From: Mark Rutland <mark.rutland@arm.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
Oliver Upton <oliver.upton@linux.dev>,
Will Deacon <will@kernel.org>,
kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org,
Fuad Tabba <tabba@google.com>
Subject: Re: [PATCH 1/2] KVM: arm64: Replace custom macros with fields from ID_AA64PFR0_EL1
Date: Fri, 10 May 2024 19:09:31 +0100 [thread overview]
Message-ID: <Zj5i2x8Sh95YIfeq@J2N7QTR9R3> (raw)
In-Reply-To: <ab6466f2-023e-4b5f-bb60-aadb9eee089a@arm.com>
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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next prev parent reply other threads:[~2024-05-10 18:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-18 5:38 [PATCH 0/2] arm64: Drop ID_AA64PFR0_EL1_ELx_[64BIT_ONLY|32BIT_64BIT] Anshuman Khandual
2024-04-18 5:38 ` [PATCH 1/2] KVM: arm64: Replace custom macros with fields from ID_AA64PFR0_EL1 Anshuman Khandual
2024-04-18 7:39 ` Marc Zyngier
2024-04-29 2:23 ` Anshuman Khandual
2024-05-10 18:09 ` Mark Rutland [this message]
2024-05-13 5:28 ` Anshuman Khandual
2024-04-18 5:38 ` [PATCH 2/2] arm64/cpufeature: " Anshuman Khandual
2024-05-09 4:44 ` [PATCH 0/2] arm64: Drop ID_AA64PFR0_EL1_ELx_[64BIT_ONLY|32BIT_64BIT] Anshuman Khandual
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