Re: [PATCH 1/2] arm64/entry: Fix involuntary preemption exception masking

[Mark Rutland]

On Wed, Mar 25, 2026 at 04:46:01PM +0100, Thomas Gleixner wrote:
> On Wed, Mar 25 2026 at 11:03, Mark Rutland wrote:
> > On Sun, Mar 22, 2026 at 12:25:06AM +0100, Thomas Gleixner wrote:
> > I *think* what would work for us is we could split some of the exit
> > handling (including involuntary preemption) into a "prepare" step, as we
> > have for return to userspace. That way, arm64 could handle exiting
> > something like:
> >
> > 	local_irq_disable();
> > 	irqentry_exit_prepare(); // new, all generic logic
> > 	local_daif_mask();
> > 	arm64_exit_to_kernel_mode() {
> > 		...
> > 		irqentry_exit(); // ideally irqentry_exit_to_kernel_mode().
> > 		...
> > 	}
> >
> > ... and other architectures can use a combined exit_to_kernel_mode() (or
> > whatever we call that), which does both, e.g.
> >
> > 	// either noinstr, __always_inline, or a macro
> > 	void irqentry_prepare_and_exit(void)
> 
> That's a bad idea as that would require to do a full kernel rename of
> all existing irqentry_exit() users.
> 
> > 	{
> > 		irqentry_exit_prepare();
> > 		irqentry_exit();
> > 	}
> 
> Aside of the naming that should work.

Thanks for confirming!

I've pushed a (very early, WIP) draft to

  https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/entry/rework

... which is missing commit messages, comments, etc, but seems to work.

I'll see about getting that tested, cleaned up, and on-list.

Mark.