Re: [PATCH] arm64: Introduce ISAR6 CPU ID register

[Anshuman Khandual]

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@xxxxxxx>
>> Cc: Will Deacon <will@xxxxxxxxxx>
>> Cc: Marc Zyngier <maz@xxxxxxxxxx>
>> Cc: James Morse <james.morse@xxxxxxx>
>> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>> ---
>> Âarch/arm64/include/asm/cpu.hÂÂÂ | 1 +
>> Âarch/arm64/include/asm/sysreg.h | 9 +++++++++
>> Âarch/arm64/kernel/cpufeature.c | 7 ++++++-
>> Âarch/arm64/kernel/cpuinfo.cÂÂÂÂ | 1 +
>> Âarch/arm64/kvm/sys_regs.cÂÂÂÂÂÂ | 2 +-
>> Â5 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 {
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_isar3;
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_isar4;
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_isar5;
>> +ÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_isar6;
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_mmfr0;
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ reg_id_mmfr1;
>> ÂÂÂÂ u32ÂÂÂÂÂÂÂ 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 @@
>> Â#define SYS_ID_ISAR4_EL1ÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 2, 4)
>> Â#define SYS_ID_ISAR5_EL1ÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 2, 5)
>> Â#define SYS_ID_MMFR4_EL1ÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 2, 6)
>> +#define SYS_ID_ISAR6_EL1ÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 2, 7)
>>
>> Â#define SYS_MVFR0_EL1ÂÂÂÂÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 3, 0)
>> Â#define SYS_MVFR1_EL1ÂÂÂÂÂÂÂÂÂÂÂ sys_reg(3, 0, 0, 3, 1)
>> @@ -683,6 +684,14 @@
>> Â#define ID_ISAR5_AES_SHIFTÂÂÂÂÂÂÂ 4
>> Â#define ID_ISAR5_SEVL_SHIFTÂÂÂÂÂÂÂ 0
>>
>> +#define ID_ISAR6_JSCVT_SHIFTÂÂÂÂÂÂÂ 0
>> +#define ID_ISAR6_DP_SHIFTÂÂÂÂÂÂÂ 4
>> +#define ID_ISAR6_FHM_SHIFTÂÂÂÂÂÂÂ 8
>> +#define ID_ISAR6_SB_SHIFTÂÂÂÂÂÂÂ 12
>> +#define ID_ISAR6_SPECRES_SHIFTÂÂÂÂÂÂÂ 16
>> +#define ID_ISAR6_BF16_SHIFTÂÂÂÂÂÂÂ 20
>> +#define ID_ISAR6_I8MM_SHIFTÂÂÂÂÂÂÂ 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.

> 
>> +
>> Â#define MVFR0_FPROUND_SHIFTÂÂÂÂÂÂÂ 28
>> Â#define MVFR0_FPSHVEC_SHIFTÂÂÂÂÂÂÂ 24
>> Â#define MVFR0_FPSQRT_SHIFTÂÂÂÂÂÂÂ 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[] = {
>> Â * Common ftr bits for a 32bit register with all hidden, strict
>> Â * attributes, with 4bit feature fields and a default safe value of
>> Â * 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]
>> Â */
>> Âstatic const struct arm64_ftr_bits ftr_generic_32bits[] = {
>> ÂÂÂÂ ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>> ÂÂÂÂ ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>> ÂÂÂÂ ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>> ÂÂÂÂ ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>> +ÂÂÂ ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>>
>> ÂÂÂÂ /* Op1 = 0, CRn = 0, CRm = 3 */
>> ÂÂÂÂ ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
>> @@ -603,6 +604,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
>> +ÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
>> ÂÂÂÂÂÂÂÂ init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
>> @@ -756,6 +758,8 @@ void update_cpu_features(int cpu,
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ info->reg_id_isar4, boot->reg_id_isar4);
>> ÂÂÂÂÂÂÂÂ taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ info->reg_id_isar5, boot->reg_id_isar5);
>> +ÂÂÂÂÂÂÂ taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ info->reg_id_isar6, boot->reg_id_isar6);
>>
>> ÂÂÂÂÂÂÂÂ /*
>> ÂÂÂÂÂÂÂÂÂ * 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)
>> ÂÂÂÂ read_sysreg_case(SYS_ID_ISAR3_EL1);
>> ÂÂÂÂ read_sysreg_case(SYS_ID_ISAR4_EL1);
>> ÂÂÂÂ read_sysreg_case(SYS_ID_ISAR5_EL1);
>> +ÂÂÂ read_sysreg_case(SYS_ID_ISAR6_EL1);
>> ÂÂÂÂ read_sysreg_case(SYS_MVFR0_EL1);
>> ÂÂÂÂ read_sysreg_case(SYS_MVFR1_EL1);
>> ÂÂÂÂ 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)
>> ÂÂÂÂÂÂÂÂ info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
>> ÂÂÂÂÂÂÂÂ info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
>> ÂÂÂÂÂÂÂÂ info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
>> +ÂÂÂÂÂÂÂ info->reg_id_isar6 = read_cpuid(ID_ISAR6_EL1);
>> ÂÂÂÂÂÂÂÂ info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
>> ÂÂÂÂÂÂÂÂ info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
>> ÂÂÂÂÂÂÂÂ 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[] = {
>> ÂÂÂÂ ID_SANITISED(ID_ISAR4_EL1),
>> ÂÂÂÂ ID_SANITISED(ID_ISAR5_EL1),
>> ÂÂÂÂ ID_SANITISED(ID_MMFR4_EL1),
>> -ÂÂÂ ID_UNALLOCATED(2,7),
>> +ÂÂÂ ID_SANITISED(ID_ISAR6_EL1),
>>
>> ÂÂÂÂ /* CRm=3 */
>> ÂÂÂÂ ID_SANITISED(MVFR0_EL1),
> 
> Otherwise,
> 
> Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
> 
> ÂÂÂÂÂÂÂ M.