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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Stanislav Fomichev <sdf@fomichev.me>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Shuah Khan <shuah@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Stanislav Fomichev <sdf@google.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Subject: Re: [PATCHv2 bpf-next 1/3] bpf, tests: tweak endianness selection
Date: Fri, 22 Mar 2019 11:46:52 +0900	[thread overview]
Message-ID: <20190322024652.GA3679@jagdpanzerIV> (raw)
In-Reply-To: <20190321154928.GT7431@mini-arch.hsd1.ca.comcast.net>

On (03/21/19 08:49), Stanislav Fomichev wrote:
> On 03/21, Sergey Senozhatsky wrote:
> > On (03/20/19 20:24), Alexei Starovoitov wrote:
> > > On Wed, Mar 20, 2019 at 09:53:33PM +0900, Sergey Senozhatsky wrote:
> > > > Not all compilers have __builtin_bswap16() and __builtin_bswap32(),
> > > > thus not all compilers are able to compile the following code:
> > > > 
> > > >         (__builtin_constant_p(x) ? \
> > > >                 ___constant_swab16(x) : __builtin_bswap16(x))
> > > > 
> > > > That's the reason why bpf_ntohl() doesn't work on GCC < 4.8, for
> > > > instance:
> > > 
> > > nack to fixes to support such old compilers.
> > 
> > Fair enough.
> What is too old? Documentation/process/changes.rst says that minimum
> supported gcc is 4.6, do we lift that requirement for the tests?

Hmm, good point, Stanislav. I thought it was gcc 4.9 which introduced
asm goto and hence 4.9 is the minimum supported version. But it seems
that it was 4.5/4.6, so the min supported gcc version is 4.6. Which
means that those bpf defines won't work on some compilers.

Alexei, does your NACK still stand?

	-ss

  reply	other threads:[~2019-03-22  2:46 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-20 12:53 [PATCHv2 bpf-next 1/3] bpf, tests: tweak endianness selection Sergey Senozhatsky
2019-03-20 12:53 ` [PATCHv2 bpf-next 2/3] bpf, tests: drop unused __bpf_constant_foo defines Sergey Senozhatsky
2019-03-20 12:56   ` Sergey Senozhatsky
2019-03-20 12:53 ` [PATCHv2 bpf-next 3/3] bpf, tests: don't use __bpf_constant_htons() Sergey Senozhatsky
2019-03-20 12:55   ` Sergey Senozhatsky
2019-03-20 17:13 ` [PATCHv2 bpf-next 1/3] bpf, tests: tweak endianness selection Stanislav Fomichev
2019-03-20 22:20   ` Yonghong Song
2019-03-20 22:27     ` Stanislav Fomichev
2019-03-20 22:45       ` Yonghong Song
2019-03-20 23:08         ` Daniel Borkmann
2019-03-21  0:03           ` Stanislav Fomichev
2019-03-21  0:23             ` Yonghong Song
2019-03-21  0:34       ` Sergey Senozhatsky
2019-03-21  0:22   ` Sergey Senozhatsky
2019-03-21  3:24 ` Alexei Starovoitov
2019-03-21  5:08   ` Sergey Senozhatsky
2019-03-21 15:49     ` Stanislav Fomichev
2019-03-22  2:46       ` Sergey Senozhatsky [this message]
2019-03-22  3:12         ` Alexei Starovoitov

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