linux-kernel - Re: [PATCH v2] arch: define weak abort

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Date:   Wed, 13 Dec 2017 21:46:26 +0000
From:   Alexey Brodkin <Alexey.Brodkin@...opsys.com>
To:     "sudipm.mukherjee@...il.com" <sudipm.mukherjee@...il.com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Vineet.Gupta1@...opsys.com" <Vineet.Gupta1@...opsys.com>,
        "linux-snps-arc@...ts.infradead.org" 
        <linux-snps-arc@...ts.infradead.org>
Subject: Re: [PATCH v2] arch: define weak abort

Hi Sudip,

On Tue, 2017-12-12 at 22:49 +0000, Sudip Mukherjee wrote:
> gcc toggle -fisolate-erroneous-paths-dereference (default at -O2
> onwards) isolates faulty code paths such as null pointer access, divide
> by zero etc. If gcc port doesnt implement __builtin_trap, an abort() is
> generated which causes kernel link error.
> 
> In this case, gcc is generating abort due to 'divide by zero' in
> lib/mpi/mpih-div.c.
> 
> Currently 'frv' and 'arc' are failing. Previously other arch was also
> broken like m32r was fixed by d22e3d69ee1a ("m32r: fix build failure").
> 
> Lets define this weak function which is common for all arch and fix the
> problem permanently. We can even remove the arch specific 'abort' after
> this is done.
> 
> Cc: Alexey Brodkin <Alexey.Brodkin@...opsys.com>
> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@...il.com>
> ---
> 
> Hi Alexey,
> I was thinking of sending the m32r revert patch in few days. My m32r
> builds are having a little problem and should be fixed by this weekend.
> I can not test m32r before that.

Understood, that's fine by me.

> We can also send a patch to remove the
> same code in arm and unicore32.

Sure that would be really great!

-Alexey