diff mbox series

[v3,1/6] arm64: Detect the ARMv8.4 TTL feature

Message ID 20200525125300.794-2-yezhenyu2@huawei.com (mailing list archive)
State New, archived
Headers show
Series arm64: tlb: add support for TTL feature | expand

Commit Message

Zhenyu Ye May 25, 2020, 12:52 p.m. UTC 
From: Marc Zyngier <maz@kernel.org>

In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL
feature allows TLBs to be issued with a level allowing for quicker
invalidation.

Let's detect the feature for now. Further patches will implement
its actual usage.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/cpucaps.h |  3 ++-
 arch/arm64/include/asm/sysreg.h  |  1 +
 arch/arm64/kernel/cpufeature.c   | 11 +++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

Comments

Anshuman Khandual May 26, 2020, 2:39 a.m. UTC | #1 
Hello Zhenyu,

On 05/25/2020 06:22 PM, Zhenyu Ye wrote:
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index c4ac0ac25a00..477d84ba1056 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -725,6 +725,7 @@
>  
>  /* id_aa64mmfr2 */
>  #define ID_AA64MMFR2_E0PD_SHIFT		60
> +#define ID_AA64MMFR2_TTL_SHIFT		48
>  #define ID_AA64MMFR2_FWB_SHIFT		40
>  #define ID_AA64MMFR2_AT_SHIFT		32
>  #define ID_AA64MMFR2_LVA_SHIFT		16
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 9fac745aa7bb..d993dc6dc7d5 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -244,6 +244,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
>  
>  static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
>  	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_E0PD_SHIFT, 4, 0),
> +	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_TTL_SHIFT, 4, 0),
>  	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
>  	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
>  	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
> @@ -1622,6 +1623,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
>  		.matches = has_cpuid_feature,
>  		.cpu_enable = cpu_has_fwb,
>  	},

This patch (https://patchwork.kernel.org/patch/11557359/) is adding some
more ID_AA64MMFR2 features including the TTL. I am going to respin parts
of the V4 series patches along with the above mentioned patch. So please
rebase this series accordingly, probably on latest next.

- Anshuman
Zhenyu Ye May 26, 2020, 6:40 a.m. UTC | #2 
Hi Anshuman,

On 2020/5/26 10:39, Anshuman Khandual wrote:
> This patch (https://patchwork.kernel.org/patch/11557359/) is adding some
> more ID_AA64MMFR2 features including the TTL. I am going to respin parts
> of the V4 series patches along with the above mentioned patch. So please
> rebase this series accordingly, probably on latest next.
> 

I noticed that some patches of your series have been merged into arm64
tree (for-next/cpufeature), such as TLB range, but this one not. Why?

BTW, this patch is provided by Marc in his NV series [1], maybe you
should also let him know.

I will rebase my series after your patch is merged.

[1] https://lore.kernel.org/linux-arm-kernel/d6032191-ba0e-82a4-4dde-11beef369a11@arm.com/

Thanks,
Zhenyu
Marc Zyngier May 26, 2020, 10:06 a.m. UTC | #3 
On 2020-05-26 07:40, Zhenyu Ye wrote:
> Hi Anshuman,
> 
> On 2020/5/26 10:39, Anshuman Khandual wrote:
>> This patch (https://patchwork.kernel.org/patch/11557359/) is adding 
>> some
>> more ID_AA64MMFR2 features including the TTL. I am going to respin 
>> parts
>> of the V4 series patches along with the above mentioned patch. So 
>> please
>> rebase this series accordingly, probably on latest next.

No. Please.

>> 
> 
> I noticed that some patches of your series have been merged into arm64
> tree (for-next/cpufeature), such as TLB range, but this one not. Why?
> 
> BTW, this patch is provided by Marc in his NV series [1], maybe you
> should also let him know.
> 
> I will rebase my series after your patch is merged.

Please don't rebase on -next. That's the worse thing to do. Always base
your series on a well known -rc, and stick to that. Maintainers can
always do the rebase and resolve conflicts.

Thanks,

         M.
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 8eb5a088ae65..cabb0c49a1d1 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -61,7 +61,8 @@ 
 #define ARM64_HAS_AMU_EXTN			51
 #define ARM64_HAS_ADDRESS_AUTH			52
 #define ARM64_HAS_GENERIC_AUTH			53
+#define ARM64_HAS_ARMv8_4_TTL			54
 
-#define ARM64_NCAPS				54
+#define ARM64_NCAPS				55
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index c4ac0ac25a00..477d84ba1056 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -725,6 +725,7 @@ 
 
 /* id_aa64mmfr2 */
 #define ID_AA64MMFR2_E0PD_SHIFT		60
+#define ID_AA64MMFR2_TTL_SHIFT		48
 #define ID_AA64MMFR2_FWB_SHIFT		40
 #define ID_AA64MMFR2_AT_SHIFT		32
 #define ID_AA64MMFR2_LVA_SHIFT		16
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9fac745aa7bb..d993dc6dc7d5 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -244,6 +244,7 @@  static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_E0PD_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_TTL_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
@@ -1622,6 +1623,16 @@  static const struct arm64_cpu_capabilities arm64_features[] = {
 		.matches = has_cpuid_feature,
 		.cpu_enable = cpu_has_fwb,
 	},
+	{
+		.desc = "ARMv8.4 Translation Table Level",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HAS_ARMv8_4_TTL,
+		.sys_reg = SYS_ID_AA64MMFR2_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR2_TTL_SHIFT,
+		.min_field_value = 1,
+		.matches = has_cpuid_feature,
+	},
 #ifdef CONFIG_ARM64_HW_AFDBM
 	{
 		/*