[OpenBIOS] [PATCH 1/8] Rename ofmem_arch_early_map_pages() to ofmem_arch_map_pages().

[Igor Kovalenko]

On Tue, Apr 10, 2012 at 7:11 PM, Mark Cave-Ayland
<mark.cave-ayland at ilande.co.uk> wrote:
> On 10/04/12 13:20, Andreas Färber wrote:
>
>> Hi Mark,
>>
>> Am 06.04.2012 21:48, schrieb Mark Cave-Ayland:
>>>
>>> This OFMEM call does actually map the page for the architectures that
>>> require it, so let's change its name so that we now have a symmetrical
>>> ofmem_arch_map_pages() and ofmem_arch_unmap_pages() API.
>>
>>
>> I don't really mind either way, assuming you've compile-tested it.
>
>
> Sure, I've tested PPC with my patches applied and it seems to work - I
> notice though that PPC looks as if it already allocates it's Forth machine
> memory outside of the image - please correct me if I'm wrong? I'm not too
> familiar with the way the PPC MMU works with hash tables.
>
>
>> I would've assumed though and "early" indicates at which times in the
>> code this function may be used?
>
>
> Well, it's more interesting than that. For SPARC, when you map the memory it
> is first added to the translation_t linked list. The TLB miss handlers
> simply iterate over this list in order to find the mapping before
> continuing. Therefore when creating a mapping, since the translation_t list
> already contains the entry created by ofmem_map_page_range(), all the
> ofmem_arch_map_pages() function has to do is update any existing TLB
> entries.
>

The "early" variant was intended to perform one-time injection of
mapped pages that were acquired before c source code is entered so it
was not safe to call common mapping routine yet. I was afraid to
implement mapping code in assembly.

-- 
Kind regards,
Igor V. Kovalenko