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

Alex Bennée
2017-08-21T09:33:55Z

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)
> +
> #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
> +
> +#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)",

--
Alex Bennée