On Fri, Jul 5, 2013 at 6:30 PM, Gedare Bloom <ged...@rtems.org> wrote:
> On Fri, Jul 5, 2013 at 12:11 PM, Hesham Moustafa > <heshamelmat...@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. > > Yes, the page table entries are statically initialized to Zero (fault sections) at boot time and then apply attributes and mapping through a config table at boot time too. There is a NORMAL_SHARE attribute that can be applied to a memory region in Cortex-a9 platform that enables the HW to achieve consistency for that area of memory. I do not know whether applying that attribute is enough or we have to use some locks. > Is it possible to force a thread to run on a specific core ? or the > current > > SMP scheduler handles that ? > > > > I am thinking of applying a SHARED_MEMORY attribute on page tables itself > > and implement the mentioned use case. > > > > Regards, > > Hesham > > > > _______________________________________________ > > rtems-devel mailing list > > rtems-devel@rtems.org > > http://www.rtems.org/mailman/listinfo/rtems-devel > > >
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