Re: [PATCH 3/3] xen/public: arch-arm: All PSR_* defines should be unsigned

[Juergen Gross <jgross@xxxxxxxx>]

On 18.08.23 09:39, Julien Grall wrote:
> Hi Jan,
>
> On 18/08/2023 07:33, Jan Beulich wrote:
> > On 17.08.2023 23:43, Julien Grall wrote:
> > > --- a/xen/include/public/arch-arm.h
> > > +++ b/xen/include/public/arch-arm.h
> > > @@ -339,36 +339,36 @@ typedef uint64_t xen_callback_t;
> > >   /* PSR bits (CPSR, SPSR) */
> > > -#define PSR_THUMB       (1<<5)        /* Thumb Mode enable */
> > > -#define PSR_FIQ_MASK    (1<<6)        /* Fast Interrupt mask */
> > > -#define PSR_IRQ_MASK    (1<<7)        /* Interrupt mask */
> > > -#define PSR_ABT_MASK    (1<<8)        /* Asynchronous Abort mask */
> > > -#define PSR_BIG_ENDIAN  (1<<9)        /* arm32: Big Endian Mode */
> > > -#define PSR_DBG_MASK    (1<<9)        /* arm64: Debug Exception mask */
> > > -#define PSR_IT_MASK     (0x0600fc00)  /* Thumb If-Then Mask */
> > > -#define PSR_JAZELLE     (1<<24)       /* Jazelle Mode */
> > > -#define PSR_Z           (1<<30)       /* Zero condition flag */
> > > +#define PSR_THUMB       (1U <<5)      /* Thumb Mode enable */
> > > +#define PSR_FIQ_MASK    (1U <<6)      /* Fast Interrupt mask */
> > > +#define PSR_IRQ_MASK    (1U <<7)      /* Interrupt mask */
> > > +#define PSR_ABT_MASK    (1U <<8)      /* Asynchronous Abort mask */
> > Nit: Did you mean to insert blanks also on the rhs of the <<, like you ...
> >
> > > +#define PSR_BIG_ENDIAN  (1U << 9)     /* arm32: Big Endian Mode */
> > > +#define PSR_DBG_MASK    (1U << 9)     /* arm64: Debug Exception mask */
> > > +#define PSR_IT_MASK     (0x0600fc00U) /* Thumb If-Then Mask */
> > > +#define PSR_JAZELLE     (1U << 24)    /* Jazelle Mode */
> > > +#define PSR_Z           (1U << 30)    /* Zero condition flag */
> > ... did everywhere here?
> Yes I did. I will update the patch.
>
> > As an aside I wonder why they're here: They look like definitions of
> > processor registers, which aren't under our (Xen's) control.
> I agree they are not under Xen's control. However, they are used by the 
> toolstack and IIRC back then they were not available in any other headers.
> Note that they are only available by the tools and the hypervisor (see #ifdef 
> above).
> > I ask in
> > part because the presence of such constants may then be taken as
> > justification to add similar things in new ports. Yet such definitions
> > shouldn't be put here.
>  From my understanding we are using the public headers to provide macros/defines 
> that are used by both the toolstack and the hypervisor. If they are not meant to 
> be exposed to the guest, then they will be protected with "#if defined(__XEN__) 
> || defined(__XEN_TOOLS__)".
> I think we are in a similar situation here. So it is not clear where they should 
> be put if we need to share them between the hypervisor and the toolstack.
What about include/xen/lib? There are headers below that linked at build time
via tools/include/Makefile to tools/include/xen/lib.


Juergen

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