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From:   Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [RFC PATCH v2 01/10] lib: vdso: ensure all arches have 32bit fallback
Date:   Fri, 10 Jan 2020 11:02:38 -1000
Message-Id: <53785EAC-A04C-4B02-9698-D11D75BE2C4D@amacapital.net>
References: <87sgknrpxy.fsf@nanos.tec.linutronix.de>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Arnd Bergmann <arnd@arndb.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Andrew Lutomirski <luto@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        "open list:MIPS" <linux-mips@vger.kernel.org>,
        X86 ML <x86@kernel.org>
In-Reply-To: <87sgknrpxy.fsf@nanos.tec.linutronix.de>
To:     Thomas Gleixner <tglx@linutronix.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


> On Jan 10, 2020, at 10:56 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
>=20
> =EF=BB=BFAndy Lutomirski <luto@kernel.org> writes:
>=20
>>> On Mon, Dec 23, 2019 at 6:31 AM Christophe Leroy
>>> <christophe.leroy@c-s.fr> wrote:
>>>=20
>>> In order to simplify next step which moves fallback call at arch
>>> level, ensure all arches have a 32bit fallback instead of handling
>>> the lack of 32bit fallback in the common code based
>>> on VDSO_HAS_32BIT_FALLBACK
>>=20
>> I don't like this.  You've implemented what appear to be nonsensical
>> fallbacks (the 32-bit fallback for a 64-bit vDSO build?  There's no
>> such thing).
>>=20
>> How exactly does this simplify patch 2?
>=20
> There is a patchset from Vincenzo which fell through the cracks which
> addresses the VDS_HAS_32BIT_FALLBACK issue properly. I'm about to pick
> it up. See:
>=20
> https://lore.kernel.org/lkml/20190830135902.20861-1-vincenzo.frascino@arm.=
com/
>=20

Thanks.  I had been wondering why the conditionals were still there, since I=
 remember seeing these patches.

> Thanks,
>=20
>        tglx