Re: [XEN PATCH][for-4.19 v4 3/8] x86: add deviation comments for asm-only functions

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 24/10/2023 09:50, Jan Beulich wrote:
> On 23.10.2023 11:56, Nicola Vetrini wrote:
> > As stated in rules.rst, functions used only in asm code
> > are allowed to have no prior declaration visible when being
> > defined, hence these functions are deviated.
> > This also fixes violations of MISRA C:2012 Rule 8.4.
> >
> > Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> > Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > ---
> > Changes in v3:
> > - added SAF deviations for vmx counterparts to svm functions.
> Same comment regarding the R-b here as for patch 2.
>
> > --- a/xen/arch/x86/hvm/svm/intr.c
> > +++ b/xen/arch/x86/hvm/svm/intr.c
> > @@ -123,6 +123,7 @@ static void svm_enable_intr_window(struct vcpu *v, 
> > struct hvm_intack intack)
> >          vmcb, general1_intercepts | GENERAL1_INTERCEPT_VINTR);
> >  }
> >
> > +/* SAF-1-safe */
> >  void svm_intr_assist(void)
> >  {
> >      struct vcpu *v = current;
> Linux has the concept of "asmlinkage" for functions interfacing C and
> assembly. Was it considered to use that - even if expanding to nothing
> for all present architectures - as a way to annotate affected 
> definitions
> in place of the SAF-*-safe comments?
>
> Jan
It was proposed by Julien a while ago (I think it the thread on 
deviations.rst) to define
a macro asmcall that expands to nothing, to mark all such functions. 
Right now, it's not
strictly necessary (given that there are already some uses of SAF in 
Stefano's for-4.19 branch.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)