From: Will Deacon <will@kernel.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 03/16] arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0
Date: Tue, 5 May 2020 12:10:45 +0100 [thread overview]
Message-ID: <20200505111045.GE19710@willie-the-truck> (raw)
In-Reply-To: <1588426445-24344-4-git-send-email-anshuman.khandual@arm.com>
On Sat, May 02, 2020 at 07:03:52PM +0530, Anshuman Khandual wrote:
> Double lock feature can have the following possible values.
>
> 0b0000 - Double lock implemented
> 0b1111 - Double lock not implemented
>
> But in case of a conflict the safe value should be 0b1111. Hence this must
> be a signed feature instead. Also change FTR_EXACT to FTR_LOWER_SAFE.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
>
> Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/kernel/cpufeature.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 51386dade423..cba43e4a5c79 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -338,7 +338,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
> };
>
> static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> - ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 36, 28, 0),
> + S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 36, 28, 0),
Wait, isn't this buggered today? Shouldn't that 28 be a 4? I think we really
need to:
1. Make it impossible to describe overlapping fields, incomplete
registers etc (ideally at build-time)
2. Have a macro that for 4-bit fields so you don't have to type '4'
all the time
Suzuki, any ideas how we can make this a bit more robust?
Will
next prev parent reply other threads:[~2020-05-05 11:10 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-02 13:33 [PATCH V3 00/16] arm64/cpufeature: Introduce ID_PFR2, ID_DFR1, ID_MMFR5 and other changes Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 01/16] arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 02/16] arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register Anshuman Khandual
2020-05-04 20:24 ` Will Deacon
2020-05-05 6:50 ` Anshuman Khandual
2020-05-05 10:42 ` Will Deacon
2020-05-08 4:25 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 03/16] arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0 Anshuman Khandual
2020-05-05 11:10 ` Will Deacon [this message]
2020-05-08 4:59 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 04/16] arm64/cpufeature: Introduce ID_PFR2 CPU register Anshuman Khandual
2020-05-05 11:12 ` Will Deacon
2020-05-05 11:16 ` Mark Rutland
2020-05-05 11:18 ` Mark Rutland
2020-05-05 11:27 ` Will Deacon
2020-05-05 11:50 ` Mark Rutland
2020-05-05 12:12 ` Will Deacon
2020-05-05 12:49 ` Mark Rutland
2020-05-08 8:32 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 05/16] arm64/cpufeature: Introduce ID_DFR1 " Anshuman Khandual
2020-05-03 21:35 ` Suzuki K Poulose
2020-05-02 13:33 ` [PATCH V3 06/16] arm64/cpufeature: Introduce ID_MMFR5 " Anshuman Khandual
2020-05-04 20:33 ` Will Deacon
2020-05-05 7:01 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 07/16] arm64/cpufeature: Add remaining feature bits in ID_PFR0 register Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 08/16] arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register Anshuman Khandual
2020-05-05 11:14 ` Will Deacon
2020-05-06 6:43 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 09/16] arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register Anshuman Khandual
2020-05-05 4:54 ` Suzuki K Poulose
2020-05-05 7:06 ` Anshuman Khandual
2020-05-02 13:33 ` [PATCH V3 10/16] arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register Anshuman Khandual
2020-05-05 4:59 ` Suzuki K Poulose
2020-05-06 6:35 ` Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 11/16] arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register Anshuman Khandual
2020-05-05 9:24 ` Suzuki K Poulose
2020-05-06 6:33 ` Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 12/16] arm64/cpufeature: Add remaining feature bits in ID_AA64MMFR0 register Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 13/16] arm64/cpufeature: Add remaining feature bits in ID_AA64MMFR1 register Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 14/16] arm64/cpufeature: Add remaining feature bits in ID_AA64MMFR2 register Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 15/16] arm64/cpufeature: Add remaining feature bits in ID_AA64DFR0 register Anshuman Khandual
2020-05-02 13:34 ` [PATCH V3 16/16] arm64/cpufeature: Replace all open bits shift encodings with macros Anshuman Khandual
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