Hi,
On 5/16/2019 10:21 AM, Fengguang Wu wrote:
CC current 0day kbuild test maintainers Philip and Rong. -fengguang
On Tue, May 14, 2019 at 11:49:18PM -0700, Nathan Chancellor wrote:
On Wed, May 15, 2019 at 08:42:13AM +0200, Arnd Bergmann wrote:
On Wed, May 15, 2019 at 8:40 AM Nathan Chancellor
<natechancellor@xxxxxxxxx> wrote:
> On Wed, May 15, 2019 at 08:31:49AM +0200, Arnd Bergmann wrote:
> > On Wed, May 15, 2019 at 7:04 AM Leon Romanovsky
<leonro@xxxxxxxxxxxx> wrote:
> > > On Tue, May 14, 2019 at 09:32:02PM -0300, Jason Gunthorpe wrote:
> > > > On Tue, May 14, 2019 at 12:45:10PM -0700, Nathan Chancellor
wrote:
> > > > > Hi all,
> > > > >
> > > > > I checked the RDMA mailing list and trees and I haven't
seen this
> > > > > reported/fixed yet (forgive me if it has) but when
building for arm32
> > > > > with multi_v7_defconfig and the following configs
(distilled from
> > > > > allyesconfig):
> > > > >
> > > > > CONFIG_INFINIBAND=y
> > > > > CONFIG_INFINIBAND_ON_DEMAND_PAGING=y
> > > > > CONFIG_INFINIBAND_USER_ACCESS=y
> > > > > CONFIG_MLX5_CORE=y
> > > > > CONFIG_MLX5_INFINIBAND=y
> > > > >
> > > > > The following link time errors occur:
> > > > >
> > > > > arm-linux-gnueabi-ld: drivers/infiniband/hw/mlx5/main.o:
in function `mlx5_ib_alloc_dm':
> > > > > main.c:(.text+0x60c): undefined reference to
`__aeabi_uldivmod'
> > > > > arm-linux-gnueabi-ld: drivers/infiniband/hw/mlx5/cmd.o: in
function `mlx5_cmd_alloc_sw_icm':
> > > > > cmd.c:(.text+0x6d4): undefined reference to
`__aeabi_uldivmod'
> > > > > arm-linux-gnueabi-ld: drivers/infiniband/hw/mlx5/cmd.o: in
function `mlx5_cmd_dealloc_sw_icm':
> > > > > cmd.c:(.text+0x9ec): undefined reference to
`__aeabi_uldivmod'
> > > >
> > > > Fengguang, I'm surprised that 0-day didn't report this
earlier..
> > >
> > > I got many successful emails after I pushed this patch to
0-day testing.
> >
> > The long division warnings can compiler specific, and depend on
certain
> > optimization options, as compilers can optimize out certain
divisions and
> > replace them with multiplications and/or shifts, or prove that
they can be
> > replaced with a 32-bit division. If this is a case that gcc
manages to
> > optimize but clang does not, it might be worth looking into
whether an
> > optimization can be added to clang, in addition to improving the
source.
>
> While I did run initially run into this with clang, the errors
above are
> with gcc (mainly to show this was going to be a universal problem and
> not just something with clang).
Which gcc version did you use here? Anything particularly old or
particularly
new? I think 0-day is on a fairly recent gcc-8, but not the latest
gcc-9
release.
8.2.0 it seems (I've been meaning to build from the 9.x branch though
since it appears that Arch's arm-linux-gnueabi-gcc isn't going to get
updated since it's in the AUR).
Thanks for the reminding, we met some problems with gcc 8.1.0 once,
then we uses "arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0" as the
default gcc for arm,
It seems we have missed some build issues detected by new gcc. we're
going to upgrade gcc ASAP.
Best Regards,
Rong Chen
