Re: [patch V4 part 3 10/29] x86/idtentry: Provide macros to define/declare IDT entry points

Thomas Gleixner
2020-05-11T10:39:45Z

Andy Lutomirski <luto@kernel.org> writes:
> On Tue, May 5, 2020 at 7:15 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>>
>> Provide DECLARE/DEFINE_IDTENTRY() macros.
>
> Acked-by: Andy Lutomirski <luto@kernel.org>
>
> except:
>
>>
>> DEFINE_IDTENTRY() provides a wrapper which acts as the function
>> definition. The exception handler body is just appended to it with curly
>> brackets. The entry point is marked notrace/noprobe so that irq tracing and
>> the enter_from_user_mode() can be moved into the C-entry point.
>
> "noinstr", perhaps? I'm guessing you write this text before noinstr
> happened.

Yes.

> Also, would it perhaps make sense in the future to include the
> idtentry macro somehow (via inline asm or gcc options) so that
> DEFINE_IDTENTRY() could emit the stub instead of leaving it to
> DECLARE_IDTENTRY()? It might end up too messy in practice, I suppose.
> This is obviously not worth changing right now, but maybe down the
> road.

Maybe. Right now my entry/rcu/tracing induced brainmelt is far too
advanced to try thinking about it :)