1 files changed, 37 insertions, 2 deletions

diff --git a/meta/classes/kernel-yocto.bbclass b/meta/classes/kernel-yocto.bbclass
index 1e226a5722..14551a23f2 100644
--- a/meta/classes/kernel-yocto.bbclass
+++ b/meta/classes/kernel-yocto.bbclass
@@ -56,6 +56,7 @@ def get_machine_branch(d, default):
     return default
 
 do_kernel_metadata() {
+        set +e
         cd ${S}
         export KMETA=${KMETA}
 
@@ -75,6 +76,41 @@ do_kernel_metadata() {
                 machine_srcrev="${SRCREV}"
         fi
 
+        # In a similar manner to the kernel itself:
+        #
+        #   defconfig: $(obj)/conf
+        #   ifeq ($(KBUILD_DEFCONFIG),)
+        #       $< --defconfig $(Kconfig)
+        #   else
+        #       @echo "*** Default configuration is based on '$(KBUILD_DEFCONFIG)'"
+        #       $(Q)$< --defconfig=arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG) $(Kconfig)
+        #   endif
+        #
+        # If a defconfig is specified via the KBUILD_DEFCONFIG variable, we copy it
+        # from the source tree, into a common location and normalized "defconfig" name,
+        # where the rest of the process will include and incoroporate it into the build
+        #
+        # If the fetcher has already placed a defconfig in WORKDIR (from the SRC_URI),
+        # we don't overwrite it, but instead warn the user that SRC_URI defconfigs take
+        # precendence.
+        #
+        if [ -n "${KBUILD_DEFCONFIG}" ]; then
+                if [ -f "${S}/arch/${ARCH}/configs/${KBUILD_DEFCONFIG}" ]; then
+                        if [ -f "${WORKDIR}/defconfig" ]; then
+                                # If the two defconfigs are the same, leave the existing one in place
+                                cmp "${WORKDIR}/defconfig" "${S}/arch/${ARCH}/configs/${KBUILD_DEFCONFIG}"
+                                if [ $? -ne 0 ]; then
+                                        bbnote "defconfig detected in WORKDIR. ${KBUILD_DEFCONFIG} skipped"
+                                else
+                                        cp -f ${S}/arch/${ARCH}/configs/${KBUILD_DEFCONFIG} ${WORKDIR}/defconfig
+                                        sccs="${WORKDIR}/defconfig"
+                                fi
+                        fi
+                else
+                        bbfatal "A KBUILD_DECONFIG '${KBUILD_DEFCONFIG}' was specified, but not present in the source tree"
+                fi
+        fi
+
         # if we have a defined/set meta branch we should not be generating
         # any meta data. The passed branch has what we need.
         if [ -n "${KMETA}" ]; then
@@ -86,11 +122,10 @@ do_kernel_metadata() {
                 bbfatal "Could not create ${machine_branch}"
         fi
 
-        sccs="${@" ".join(find_sccs(d))}"
+        sccs="$sccs ${@" ".join(find_sccs(d))}"
         patches="${@" ".join(find_patches(d))}"
         feat_dirs="${@" ".join(find_kernel_feature_dirs(d))}"
 
-        set +e
         # add any explicitly referenced features onto the end of the feature
         # list that is passed to the kernel build scripts.
         if [ -n "${KERNEL_FEATURES}" ]; then