kbuild: merge vmlinux_link() between ARCH=um and other architectures

For ARCH=um, ${CC} is used as the linker driver. Hence, the linker
options are prefixed with -Wl, .

Merge the similar code.

I replaced the -T option with the long option --script= so that it
works well with/without ${wl}.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

scripts/link-vmlinux.sh

@@ -149,13 +149,12 @@ objtool_link()
 # ${2}, ${3}, ... - optional extra .o files
 vmlinux_link()
 {
-	local lds="${objtree}/${KBUILD_LDS}"
 	local output=${1}
-	local objects
-	local strip_debug
-	local map_option
 	local objs
 	local libs
+	local ld
+	local ldflags
+	local ldlibs
 
 	info LD ${output}
 
@@ -171,42 +170,33 @@ vmlinux_link()
 		libs="${KBUILD_VMLINUX_LIBS}"
 	fi
 
+	if [ "${SRCARCH}" = "um" ]; then
+		wl=-Wl,
+		ld="${CC}"
+		ldflags="${CFLAGS_vmlinux}"
+		ldlibs="-lutil -lrt -lpthread"
+	else
+		wl=
+		ld="${LD}"
+		ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
+		ldlibs=
+	fi
+
+	ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
+
 	# The kallsyms linking does not need debug symbols included.
 	if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
-		strip_debug=-Wl,--strip-debug
+		ldflags="${ldflags} ${wl}--strip-debug"
 	fi
 
 	if [ -n "${CONFIG_VMLINUX_MAP}" ]; then
-		map_option="-Map=${output}.map"
+		ldflags="${ldflags} ${wl}-Map=${output}.map"
 	fi
 
-	if [ "${SRCARCH}" != "um" ]; then
+	${ld} ${ldflags} -o ${output}					\
-		objects="--whole-archive ${objs} --no-whole-archive	\
+		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\
-			 --start-group ${libs} --end-group		\
+		${wl}--start-group ${libs} ${wl}--end-group		\
-			 $@"
+		$@ ${ldlibs}
-
-		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}	\
-			${strip_debug#-Wl,}			\
-			-o ${output}				\
-			${map_option}				\
-			-T ${lds} ${objects}
-	else
-		objects="-Wl,--whole-archive			\
-			${KBUILD_VMLINUX_OBJS}			\
-			-Wl,--no-whole-archive			\
-			-Wl,--start-group			\
-			${KBUILD_VMLINUX_LIBS}			\
-			-Wl,--end-group				\
-			${@}"
-
-		${CC} ${CFLAGS_vmlinux}				\
-			${strip_debug}				\
-			-o ${output}				\
-			${map_option:+-Wl,${map_option}}	\
-			-Wl,-T,${lds}				\
-			${objects}				\
-			-lutil -lrt -lpthread
-	fi
 }
 
 # generate .BTF typeinfo from DWARF debuginfo