[PATCH v3 4/6] arm: add early_ioremap support

[Russell King - ARM Linux]

On Wed, Jan 15, 2014 at 04:32:03PM -0800, Laura Abbott wrote:
> Neither x86 nor arm64 get rid of existing mapping in paging_init. Is  
> there a reason this needs to be here for arm? Are there concerns about  
> alias mappings?

The early mappings we setup in the assembly code are imperfect - they're
an approximation.  We map just about enough memory to get the kernel
going, and we setup a mapping for the debug stuff using a section
mapping, which may not be appropriate.

The permissions too are a just chosen to get things going, and the
subsequent replacement of the page table entries is to fix all that up.
We really don't want any old entries left behind.

-- 
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