Re: [XEN PATCH v2 03/10] misra: add deviations for direct inclusion guards

[Simone Ballarin <simone.ballarin@xxxxxxxxxxx>]

On 12/09/23 11:52, Jan Beulich wrote:
> On 12.09.2023 11:36, Simone Ballarin wrote:
> > --- a/docs/misra/safe.json
> > +++ b/docs/misra/safe.json
> > @@ -36,6 +36,14 @@
> >           },
> >           {
> >               "id": "SAF-4-safe",
> > +            "analyser": {
> > +                "eclair": "MC3R1.D4.10"
> > +            },
> > +            "name": "Dir 4.10: direct inclusion guard before",
> > +            "text": "Headers with just the direct inclusion guard before the 
> > inclusion guard are safe."
> > +        },
> > +        {
> > +            "id": "SAF-5-safe",
> >               "analyser": {},
> >               "name": "Sentinel",
> >               "text": "Next ID to be used"
> > diff --git a/xen/arch/arm/include/asm/hypercall.h 
> > b/xen/arch/arm/include/asm/hypercall.h
> > index ccd26c5184..24f8c61a73 100644
> > --- a/xen/arch/arm/include/asm/hypercall.h
> > +++ b/xen/arch/arm/include/asm/hypercall.h
> > @@ -1,3 +1,4 @@
> > +/* SAF-3-safe direct inclusion guard before */
> >   #ifndef __XEN_HYPERCALL_H__
> >   #error "asm/hypercall.h should not be included directly - include xen/hypercall.h 
> > instead"
> >   #endif
> > diff --git a/xen/arch/x86/include/asm/hypercall.h 
> > b/xen/arch/x86/include/asm/hypercall.h
> > index ec2edc771e..dfdfe80021 100644
> > --- a/xen/arch/x86/include/asm/hypercall.h
> > +++ b/xen/arch/x86/include/asm/hypercall.h
> > @@ -2,6 +2,7 @@
> >    * asm-x86/hypercall.h
> >    */
> >   
> > +/* SAF-3-safe direct inclusion guard before */
> >   #ifndef __XEN_HYPERCALL_H__
> >   #error "asm/hypercall.h should not be included directly - include xen/hypercall.h 
> > instead"
> >   #endif
> > diff --git a/xen/include/xen/unaligned.h b/xen/include/xen/unaligned.h
> > index 0a2b16d05d..190ada7800 100644
> > --- a/xen/include/xen/unaligned.h
> > +++ b/xen/include/xen/unaligned.h
> > @@ -3,6 +3,7 @@
> >    * without faulting, and at least reasonably efficiently.  Other architectures
> >    * will need to have a custom asm/unaligned.h.
> >    */
> > +/* SAF-3-safe direct inclusion guard before */
> >   #ifndef __ASM_UNALIGNED_H__
> >   #error "xen/unaligned.h should not be included directly - include asm/unaligned.h 
> > instead"
> >   #endif
> Apart from the recurring off-by-1, will this have the intended effect of
> Eclair still choking if there's then no inclusion guard following these
> early constructs?
>
> Jan
No, if you put something between the direct inclusion guard and the 
inclusion guard, no violation will be generated.
--
Simone Ballarin, M.Sc.

Field Application Engineer, BUGSENG (https://bugseng.com)