Re: [meta-ti][master][PATCH v4 1/3] linux-ti-staging: Add LUKS encryption config

On Thu Mar 5, 2026 at 3:12 PM CST, Denys Dmytriyenko wrote:
> On Thu, Mar 05, 2026 at 02:51:44PM -0600, Ryan Eatmon via lists.yoctoproject.org wrote:
>> 
>> 
>> On 3/5/2026 11:21 AM, Shiva Tripathi wrote:
>> >Add conditional kernel configuration fragment for LUKS encryption with
>> >fTPM support. This enables dm-crypt and necessary crypto algorithms
>> >when MACHINE_FEATURES contains 'luks-encryption'.
>> >
>> >Signed-off-by: Shiva Tripathi <[email protected]>
>> >---
>> >  .../linux/linux-ti-staging-6.18/luks-ftpm.cfg | 28 +++++++++++++++++++
>> >  .../linux/linux-ti-staging_6.18.bb            |  9 ++++++
>> >  2 files changed, 37 insertions(+)
>> >  create mode 100644 meta-ti-bsp/recipes-kernel/linux/linux-ti-staging-6.18/luks-ftpm.cfg
>> >
>> >diff --git a/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging-6.18/luks-ftpm.cfg b/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging-6.18/luks-ftpm.cfg
>> >new file mode 100644
>> >index 00000000..234cc087
>> >--- /dev/null
>> >+++ b/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging-6.18/luks-ftpm.cfg
>> >@@ -0,0 +1,28 @@
>> >+# Device Mapper support
>> >+CONFIG_MD=y
>> >+CONFIG_BLK_DEV_DM=y
>> >+CONFIG_DM_CRYPT=y
>> >+
>> >+# Crypto algorithms for LUKS
>> >+CONFIG_CRYPTO_XTS=y
>> >+CONFIG_CRYPTO_AES=y
>> >+CONFIG_CRYPTO_AES_ARM64=y
>> >+CONFIG_CRYPTO_AES_ARM64_CE=y
>> >+CONFIG_CRYPTO_AES_ARM64_CE_BLK=y
>> >+CONFIG_CRYPTO_SHA256=y
>> >+CONFIG_CRYPTO_SHA256_ARM64=y
>> >+CONFIG_CRYPTO_SHA512=y
>> >+CONFIG_CRYPTO_USER_API_HASH=y
>> >+CONFIG_CRYPTO_USER_API_SKCIPHER=y
>> >+
>> >+# Additional crypto support for LUKS2
>> >+CONFIG_CRYPTO_CBC=y
>> >+CONFIG_CRYPTO_ECB=y
>> >+CONFIG_CRYPTO_ESSIV=y
>> >+CONFIG_CRYPTO_LRW=y
>> >+CONFIG_CRYPTO_PCBC=y
>> >+
>> >+# TPM kernel modules needed for initramfs
>> >+CONFIG_TCG_TIS_CORE=m
>> >+CONFIG_TCG_CRB=m
>> >+
>> >diff --git a/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging_6.18.bb b/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging_6.18.bb
>> >index 8e4ccd7d..69d6217f 100644
>> >--- a/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging_6.18.bb
>> >+++ b/meta-ti-bsp/recipes-kernel/linux/linux-ti-staging_6.18.bb
>> >@@ -35,3 +35,12 @@ module_conf_rpmsg_client_sample = "blacklist rpmsg_client_sample"
>> >  module_conf_ti_k3_r5_remoteproc = "softdep ti_k3_r5_remoteproc pre: virtio_rpmsg_bus"
>> >  module_conf_ti_k3_dsp_remoteproc = "softdep ti_k3_dsp_remoteproc pre: virtio_rpmsg_bus"
>> >  KERNEL_MODULE_PROBECONF += "rpmsg_client_sample ti_k3_r5_remoteproc ti_k3_dsp_remoteproc"
>> >+
>> 
>> After thinking about this a little more... I'm thinking that the
>> luks-encryption is more of a DISTRO_FEATURE and not a
>> MACHINE_FEATURE. "tpm" would be a MACHINE_FEATURE.
>
> This was the first thought I had - it's a distro feature.
>
>
>> And the best most correct thing to do would be to do some
>> combination of the two.  I assume that only some of our boards have
>> tpm support, right?
>
> On the other hand, isn't fTPM a software-only implementation of TPM?
>

Yeah, though they should behave the same in userspace. It seems like there is a
bug preventing systemd-cryptenroll from working in our case though. Obviously
there are some quirks here.

>> So I would go through the effort to add that to all of the correct
>> boards, and then change the logic to check both variables.  I'll
>> reply on the other patches with those changes.
>> 
>> 
>> >+# LUKS encryption with fTPM kernel configuration
>> >+SRC_URI:append:k3 = " \
>> >+    ${@bb.utils.contains('MACHINE_FEATURES', 'luks-encryption', 'file://luks-ftpm.cfg', '', d)} \
>> 
>> ${@bb.utils.contains('DISTRO_FEATURES', 'luks',
>> 'file://luks-ftpm.cfg', '', d)}
>> 
>> 
>> >+"
>> >+KERNEL_CONFIG_FRAGMENTS:append:k3 = " \
>> >+    ${@bb.utils.contains('MACHINE_FEATURES', 'luks-encryption', '${UNPACKDIR}/luks-ftpm.cfg', '', d)} \
>> >+"
>> >+
>> 
>> ${@bb.utils.contains('DISTRO_FEATURES', 'luks',
>> '${UNPACKDIR}/luks-ftpm.cfg', '', d)}