Commit fbe6e37d authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michal Marek
Browse files

kbuild: add arch specific post-link Makefile 



Allow architectures to create arch/xxx/Makefile.postlink with targets
for vmlinux, modules.ko, and clean, which will be invoked after final
linking of vmlinux and modules.

powerpc will use this to check vmlinux linker relocations for sanity,
and may use it to fix up alternate instruction patch branch addresses.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
parent b67067f1

Documentation/kbuild/makefiles.txt

+16 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ This document describes the Linux kernel Makefiles. 
	   --- 6.8 Custom kbuild commands

	   --- 6.9 Preprocessing linker scripts

	   --- 6.10 Generic header files

	   --- 6.11 Post-link pass



	=== 7 Kbuild syntax for exported headers

		--- 7.1 header-y
@@ -1237,6 +1238,21 @@ When kbuild executes, the following steps are followed (roughly): 
	to list the file in the Kbuild file.

	See "7.4 generic-y" for further info on syntax etc.



--- 6.11 Post-link pass



	If the file arch/xxx/Makefile.postlink exists, this makefile

	will be invoked for post-link objects (vmlinux and modules.ko)

	for architectures to run post-link passes on. Must also handle

	the clean target.



	This pass runs after kallsyms generation. If the architecture

	needs to modify symbol locations, rather than manipulate the

	kallsyms, it may be easier to add another postlink target for

	.tmp_vmlinux? targets to be called from link-vmlinux.sh.



	For example, powerpc uses this to check relocation sanity of

	the linked vmlinux file.



=== 7 Kbuild syntax for exported headers



The kernel includes a set of headers that is exported to userspace.

Makefile

+7 −3
Original line number Diff line number Diff line
@@ -957,9 +957,12 @@ endif 
include/generated/autoksyms.h: FORCE

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh true



# Final link of vmlinux

      cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux)

quiet_cmd_link-vmlinux = LINK    $@

ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)



# Final link of vmlinux with optional arch pass after final link

    cmd_link-vmlinux =                                                 \

	$(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) ;       \

	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)



vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE

	+$(call if_changed,link-vmlinux)
@@ -1286,6 +1289,7 @@ $(clean-dirs): 


vmlinuxclean:

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean

	$(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean)



clean: archclean vmlinuxclean

scripts/Makefile.modpost

+9 −5
Original line number Diff line number Diff line
@@ -115,14 +115,18 @@ $(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE 


targets += $(modules:.ko=.mod.o)



# Step 6), final link of the modules

ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)



# Step 6), final link of the modules with optional arch pass after final link

quiet_cmd_ld_ko_o = LD [M]  $@

      cmd_ld_ko_o = $(LD) -r $(LDFLAGS)                                 \

      cmd_ld_ko_o =                                                     \

	$(LD) -r $(LDFLAGS)                                             \

                 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)             \

                             -o $@ $(filter-out FORCE,$^)

                 -o $@ $(filter-out FORCE,$^) ;                         \

	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)



$(modules): %.ko :%.o %.mod.o FORCE

	$(call if_changed,ld_ko_o)

	+$(call if_changed,ld_ko_o)



targets += $(modules)

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