Re: arch/mips/vdso/gettimeofday.c:1:0: error: '-march=r3900' requires '-mfp32'

From: Fengguang Wu <fengguang.wu@intel.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: kbuild-all@01.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>
Subject: Re: arch/mips/vdso/gettimeofday.c:1:0: error: '-march=r3900' requires '-mfp32'
Date: Tue, 5 Jan 2016 22:30:39 +0800	[thread overview]
Message-ID: <20160105143039.GA5772@wfg-t540p.sh.intel.com> (raw)
In-Reply-To: <568BCD07.6090401@roeck-us.net>

Hi Guenter,

On Tue, Jan 05, 2016 at 06:02:47AM -0800, Guenter Roeck wrote:
> On 01/05/2016 12:22 AM, Fengguang Wu wrote:
> >On Tue, Jan 05, 2016 at 12:09:14AM -0800, Guenter Roeck wrote:
> >>On 01/04/2016 11:23 PM, kbuild test robot wrote:
> >>>Hi Guenter,
> >>>
> >>>First bad commit (maybe != root cause):
> >>>
> >>>tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> >>>head:   168309855a7d1e16db751e9c647119fe2d2dc878
> >>>commit: 398c7500a1f5f74e207bd2edca1b1721b3cc1f1e MIPS: VDSO: Fix build error with binutils 2.24 and earlier
> >>>date:   6 days ago
> >>>config: mips-jmr3927_defconfig (attached as .config)
> >>>reproduce:
> >>>         wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
> >>>         chmod +x ~/bin/make.cross
> >>>         git checkout 398c7500a1f5f74e207bd2edca1b1721b3cc1f1e
> >>>         # save the attached .config to linux build tree
> >>>         make.cross ARCH=mips
> >>>
> >>>All errors (new ones prefixed by >>):
> >>>
> >>>>>arch/mips/vdso/gettimeofday.c:1:0: error: '-march=r3900' requires '-mfp32'
> >>>     /*
> >>>     ^
> >>>
> >>AFAICS this is using the mips cross compiler version 4.9.0 from kernel.org [1],
> >>which in turn uses binutils 2.24. At least this is what make.cross tries to install.
> >
> >Oops, sorry. I'm now using the debian MIPS cross compiler 5.2.1 ...
> >make.cross has not been updated yet.
> >
> No problem. FWIW, I tested my patch with the compiler from Yocto 2.0, which
> uses gcc 5.2.0 and binutils 2.25.1, with no problem.
> 
> Do you have directions on how to install a debian cross compiler into a Ubuntu system ?
> Alternatively, what version of binutils does the mips cross compiler use ?

These are the installed version in my Debian:

||/ Name                                 Version                 Architecture            Description
+++-====================================-=======================-=======================-=============================================================================
ii  gcc-5-mips-linux-gnu                 5.2.1-16cross1          amd64                   GNU C compiler
ii  gcc-5-mipsel-linux-gnu               5.2.1-16cross1          amd64                   GNU C compiler
ii  binutils-mips-linux-gnu              2.25-8                  amd64                   GNU binary utilities, for mips-linux-gnu target
ii  binutils-mipsel-linux-gnu            2.25-8                  amd64                   GNU binary utilities, for mipsel-linux-gnu target

You may check if these packages are available on Ubuntu.  Anyway the
versions are close to yours. This is interesting, I'll do more checks.

Thanks,
Fengguang

> >>I downloaded it and used it to compile both the attached configuration as well
> >>as jmr3927_defconfig. Both are building just fine for me. On top of that,
> >>arch/mips/vdso/gettimeofday.c should not build in the first place with binutils 2.24
> >>(and doesn't build for me).
> >>
> >>What am I missing ?
> >>
> >>Guenter
> >>
> >>---
> >>[1] https://www.kernel.org/pub/tools/crosstool/files/bin/x86_64/4.9.0/x86_64-gcc-4.9.0-nolibc_mips-linux.tar.xz
> >