[PATCH] UBUNTU: [Packaging] kernelconfig -- only update/edit configurations on architectures we have compiler support

[Dimitri John Ledkov]

From: Andy Whitcroft <apw at canonical.com>

We can only rebuild, edit, or update a configuration for an architecture
nativly on that architecture or using a compatible cross-compiler for
that architecture.  Skip architectures for which we do not have an
apropriate compiler.  When we do not perform the requested operation on
all architectures report those which have been skipped clearly at the
bottom of the output.

    WARNING: configuration operation applied only to a subset of
        architectures (skipped i386 armhf arm64 ppc64el s390x)

[seth.forshee at canonical.com: remove i386 special case.]
Signed-off-by: Andy Whitcroft <apw at canonical.com>
Signed-off-by: Dimitri John Ledkov <xnox at ubuntu.com>
BugLink: https://bugs.launchpad.net/bugs/1863116
---
 Tested by multiple people, and we all love this on power/s390x/arm64.

 Please apply for unstable | groovy | focal.

 debian/scripts/misc/kernelconfig | 79 +++++++++++++++++++-------------
 1 file changed, 47 insertions(+), 32 deletions(-)

diff --git a/debian/scripts/misc/kernelconfig b/debian/scripts/misc/kernelconfig
index fc50c48df3b7..dd45d2f2b085 100755
--- a/debian/scripts/misc/kernelconfig
+++ b/debian/scripts/misc/kernelconfig
@@ -39,6 +39,8 @@ if [ "$mode" = "genconfigs" ]; then
 	test -d CONFIGS || mkdir CONFIGS
 fi
 
+warning_partial=
+
 for arch in $archs; do
 	rm -rf build
 	mkdir build
@@ -64,9 +66,15 @@ for arch in $archs; do
 	# Environment variables for 'make *config'. We omit CROSS_COMPILE
 	# for i386 since it is no longer supported after 19.04, however
 	# we maintain the configs for hwe.
+	modify_config=true
 	env="ARCH=$kernarch"
-	if [ "$arch" != "i386" ]; then
+	compiler_path=$(which "${cross_compile}gcc" || true)
+	if [ "$compiler_path" != '' ]; then
 		env="$env CROSS_COMPILE=$cross_compile"
+	else
+		echo "WARNING: ${cross_compile}gcc not installed"
+		modify_config=
+		warning_partial="$warning_partial $arch"
 	fi
 
 	archconfdir=$confdir/$arch
@@ -100,38 +108,39 @@ for arch in $archs; do
 			fullconf="$tmpdir/$arch-$config-full"
 			cat "$fullconf" > build/.config
 			# Call oldconfig or menuconfig
-			case "$mode" in
-			    editconfigs)
-				# Interactively edit config parameters
-				while : ; do
-					echo -n "Do you want to edit config: $arch/$config? [Y/n] "
-					read choice
-					
-					case "$choice" in
-					y* | Y* | "" )
-						make O=`pwd`/build $env menuconfig
-						break ;;
-					n* | N* )
-						# 'syncconfig' prevents
-						# errors for '-' options set
-						# in common config fragments
-						make O=`pwd`/build $env syncconfig
-						break ;;
-					*)
-						echo "Entry not valid"
-					esac
-				done
-				;;
-			    *)
-				echo "* Run $mode (yes=$yes) on $arch/$config ..."
-				if [ "$yes" -eq 1 ]; then
-					yes "" | make O=`pwd`/build $env "$mode"
-				else
-					make O=`pwd`/build $env "$mode"
-				fi ;;
-			esac
+			if [ "$modify_config" ]; then
+				case "$mode" in
+				    editconfigs)
+					# Interactively edit config parameters
+					while : ; do
+						echo -n "Do you want to edit config: $arch/$config? [Y/n] "
+						read choice
+						case "$choice" in
+						y* | Y* | "" )
+							make O=`pwd`/build $env menuconfig
+							break ;;
+						n* | N* )
+							# 'syncconfig' prevents
+							# errors for '-' options set
+							# in common config fragments
+							make O=`pwd`/build $env syncconfig
+							break ;;
+						*)
+							echo "Entry not valid"
+						esac
+					done
+					;;
+				    *)
+					echo "* Run $mode (yes=$yes) on $arch/$config ..."
+					if [ "$yes" -eq 1 ]; then
+						yes "" | make O=`pwd`/build $env "$mode"
+					else
+						make O=`pwd`/build $env "$mode"
+					fi ;;
+				esac
+			fi
 			cat build/.config > $archconfdir/$config
-			cat build/.config > "$tmpdir/CONFIGS/$arch-$config"
+			[ "$modify_config" ] && cat build/.config >"$tmpdir/CONFIGS/$arch-$config"
 			if [ "$keep" = "1" ]; then
 				cat build/.config > CONFIGS/$arch-$config
 			fi
@@ -176,6 +185,7 @@ for arch in $archs; do
 		flavour="${config##*.}"
 		if [ -f $archconfdir/$config ]; then
 			fullconf="$tmpdir/CONFIGS/$arch-$config"
+			[ ! -f "$fullconf" ] && continue
 			"$bindir/../config-check" "$fullconf" "$arch" "$flavour" "$confdir" "0" "0" || let "fail=$fail+1"
 		fi
 	done
@@ -189,3 +199,8 @@ fi
 
 rm -rf build
 
+if [ "$warning_partial" ]; then
+	echo ""
+	echo "WARNING: configuration operation applied only to a subset of architectures (skipped$warning_partial)" 1>&2
+	echo ""
+fi
-- 
2.27.0