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SubjectRe: [PATCH] arm64: Add support for new control bits CTR_EL0.IDC and CTR_EL0.IDC
Hi Shanker,

On Fri, Feb 16, 2018 at 06:57:46PM -0600, Shanker Donthineni wrote:
> Two point of unification cache maintenance operations 'DC CVAU' and
> 'IC IVAU' are optional for implementors as per ARMv8 specification.
> This patch parses the updated CTR_EL0 register definition and adds
> the required changes to skip POU operations if the hardware reports
> CTR_EL0.IDC and/or CTR_EL0.IDC.
>
> CTR_EL0.DIC: Instruction cache invalidation requirements for
> instruction to data coherence. The meaning of this bit[29].
> 0: Instruction cache invalidation to the point of unification
> is required for instruction to data coherence.
> 1: Instruction cache cleaning to the point of unification is
> not required for instruction to data coherence.
>
> CTR_EL0.IDC: Data cache clean requirements for instruction to data
> coherence. The meaning of this bit[28].
> 0: Data cache clean to the point of unification is required for
> instruction to data coherence, unless CLIDR_EL1.LoC == 0b000
> or (CLIDR_EL1.LoUIS == 0b000 && CLIDR_EL1.LoUU == 0b000).
> 1: Data cache clean to the point of unification is not required
> for instruction to data coherence.
>
> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
> Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
> ---
> arch/arm64/include/asm/assembler.h | 48 ++++++++++++++++++++++++--------------
> arch/arm64/include/asm/cache.h | 2 ++
> arch/arm64/kernel/cpufeature.c | 2 ++
> arch/arm64/mm/cache.S | 26 ++++++++++++++-------
> 4 files changed, 51 insertions(+), 27 deletions(-)

I was looking at our CTR_EL0 code last week but forgot to post the patch I
wrote fixing up some of the fields. I just send it now, so please can
you rebase on top of:

http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/560488.html

Also:

> diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
> index ea9bb4e..aea533b 100644
> --- a/arch/arm64/include/asm/cache.h
> +++ b/arch/arm64/include/asm/cache.h
> @@ -22,6 +22,8 @@
> #define CTR_L1IP_MASK 3
> #define CTR_CWG_SHIFT 24
> #define CTR_CWG_MASK 15
> +#define CTR_IDC_SHIFT 28
> +#define CTR_DIC_SHIFT 29
>
> #define CTR_L1IP(ctr) (((ctr) >> CTR_L1IP_SHIFT) & CTR_L1IP_MASK)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 29b1f87..f42bb5a 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -200,6 +200,8 @@ static int __init register_cpu_hwcaps_dumper(void)
>
> static const struct arm64_ftr_bits ftr_ctr[] = {
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RAO */
> + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DIC_SHIFT, 1, 0), /* DIC */
> + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IDC_SHIFT, 1, 0), /* IDC */
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, 24, 4, 0), /* CWG */
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0), /* ERG */
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 1), /* DminLine */

Could you update the other table entries here to use the CTR_*_SHIFT values
as well?

Thanks,

Will

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