Re: [XEN PATCH] arm64/vfp: address MISRA C:2012 Dir 4.3

[Julien Grall <julien@xxxxxxx>]

Hi Nicola,

On 23/08/2023 17:09, Nicola Vetrini wrote:
> On 23/08/2023 16:59, Julien Grall wrote:
> > Hi,
> >
> > On 23/08/2023 15:27, Nicola Vetrini wrote:
> > > Directive 4.3 prescribes the following:
> > > "Assembly language shall be encapsulated and isolated",
> > > on the grounds of improved readability and ease of maintenance.
> > > The Directive is violated in this case by asm code in between C code.
> > >
> > > A macro is the chosen encapsulation mechanism.
> > I would rather prefer if we use a static inline.
> Just to prevent an possible back and forth on a similar patch:
> is it ok to adopt the same approach with the inline asm in
> xen/arch/arm/arm64/lib/bitops.c in the definition of the macros
> 'bitop' and 'testop'?
So, in the VFP I agree that moving the assembly part outside of 
vfp_*_state() makes sense even without MISRA. But I don't agree with 
moving the assembly code out as the C function is tightly coupled with 
the assembly code.
So this would please MISRA but IHMO would make the code more difficult 
to understand. So I think we should deviate for the bitops.
Bertrand, Stefano, what do you think?

Cheers,

--
Julien Grall