kernel/image/depmodwrapper: Fixups for depmod

With the rpm package backend enabled, running:

bitbake <image>
bitbake virtual/kernel -c clean
bitbake <image> -c rootfs -f

results in an image with incorrect kernel module dependency information.
The problem is that the System.map and kernel-abiversion files are needed
for depmod and after the recent kernel changes, these are no longer in
sstate.

Its reasonable to require the kernel to unpack/build if you're
about to build a module against it. It is not reasonable to require this
just to build a rootfs.

Therefore stash the needed files specifically for depmod.

Also fix some STAGING_KERNEL_DIR references which were incorrect, found
whilst sorting through his change.

(From OE-Core rev: b851504dcf5e147c9efb1c7b6a4d22c1a1a87cd7)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/image.bbclass

@@ -95,7 +95,7 @@ def rootfs_variables(d):
                  'SDK_OUTPUT','SDKPATHNATIVE','SDKTARGETSYSROOT','SDK_DIR','SDK_VENDOR','SDKIMAGE_INSTALL_COMPLEMENTARY','SDK_PACKAGE_ARCHS','SDK_OUTPUT','SDKTARGETSYSROOT','MULTILIBRE_ALLOW_REP',
                  'MULTILIB_TEMP_ROOTFS','MULTILIB_VARIANTS','MULTILIBS','ALL_MULTILIB_PACKAGE_ARCHS','MULTILIB_GLOBAL_VARIANTS','BAD_RECOMMENDATIONS','NO_RECOMMENDATIONS','PACKAGE_ARCHS',
                  'PACKAGE_CLASSES','TARGET_VENDOR','TARGET_VENDOR','TARGET_ARCH','TARGET_OS','OVERRIDES','BBEXTENDVARIANT','FEED_DEPLOYDIR_BASE_URI','INTERCEPT_DIR','BUILDNAME','USE_DEVFS',
-                 'STAGING_KERNEL_DIR','COMPRESSIONTYPES']
+                 'COMPRESSIONTYPES']
     variables.extend(command_variables(d))
     variables.extend(variable_depends(d))
     return " ".join(variables)

meta/classes/kernel-module-split.bbclass

@@ -75,7 +75,7 @@ python split_kernel_module_packages () {
         if not os.path.exists(system_map_file):
             system_map_file = "%s/System.map-%s" % (staging_kernel_dir, kernelver)
             if not os.path.exists(system_map_file):
-                bb.fatal("System.map-%s does not exist in '%s/boot' nor STAGING_KERNEL_DIR '%s'" % (kernelver, dvar, staging_kernel_dir))
+                bb.fatal("System.map-%s does not exist in '%s/boot' nor STAGING_KERNEL_BUILDDIR '%s'" % (kernelver, dvar, staging_kernel_dir))
 
         cmd = "depmod -n -a -b %s -F %s %s" % (dvar, system_map_file, kernelver_stripped)
         f = os.popen(cmd, 'r')

meta/classes/kernel.bbclass

@@ -231,6 +231,11 @@ kernel_do_install() {
 	[ -e Module.symvers ] && install -m 0644 Module.symvers ${D}/boot/Module.symvers-${KERNEL_VERSION}
 	install -d ${D}${sysconfdir}/modules-load.d
 	install -d ${D}${sysconfdir}/modprobe.d
+
+	# Stash data for depmod
+	install -d ${D}${datadir}/kernel-depmod/
+	echo "${KERNEL_VERSION}" > ${D}${datadir}/kernel-depmod/kernel-abiversion
+	cp System.map ${D}${datadir}/kernel-depmod/System.map-${KERNEL_VERSION}
 }
 do_install[prefuncs] += "package_get_auto_pr"
 
@@ -280,14 +285,21 @@ do_shared_workdir () {
 	fi
 }
 
-# We have an empty sysroot_stage_all to keep the default routine from
-# package.bbclass from expanding the kernel source into the sysroot and
-# colliding with linux-firmware files
+# Only stage the files we need for depmod, not the modules/firmware
 sysroot_stage_all () {
+	sysroot_stage_dir ${D}${datadir}/kernel-depmod ${SYSROOT_DESTDIR}${datadir}/kernel-depmod
 }
 
 KERNEL_CONFIG_COMMAND ?= "oe_runmake_call -C ${S} O=${B} oldnoconfig || yes '' | oe_runmake -C ${S} O=${B} oldconfig"
 
+PACKAGE_PREPROCESS_FUNCS += "kernel_package_preprocess"
+
+kernel_package_preprocess () {
+    rm -rf ${PKGD}${datadir}/kernel-depmod
+    rmdir ${PKGD}${datadir}
+    rmdir ${PKGD}${exec_prefix}
+}
+
 kernel_do_configure() {
 	# fixes extra + in /lib/modules/2.6.37+
 	# $ scripts/setlocalversion . => +