Re: [Minios-devel] [PATCH v3 10/43] arm64: add exception support

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 02/05/18 10:47, Huang Shijie wrote:
> On Mon, Apr 30, 2018 at 09:12:27AM +0100, Julien Grall wrote:
> > On 28/04/2018 07:20, Huang Shijie wrote:
> > > On Wed, Apr 18, 2018 at 06:48:24PM +0100, Julien Grall wrote:
> > > > > +    save_registers 1
> > > > > +    mov     x0, sp
> > > > > +    mrs     x1, esr_el1;
> > > > > +    mrs     x2, far_el1;
> > > > Do you expect the mini-OS to always run with interrupt disabled in EL1? If
> > > At the beginning, we can run with interrupt disabled in EL1.
> > > It makes the code simple. :)
> > The question is more what do you expect to run in that exception context.
> > Would it ever be possible that the C-Code will re-enable interrupt and then
> > you get caught later on?
> there is no code to re-enable interrupt in C-code.
> I cannot find such code now.
Have a look at local_irq_enable() around the code.

> > I am not necessarily asking you to enable the interrupt here. But you surely
> > assess the impact of keeping interrupt disabled. Are they going to be
> > enabled still for the thread (they run in EL1)?
> Do you suggest I should enable the interrupt in the save_registers?
You probably know better than me Mini-OS... so I was suggesting that you 
should explain the impact of keeping the interrupt disabled here.
Cheers,

--
Julien Grall

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