kbuild: rename prepare to archprepare to fix dependency chain

When introducing the generic asm-offsets.h support the dependency
chain for the prepare targets was changed. All build scripts expecting
include/asm/asm-offsets.h to be made when using the prepare target would broke.
With the limited number of prepare targets left in arch Makefiles
the trivial solution was to introduce a new arch specific target: archprepare

The dependency chain looks like this now:

prepare
  |
  +--> prepare0
         |
         +--> archprepare
                |
		+--> scripts_basic
                +--> prepare1
                       |
                       +---> prepare2
                               |
                               +--> prepare3

So prepare 3 is processed before prepare2 etc.
This guaantees that the asm symlink, version.h, scripts_basic
are all updated before archprepare is processed.

prepare0 which build the asm-offsets.h file will need the
actions performed by archprepare.

The head target is now named prepare, because users scripts will most
likely use that target, but prepare-all has been kept for compatibility.
Updated Documentation/kbuild/makefiles.txt.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 15 insertions, 8 deletions

diff --git a/Makefile b/Makefile
index 382298f37ad..e90ee6a3eef 100644
--- a/Makefile
+++ b/Makefile
@@ -776,15 +776,20 @@ $(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
 # Error messages still appears in the original language
 
 .PHONY: $(vmlinux-dirs)
-$(vmlinux-dirs): prepare-all scripts
+$(vmlinux-dirs): prepare scripts
 	$(Q)$(MAKE) $(build)=$@
 
 # Things we need to do before we recursively start building the kernel
-# or the modules are listed in "prepare-all".
-# A multi level approach is used. prepare1 is updated first, then prepare0.
-# prepare-all is the collection point for the prepare targets.
+# or the modules are listed in "prepare".
+# A multi level approach is used. prepareN is processed before prepareN-1.
+# archprepare is used in arch Makefiles and when processed asm symlink,
+# version.h and scripts_basic is processed / created.
 
-.PHONY: prepare-all prepare prepare0 prepare1 prepare2 prepare3
+# Listed in dependency order
+.PHONY: prepare archprepare prepare0 prepare1 prepare2 prepare3
+
+# prepare-all is deprecated, use prepare as valid replacement
+.PHONY: prepare-all
 
 # prepare3 is used to check if we are building in a separate output directory,
 # and if so do:
@@ -813,11 +818,13 @@ ifneq ($(KBUILD_MODULES),)
 	$(Q)mkdir -p $(MODVERDIR)
 endif
 
-prepare0: prepare prepare1 FORCE
+archprepare: prepare1 scripts_basic
+
+prepare0: archprepare FORCE
 	$(Q)$(MAKE) $(build)=.
 
 # All the preparing..
-prepare-all: prepare0
+prepare prepare-all: prepare0
 
 #	Leave this as default for preprocessing vmlinux.lds.S, which is now
 #	done in arch/$(ARCH)/kernel/Makefile
@@ -908,7 +915,7 @@ modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux)
 
 # Target to prepare building external modules
 .PHONY: modules_prepare
-modules_prepare: prepare-all scripts
+modules_prepare: prepare scripts
 
 # Target to install modules
 .PHONY: modules_install