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

Commit Message

Laura Abbott March 29, 2018, 6:01 p.m. UTC

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 <[e-mail]>
---
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

Comments

Masahiro Yamada May 7, 2018, 6:38 a.m. UTC | #1

2018-03-30 3:01 GMT+09:00 Laura Abbott <[e-mail]>:

> 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
> +}


Do you need this just for wrapping <generate/build-salt.h> ?


How about generating scripts/build-salt.lds
directly by scripts/gensalt ?

<generated/build-salt.h> is unneeded, then
"some sporadic failures about missing the generated header"
will be solved.



I think something like follows will be simpler and better.


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

define filechk_build-salt.lds
        ($(CONFIG_SHELL) $(srctree)/scripts/gensalt $(CONFIG_BUILD_ID_SALT))
endef

$(obj)/build-salt.lds: $(src)/gensalt FORCE
        $(call filechk,build-salt.lds)

Patch

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			\