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From: Arnd Bergmann <arnd@arndb.de>
To: Dave Gerlach <d-gerlach@ti.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org, linux-arch@vger.kernel.org,
        devicetree@vger.kernel.org, Russ Dill <russ.dill@ti.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Shawn Guo <shawn.guo@freescale.com>, Tony Lindgren <tony@atomide.com>,
        Anson.Huang@freescale.com, Russ Dill <Russ.Dill@ti.com>
Subject: Re: [RFC PATCH 1/2] asm-generic: io: Add exec versions of ioremap
Date: Wed, 26 Nov 2014 22:32:47 +0100
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On Wednesday 26 November 2014 15:14:00 Dave Gerlach wrote:
> @@ -66,6 +66,11 @@ extern void ioport_unmap(void __iomem *);
>  #define ioremap_wc ioremap_nocache
>  #endif
>  
> +#ifndef ARCH_HAS_IOREMAP_EXEC
> +#define ioremap_exec ioremap
> +#define ioremap_exec_nocache ioremap_nocache
> +#endif
> +
>  #ifdef CONFIG_PCI
>  /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */
>  struct pci_dev;
> 

ioremap and ioremap_nocache are the same, and there is no
architecture-independent interface to map an MMIO range as
cached because a lot of architectures can't do that.

Also, I think there are architectures that cannot execute
from uncached memory, so I think adding this as a generic
API is not a good idea.

	Arnd