[PATCH 1/2] powerpc: fix graceful debugger recovery

[Michael Ellerman]

Nicholas Piggin <npiggin at gmail.com> writes:

> When exiting xmon with 'x' (exit and recover), oops_begin bails
> out immediately, but die then calls __die() and oops_end(), which
> cause a lot of bad things to happen.

In fact oops_begin() returns 1, which oops_end() then passes directly to
raw_local_irq_restore() as flags. On 64-bit that actually works because
arch_local_irq_restore() takes just "en" (enable), not real flags. But
on 32-bit it's supposed to be the MSR value. So that's impressively
broken.

> If the debugger was attached then went to graceful recovery, exit
> from die() immediately.

Right. Crucially it doesn't change anything in terms of the actual logic
of oops_begin(), ie. previously oops_begin() did nothing prior to
calling debugger(), and after this patch that remains the same (which
you did mention above but just spelling it out for myself).

cheers