kernel-fitimage: allow overriding FIT configuration prefix

The prefix was recently changed to play ball with the CVE-2021-27138
workaround in U-Boot. Already deployed bootloaders though may still
expect a configuration name containing @ or they may not be affected
by this issue.

Also, uses may want to customize it beyond the [@-] issue: When
device trees are built from a recipe using kernel-devicetree.bbclass
the configuration nodes will contain the parent directories, e.g.

KERNEL_DEVICETREE = "freescale/imx8mm-myboard.dtb"

will become "conf-freescale_imx8mm-myboard.dtb". When moving to
devicetree.bbclass, this prefix go away. With this change here,
users can restore it easily by setting FIT_CONF_PREFIX =
"conf-freescale_", ensuring backwards compatibility.

(From OE-Core rev: 7892ee3dc37d302c8eb9c13cd8bb4b7b6e103949)

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/meta/classes/kernel-fitimage.bbclass b/meta/classes/kernel-fitimage.bbclass
index c16977c477..8a9b195d6e 100644
--- a/meta/classes/kernel-fitimage.bbclass
+++ b/meta/classes/kernel-fitimage.bbclass
@@ -64,6 +64,9 @@ FIT_DESC ?= "Kernel fitImage for ${DISTRO_NAME}/${PV}/${MACHINE}"
 # Sign individual images as well
 FIT_SIGN_INDIVIDUAL ?= "0"
 
+FIT_CONF_PREFIX ?= "conf-"
+FIT_CONF_PREFIX[doc] = "Prefix to use for FIT configuration node name"
+
 # Keys used to sign individually image nodes.
 # The keys to sign image nodes must be different from those used to sign
 # configuration nodes, otherwise the "required" property, from
@@ -358,7 +361,7 @@ fitimage_emit_section_config() {
         # Test if we have any DTBs at all
         sep=""
         conf_desc=""
-        conf_node="conf-"
+        conf_node="${FIT_CONF_PREFIX}"
         kernel_line=""
         fdt_line=""
         ramdisk_line=""
@@ -407,9 +410,9 @@ fitimage_emit_section_config() {
                 # default node is selected based on dtb ID if it is present,
                 # otherwise its selected based on kernel ID
                 if [ -n "$dtb_image" ]; then
-                        default_line="default = \"conf-$dtb_image\";"
+                        default_line="default = \"${FIT_CONF_PREFIX}$dtb_image\";"
                 else
-                        default_line="default = \"conf-$kernel_id\";"
+                        default_line="default = \"${FIT_CONF_PREFIX}$kernel_id\";"
                 fi
         fi