SMP/MMU updating page tables on realview BSP

[Sebastian Huber]

On 05/07/13 18:30, Gedare Bloom wrote:
> On Fri, Jul 5, 2013 at 12:11 PM, Hesham Moustafa
> <heshamelmatary at gmail.com>  wrote:
>> >Hi,
>> >
>> >I am working on a use case for cortex-a9/realview BSP that deals with page
>> >tables and MMU. I need your help in gathering the required API and calls and
>> >any other details to implement the following case (if applicable) :
>> >
>> >1- A thread running on a core that updates the page table.
>> >2- On another core another thread is running and trying to update the page
>> >table.
>> >
>> >Is that use case possible, or disabling dispatches, MMU, and interrupts
>> >avoids that situation ?
>> >
> I think this is a possible situation. I suppose right now the page
> tables are statically initialized by a boot processor, but if you
> enable dynamically modifying the page table, then you need to protect
> that memory somehow. Probably with a spin lock.
>

Currently the cache and MMU support on the Cortex-A9 BSPs is broken, 
e.g. it doesn't work on real hardware.  We work on this issue, but it 
will take a couple of weeks to get it fixed.

The MMU management on SMP will be hard.  Please read the ARMv7 reference 
manual carefully.

-- 
Sebastian Huber, embedded brains GmbH

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