From: Suzuki.Poulose@arm.com (Suzuki K Poulose)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 3/7] arm64: Add helpers for detecting AArch32 support at EL0
Date: Thu, 14 Apr 2016 17:46:08 +0100 [thread overview]
Message-ID: <570FC950.1070904@arm.com> (raw)
In-Reply-To: <20160414163933.GG4584@arm.com>
On 14/04/16 17:39, Will Deacon wrote:
> On Thu, Mar 31, 2016 at 06:27:31PM +0100, Suzuki K Poulose wrote:
>> Adds a helper to extract the support for AArch32 at EL0
>>
>> Tested-by: Yury Norov <ynorov@caviumnetworks.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> +static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
>> +{
>> + u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
>> +
>> + return val == ID_AA64PFR0_EL0_32BIT_64BIT;
>
> Should this be >=? What are the rules for this register?
This feature value is kind of "FTR_EXACT" where, we don't know what the relationship
of the values are. Here is the list of possible values :
0001 EL0 can be executed in AArch64 state only.
0010 EL0 can be executed in either AArch64 or AArch32 state.
All the other values are reserved. So I believe "==" is better check.
Suzuki
WARNING: multiple messages have this Message-ID (diff)
From: Suzuki K Poulose <Suzuki.Poulose@arm.com>
To: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, mark.rutland@arm.com,
marc.zyngier@arm.com, ynorov@caviumnetworks.com
Subject: Re: [PATCH v3 3/7] arm64: Add helpers for detecting AArch32 support at EL0
Date: Thu, 14 Apr 2016 17:46:08 +0100 [thread overview]
Message-ID: <570FC950.1070904@arm.com> (raw)
In-Reply-To: <20160414163933.GG4584@arm.com>
On 14/04/16 17:39, Will Deacon wrote:
> On Thu, Mar 31, 2016 at 06:27:31PM +0100, Suzuki K Poulose wrote:
>> Adds a helper to extract the support for AArch32 at EL0
>>
>> Tested-by: Yury Norov <ynorov@caviumnetworks.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> +static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
>> +{
>> + u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
>> +
>> + return val == ID_AA64PFR0_EL0_32BIT_64BIT;
>
> Should this be >=? What are the rules for this register?
This feature value is kind of "FTR_EXACT" where, we don't know what the relationship
of the values are. Here is the list of possible values :
0001 EL0 can be executed in AArch64 state only.
0010 EL0 can be executed in either AArch64 or AArch32 state.
All the other values are reserved. So I believe "==" is better check.
Suzuki
next prev parent reply other threads:[~2016-04-14 16:46 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 17:27 [PATCH v3 0/7] arm64: Support for systems without AArch32 state Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 1/7] arm64: hwcaps: Cleanup naming Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 2/7] arm64: HWCAP: Split COMPAT HWCAP table entries Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 3/7] arm64: Add helpers for detecting AArch32 support at EL0 Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-04-14 16:39 ` Will Deacon
2016-04-14 16:39 ` Will Deacon
2016-04-14 16:46 ` Suzuki K Poulose [this message]
2016-04-14 16:46 ` Suzuki K Poulose
2016-04-14 16:47 ` Will Deacon
2016-04-14 16:47 ` Will Deacon
2016-03-31 17:27 ` [PATCH v3 4/7] arm64: cpufeature: Check availability of AArch32 Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 5/7] arm64: cpufeature: Track 32bit EL0 support Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-04-14 16:43 ` Will Deacon
2016-04-14 16:43 ` Will Deacon
2016-04-14 16:50 ` Suzuki K Poulose
2016-04-14 16:50 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 6/7] arm64: Add a wrapper for personality() syscall Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
2016-04-14 16:44 ` Will Deacon
2016-04-14 16:44 ` Will Deacon
2016-04-14 16:47 ` Suzuki K Poulose
2016-04-14 16:47 ` Suzuki K Poulose
2016-03-31 17:27 ` [PATCH v3 7/7] arm64: compat: Check for AArch32 state Suzuki K Poulose
2016-03-31 17:27 ` Suzuki K Poulose
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