[PATCH v6 kspp-next 02/22] kbuild: merge vmlinux_link() between the ordinary link and Clang LTO

From: Alexander Lobakin
Date: Tue Aug 31 2021 - 10:42:32 EST


From: Masahiro Yamada <masahiroy@xxxxxxxxxx>

When Clang LTO is enabled, vmlinux_link() reuses vmlinux.o instead of
re-linking ${KBUILD_VMLINUX_OBJS} and ${KBUILD_VMLINUX_LIBS}.

That is the only difference here, so merge the similar code.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
scripts/link-vmlinux.sh | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 36ef7b37fc5d..a6c4d0bce3ba 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -154,12 +154,23 @@ vmlinux_link()
local objects
local strip_debug
local map_option
+ local objs
+ local libs

info LD ${output}

# skip output file argument
shift

+ if [ -n "${CONFIG_LTO_CLANG}" ]; then
+ # Use vmlinux.o instead of performing the slow LTO link again.
+ objs=vmlinux.o
+ libs=
+ else
+ objs="${KBUILD_VMLINUX_OBJS}"
+ libs="${KBUILD_VMLINUX_LIBS}"
+ fi
+
# The kallsyms linking does not need debug symbols included.
if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
strip_debug=-Wl,--strip-debug
@@ -170,22 +181,9 @@ vmlinux_link()
fi

if [ "${SRCARCH}" != "um" ]; then
- if [ -n "${CONFIG_LTO_CLANG}" ]; then
- # Use vmlinux.o instead of performing the slow LTO
- # link again.
- objects="--whole-archive \
- vmlinux.o \
- --no-whole-archive \
- ${@}"
- else
- objects="--whole-archive \
- ${KBUILD_VMLINUX_OBJS} \
- --no-whole-archive \
- --start-group \
- ${KBUILD_VMLINUX_LIBS} \
- --end-group \
- ${@}"
- fi
+ objects="--whole-archive ${objs} --no-whole-archive \
+ --start-group ${libs} --end-group \
+ $@"

${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
${strip_debug#-Wl,} \
--
2.31.1