kbuild: add CONFIG_VMLINUX_MAP expert option
It can be quite useful to have ld emit a link map file, in order to
debug or verify that special sections end up where they are supposed
to, and to see what LD_DEAD_CODE_DATA_ELIMINATION manages to get rid
of.
The only reason I'm not just adding this unconditionally is that the
.map file can be rather large (several MB), and that's a waste of
space when one isn't interested in these things. Also make it depend
on CONFIG_EXPERT.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 3b261b0..855fd4e 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -155,6 +155,7 @@
local output=${1}
local objects
local strip_debug
+ local map_option
info LD ${output}
@@ -166,6 +167,10 @@
strip_debug=-Wl,--strip-debug
fi
+ if [ -n "${CONFIG_VMLINUX_MAP}" ]; then
+ map_option="-Map=${output}.map"
+ fi
+
if [ "${SRCARCH}" != "um" ]; then
if [ -n "${CONFIG_LTO_CLANG}" ]; then
# Use vmlinux.o instead of performing the slow LTO
@@ -187,6 +192,7 @@
${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
${strip_debug#-Wl,} \
-o ${output} \
+ ${map_option} \
-T ${lds} ${objects}
else
objects="-Wl,--whole-archive \
@@ -200,6 +206,7 @@
${CC} ${CFLAGS_vmlinux} \
${strip_debug} \
-o ${output} \
+ ${map_option:+-Wl,${map_option}} \
-Wl,-T,${lds} \
${objects} \
-lutil -lrt -lpthread
@@ -303,6 +310,7 @@
rm -f .tmp_vmlinux*
rm -f System.map
rm -f vmlinux
+ rm -f vmlinux.map
rm -f vmlinux.o
}