Date: Sat, 16 Apr 2016 11:20:18 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Toshi Kani <toshi.kani@hpe.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
        "Maciej W. Rozycki" <macro@linux-mips.org>,
        Julia Lawall <julia.lawall@lip6.fr>, Toshi Kani <toshi.kani@hp.com>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Dave Airlie <airlied@redhat.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-arch@vger.kernel.org, X86 ML <x86@kernel.org>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Borislav Petkov <bp@alien8.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>, Brian Gerst <brgerst@gmail.com>
Subject: Re: Overlapping ioremap() calls, set_memory_*() semantics
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* Toshi Kani <toshi.kani@hpe.com> wrote:

> On x86, ioremap() and remap_pfn_range() already fail on a conflicting cache
> type if it is not allowed by the rule defined in is_new_memtype_allowed().
> ?This exception handling is necessary for remap_pfn_range() called by
> /dev/mem, but I do not think it's necessary for ioremap(). ?I think we can
> start from adding a warning message to ioremap().

Agreed, we should warn and map the situation before doing any behavioral change 
that isn't a fix.

Thanks,

	Ingo