From: Jiong Wang <jiong.wang@netronome.com>
To: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Jiong Wang <jiong.wang@netronome.com>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
"David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
oss-drivers@netronome.com, linux-kernel@vger.kernel.org,
xdp-newbies@vger.kernel.org, valdis@vt.edu
Subject: Re: [oss-drivers] netronome/nfp/bpf/jit.c cannot be build with -O3
Date: Tue, 07 May 2019 12:31:29 +0100 [thread overview]
Message-ID: <87ef5abiwe.fsf@netronome.com> (raw)
In-Reply-To: <4414f1798ea3c0f70128b7e4caa14edc@natalenko.name>
Oleksandr Natalenko writes:
> Hi.
>
> On 07.05.2019 00:01, Jiong Wang wrote:
>> I guess it's because constant prop. Could you try the following change
>> to
>> __emit_shift?
>>
>> drivers/net/ethernet/netronome/nfp/bpf/jit.c
>> __emit_shift:331
>> - if (sc == SHF_SC_L_SHF)
>> + if (sc == SHF_SC_L_SHF && shift)
>> shift = 32 - shift;
>>
>> emit_shf_indir is passing "0" as shift to __emit_shift which will
>> eventually be turned into 32 and it was OK because we truncate to
>> 5-bit,
>> but before truncation, it will overflow the shift mask.
>
> Yup, it silences the error for me.
Thanks for the testing.
I have also reproduced this issue after switching to gcc 8.3, and confirmed
the error is triggered from "value too large for the field" check inside
__BF_FIELD_CHECK due to immediate "32" is out of range for mask 0x1f.
Will send out a fix.
Regards,
Jiong
prev parent reply other threads:[~2019-05-07 11:31 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 19:40 netronome/nfp/bpf/jit.c cannot be build with -O3 Oleksandr Natalenko
2019-05-06 21:00 ` Jakub Kicinski
2019-05-06 21:24 ` Oleksandr Natalenko
2019-05-06 21:35 ` Jakub Kicinski
2019-05-07 5:01 ` Oleksandr Natalenko
2019-05-06 22:01 ` [oss-drivers] " Jiong Wang
2019-05-07 5:05 ` Oleksandr Natalenko
2019-05-07 11:31 ` Jiong Wang [this message]
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