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From:   Pavel Tatashin <pasha.tatashin@soleen.com>
Date:   Thu, 21 Nov 2019 19:39:22 -0500
Message-ID: <CA+CK2bAm0r8zLMz_gdq30zF8io5RzVnbXFSV9NkyT_uUxKJwLA@mail.gmail.com>
Subject: Re: [PATCH 1/3] arm/arm64/xen: use C inlines for privcmd_call
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc:     Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>, stefan@agner.ch,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Will Deacon <will@kernel.org>, boris.ostrovsky@oracle.com,
        Sasha Levin <sashal@kernel.org>, sstabellini@kernel.org,
        James Morris <jmorris@namei.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        xen-devel@lists.xenproject.org,
        Vladimir Murzin <vladimir.murzin@arm.com>,
        Marc Zyngier <marc.zyngier@arm.com>, alexios.zavras@intel.com,
        Thomas Gleixner <tglx@linutronix.de>, allison@lohutok.net,
        jgross@suse.com, steve.capper@arm.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        James Morse <james.morse@arm.com>, info@metux.net
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> > That may be, but be very careful that you only use them in ARMv7-only
> > code.  Using them elsewhere is unsafe as the domain register is used
> > for other purposes, and merely blatting over it (as your
> > uaccess_enable and uaccess_disable functions do) is unsafe.
>
> In fact, I'll turn that into a bit more than a suggestion.  I'll make
> it a NAK on adding them to 32-bit ARM.
>

That's fine, and I also did not want to change ARM 32-bit. But, do you
have a suggestion how differentiate between arm64 and arm in
include/xen/arm/hypercall.h without ugly ifdefs?

Thank you,
Pasha