[PATCH 9/9] ARM: vexpress: Config option for early printk console

[Will Deacon]

Hi Pawel,

On Wed, Jul 11, 2012 at 02:36:31PM +0100, Pawel Moll wrote:
> +#else /* CONFIG_DEBUG_LL_UART_NONE */
> +
> +		.macro	addruart, rp, rv, tmp
> +		/*
> +		 * Have to provide reasonable dummy values,
> +		 * otherwise code in head.S crashes badly...
> +		 */
> +		mov	\rp, #0
> +		mov	\rv, #0
> +		.endm

Eek, this means we take out an I/O section mapping at zero, doesn't it?
Is that really a good idea? It scares me because (a) it's below PAGE_OFFSET
and (b) we don't know consistently what's at physical address 0.

Perhaps we could change head.S to avoid the mapping if addruart returns a
NULL virtual address?

Will