Re: [Minios-devel] [UNIKRAFT PATCHv3 5/7] plat/common: Find and register IRQ for arch_timer

[Julien Grall <julien.grall@xxxxxxx>]

On 9/17/19 8:01 AM, Justin He (Arm Technology China) wrote:
> Hi Julien (welcome back from holiday 😊 )
Hi,

Thanks :).

> > -----Original Message-----
> > From: Julien Grall <julien.grall@xxxxxxx>
> > Sent: 2019年9月17日 3:53
> > To: Justin He (Arm Technology China) <Justin.He@xxxxxxx>; Santiago
> > Pagani <Santiago.Pagani@xxxxxxxxx>; minios-devel@xxxxxxxxxxxxxxxxxxxx;
> > Simon Kuenzer <simon.kuenzer@xxxxxxxxx>; Sharan Santhanam
> > <Sharan.Santhanam@xxxxxxxxx>
> > Cc: Kaly Xin (Arm Technology China) <Kaly.Xin@xxxxxxx>; Wei Chen (Arm
> > Technology China) <Wei.Chen@xxxxxxx>; Jianyong Wu (Arm Technology
> > China) <Jianyong.Wu@xxxxxxx>
> > Subject: Re: [UNIKRAFT PATCHv3 5/7] plat/common: Find and register IRQ
> > for arch_timer
> >
> > On 9/16/19 8:52 AM, Justin He (Arm Technology China) wrote:
> > > Hi  Santiago
> > Hi all,
> >
> > @Santiago, it is quite difficult to follow the thread when you start
> > your answer with "COMMENT". May I ask you to configure your e-mail
> > client to quote properly (i.e >)?
> >
> > Furthermore, disclaimer footer should be avoided on the mailing list.
> > You are basically saying this is confidential but you send to everyone
> > (mailing list are archived)...
> OK
It wasn't directed to you ;).

> > [...]
> >
> > > > COMMENT: There is nothing that we would like to do here? Not even
> > > > disable the IRQ? As the timer is not stopped, when the counter
> > overflows
> > > > we would get a new interrupt otherwise (although the overflow could
> > > > happen in a very very long time, right?)
> > > In previous version, we added a generic_timer_mask_irq() in
> > > generic_timer_irq_handler. But as per the suggestion [1] from Julien, we
> > > removed it. Besides, we referred to the minios logic at [2], it only called
> > > unmask and mask in block_domain (which is equivalent to unikraft's
> > > generic_timer_cpu_block)
> > Looking at my comments again, I am not sure where I suggested to remove
> > generic_timer_mask_irq()... Can you expand it?
> Okay... sorry for my mistakes. I will add generic_timer_mask_irq() back.
> > FWIW, the two main comments on the previous versions were:
> >      1) isb() should be added after updating the system register to
> > ensure that the system system is synchronized
> >      2) This is common code between arm32 and arm64. But the system
> > register name are arm64... Accesses should be stub in arch-specific
> > header so the code can work for both arm32 and arm64.
> I renamed plat/common/arm/time.c to plat/common/arm/time_arm64.c
> Seems that is not enough for you?  If no, I have no objections to make
> a stub  for arm32.
Well, the only bits arm64 specifics in this file are the access to the 
system registers. So renaming to time_arm64.c seems a bit overkill...
If there are plan to make arm32 a correct port on Unikraft, then 
splitting the code would be the best. If there are no plan to get arm32, 
then maybe you should think of killing it completely.
Cheers,

--
Julien Grall

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