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authorMichal Marek <mmarek@suse.cz>2015-03-11 11:01:01 +0100
committerMichal Marek <mmarek@suse.cz>2015-03-24 17:37:25 +0100
commit70a4fd6c56d0f581a63dffd8c31d180e96ecf6a6 (patch)
tree1a1640ae201a1d8faa2fd740a027cc8d699c28fe /Kbuild
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
downloadlinux-70a4fd6c56d0f581a63dffd8c31d180e96ecf6a6.tar.gz
kbuild: Don't reset timestamps in include/generated if not needed
Use filechk to generate asm-offsets.h and bounds.h. Based on a patch by
Valdis Kletnieks.

Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Acked-By: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Diffstat (limited to 'Kbuild')
-rw-r--r--Kbuild18
1 files changed, 9 insertions, 9 deletions
diff --git a/Kbuild b/Kbuild
index ab8ded92e870..96d062906c05 100644
--- a/Kbuild
+++ b/Kbuild
@@ -13,8 +13,9 @@ define sed-y
 	s:->::; p;}"
 endef
 
-quiet_cmd_offsets = GEN     $@
-define cmd_offsets
+# Use filechk to avoid rebuilds when a header changes, but the resulting file
+# does not
+define filechk_offsets
 	(set -e; \
 	 echo "#ifndef $2"; \
 	 echo "#define $2"; \
@@ -24,9 +25,9 @@ define cmd_offsets
 	 echo " * This file was generated by Kbuild"; \
 	 echo " */"; \
 	 echo ""; \
-	 sed -ne $(sed-y) $<; \
+	 sed -ne $(sed-y); \
 	 echo ""; \
-	 echo "#endif" ) > $@
+	 echo "#endif" )
 endef
 
 #####
@@ -42,9 +43,8 @@ kernel/bounds.s: kernel/bounds.c FORCE
 	$(Q)mkdir -p $(dir $@)
 	$(call if_changed_dep,cc_s_c)
 
-$(obj)/$(bounds-file): kernel/bounds.s Kbuild
-	$(Q)mkdir -p $(dir $@)
-	$(call cmd,offsets,__LINUX_BOUNDS_H__)
+$(obj)/$(bounds-file): kernel/bounds.s FORCE
+	$(call filechk,offsets,__LINUX_BOUNDS_H__)
 
 #####
 # 2) Generate asm-offsets.h
@@ -62,8 +62,8 @@ arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
 	$(Q)mkdir -p $(dir $@)
 	$(call if_changed_dep,cc_s_c)
 
-$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
-	$(call cmd,offsets,__ASM_OFFSETS_H__)
+$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
+	$(call filechk,offsets,__ASM_OFFSETS_H__)
 
 #####
 # 3) Check for missing system calls