On 31 July 2014 11:57, Will Deacon [off-list ref] wrote:

Hi Ard,

On Thu, Jul 31, 2014 at 09:56:42AM +0100, Ard Biesheuvel wrote:

quoted

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 <redacted>
---
 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