Re: [PATCH v1 17/24] kvm: arm64: Add __hyp_pa_symbol helper macro

[Marc Zyngier]

On 2020-11-09 16:59, Quentin Perret wrote:
> Hey David,
>
> On Monday 09 Nov 2020 at 11:32:26 (+0000), David Brazdil wrote:
> > Add helper macro for computing the PA of a kernel symbol in nVHE hyp
> > code. This will be useful for computing the PA of a PSCI CPU_ON entry
> > point.
> >
> > Signed-off-by: David Brazdil <dbrazdil@xxxxxxxxxx>
> > ---
> >  arch/arm64/kvm/hyp/nvhe/psci.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/hyp/nvhe/psci.c 
> > b/arch/arm64/kvm/hyp/nvhe/psci.c
> > index b0b5df590ba5..7510b9e174e9 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/psci.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/psci.c
> > @@ -20,6 +20,16 @@ s64 hyp_physvirt_offset;
> >
> >  #define __hyp_pa(x) ((phys_addr_t)((x)) + hyp_physvirt_offset)
> >
> > +#define __hyp_pa_symbol(sym)					\
> > +	({							\
> > +		extern char sym[];				\
> > +		unsigned long kern_va;				\
> > +								\
> > +		asm volatile("ldr %0, =%1" : "=r" (kern_va)	\
> > +					   : "S" (sym));	\
> > +		kern_va - kimage_voffset;			\
> > +	})
> > +
>
> Could this be simplified to __hyp_pa(hyp_symbol_addr(sym))? That would
> avoid the dependency on kimage_voffset.

I'm going to move away from evaluating kimage_voffset at runtime anyway,
see [1].

Thanks,

        M.

[1] https://lore.kernel.org/r/20201109175923.445945-1-maz@xxxxxxxxxx
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