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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
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>,
	LKML <linux-kernel@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH bpf-next 2/8] samples: bpf: Makefile: remove target for native build
Date: Fri, 6 Sep 2019 17:04:08 -0700	[thread overview]
Message-ID: <CAADnVQKOT8D9156p49AQ0q0z5Zks5te4Ofi6DrBfpnitmRBgmg@mail.gmail.com> (raw)
In-Reply-To: <20190906235207.GA3053@khorivan>

On Fri, Sep 6, 2019 at 4:52 PM Ivan Khoronzhuk
<ivan.khoronzhuk@linaro.org> wrote:
>
> On Fri, Sep 06, 2019 at 04:31:39PM -0700, Alexei Starovoitov wrote:
> >On Thu, Sep 05, 2019 at 12:22:06AM +0300, Ivan Khoronzhuk wrote:
> >> No need to set --target for native build, at least for arm, the
> >> default target will be used anyway. In case of arm, for at least
> >> clang 5 - 10 it causes error like:
> >>
> >> clang: warning: unknown platform, assuming -mfloat-abi=soft
> >> LLVM ERROR: Unsupported calling convention
> >> make[2]: *** [/home/root/snapshot/samples/bpf/Makefile:299:
> >> /home/root/snapshot/samples/bpf/sockex1_kern.o] Error 1
> >>
> >> Only set to real triple helps: --target=arm-linux-gnueabihf
> >> or just drop the target key to use default one. Decision to just
> >> drop it and thus default target will be used (wich is native),
> >> looks better.
> >>
> >> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
> >> ---
> >>  samples/bpf/Makefile | 2 --
> >>  1 file changed, 2 deletions(-)
> >>
> >> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> >> index 61b7394b811e..a2953357927e 100644
> >> --- a/samples/bpf/Makefile
> >> +++ b/samples/bpf/Makefile
> >> @@ -197,8 +197,6 @@ BTF_PAHOLE ?= pahole
> >>  ifdef CROSS_COMPILE
> >>  HOSTCC = $(CROSS_COMPILE)gcc
> >>  CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%))
> >> -else
> >> -CLANG_ARCH_ARGS = -target $(ARCH)
> >>  endif
> >
> >I don't follow here.
> >Didn't you introduce this bug in patch 1 and now fixing it in patch 2?
> >
>
> It looks like but that's not true.
> Previous patch adds target only for cross compiling,
> before the patch the target was used for both, cross compiling and w/o cc.
>
> This patch removes target only for native build (it's not cross compiling).
>
> By fact, it's two separate significant changes.

How so?
before first patch CLANG_ARCH_ARGS is only used under CROSS_COMPILE.
After the first patch CLANG_ARCH_ARGS is now suddenly defined w/o CROSS_COMPILE
and second patch brings it to the state before first patch.

  reply	other threads:[~2019-09-07  0:04 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04 21:22 [PATCH bpf-next 0/8] samples: bpf: improve/fix cross-compilation Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 1/8] samples: bpf: Makefile: use --target from cross-compile Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 2/8] samples: bpf: Makefile: remove target for native build Ivan Khoronzhuk
2019-09-06 23:31   ` Alexei Starovoitov
2019-09-06 23:52     ` Ivan Khoronzhuk
2019-09-07  0:04       ` Alexei Starovoitov [this message]
2019-09-07  0:19         ` Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 3/8] libbpf: Makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 4/8] samples: bpf: use own EXTRA_CFLAGS for clang commands Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 5/8] samples: bpf: Makefile: use vars from KBUILD_CFLAGS to handle linux headers Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 6/8] samples: bpf: makefile: fix HDR_PROBE "echo" Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 7/8] samples: bpf: add makefile.prog for separate CC build Ivan Khoronzhuk
2019-09-04 21:22 ` [PATCH bpf-next 8/8] samples: bpf: Makefile: base progs build on Makefile.progs Ivan Khoronzhuk
2019-09-06 23:34   ` Alexei Starovoitov
2019-09-07  1:24     ` Ivan Khoronzhuk

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