linux-kernel - Re: [RFC PATCH v2 01/10] lib: vdso: ensure all arches have 32bit fallback

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Message-ID: <CALCETrULuV5iAU3kSjMdcpV6DFGEw1z2so0DfDca6hoLB4X4cA@mail.gmail.com>
Date:   Mon, 23 Dec 2019 18:07:30 -0800
From:   Andy Lutomirski <luto@...nel.org>
To:     Christophe Leroy <christophe.leroy@....fr>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Arnd Bergmann <arnd@...db.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Andrew Lutomirski <luto@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "open list:MIPS" <linux-mips@...r.kernel.org>,
        X86 ML <x86@...nel.org>
Subject: Re: [RFC PATCH v2 01/10] lib: vdso: ensure all arches have 32bit fallback

On Mon, Dec 23, 2019 at 6:31 AM Christophe Leroy
<christophe.leroy@....fr> wrote:
>
> 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

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).

How exactly does this simplify patch 2?

--Andy