Re: Use arm64's scheme for registering first-level IRQ handlers on RISC-V

From: Arnd Bergmann
Date: Thu Jan 18 2018 - 11:43:51 EST


On Thu, Jan 18, 2018 at 4:40 PM, Palmer Dabbelt <palmer@xxxxxxxxxx> wrote:
> This patch set has been sitting around for a while, but it got a bit lost in
> the shuffle. In RISC-V land we currently couple do_IRQ (the C entry point for
> interrupt handling) to our first-level interrupt controller. While this isn't
> completely crazy (as the first-level interrupt controller is specified by the
> ISA), it is a bit awkward.
>
> This patch set decouples our trap handler from our first-level IRQ chip driver
> by copying what a handful of other architectures are doing. This does add an
> additional load to the interrupt handling path, but there's a handful of
> performance problems in there that I've been meaning to look at so I don't mind
> adding another one for now. The advantage is that our irqchip driver is
> decoupled from our arch port, at least at compile time.

Yes, this sounds like a useful cleanup. I also agree with all of Christoph's
suggestions, otherwise it looks good to me.

Arnd