[RFC PATCH 7/8] mm/ioremap: Consider IOREMAP space in generic ioremap

[Christophe Leroy]

I'm more focussed on powerpc32

+ Adding linuxppc-dev, someone else might help.

Le 16/10/2022 à 13:51, Arnd Bergmann a écrit :
> On Sun, Oct 16, 2022, at 9:54 AM, Alexander Gordeev wrote:
>> On Wed, Oct 12, 2022 at 12:39:11PM +0200, Arnd Bergmann wrote:
>>> "Some" means exactly powerpc64, right? It looks like microblaze
>>> and powerpc32 still share some of this code, but effectively
>>> just use the vmalloc area once the slab allocator is up.
>>>
>>> Is the special case still useful for powerpc64 or could this be
>>> changed to do it the same as everything else?
>>
>> Or make it the other way around and set IOREMAP_START/IOREMAP_END
>> to VMALLOC_START/VMALLOC_END by default?
> 
> Sure, if there is a reason for actually making them different.
>  From the git history, it appears that before commit 3d5134ee8341
> ("[POWERPC] Rewrite IO allocation & mapping on powerpc64"), the
> ioremap() and vmalloc() handling was largely duplicated. Ben
> cleaned it up by making most of the implementation shared but left
> the separate address spaces.
> 
> My guess is that there was no technical reason for this, other
> than having no reason to change the behavior at the time.
> 
>         Arnd