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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: kbuild test robot <lkp@intel.com>
Cc: Simon Horman <horms+renesas@verge.net.au>,
	kbuild-all@01.org,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [renesas-drivers:topic/clk-r8a77990-z2-v3 11/13] rcar-gen3-cpg.c:undefined reference to `__udivdi3'
Date: Wed, 6 Feb 2019 08:03:54 +0100	[thread overview]
Message-ID: <CAMuHMdXO3ULebpw5m1ikFeAsZdf1JytqTD+bLvGq3WEo3HdytQ@mail.gmail.com> (raw)
In-Reply-To: <201902060735.NFAVGNjO%fengguang.wu@intel.com>

On Wed, Feb 6, 2019 at 12:38 AM kbuild test robot <lkp@intel.com> wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git topic/clk-r8a77990-z2-v3
> head:   3423d0ef4af282d1a1021b40cc2e739c08c9046b
> commit: 0961e355977f7806b926ea0ae29c5cffa7867894 [11/13] clk: renesas: rcar-gen3: Support Z and Z2 clocks with high frequency parents
> config: i386-allmodconfig (attached as .config)
> compiler: gcc-8 (Debian 8.2.0-14) 8.2.0
> reproduce:
>         git checkout 0961e355977f7806b926ea0ae29c5cffa7867894
>         # save the attached .config to linux build tree
>         make ARCH=i386
>
> All errors (new ones prefixed by >>):
>
>    ld: drivers/clk/renesas/rcar-gen3-cpg.o: in function `cpg_z_clk_set_rate':
> >> rcar-gen3-cpg.c:(.text+0x13c): undefined reference to `__udivdi3'

Thanks for the report!

I guess this is due to

+       mult = DIV_ROUND_CLOSEST(rate * 32ULL * zclk->fixed_div, parent_rate);

While Simon had tested this on arm, apparently it fails on (at least) i386
and mips.

Changing "32ULL" to "32UL" should fix this, but means a sure overflow if this
code is ever used on or copied for a 32-bit platform.

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

  reply	other threads:[~2019-02-06  7:04 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-05 23:37 [renesas-drivers:topic/clk-r8a77990-z2-v3 11/13] rcar-gen3-cpg.c:undefined reference to `__udivdi3' kbuild test robot
2019-02-06  7:03 ` Geert Uytterhoeven [this message]
2019-02-11 12:47   ` Geert Uytterhoeven

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