Re: [PATCH 07/10] serial: mvebu-uart: implement UART clock driver for configuring UART base clock

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Pali,

On Fri, Jun 25, 2021 at 11:31 AM Pali Rohár <pali@kernel.org> wrote:
> On Friday 25 June 2021 16:15:38 kernel test robot wrote:
> > I love your patch! Yet something to improve:
> >
> > [auto build test ERROR on robh/for-next]
> > [also build test ERROR on tty/tty-testing clk/clk-next linus/master v5.13-rc7 next-20210624]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch]
> >
> > url:    https://github.com/0day-ci/linux/commits/Pali-Roh-r/serial-mvebu-uart-Fixes-and-new-support-for-higher-baudrates/20210625-065146
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
> > config: m68k-allmodconfig (attached as .config)
> > compiler: m68k-linux-gcc (GCC) 9.3.0
> > reproduce (this is a W=1 build):
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # https://github.com/0day-ci/linux/commit/747483a6b8f2de98afe461dbf91227404a8e2e81
> >         git remote add linux-review https://github.com/0day-ci/linux
> >         git fetch --no-tags linux-review Pali-Roh-r/serial-mvebu-uart-Fixes-and-new-support-for-higher-baudrates/20210625-065146
> >         git checkout 747483a6b8f2de98afe461dbf91227404a8e2e81
> >         # save the attached .config to linux build tree
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All errors (new ones prefixed by >>):
> >
> >    m68k-linux-ld: drivers/tty/serial/mvebu-uart.o: in function `mvebu_uart_clock_prepare':
> >    mvebu-uart.c:(.text+0x6d0): undefined reference to `__udivdi3'
> > >> m68k-linux-ld: mvebu-uart.c:(.text+0x78c): undefined reference to `__udivdi3'
>
> Hello! Could you help me how to fix this issue? I'm using macro
> DIV_ROUND_CLOSEST() with two u64 values in that function. And I really
> do not know details about m68k arch and I never touched this arch.
>
> There is missing number of line which caused this error. So if it is
> possible I have suggestion for bot to compile kernel with -g flag. In
> this case linker show exact line number (and not only hex address) which
> caused that linker error. Also in future it could help identify source
> of errors...

This error means your driver uses a 64-bit division without using the
proper methods from include/linux/math64.h.

It may happen when compiling for any 32-bit architecture.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds