[RFCv2 PATCH 2/3] kbuild: Link with generated build-salt header

From: Laura Abbott
Date: Thu Mar 29 2018 - 14:01:34 EST


Now that we have a header with appropriate data, link it into the kernel
and modules. If BUILD_ID_SALT isn't set, the script should be empty.

Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
v2: Changed names to be consistent
---
Makefile | 4 +++-
scripts/.gitignore | 1 +
scripts/Makefile | 2 +-
scripts/build-salt.lds.S | 5 +++++
scripts/link-vmlinux.sh | 3 ++-
5 files changed, 12 insertions(+), 3 deletions(-)
create mode 100644 scripts/build-salt.lds.S

diff --git a/Makefile b/Makefile
index b80c2d6d0854..171f82295e5e 100644
--- a/Makefile
+++ b/Makefile
@@ -425,7 +425,8 @@ KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
-KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
+KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds \
+ -T $(srctree)/scripts/build-salt.lds
GCC_PLUGINS_CFLAGS :=

export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
@@ -1004,6 +1005,7 @@ export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y2) $(drivers-y) $(net-y) $(virt-y)
export KBUILD_VMLINUX_LIBS := $(libs-y1)
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
+export EXTRA_LDS := scripts/build-salt.lds
export LDFLAGS_vmlinux
# used by scripts/package/Makefile
export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools)
diff --git a/scripts/.gitignore b/scripts/.gitignore
index 0442c06eefcb..1c840ef4f0c8 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -13,3 +13,4 @@ asn1_compiler
extract-cert
sign-file
insert-sys-cert
+build-salt.lds
diff --git a/scripts/Makefile b/scripts/Makefile
index 25ab143cbe14..47f6ed5b0bcd 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -25,7 +25,7 @@ HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
HOSTLOADLIBES_sign-file = -lcrypto
HOSTLOADLIBES_extract-cert = -lcrypto

-always := $(hostprogs-y) $(hostprogs-m)
+always := $(hostprogs-y) $(hostprogs-m) build-salt.lds

# The following hostprogs-y programs are only build on demand
hostprogs-y += unifdef
diff --git a/scripts/build-salt.lds.S b/scripts/build-salt.lds.S
new file mode 100644
index 000000000000..f85981f1187e
--- /dev/null
+++ b/scripts/build-salt.lds.S
@@ -0,0 +1,5 @@
+#include <generated/build-salt.h>
+
+SECTIONS {
+ BUILD_ID_SALT
+}
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index be56a1153014..2b57e0139acb 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -93,6 +93,7 @@ modpost_link()
vmlinux_link()
{
local lds="${objtree}/${KBUILD_LDS}"
+ local extra_lds="${objtree}/${EXTRA_LDS}"
local objects

if [ "${SRCARCH}" != "um" ]; then
@@ -114,7 +115,7 @@ vmlinux_link()
fi

${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
- -T ${lds} ${objects}
+ -T ${lds} -T ${extra_lds} ${objects}
else
if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
objects="-Wl,--whole-archive \
--
2.16.2