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SubjectRe: [PATCH] arm64: Introduce ISAR6 CPU ID register
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On 12/12/2019 05:13 PM, Marc Zyngier wrote:
> On 2019-12-12 10:14, Anshuman Khandual wrote:
>> This adds basic building blocks required for ISAR6 CPU ID register which
>> identifies support for various instruction implementation on AArch32 state.
>
> nit: the register name is ID_ISAR6.

Sure, will change.

>
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Marc Zyngier <maz@kernel.org>
>> Cc: James Morse <james.morse@arm.com>
>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: kvmarm@lists.cs.columbia.edu
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>  arch/arm64/include/asm/cpu.h    | 1 +
>>  arch/arm64/include/asm/sysreg.h | 9 +++++++++
>>  arch/arm64/kernel/cpufeature.c  | 7 ++++++-
>>  arch/arm64/kernel/cpuinfo.c     | 1 +
>>  arch/arm64/kvm/sys_regs.c       | 2 +-
>>  5 files changed, 18 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
>> index d72d995..b4a4053 100644
>> --- a/arch/arm64/include/asm/cpu.h
>> +++ b/arch/arm64/include/asm/cpu.h
>> @@ -39,6 +39,7 @@ struct cpuinfo_arm64 {
>>      u32        reg_id_isar3;
>>      u32        reg_id_isar4;
>>      u32        reg_id_isar5;
>> +    u32        reg_id_isar6;
>>      u32        reg_id_mmfr0;
>>      u32        reg_id_mmfr1;
>>      u32        reg_id_mmfr2;
>> diff --git a/arch/arm64/include/asm/sysreg.h
>> b/arch/arm64/include/asm/sysreg.h
>> index 6db3a9b..4fd3327 100644
>> --- a/arch/arm64/include/asm/sysreg.h
>> +++ b/arch/arm64/include/asm/sysreg.h
>> @@ -146,6 +146,7 @@
>>  #define SYS_ID_ISAR4_EL1        sys_reg(3, 0, 0, 2, 4)
>>  #define SYS_ID_ISAR5_EL1        sys_reg(3, 0, 0, 2, 5)
>>  #define SYS_ID_MMFR4_EL1        sys_reg(3, 0, 0, 2, 6)
>> +#define SYS_ID_ISAR6_EL1        sys_reg(3, 0, 0, 2, 7)
>>
>>  #define SYS_MVFR0_EL1            sys_reg(3, 0, 0, 3, 0)
>>  #define SYS_MVFR1_EL1            sys_reg(3, 0, 0, 3, 1)
>> @@ -683,6 +684,14 @@
>>  #define ID_ISAR5_AES_SHIFT        4
>>  #define ID_ISAR5_SEVL_SHIFT        0
>>
>> +#define ID_ISAR6_JSCVT_SHIFT        0
>> +#define ID_ISAR6_DP_SHIFT        4
>> +#define ID_ISAR6_FHM_SHIFT        8
>> +#define ID_ISAR6_SB_SHIFT        12
>> +#define ID_ISAR6_SPECRES_SHIFT        16
>> +#define ID_ISAR6_BF16_SHIFT        20
>> +#define ID_ISAR6_I8MM_SHIFT        24
>
> I couldn't find the last two items in the E.a revision of the ARMv8 ARM.
> I guess they are for post 8.5 revisions of the architecture?

Yes.

>
>> +
>>  #define MVFR0_FPROUND_SHIFT        28
>>  #define MVFR0_FPSHVEC_SHIFT        24
>>  #define MVFR0_FPSQRT_SHIFT        20
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index f344cea..3b9ac8b 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -346,7 +346,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
>>   * Common ftr bits for a 32bit register with all hidden, strict
>>   * attributes, with 4bit feature fields and a default safe value of
>>   * 0. Covers the following 32bit registers:
>> - * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
>> + * id_isar[0-4, 6], id_mmfr[1-3], id_pfr1, mvfr[0-1]
>>   */
>>  static const struct arm64_ftr_bits ftr_generic_32bits[] = {
>>      ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>>      ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>>      ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>>      ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>> +    ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>>
>>      /* Op1 = 0, CRn = 0, CRm = 3 */
>>      ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
>> @@ -603,6 +604,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
>>          init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
>>          init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
>>          init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
>> +        init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
>>          init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
>>          init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
>>          init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
>> @@ -756,6 +758,8 @@ void update_cpu_features(int cpu,
>>                      info->reg_id_isar4, boot->reg_id_isar4);
>>          taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
>>                      info->reg_id_isar5, boot->reg_id_isar5);
>> +        taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
>> +                    info->reg_id_isar6, boot->reg_id_isar6);
>>
>>          /*
>>           * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
>> @@ -834,6 +838,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
>>      read_sysreg_case(SYS_ID_ISAR3_EL1);
>>      read_sysreg_case(SYS_ID_ISAR4_EL1);
>>      read_sysreg_case(SYS_ID_ISAR5_EL1);
>> +    read_sysreg_case(SYS_ID_ISAR6_EL1);
>>      read_sysreg_case(SYS_MVFR0_EL1);
>>      read_sysreg_case(SYS_MVFR1_EL1);
>>      read_sysreg_case(SYS_MVFR2_EL1);
>> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
>> index 10121f5..6005d38 100644
>> --- a/arch/arm64/kernel/cpuinfo.c
>> +++ b/arch/arm64/kernel/cpuinfo.c
>> @@ -362,6 +362,7 @@ static void __cpuinfo_store_cpu(struct
>> cpuinfo_arm64 *info)
>>          info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
>>          info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
>>          info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
>> +        info->reg_id_isar6 = read_cpuid(ID_ISAR6_EL1);
>>          info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
>>          info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
>>          info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index 7dadd24..a6b8ca1 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -1424,7 +1424,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>>      ID_SANITISED(ID_ISAR4_EL1),
>>      ID_SANITISED(ID_ISAR5_EL1),
>>      ID_SANITISED(ID_MMFR4_EL1),
>> -    ID_UNALLOCATED(2,7),
>> +    ID_SANITISED(ID_ISAR6_EL1),
>>
>>      /* CRm=3 */
>>      ID_SANITISED(MVFR0_EL1),
>
> Otherwise,
>
> Acked-by: Marc Zyngier <maz@kernel.org>
>
>         M.

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