Re: Interrupt flow in the NetBSD kernel

[David Young <dyoung%pobox.com@localhost>]

On Sun, Jun 21, 2015 at 08:01:47AM -0700, Matt Thomas wrote:
> 
> > On Jun 21, 2015, at 7:30 AM, Kamil Rytarowski <n54%gmx.com@localhost> wrote:
> > 
> > I have got few questions regarding the interrupt flow in the kernel.
> > Please tell whether my understanding is correct.
> 
> You are confusing interrupts with exceptions.  Interrupts are 
> asynchronous events.  Exceptions are (usually) synchronous and
> are the result of an instruction.

I took Kamil's question to be, "When interrupts at the highest priority
level are blocked, can control flow still be interrupted?  How?"  The
answer to the question is yes.  Both synchronous events (exceptions,
such as "data abort" on ARM) and asynchronous events (non-maskable
interrupts, such as NMI on x86) can interrupt control flow.

Dave

-- 
David Young
dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981