Re: [REGRESSION] 32-bit ARM's BKPT instruction no longer works

[Linus Walleij]

On Fri, Jun 26, 2026 at 3:08 PM Russell King <linux@xxxxxxxxxxxxxxx> wrote:

> Aren't regressions wonderful!

Makes me feel alive! ;)

> So I think safest is that everyone just moves away from BKPT.

I agree.

I'm waiting for the compiler guys to see if they have some good idea
on what to do istead.

Since it is a security feature, to me hanging in an eternal loop waiting
for watchdog reset or power off is better than issuing BKPT.
But that's pretty nasty.

Can the compiler simply use a read of the guard region at ffc00000
to raise a SIGBUS? (This is inherently a Linux-only solution but,
perhaps this can be parameterized?)

Yours,
Linus Walleij