD,$(depfile) $(_tprogc_flags)
>> +
>> +# Create executable from a single .c file
>> +# tprog-csingle -> Executable
>> +quiet_cmd_tprog-csingle        = CC  $@
>> +      cmd_tprog-csingle        = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ $< \
>> +               $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F))
>> +$(tprog-csingle): $(obj)/%: $(src)/%.c FORCE
>> +       $(call if_changed_dep,tprog-csingle)
>> +
>> +# Link an executable based on list of .o files, all plain c
>> +# tprog-cmulti -> executable
>> +quiet_cmd_tprog-cmulti = LD  $@
>> +      cmd_tprog-cmulti = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ \
>> +                         $(addprefix $(obj)/,$($(@F)-objs)) \
>> +                         $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F))
>> +$(tprog-cmulti): $(tprog-cobjs) FORCE
>> +       $(call if_changed,tprog-cmulti)
>> +$(call multi_depend, $(tprog-cmulti), , -objs)
>> +
>> +# Create .o file from a single .c file
>> +# tprog-cobjs -> .o
>> +quiet_cmd_tprog-cobjs  = CC  $@
>> +      cmd_tprog-cobjs  = $(CC) $(tprogc_flags) -c -o $@ $<
>> +$(tprog-cobjs): $(obj)/%.o: $(src)/%.c FORCE
>> +       $(call if_changed_dep,tprog-cobjs)
>> --
>> 2.17.1
>>
>
>tprogs is quite confusing, but overall looks good to me.
I tend to leave it as tprogs, unless it's going to be progs and agreed with
Yonghong.

It follows logic:
- tprogs for bins
- bpfprogs or bojs or bprogs (could be) for bpf obj

-- 
Regards,
Ivan Khoronzhuk

  reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-16 10:54 [PATCH v3 bpf-next 00/14] samples: bpf: improve/fix cross-compilation Ivan Khoronzhuk
2019-09-16 10:54 ` [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo" Ivan Khoronzhuk
2019-09-16 20:13   ` Andrii Nakryiko
2019-09-16 21:22     ` Ivan Khoronzhuk
2019-09-16 21:35     ` Andreas Schwab
2019-09-16 22:01       ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 02/14] samples: bpf: makefile: fix cookie_uid_helper_example obj build Ivan Khoronzhuk
2019-09-16 20:18   ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 03/14] samples: bpf: makefile: use --target from cross-compile Ivan Khoronzhuk
2019-09-16 20:25   ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 04/14] samples: bpf: use own EXTRA_CFLAGS for clang commands Ivan Khoronzhuk
2019-09-16 20:35   ` Andrii Nakryiko
2019-09-16 22:01     ` Ivan Khoronzhuk
2019-09-16 10:54 ` [PATCH v3 bpf-next 05/14] samples: bpf: makefile: use __LINUX_ARM_ARCH__ selector for arm Ivan Khoronzhuk
2019-09-16 20:44   ` Andrii Nakryiko
2019-09-16 22:04     ` Ivan Khoronzhuk
2019-09-16 10:54 ` [PATCH v3 bpf-next 06/14] samples: bpf: makefile: drop unnecessarily inclusion for bpf_load Ivan Khoronzhuk
2019-09-16 20:52   ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 07/14] samples: bpf: add makefile.target for separate CC target build Ivan Khoronzhuk
2019-09-17 23:19   ` Andrii Nakryiko
2019-09-18 10:12     ` Ivan Khoronzhuk [this message]
2019-09-18 21:22       ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 08/14] samples: bpf: makefile: base target programs rules on Makefile.target Ivan Khoronzhuk
2019-09-17 23:28   ` Andrii Nakryiko
2019-09-18 10:23     ` Ivan Khoronzhuk
2019-09-16 10:54 ` [PATCH v3 bpf-next 09/14] samples: bpf: makefile: use own flags but not host when cross compile Ivan Khoronzhuk
2019-09-17 10:14   ` Sergei Shtylyov
2019-09-17 23:42   ` Andrii Nakryiko
2019-09-18 10:35     ` Ivan Khoronzhuk
2019-09-18 21:29       ` Andrii Nakryiko
2019-09-19 14:18         ` Ivan Khoronzhuk
2019-09-19 17:54           ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 10/14] samples: bpf: makefile: use target CC environment for HDR_PROBE Ivan Khoronzhuk
2019-09-18  4:20   ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 11/14] libbpf: makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets Ivan Khoronzhuk
2019-09-18  5:19   ` Andrii Nakryiko
2019-09-18 11:05     ` Ivan Khoronzhuk
2019-09-18 21:42       ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 12/14] samples: bpf: makefile: provide C/CXX/LD flags to libbpf Ivan Khoronzhuk
2019-09-18  5:20   ` Andrii Nakryiko
2019-09-16 10:54 ` [PATCH v3 bpf-next 13/14] samples: bpf: makefile: add sysroot support Ivan Khoronzhuk
2019-09-18  5:23   ` Andrii Nakryiko
2019-09-18 11:09     ` Ivan Khoronzhuk
2019-09-16 10:54 ` [PATCH v3 bpf-next 14/14] samples: bpf: README: add preparation steps and sysroot info Ivan Khoronzhuk
2019-09-18  5:33 ` [PATCH v3 bpf-next 00/14] samples: bpf: improve/fix cross-compilation Andrii Nakryiko

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