Re: [RFC PATCH v3 1/2] arm64: tlb: Detect the ARMv8.4 TLBI RANGE feature

[Zhenyu Ye]

On 2020/5/5 18:14, Mark Rutland wrote:
> On Tue, Apr 14, 2020 at 07:28:34PM +0800, Zhenyu Ye wrote:
>> ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
>> range of input addresses. This patch detect this feature.
>>
>> Signed-off-by: Zhenyu Ye <yezhenyu2@xxxxxxxxxx>
>> ---
>>  arch/arm64/include/asm/cpucaps.h |  3 ++-
>>  arch/arm64/include/asm/sysreg.h  |  4 ++++
>>  arch/arm64/kernel/cpufeature.c   | 11 +++++++++++
>>  3 files changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
>> index 8eb5a088ae65..950095a72617 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_TLBI_RANGE			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 ebc622432831..ac1b98650234 100644
>> --- a/arch/arm64/include/asm/sysreg.h
>> +++ b/arch/arm64/include/asm/sysreg.h
>> @@ -592,6 +592,7 @@
>>  
>>  /* id_aa64isar0 */
>>  #define ID_AA64ISAR0_RNDR_SHIFT		60
>> +#define ID_AA64ISAR0_TLBI_RANGE_SHIFT	56
>>  #define ID_AA64ISAR0_TS_SHIFT		52
>>  #define ID_AA64ISAR0_FHM_SHIFT		48
>>  #define ID_AA64ISAR0_DP_SHIFT		44
>> @@ -605,6 +606,9 @@
>>  #define ID_AA64ISAR0_SHA1_SHIFT		8
>>  #define ID_AA64ISAR0_AES_SHIFT		4
>>  
>> +#define ID_AA64ISAR0_TLBI_RANGE_NI	0x0
>> +#define ID_AA64ISAR0_TLBI_RANGE		0x2
>> +
>>  /* id_aa64isar1 */
>>  #define ID_AA64ISAR1_I8MM_SHIFT		52
>>  #define ID_AA64ISAR1_DGH_SHIFT		48
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index 9fac745aa7bb..31bcfd0722b5 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -124,6 +124,7 @@ static bool __system_matches_cap(unsigned int n);
>>   */
>>  static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
>>  	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RNDR_SHIFT, 4, 0),
>> +	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TLBI_RANGE_SHIFT, 4, 0),
> 
> This should be FTR_HIDDEN as userspace has no reason to see this.
> 
> Otherwise this all seems to match the ARM ARM.
> 
> Mark.
> 

OK, I will change it to FTR_HIDDEN in next version series.

Thanks,
Zhenyu