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Date:   Wed, 22 Jan 2020 07:18:54 -0600
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, ruscur@russell.cc,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: GCC bug ? Re: [PATCH v2 10/10] powerpc/32s: Implement Kernel Userspace Access Protection
Message-ID: <20200122131854.GK3191@gate.crashing.org>
References: <cover.1552292207.git.christophe.leroy@c-s.fr> <a2847248a92cb1641b1740fa121c5a30593ae662.1552292207.git.christophe.leroy@c-s.fr> <87ftqfu7j1.fsf@concordia.ellerman.id.au> <a008a182-f1db-073c-7d38-27bfd1fd8676@c-s.fr> <20200121195501.GJ3191@gate.crashing.org> <8501a33e-6c76-b6bd-9d8e-985313f94579@c-s.fr>
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Hi!

On Wed, Jan 22, 2020 at 07:57:15AM +0100, Christophe Leroy wrote:
> GCC doc also says:
> 
> "if you use it in an inlined function and pass an argument of the 
> function as the argument to the built-in, GCC never returns 1 when you 
> call the inline function with a string constant"
> 
> Does GCC considers (void*)0 as a string constant ?

No, because it isn't (it's a pointer, not an array of characters).


Segher