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

["Alex Bennée" <alex.bennee@linaro.org>]

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