meta-aspeed: Add socsec SPL signing for AST2600

Add the necessary build infrastructure to allow ASPEED AST2600 devices
to use socsec to sign the U-boot SPL, allowing Aspeed's Verified Boot to
validate it.

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
Change-Id: I7b38a59596819982f0a222812fcc64dfb91e104f

2 files changed, 67 insertions, 0 deletions

diff --git a/meta-aspeed/classes/socsec-sign.bbclass b/meta-aspeed/classes/socsec-sign.bbclass
new file mode 100644
index 000000000..1b1576592
--- /dev/null
+++ b/meta-aspeed/classes/socsec-sign.bbclass
@@ -0,0 +1,66 @@
+# ASPEED AST2600 devices can use Aspeed's utility 'socsec'
+# to sign the SPL (pubkey written to OTP region)
+# The variables below carry default values to the spl_sign()
+# function below.
+SOCSEC_SIGN_ENABLE ?= "0"
+SOCSEC_SIGN_KEY ?= ""
+SOCSEC_SIGN_SOC ?= "2600"
+SOCSEC_SIGN_ALGO ?= "RSA4096_SHA512"
+SOCSEC_SIGN_HELPER ?= ""
+# u-boot-aspeed-sdk commit '2c3b53489c ast2600: Modify SPL SRAM layout'
+# changes the SDRAM layout so that the verification region does NOT
+# intersects the stack. The parameter below can be used to instruct
+# socsec to work in either mode (ommitting it throws a warning), but
+# newer (post v00.03.03) u-boot-aspeed-sdk need this set to false
+SOCSEC_SIGN_EXTRA_OPTS ?= "--stack_intersects_verification_region=false"
+DEPENDS += '${@oe.utils.conditional("SOCSEC_SIGN_ENABLE", "1", " socsec-native", "", d)}'
+
+
+# Signs the SPL binary with a pre-established key
+sign_spl_helper() {
+    signing_helper_args=""
+
+    if [ "${SOC_FAMILY}" != "aspeed-g6" ] ; then
+        echo "Warning: SPL signing is only supported on AST2600 boards"
+    elif [ ! -e "${SOCSEC_SIGN_KEY}" ] ; then
+        echo "Warning: Invalid socsec signing key - SPL verified boot won't be available"
+    else
+        rm -f ${SPL_BINARY}.staged
+
+        if [ -n "${SOCSEC_SIGN_HELPER}" ] ; then
+            signing_helper_args="--signing_helper ${SOCSEC_SIGN_HELPER}"
+        fi
+        socsec make_secure_bl1_image \
+            --soc ${SOCSEC_SIGN_SOC}  \
+            --algorithm ${SOCSEC_SIGN_ALGO} \
+            --rsa_sign_key ${SOCSEC_SIGN_KEY} \
+            --bl1_image ${DEPLOYDIR}/${SPL_IMAGE} \
+            ${signing_helper_args} \
+            ${SOCSEC_SIGN_EXTRA_OPTS} \
+            --output ${SPL_BINARY}.staged
+        cp -f ${SPL_BINARY}.staged ${B}/${CONFIG_B_PATH}/${SPL_BINARY}
+        mv -f ${SPL_BINARY}.staged ${DEPLOYDIR}/${SPL_IMAGE}
+    fi
+}
+
+sign_spl() {
+    mkdir -p ${DEPLOYDIR}
+    if [ -n "${UBOOT_CONFIG}" ]; then
+        for config in ${UBOOT_MACHINE}; do
+            CONFIG_B_PATH="${config}"
+            cd ${B}/${config}
+            sign_spl_helper
+        done
+    else
+        CONFIG_B_PATH=""
+        cd ${B}
+        sign_spl_helper
+    fi
+}
+
+
+do_deploy_append() {
+    if [ "${SOCSEC_SIGN_ENABLE}" = "1" -a -n "${SPL_BINARY}" ] ; then
+        sign_spl
+    fi
+}
diff --git a/meta-aspeed/recipes-bsp/u-boot/u-boot-aspeed-sdk_2019.04.bb b/meta-aspeed/recipes-bsp/u-boot/u-boot-aspeed-sdk_2019.04.bb
index 99bcafc09..54884b0f1 100644
--- a/meta-aspeed/recipes-bsp/u-boot/u-boot-aspeed-sdk_2019.04.bb
+++ b/meta-aspeed/recipes-bsp/u-boot/u-boot-aspeed-sdk_2019.04.bb
@@ -3,6 +3,7 @@ require u-boot-common-aspeed-sdk_${PV}.inc
 UBOOT_MAKE_TARGET ?= "DEVICE_TREE=${UBOOT_DEVICETREE}"
 
 require u-boot-aspeed.inc
+inherit socsec-sign
 
 PROVIDES += "u-boot"
 DEPENDS += "bc-native dtc-native"