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Date:   Mon, 30 Sep 2019 09:52:58 -0700
From:   Stephen Hemminger <stephen@networkplumber.org>
To:     Borislav Petkov <bp@alien8.de>
Cc:     Michal Kubecek <mkubecek@suse.cz>, linux-rdma@vger.kernel.org,
        Saeed Mahameed <saeedm@mellanox.com>,
        Leon Romanovsky <leon@kernel.org>, netdev@vger.kernel.org,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: ERROR: "__umoddi3"
 [drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko] undefined!
Message-ID: <20190930095258.1db16eb2@hermes.lan>
In-Reply-To: <20190930162910.GI29694@zn.tnic>
References: <20190930141316.GG29694@zn.tnic>
        <20190930154535.GC22120@unicorn.suse.cz>
        <20190930162910.GI29694@zn.tnic>
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On Mon, 30 Sep 2019 18:29:10 +0200
Borislav Petkov <bp@alien8.de> wrote:

> On Mon, Sep 30, 2019 at 05:45:35PM +0200, Michal Kubecek wrote:
> > On Mon, Sep 30, 2019 at 04:13:17PM +0200, Borislav Petkov wrote:  
> > > I'm seeing this on i386 allyesconfig builds of current Linus master:
> > > 
> > > ERROR: "__umoddi3" [drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko] undefined!
> > > make[1]: *** [__modpost] Error 1
> > > make: *** [modules] Error 2  
> > 
> > This is usually result of dividing (or modulo) by a 64-bit integer. Can
> > you identify where (file and line number) is the __umoddi3() call
> > generated?  
> 
> Did another 32-bit allyesconfig build. It said:
> 
> ld: drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.o: in function `mlx5dr_icm_alloc_chunk':
> dr_icm_pool.c:(.text+0x733): undefined reference to `__umoddi3'
> make: *** [vmlinux] Error 1
> 
> The .s file then points to the exact location:
> 
> # drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c:140:   align_diff = icm_mr->icm_start_addr % align_base;
>         pushl   %ebx    # align_base
>         pushl   %ecx    # align_base
>         call    __umoddi3       #
>         popl    %edx    #
>         popl    %ecx    #

Since align_base is a power of 2 masking should work as well.