kbuild: introduce utsrelease.h

include/linux/version.h contained both actual KERNEL version
and UTS_RELEASE that contains a subset from git SHA1 for when
kernel was compiled as part of a git repository.
This had the unfortunate side-effect that all files including version.h
would be recompiled when some git changes was made due to changes SHA1.
Split it out so we keep independent parts in separate files.

Also update checkversion.pl script to no longer check for UTS_RELEASE.

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

1 files changed, 18 insertions, 12 deletions

diff --git a/Makefile b/Makefile
index 1cc793ff42d4..b36aeb617bd2 100644
--- a/Makefile
+++ b/Makefile
@@ -812,8 +812,8 @@ endif
 # prepare2 creates a makefile if using a separate output directory
 prepare2: prepare3 outputmakefile
 
-prepare1: prepare2 include/linux/version.h include/asm \
-                   include/config/auto.conf
+prepare1: prepare2 include/linux/version.h include/linux/utsrelease.h \
+                   include/asm include/config/auto.conf
 ifneq ($(KBUILD_MODULES),)
         $(Q)mkdir -p $(MODVERDIR)
         $(Q)rm -f $(MODVERDIR)/*
@@ -848,21 +848,26 @@ include/asm:
 # needs to be updated, so this check is forced on all builds
 
 uts_len := 64
+define filechk_utsrelease.h
+        if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
+          echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2;    \
+          exit 1;                                                         \
+        fi;                                                               \
+        (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\";)
+endef
 
 define filechk_version.h
-        if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
-          echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2; \
-          exit 1; \
-        fi; \
-        (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\"; \
-          echo \#define LINUX_VERSION_CODE `expr $(VERSION) \\* 65536 + $(PATCHLEVEL) \\* 256 + $(SUBLEVEL)`; \
-         echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))'; \
-        )
+        (echo \#define LINUX_VERSION_CODE $(shell                             \
+        expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + $(SUBLEVEL));     \
+        echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
 endef
 
-include/linux/version.h: $(srctree)/Makefile include/config/kernel.release FORCE
+include/linux/version.h: $(srctree)/Makefile FORCE
         $(call filechk,version.h)
 
+include/linux/utsrelease.h: include/config/kernel.release FORCE
+        $(call filechk,utsrelease.h)
+
 # ---------------------------------------------------------------------------
 
 PHONY += depend dep
@@ -955,7 +960,8 @@ CLEAN_FILES +=	vmlinux System.map \
 # Directories & files removed with 'make mrproper'
 MRPROPER_DIRS  += include/config include2
 MRPROPER_FILES += .config .config.old include/asm .version .old_version \
-                  include/linux/autoconf.h include/linux/version.h \
+                  include/linux/autoconf.h include/linux/version.h      \
+                  include/linux/utsrelease.h                            \
                   Module.symvers tags TAGS cscope*
 
 # clean - Delete most, but leave enough to build external modules