| Date | Wed, 7 Oct 2015 17:36:51 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH v2 06/22] arm64: sys_reg: Define System register encoding |
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On Mon, Oct 05, 2015 at 06:01:55PM +0100, Suzuki K. Poulose wrote: > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -22,11 +22,11 @@ > > #include <asm/opcodes.h> > > -#define SCTLR_EL1_CP15BEN (0x1 << 5) > -#define SCTLR_EL1_SED (0x1 << 8) > - > /* > - * ARMv8 ARM reserves the following encoding for system registers: > + * sys_reg: Defines the ARMv8 ARM encoding for the System register. > + * > + * ARMv8 ARM reserves the following encoding for system registers in the > + * instructions accessing them.
Nitpick: the sentence should end with a colon.
> * (Ref: ARMv8 ARM, Section: "System instruction class encoding overview", > * C5.2, version:ARM DDI 0487A.f) > * [20-19] : Op0 > @@ -34,15 +34,40 @@ > * [15-12] : CRn > * [11-8] : CRm > * [7-5] : Op2 > + * Hence we use [ sys_reg() << 5 ] in the mrs/msr instructions.
Do we really need to have all the ids shifted right by 5? I can't see where it helps. OTOH, it makes the code more complicated by having to remember to shift the id left by 5.
> + *
Nitpick: no need for another line.
-- Catalin
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