Re: [Xen-devel] [PATCH 01/24] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall <julien.grall@xxxxxxx>]

Hi Tim,

On 06/14/2017 09:49 AM, Tim Deegan wrote:
> At 17:13 +0100 on 13 Jun (1497373980), Julien Grall wrote:
> > INVALID_{G,M}FN are defined using static inline helpers _{g,m}fn.
> > This means, they cannot be used to initialize a build time static variable:
> >
> > In file included from mm.c:24:0:
> > xen/xen/include/xen/mm.h:59:26: error: initializer element is not constant
> >   #define INVALID_MFN      _mfn(~0UL)
> >
> > Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Acked-by: Tim Deegan <tim@xxxxxxx>
>
> > I know that this solution will not work for non-debug build. I would
> > like input from the community on way to fix it nicely.
> It seems to WFM: https://godbolt.org/g/vEVNY3
To be honest, I thought it would not work and a bit surprised that it 
actually works.
I am happy to keep like that or introduced a new define (such as 
TYPE_SAFE_CONSTANT suggested by Jan).
Cheers,

--
Julien Grall

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