Re: [PATCH 1/4] xen/arm: traps: Fix MISRA C 2012 Rule 8.4 violations

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

Hi Julien,

On 7/6/22 00:56, Julien Grall wrote:
> On 05/07/2022 22:49, Xenia Ragiadakou wrote:
> > On 7/6/22 00:28, Julien Grall wrote:
> > > Hi Xenia,
> > >
> > > On 05/07/2022 22:02, Xenia Ragiadakou wrote:
> > > > Add the function prototypes of the functions below in 
> > > > <asm/processor.h> header
> > > > file so that they are visible before the function definitions in 
> > > > traps.c.
> > > > enter_hypervisor_from_guest_preirq()
> > > > enter_hypervisor_from_guest()
> > > > do_trap_hyp_sync()
> > > > do_trap_guest_sync()
> > > > do_trap_irq()
> > > > do_trap_fiq()
> > > > leave_hypervisor_to_guest()
> > > I have actually came across those missing prototypes in the past and 
> > > I have refrained to add them because they are not meant to be called 
> > > from C.
> > > While I agree this is a violation of Misra C, I am still not 
> > > convinced they should be added (there is no need to verify the 
> > > prototype).
> > Yes, there is no need. Here, I decided to follow the example of 
> > do_trap_hyp_serror() and do_trap_guest_serror() for consistency.
> do_trap_guest_serror() is called from C code (see arch/arm32/traps.c).
You are right, my mistake.

> do_trap_hyp_serror() is called only from assembly. I would argue that if 
> you want consistency, then you should drop the prototype rather than 
> modifying 90% of the other examples.
> Otherwise, this is not really consistency but more a design choice (you 
> want to be fully compliant with MISRA).
I agree with you that there is no need to declare the variables and 
functions that are called only from assembly, prior to their 
definitions. So, this kind of violations could be grouped together and 
provide a formal deviation. This seems to me reasonable.
--
Xenia