Re: [XEN PATCH 5/7] xen/arm: traps: add ASSERT_UNREACHABLE() where needed

[Julien Grall <julien@xxxxxxx>]

Hi,

On 11/12/2023 12:32, Julien Grall wrote:
> Hi,
>
> On 11/12/2023 10:30, Nicola Vetrini wrote:
> > The branches of the switch after a call to 'do_unexpected_trap'
> > cannot return, but there is one path that may return, hence
> > only some clauses are marked with ASSERT_UNREACHABLE().
> I don't understand why this is necessary. The code should never be 
> reachable because do_unexpected_trap() is a noreturn().
From the matrix discussion, it wasn't clear what was my position on 
this patch.
I would much prefer if the breaks are kept. I could accept:

ASSERT_UNREACHABLE();
break;

But this solution is a Nack because if you are concerned about functions 
like do_unexpected_trap() to return by mistaken, then it needs to also 
be safe in production.
The current proposal is not safe.

Cheers,

--
Julien Grall