From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Yonghong Song <yhs@fb.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next] selftests/bpf: change llvm flag -mcpu=probe to -mcpu=v3
Date: Tue, 18 Feb 2020 23:34:17 -0800 [thread overview]
Message-ID: <CAEf4BzagQu2ecGBP8jiOOkSz39pBzGBPuTcF48yzpfnzwKehdA@mail.gmail.com> (raw)
In-Reply-To: <20200219004236.2291125-1-yhs@fb.com>
On Tue, Feb 18, 2020 at 4:44 PM Yonghong Song <yhs@fb.com> wrote:
>
> The latest llvm supports cpu version v3, which is cpu version v1
> plus some additional 64bit jmp insns and 32bit jmp insn support.
>
> In selftests/bpf Makefile, the llvm flag -mcpu=probe did runtime
> probe into the host system. Depending on compilation environments,
> it is possible that runtime probe may fail, e.g., due to
> memlock issue. This will cause generated code with cpu version v1.
> This may cause confusion as the same compiler and the same C code
> generates different byte codes in different environment.
>
> Let us change the llvm flag -mcpu=probe to -mcpu=v3 so the
> generated code will be the same regardless of the compilation
> environment.
>
> Signed-off-by: Yonghong Song <yhs@fb.com>
> ---
Acked-by: Andrii Nakryiko <andriin@fb.com>
> tools/testing/selftests/bpf/Makefile | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
[...]
next prev parent reply other threads:[~2020-02-19 7:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 0:42 [PATCH bpf-next] selftests/bpf: change llvm flag -mcpu=probe to -mcpu=v3 Yonghong Song
2020-02-19 7:34 ` Andrii Nakryiko [this message]
2020-02-19 16:56 ` Daniel Borkmann
2020-02-19 17:04 ` Yonghong Song
2020-02-19 17:06 ` Alexei Starovoitov
2020-02-19 23:17 ` Alexei Starovoitov
2020-02-20 0:15 ` Daniel Borkmann
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