From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Wed, 23 Oct 2013 10:18:18 +0100
Subject: [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings
In-Reply-To: <1382362594-24947-1-git-send-email-msalter@redhat.com>
References: <1382362594-24947-1-git-send-email-msalter@redhat.com>
Message-ID: <1382519898.10408.1.camel@mbp>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, 2013-10-21 at 14:36 +0100, msalter at redhat.com wrote:
> diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> index 1725cd6..fb44b3d 100644
> --- a/arch/arm64/mm/ioremap.c
> +++ b/arch/arm64/mm/ioremap.c
> @@ -79,6 +79,21 @@ void __iounmap(volatile void __iomem *io_addr)
>  {
>  	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
>  
> +	/* Nothing to do for normal memory. See ioremap_cache() */
> +	if (pfn_valid(__virt_to_phys(addr) >> PAGE_SHIFT))
> +		return;

addr here can be some I/O address mapped previously, so __virt_to_phys()
is not valid (you don't actually get the pfn by shifting).

Catalin