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Message-ID: <71c63813-bbf1-8baa-3b94-f5184cc5e872@linux.ibm.com>
Date:   Thu, 13 Apr 2023 08:18:12 -0500
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Subject: Re: [PATCH] Remove POWER10_CPU dependency and move
 PPC_MODULE_FEATURE_P10.
Content-Language: en-US
To:     Michael Ellerman <mpe@ellerman.id.au>, linux-crypto@vger.kernel.org
Cc:     herbert@gondor.apana.org.au, leitao@debian.org,
        nayna@linux.ibm.com, appro@cryptogams.org,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        ltcgcw@linux.vnet.ibm.com, dtsen@us.ibm.com
References: <20230412181232.2051-1-dtsen@linux.ibm.com>
 <87wn2g9b9l.fsf@mpe.ellerman.id.au>
From:   Danny Tsen <dtsen@linux.ibm.com>
In-Reply-To: <87wn2g9b9l.fsf@mpe.ellerman.id.au>
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Hi Michael,

If I do separate patch for moving PPC_MODULE_FEATURE_P10, this will 
break the build since it is currently defined in aes-gcm-p10-glue.c.  
And the p10 will be detected when loading the module in 
module_cpu_feature_match(PPC_MODULE_FEATURE_P10, p10_init); so it won't 
load if it's not P10.

Thanks.

-Danny

On 4/13/23 8:12 AM, Michael Ellerman wrote:
> Danny Tsen <dtsen@linux.ibm.com> writes:
>> Remove Power10 dependency in Kconfig and detect Power10 feature at runtime.
>> Move PPC_MODULE_FEATURE_P10 definition to be in
>> arch/powerpc/include/asm/cpufeature.h.
> This should be two patches, one for the Kconfig change and one moving
> the feature flag.
>
> Also don't you need a cpu feature check in p10_init()? Otherwise the
> driver can be loaded on non-P10 CPUs, either by being built-in, or
> manually.
>
> cheers
>
>> Signed-off-by: Danny Tsen <dtsen@linux.ibm.com>
>> ---
>>   arch/powerpc/crypto/Kconfig            | 2 +-
>>   arch/powerpc/crypto/aes-gcm-p10-glue.c | 1 -
>>   arch/powerpc/include/asm/cpufeature.h  | 1 +
>>   3 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/crypto/Kconfig b/arch/powerpc/crypto/Kconfig
>> index 1f8f02b494e1..7113f9355165 100644
>> --- a/arch/powerpc/crypto/Kconfig
>> +++ b/arch/powerpc/crypto/Kconfig
>> @@ -96,7 +96,7 @@ config CRYPTO_AES_PPC_SPE
>>   
>>   config CRYPTO_AES_GCM_P10
>>   	tristate "Stitched AES/GCM acceleration support on P10 or later CPU (PPC)"
>> -	depends on PPC64 && POWER10_CPU && CPU_LITTLE_ENDIAN
>> +	depends on PPC64 && CPU_LITTLE_ENDIAN
>>   	select CRYPTO_LIB_AES
>>   	select CRYPTO_ALGAPI
>>   	select CRYPTO_AEAD
>> diff --git a/arch/powerpc/crypto/aes-gcm-p10-glue.c b/arch/powerpc/crypto/aes-gcm-p10-glue.c
>> index 1533c8cdd26f..bd3475f5348d 100644
>> --- a/arch/powerpc/crypto/aes-gcm-p10-glue.c
>> +++ b/arch/powerpc/crypto/aes-gcm-p10-glue.c
>> @@ -22,7 +22,6 @@
>>   #include <linux/module.h>
>>   #include <linux/types.h>
>>   
>> -#define PPC_MODULE_FEATURE_P10	(32 + ilog2(PPC_FEATURE2_ARCH_3_1))
>>   #define	PPC_ALIGN		16
>>   #define GCM_IV_SIZE		12
>>   
>> diff --git a/arch/powerpc/include/asm/cpufeature.h b/arch/powerpc/include/asm/cpufeature.h
>> index f6f790a90367..2dcc66225e7f 100644
>> --- a/arch/powerpc/include/asm/cpufeature.h
>> +++ b/arch/powerpc/include/asm/cpufeature.h
>> @@ -22,6 +22,7 @@
>>    */
>>   
>>   #define PPC_MODULE_FEATURE_VEC_CRYPTO			(32 + ilog2(PPC_FEATURE2_VEC_CRYPTO))
>> +#define PPC_MODULE_FEATURE_P10				(32 + ilog2(PPC_FEATURE2_ARCH_3_1))
>>   
>>   #define cpu_feature(x)		(x)
>>   
>> -- 
>> 2.31.1