Re: [PATCH V3 06/16] arm64/cpufeature: Introduce ID_MMFR5 CPU register

From: Will Deacon
Date: Mon May 04 2020 - 16:33:21 EST


On Sat, May 02, 2020 at 07:03:55PM +0530, Anshuman Khandual wrote:
> This adds basic building blocks required for ID_MMFR5 CPU register which
> provides information about the implemented memory model and memory
> management support in AArch32 state. This is added per ARM DDI 0487F.a
> specification.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
>
> Suggested-by: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> arch/arm64/include/asm/cpu.h | 1 +
> arch/arm64/include/asm/sysreg.h | 3 +++
> arch/arm64/kernel/cpufeature.c | 10 ++++++++++
> arch/arm64/kernel/cpuinfo.c | 1 +
> arch/arm64/kvm/sys_regs.c | 2 +-
> 5 files changed, 16 insertions(+), 1 deletion(-)

[...]

> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 2ce952d9668d..c790cc200bb1 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -403,6 +403,11 @@ static const struct arm64_ftr_bits ftr_id_isar4[] = {
> ARM64_FTR_END,
> };
>
> +static const struct arm64_ftr_bits ftr_id_mmfr5[] = {
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_MMFR5_ETS_SHIFT, 4, 0),
> + ARM64_FTR_END,
> +};
> +
> static const struct arm64_ftr_bits ftr_id_isar6[] = {
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_I8MM_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR6_BF16_SHIFT, 4, 0),
> @@ -527,6 +532,7 @@ static const struct __ftr_reg_entry {
> ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),
> ARM64_FTR_REG(SYS_ID_PFR2_EL1, ftr_id_pfr2),
> ARM64_FTR_REG(SYS_ID_DFR1_EL1, ftr_id_dfr1),
> + ARM64_FTR_REG(SYS_ID_MMFR5_EL1, ftr_id_mmfr5),
>
> /* Op1 = 0, CRn = 0, CRm = 4 */
> ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
> @@ -732,6 +738,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
> init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
> init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
> init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
> + init_cpu_ftr_reg(SYS_ID_MMFR5_EL1, info->reg_id_mmfr5);
> init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
> init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
> init_cpu_ftr_reg(SYS_ID_PFR2_EL1, info->reg_id_pfr2);
> @@ -866,6 +873,8 @@ static int update_32bit_cpu_features(int cpu, struct cpuinfo_arm64 *info,
> info->reg_id_mmfr2, boot->reg_id_mmfr2);
> taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
> info->reg_id_mmfr3, boot->reg_id_mmfr3);

Looks like MMFR4 is missing here?

> + taint |= check_update_ftr_reg(SYS_ID_MMFR5_EL1, cpu,
> + info->reg_id_mmfr5, boot->reg_id_mmfr5);

Will