Revert "ANDROID: Revert "af73d78bd384 ("kbuild: Remove debug info from kallsyms linking")""

This reverts commit 1780c41d22.

Fixed with updated toolchain.

Bug: 153164546
Change-Id: If6e431f22678db76e640b377121abb997105b8dd
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

scripts/link-vmlinux.sh

@@ -110,12 +110,18 @@ vmlinux_link()
 	local lds="${objtree}/${KBUILD_LDS}"
 	local output=${1}
 	local objects
+	local strip_debug
 
 	info LD ${output}
 
 	# skip output file argument
 	shift
 
+	# The kallsyms linking does not need debug symbols included.
+	if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
+		strip_debug=-Wl,--strip-debug
+	fi
+
 	if [ "${SRCARCH}" != "um" ]; then
 		if [ -n "${CONFIG_LTO_CLANG}" ]; then
 			# Use vmlinux.o instead of performing the slow LTO
@@ -135,6 +141,7 @@ vmlinux_link()
 		fi
 
 		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}	\
+			${strip_debug#-Wl,}			\
 			-o ${output}				\
 			-T ${lds} ${objects}
 	else
@@ -147,6 +154,7 @@ vmlinux_link()
 			${@}"
 
 		${CC} ${CFLAGS_vmlinux}				\
+			${strip_debug}				\
 			-o ${output}				\
 			-Wl,-T,${lds}				\
 			${objects}				\
@@ -173,8 +181,9 @@ gen_btf()
 		return 1
 	fi
 
-	info "BTF" ${2}
 	vmlinux_link ${1}
+
+	info "BTF" ${2}
 	LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
 
 	# Create ${2} which contains just .BTF section but no symbols. Add
@@ -221,8 +230,8 @@ kallsyms()
 kallsyms_step()
 {
 	kallsymso_prev=${kallsymso}
-	kallsymso=.tmp_kallsyms${1}.o
-	kallsyms_vmlinux=.tmp_vmlinux${1}
+	kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
+	kallsymso=${kallsyms_vmlinux}.o
 
 	vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
 	kallsyms ${kallsyms_vmlinux} ${kallsymso}
@@ -245,7 +254,6 @@ cleanup()
 {
 	rm -f .btf.*
 	rm -f .tmp_System.map
-	rm -f .tmp_kallsyms*
 	rm -f .tmp_lto.lds
 	rm -f .tmp_vmlinux*
 	rm -f System.map
@@ -317,9 +325,8 @@ tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
 
 btf_vmlinux_bin_o=""
 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
-	if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
-		btf_vmlinux_bin_o=.btf.vmlinux.bin.o
-	else
+	btf_vmlinux_bin_o=.btf.vmlinux.bin.o
+	if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
 		echo >&2 "Failed to generate BTF for vmlinux"
 		echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
 		exit 1