Re: [PATCH 06/27] arm64/sve: System register and exception syndrome definitions

Alex Bennée
2017-08-21T12:34:38Z

Alex Bennée <alex.bennee@linaro.org> writes:

> Dave Martin <Dave.Martin@arm.com> writes:
>
>> The SVE architecture adds some system registers, ID register fields
>> and a dedicated ESR exception class.
>>
>> This patch adds the appropriate definitions that will be needed by
>> the kernel.
>>
>> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
>> ---
>> arch/arm64/include/asm/esr.h | 3 ++-
>> arch/arm64/include/asm/kvm_arm.h | 1 +
>> arch/arm64/include/asm/sysreg.h | 16 ++++++++++++++++
>> arch/arm64/kernel/traps.c | 1 +
>> 4 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
>> index 8cabd57..813629e 100644
>> --- a/arch/arm64/include/asm/esr.h
>> +++ b/arch/arm64/include/asm/esr.h
>> @@ -43,7 +43,8 @@
>> #define ESR_ELx_EC_HVC64 (0x16)
>> #define ESR_ELx_EC_SMC64 (0x17)
>> #define ESR_ELx_EC_SYS64 (0x18)
>> -/* Unallocated EC: 0x19 - 0x1E */
>> +#define ESR_ELx_EC_SVE (0x19)
>> +/* Unallocated EC: 0x1A - 0x1E */
>> #define ESR_ELx_EC_IMP_DEF (0x1f)
>> #define ESR_ELx_EC_IABT_LOW (0x20)
>> #define ESR_ELx_EC_IABT_CUR (0x21)
>> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
>> index 61d694c..dbf0537 100644
>> --- a/arch/arm64/include/asm/kvm_arm.h
>> +++ b/arch/arm64/include/asm/kvm_arm.h
>> @@ -185,6 +185,7 @@
>> #define CPTR_EL2_TCPAC (1 << 31)
>> #define CPTR_EL2_TTA (1 << 20)
>> #define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT)
>> +#define CPTR_EL2_TZ (1 << 8)
>> #define CPTR_EL2_DEFAULT 0x000033ff
>>
>> /* Hyp Debug Configuration Register bits */
>> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
>> index 248339e..2d259e8 100644
>> --- a/arch/arm64/include/asm/sysreg.h
>> +++ b/arch/arm64/include/asm/sysreg.h
>> @@ -145,6 +145,7 @@
>>
>> #define SYS_ID_AA64PFR0_EL1 sys_reg(3, 0, 0, 4, 0)
>> #define SYS_ID_AA64PFR1_EL1 sys_reg(3, 0, 0, 4, 1)
>> +#define SYS_ID_AA64ZFR0_EL1 sys_reg(3, 0, 0, 4, 4)
>>
>> #define SYS_ID_AA64DFR0_EL1 sys_reg(3, 0, 0, 5, 0)
>> #define SYS_ID_AA64DFR1_EL1 sys_reg(3, 0, 0, 5, 1)
>> @@ -160,6 +161,8 @@
>> #define SYS_ACTLR_EL1 sys_reg(3, 0, 1, 0, 1)
>> #define SYS_CPACR_EL1 sys_reg(3, 0, 1, 0, 2)
>>
>> +#define SYS_ZCR_EL1 sys_reg(3, 0, 1, 2, 0)
>> +
>
> I'll have to take these on trust. They are mentioned in both the ARM ARM
> and the SVE supplement but I can't see any actual definitions of them.
>
>> #define SYS_TTBR0_EL1 sys_reg(3, 0, 2, 0, 0)
>> #define SYS_TTBR1_EL1 sys_reg(3, 0, 2, 0, 1)
>> #define SYS_TCR_EL1 sys_reg(3, 0, 2, 0, 2)
>> @@ -250,6 +253,8 @@
>>
>> #define SYS_PMCCFILTR_EL0 sys_reg (3, 3, 14, 15, 7)
>>
>> +#define SYS_ZCR_EL2 sys_reg(3, 4, 1, 2, 0)
>> +

OK no I'm working directly from the unpacked ZIP file with the rest of
the details I think this should be:

#define SYS_ZCR_EL2 sys_reg(3, 5, 1, 2, 0)

e.g. op1 = 101 / 5

>> #define SYS_DACR32_EL2 sys_reg(3, 4, 3, 0, 0)
>> #define SYS_IFSR32_EL2 sys_reg(3, 4, 5, 0, 1)
>> #define SYS_FPEXC32_EL2 sys_reg(3, 4, 5, 3, 0)
>> @@ -331,6 +336,7 @@
>> #define ID_AA64ISAR1_JSCVT_SHIFT 12
>>
>> /* id_aa64pfr0 */
>> +#define ID_AA64PFR0_SVE_SHIFT 32
>> #define ID_AA64PFR0_GIC_SHIFT 24
>> #define ID_AA64PFR0_ASIMD_SHIFT 20
>> #define ID_AA64PFR0_FP_SHIFT 16
>> @@ -339,6 +345,7 @@
>> #define ID_AA64PFR0_EL1_SHIFT 4
>> #define ID_AA64PFR0_EL0_SHIFT 0
>>
>> +#define ID_AA64PFR0_SVE 0x1
>> #define ID_AA64PFR0_FP_NI 0xf
>> #define ID_AA64PFR0_FP_SUPPORTED 0x0
>> #define ID_AA64PFR0_ASIMD_NI 0xf
>> @@ -440,6 +447,15 @@
>> #endif
>>
>>
>> +#define ZCR_ELx_LEN_SHIFT 0
>> +#define ZCR_ELx_LEN_SIZE 9
>> +#define ZCR_ELx_LEN_MASK 0x1ff
>> +

LEN should be 0/4/0xf

LEN, bits [3:0]

Constrains the scalable vector register length for EL1 and EL0 to (LEN+1)x128 bits.

>> +#define CPACR_EL1_ZEN_EL1EN (1 << 16)
>> +#define CPACR_EL1_ZEN_EL0EN (1 << 17)
>> +#define CPACR_EL1_ZEN (CPACR_EL1_ZEN_EL1EN |
>> CPACR_EL1_ZEN_EL0EN)
>
> This is a little weird as it is a 2 bit field in which 00 and 11 are not
> simply the sum of their bits. If the code wrote CPACR_EL1_ZEN_EL0EN |
> CPACR_EL1_ZEN_EL1EN to the CPACR_EL1 you wouldn't get the expected behaviour.
>
>> +
>> +
>> /* Safe value for MPIDR_EL1: Bit31:RES1, Bit30:U:0, Bit24:MT:0 */
>> #define SYS_MPIDR_SAFE_VAL (1UL << 31)
>>
>> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
>> index 0f047e9..8964795 100644
>> --- a/arch/arm64/kernel/traps.c
>> +++ b/arch/arm64/kernel/traps.c
>> @@ -621,6 +621,7 @@ static const char *esr_class_str[] = {
>> [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
>> [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
>> [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
>> + [ESR_ELx_EC_SVE] = "SVE",
>> [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
>> [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
>> [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",