[PATCH v2 07/28] ARM: KVM: Add system register accessor macros

[christoffer.dall@linaro.org (Christoffer Dall)]

On Thu, Feb 04, 2016 at 11:00:24AM +0000, Marc Zyngier wrote:
> In order to move system register (CP15, mostly) access to C code,
> add a few macros to facilitate this, and minimize the difference
> between 32 and 64bit CP15 registers.
> 
> This will get heavily used in the following patches.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm/kvm/hyp/hyp.h | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/arch/arm/kvm/hyp/hyp.h b/arch/arm/kvm/hyp/hyp.h
> index c723870..727089f 100644
> --- a/arch/arm/kvm/hyp/hyp.h
> +++ b/arch/arm/kvm/hyp/hyp.h
> @@ -27,4 +27,19 @@
>  #define kern_hyp_va(v) (v)
>  #define hyp_kern_va(v) (v)
>  
> +#define __ACCESS_CP15(CRn, Op1, CRm, Op2)	\
> +	"mrc", "mcr", __stringify(p15, Op1, %0, CRn, CRm, Op2), u32
> +#define __ACCESS_CP15_64(Op1, CRm)		\
> +	"mrrc", "mcrr", __stringify(p15, Op1, %Q0, %R0, CRm), u64
> +
> +#define __write_sysreg(v, r, w, c, t)	asm volatile(w " " c : : "r" ((t)(v)))
> +#define write_sysreg(v, ...)		__write_sysreg(v, __VA_ARGS__)
> +
> +#define __read_sysreg(r, w, c, t) ({				\
> +	t __val;						\
> +	asm volatile(r " " c : "=r" (__val));			\
> +	__val;							\
> +})
> +#define read_sysreg(...)		__read_sysreg(__VA_ARGS__)
> +
>  #endif /* __ARM_KVM_HYP_H__ */
> -- 
> 2.1.4
> 

I sort of figured that a reviewed-by tag on patches that actually use
these macros would be an implicit review of this code.

not feeling comfortable enough that I read this jibberish perfectly in
isolation, but given that the stuff compiles and works, I'll just ack
it:

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>