[PATCH v2 7/9] ARM: implement IRQ stacks

[Arnd Bergmann]

On Tue, Oct 5, 2021 at 9:15 AM Ard Biesheuvel <ardb at kernel.org> wrote:
>
> Now that we no longer rely on the stack pointer to access the current
> task struct or thread info, we can implement support for IRQ stacks
> cleanly as well.
>
> Define a per-CPU IRQ stack and switch to this stack when taking an IRQ,
> provided that we were not already using that stack in the interrupted
> context. This is never the case for IRQs taken from user space, but ones
> taken while running in the kernel could fire while one taken from user
> space has not completed yet.
>
> Signed-off-by: Ard Biesheuvel <ardb at kernel.org>

This is where I get stuck in my review, I assume it's all good here,
but I can't honestly claim to have reviewed it without a better
understanding.

Hopefully one of the others on Cc can step in here and take a
closer look.

       Arnd