On Fri, Nov 27, 2015 at 06:49:55PM +0000, Marc Zyngier wrote:
> From: Mark Rutland <mark.rutland@xxxxxxx>
>
> Rather than crafting custom macros for reading/writing each system
> register provide generics accessors, read_sysreg and write_sysreg, for
> this purpose.
>
> Unlike read_cpuid, calls to read_exception_reg are never expected
> to be optimized away or replaced with synthetic values.
how does this comment about read_exception_reg relate to this patch?
>
> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> Cc: Suzuki Poulose <suzuki.poulose@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm64/include/asm/sysreg.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index d48ab5b..c9c283a 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -20,6 +20,8 @@
> #ifndef __ASM_SYSREG_H
> #define __ASM_SYSREG_H
>
> +#include <linux/stringify.h>
> +
> #include <asm/opcodes.h>
>
> /*
> @@ -208,6 +210,8 @@
>
> #else
>
> +#include <linux/types.h>
> +
> asm(
> " .irp num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"
> " .equ __reg_num_x\\num, \\num\n"
> @@ -232,6 +236,19 @@ static inline void config_sctlr_el1(u32 clear, u32 set)
> val |= set;
> asm volatile("msr sctlr_el1, %0" : : "r" (val));
> }
> +
> +#define read_sysreg(r) ({ \
> + u64 __val; \
> + asm volatile("mrs %0, " __stringify(r) : "=r" (__val)); \
> + __val; \
> +})
> +
> +#define write_sysreg(v, r) do { \
> + u64 __val = (u64)v; \
> + asm volatile("msr " __stringify(r) ", %0" \
> + : : "r" (__val)); \
> +} while (0)
> +
> #endif
>
> #endif /* __ASM_SYSREG_H */
> --
> 2.1.4
>
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