[ECOS] data access fron an interrupt handler

["Pierre-Marie Boyer" <pm dot boyer at orange dot fr>]

Hi,

I plane to work with eCos : Install eCos kernel on a card with a LPC2106 uC
from a PC linux station, and make some tests.

But before this, I would like to know how interrupts handlers work exactly
in case of multitasking software :

 

My problem is about the globals variables access from within an interrupt
function of a particular task.

So, if the system work with several tasks. If in a task we have installed an
interrupt handler (ex:harware interrupt).

When the software is running, if this interrupt is launched by the hardware
while another task is running, what happen if in this interrupt we want
accessing (read or write) a global data of his task while this is not the
same task suspended by the interrupt ? 

Because in this case the task context is not the same, and I think that no
changing context is performed by the OS before running the interrupt.

I think this can be a problem when we are in virtual memory system (uC with
MMU ).

Could you give me some information? 

(I know this is not a specific question of eCos, but I have not found were
to ask this question. sory, and thank you in advance)
 



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