kbuild: rebuild modules when module linker scripts are updated

Currently, the timestamp of module linker scripts are not checked.
Add them to the dependency of modules so they are correctly rebuilt.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Documentation/kbuild/makefiles.rst

@@ -993,6 +993,11 @@ When kbuild executes, the following steps are followed (roughly):
 
 	The linker script with full path. Assigned by the top-level Makefile.
 
+    KBUILD_LDS_MODULE
+
+	The module linker script with full path. Assigned by the top-level
+	Makefile and additionally by the arch Makefile.
+
     KBUILD_VMLINUX_OBJS
 
 	All object files for vmlinux. They are linked to vmlinux in the same

Makefile

@@ -482,7 +482,8 @@ 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 :=
+export KBUILD_LDS_MODULE := $(srctree)/scripts/module-common.lds
 KBUILD_LDFLAGS :=
 GCC_PLUGINS_CFLAGS :=
 CLANG_FLAGS :=

arch/arm/Makefile

@@ -17,7 +17,7 @@ KBUILD_LDFLAGS_MODULE	+= --be8
 endif
 
 ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
-KBUILD_LDFLAGS_MODULE	+= -T $(srctree)/arch/arm/kernel/module.lds
+KBUILD_LDS_MODULE	+= $(srctree)/arch/arm/kernel/module.lds
 endif
 
 GZFLAGS		:=-9

arch/arm64/Makefile

@@ -101,7 +101,7 @@ endif
 CHECKFLAGS	+= -D__aarch64__
 
 ifeq ($(CONFIG_ARM64_MODULE_PLTS),y)
-KBUILD_LDFLAGS_MODULE	+= -T $(srctree)/arch/arm64/kernel/module.lds
+KBUILD_LDS_MODULE	+= $(srctree)/arch/arm64/kernel/module.lds
 endif
 
 # Default value

arch/ia64/Makefile

@@ -20,7 +20,7 @@ CHECKFLAGS	+= -D__ia64=1 -D__ia64__=1 -D_LP64 -D__LP64__
 
 OBJCOPYFLAGS	:= --strip-all
 LDFLAGS_vmlinux	:= -static
-KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/ia64/module.lds
+KBUILD_LDS_MODULE += $(srctree)/arch/ia64/module.lds
 KBUILD_AFLAGS_KERNEL := -mconstant-gp
 EXTRA		:=
 

arch/m68k/Makefile

@@ -73,7 +73,7 @@ KBUILD_AFLAGS += -D__uClinux__
 endif
 
 KBUILD_LDFLAGS := -m m68kelf
-KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/m68k/kernel/module.lds
+KBUILD_LDS_MODULE += $(srctree)/arch/m68k/kernel/module.lds
 
 ifdef CONFIG_SUN3
 LDFLAGS_vmlinux = -N

arch/parisc/Makefile

@@ -60,7 +60,7 @@ KBUILD_CFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY=1 \
 		 -DFTRACE_PATCHABLE_FUNCTION_SIZE=$(NOP_COUNT)
 
 CC_FLAGS_FTRACE := -fpatchable-function-entry=$(NOP_COUNT),$(shell echo $$(($(NOP_COUNT)-1)))
-KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/parisc/kernel/module.lds
+KBUILD_LDS_MODULE += $(srctree)/arch/parisc/kernel/module.lds
 endif
 
 OBJCOPY_FLAGS =-O binary -R .note -R .comment -S

arch/powerpc/Makefile

@@ -67,7 +67,7 @@ UTS_MACHINE := $(subst $(space),,$(machine-y))
 ifdef CONFIG_PPC32
 KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
 else
-KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/powerpc/kernel/module.lds
+KBUILD_LDS_MODULE += $(srctree)/arch/powerpc/kernel/module.lds
 ifeq ($(call ld-ifversion, -ge, 225000000, y),y)
 # Have the linker provide sfpr if possible.
 # There is a corresponding test in arch/powerpc/lib/Makefile

arch/riscv/Makefile

@@ -52,7 +52,7 @@ ifeq ($(CONFIG_CMODEL_MEDANY),y)
 	KBUILD_CFLAGS += -mcmodel=medany
 endif
 ifeq ($(CONFIG_MODULE_SECTIONS),y)
-	KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/riscv/kernel/module.lds
+	KBUILD_LDS_MODULE += $(srctree)/arch/riscv/kernel/module.lds
 endif
 
 KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax)

scripts/Makefile.modpost

@@ -126,10 +126,11 @@ quiet_cmd_ld_ko_o = LD [M]  $@
       cmd_ld_ko_o =                                                     \
 	$(LD) -r $(KBUILD_LDFLAGS)                                      \
                  $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)             \
-                 -o $@ $(real-prereqs) ;                                \
+                 $(addprefix -T , $(KBUILD_LDS_MODULE))                 \
+                 -o $@ $(filter %.o, $^);                               \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
-$(modules): %.ko :%.o %.mod.o FORCE
+$(modules): %.ko :%.o %.mod.o $(KBUILD_LDS_MODULE) FORCE
 	+$(call if_changed,ld_ko_o)
 
 targets += $(modules)