[PATCH] arm64: defconfig: enable crypto drivers as modules

[Ard Biesheuvel]

On 31 July 2014 11:57, Will Deacon <will.deacon at arm.com> wrote:
> Hi Ard,
>
> On Thu, Jul 31, 2014 at 09:56:42AM +0100, Ard Biesheuvel wrote:
>> This changes the arm64 defconfig to build the ARMv8 Crypto Extensions
>> and NEON based crypto drivers as modules rather than as built-ins. The
>> reason is that the ARMv8 Crypto Extensions based modules will be probed
>> for automatically through udev upon detecting the availability of the
>> respective crypto instructions (AES, PMULL, SHA1, SHA256), and similarly,
>> the NEON alternatives will be probed for upon request (i.e., at first use
>> of the algorithm) if no hardware acceleration is available.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> ---
>>  arch/arm64/configs/defconfig | 14 +++++++-------
>>  1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
>> index c1071268c912..3310b4166dd0 100644
>> --- a/arch/arm64/configs/defconfig
>> +++ b/arch/arm64/configs/defconfig
>> @@ -127,10 +127,10 @@ CONFIG_LOCKUP_DETECTOR=y
>>  CONFIG_SECURITY=y
>>  CONFIG_CRYPTO_ANSI_CPRNG=y
>>  CONFIG_ARM64_CRYPTO=y
>> -CONFIG_CRYPTO_SHA1_ARM64_CE=y
>> -CONFIG_CRYPTO_SHA2_ARM64_CE=y
>> -CONFIG_CRYPTO_GHASH_ARM64_CE=y
>> -CONFIG_CRYPTO_AES_ARM64_CE=y
>> -CONFIG_CRYPTO_AES_ARM64_CE_CCM=y
>> -CONFIG_CRYPTO_AES_ARM64_CE_BLK=y
>> -CONFIG_CRYPTO_AES_ARM64_NEON_BLK=y
>> +CONFIG_CRYPTO_SHA1_ARM64_CE=m
>> +CONFIG_CRYPTO_SHA2_ARM64_CE=m
>> +CONFIG_CRYPTO_GHASH_ARM64_CE=m
>> +CONFIG_CRYPTO_AES_ARM64_CE=m
>> +CONFIG_CRYPTO_AES_ARM64_CE_CCM=m
>> +CONFIG_CRYPTO_AES_ARM64_CE_BLK=m
>> +CONFIG_CRYPTO_AES_ARM64_NEON_BLK=m
>
> Whilst I'm usually fairly open to defconfig updates if they make things more
> useful to people, I think building these as modules is going to be a pain
> for those not using udev (i.e. using busybox and/or simple filesystems for a
> VM). This seems more like something a distro might choose to do as opposed
> to something that is a good idea to have enabled by default.
>
> There could be an argument for a distroconfig, but I don't have high hopes
> that anybody would actually use it in practice.
>

OK, fair enough