general question on interrupts handling

[John Baldwin]

On Thursday, March 12, 2015 06:52:25 PM Matías Perret Cantoni wrote:
> Hi!
> 
> I'm writing my first interrupt handling routine of a newbus driver and I'm
> not sure what things should I take care of in my ISR and what things the
> system will take care.
> 
> I'm working on a Xilinx Zynq-7000 platform. I'm generating a Shared
> Peripheral Interrupt from the FPGA.
> 
> For example...
> ... do I have to disable interrupts upon entering my ISR and enable them
> again before returning, o FreeBSD does it for me?
> ... do I have to clear the GIC interrupt status of my interrupt or the
> systems does it automatically when my routine returns?
> 
> Please excuse me if this is too general or silly.  If you can point me any
> documentation or sources to read, It'd be great.

For a regular interrupt handler that runs in an thread context, the system
will generally mask your device's interrupt until the interrupt thread is
scheduled and runs your handler.  After your handler returns the interrupt
will be unmasked.

For a filter interrupt handler that does not run in an interrupt thread
context, no masking is done and you generally need to mask the interrupt
yourself using a device-specific register if you cannot fully handle the
interrupt in the filter routine.

-- 
John Baldwin