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Subject: Re: [PATCH] mm/special: Create generic fallbacks for pte_special()
 and pte_mkspecial()
To:     Anshuman Khandual <anshuman.khandual@arm.com>, linux-mm@kvack.org
Cc:     Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Guo Ren <guoren@kernel.org>, Brian Cain <bcain@codeaurora.org>,
        Tony Luck <tony.luck@intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Sam Creasey <sammy@sammy.net>, Michal Simek <monstr@monstr.eu>,
        Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paulburton@kernel.org>,
        Nick Hu <nickhu@andestech.com>,
        Greentime Hu <green.hu@gmail.com>,
        Vincent Chen <deanbo422@gmail.com>,
        Ley Foon Tan <ley.foon.tan@intel.com>,
        Jonas Bonn <jonas@southpole.se>,
        Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
        Stafford Horne <shorne@gmail.com>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jeff Dike <jdike@addtoit.com>,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Guan Xuetao <gxt@pku.edu.cn>, Chris Zankel <chris@zankel.net>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org,
        linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linux-mips@vger.kernel.org, nios2-dev@lists.rocketboards.org,
        openrisc@lists.librecores.org, linux-parisc@vger.kernel.org,
        sparclinux@vger.kernel.org, linux-um@lists.infradead.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1583114190-7678-1-git-send-email-anshuman.khandual@arm.com>
From:   Helge Deller <deller@gmx.de>
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Message-ID: <c026934a-02c1-8589-f925-e267fcc367ad@gmx.de>
Date:   Mon, 2 Mar 2020 12:19:28 +0100
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 02.03.20 02:56, Anshuman Khandual wrote:
> Currently there are many platforms that dont enable HAVE_ARCH_PTE_SPECIA=
L
> but required to define quite similar fallback stubs for special page tab=
le
> entry helpers such as pte_special() and pte_mkspecial(), as they get bui=
ld
> in generic MM without a config check. This creates two generic fallback
> stub definitions for these helpers, eliminating much code duplication.
>
> mips platform has a special case where pte_special() and pte_mkspecial()
> visibility is wider than what HAVE_ARCH_PTE_SPECIAL enablement requires.
> This restricts those symbol visibility in order to avoid redefinitions
> which is now exposed through this new generic stubs and subsequent build
> failure. arm platform set_pte_at() definition needs to be moved into a C
> file just to prevent a build failure.
>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

for parisc:

Acked-by: Helge Deller <deller@gmx.de> # parisc

Helge