Messages in this thread | | | Date | Fri, 10 May 2024 19:09:31 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 1/2] KVM: arm64: Replace custom macros with fields from ID_AA64PFR0_EL1 |
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On Mon, Apr 29, 2024 at 07:53:14AM +0530, Anshuman Khandual wrote: > On 4/18/24 13:09, Marc Zyngier wrote: > > On Thu, 18 Apr 2024 06:38:03 +0100, > > Anshuman Khandual <anshuman.khandual@arm.com> wrote: > >> #define PVM_ID_AA64PFR0_RESTRICT_UNSIGNED (\ > >> - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL0), ID_AA64PFR0_EL1_ELx_64BIT_ONLY) | \ > >> - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1), ID_AA64PFR0_EL1_ELx_64BIT_ONLY) | \ > >> - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL2), ID_AA64PFR0_EL1_ELx_64BIT_ONLY) | \ > >> - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL3), ID_AA64PFR0_EL1_ELx_64BIT_ONLY) | \ > >> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL0), ID_AA64PFR0_EL1_EL0_IMP) | \ > >> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1), ID_AA64PFR0_EL1_EL1_IMP) | \ > >> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL2), ID_AA64PFR0_EL1_EL2_IMP) | \ > >> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL3), ID_AA64PFR0_EL1_EL3_IMP) | \ > > > > If you are going to rework this, can we instead use something less > > verbose such as SYS_FIELD_GET()? > > Just wondering, is not FIELD_PREP() and SYS_FIELD_GET() does the exact opposite thing. > The earlier builds the entire register value from various constituents, where as the > later extracts a single register field from a complete register value instead. Or did > I just misunderstood something here.
He means use one of the SYS_FIELD_*() helpers, e.g. SYS_FIELD_PREP_ENUM(), with which this can be:
#define PVM_ID_AA64PFR0_RESTRICT_UNSIGNED (\ SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, EL0, IMP) | \ SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, EL1, IMP) | \ SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, EL2, IMP) | \ SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, EL3, IMP) | \ SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, RAS, IMP) \ )
.. which is far less verbose, and much easier to read.
Mark.
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