[PATCH 9/9] ARM: vexpress: Config option for early printk console
From: Will Deacon <hidden>
Date: 2012-07-11 14:09:12
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