kbuild: cherry-pick kbuild changes from Linux

b42841b7bb62 kbuild: Get rid of KBUILD_STR
2aedcd098a94 kbuild: suppress annoying "... is up to date." message
9c8fa9bc08f6 kbuild: fix if_change and friends to consider argument order
ebf003f0cfb3 kbuild: Consolidate header generation from ASM offset information
2982c953570b kbuild: remove redundant $(wildcard ...) for cmd_files calculation
8a78756eb545 kbuild: create object directories simpler and faster
4d4b5c2e3b6e treewide: remove explicit rules for *offsets.s
01d509a48b46 kbuild: remove unimportant comments from ./Kbuild

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1c8cb74..63fbadd 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -57,15 +57,11 @@
 # objects depend on those (obviously)
 multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)) $($(m:.o=-y)))
 multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)) $($(m:.o=-y)))
-multi-objs   := $(multi-objs-y) $(multi-objs-m)
 
 # $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
 # tell kbuild to descend
 subdir-obj-y := $(filter %/built-in.o, $(obj-y))
 
-# $(obj-dirs) is a list of directories that contain object files
-obj-dirs := $(dir $(multi-objs) $(obj-y))
-
 # Replace multi-part objects by their individual parts, look at local dir only
 real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(extra-y)
 real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
@@ -88,7 +84,6 @@
 multi-objs-y	:= $(addprefix $(obj)/,$(multi-objs-y))
 multi-objs-m	:= $(addprefix $(obj)/,$(multi-objs-m))
 subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
-obj-dirs	:= $(addprefix $(obj)/,$(obj-dirs))
 
 # These flags are needed for modversions and compiling, so we define them here
 # already
@@ -97,10 +92,10 @@
 # Note: Files that end up in two or more modules are compiled without the
 #       KBUILD_MODNAME definition. The reason is that any made-up name would
 #       differ in different configs.
-name-fix = $(subst $(comma),_,$(subst -,_,$1))
-basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
+name-fix = $(squote)$(quote)$(subst $(comma),_,$(subst -,_,$1))$(quote)$(squote)
+basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
 modname_flags  = $(if $(filter 1,$(words $(modname))),\
-                 -D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
+                 -DKBUILD_MODNAME=$(call name-fix,$(modname)))
 
 orig_c_flags   = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \
                  $(ccflags-y) $(CFLAGS_$(basetarget).o)
@@ -153,7 +148,7 @@
 # Modified for U-Boot: LINUXINCLUDE -> UBOOTINCLUDE
 c_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(UBOOTINCLUDE)     \
 		 $(__c_flags) $(modkern_cflags)                           \
-		 -D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
+		 $(basename_flags) $(modname_flags)
 
 a_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(UBOOTINCLUDE)     \
 		 $(__a_flags) $(modkern_aflags)
@@ -576,3 +571,32 @@
 quiet_cmd_fdt_rm_props = FDTGREP $@
 	cmd_fdt_rm_props = cat $< | $(objtree)/tools/fdtgrep -r -O dtb - -o $@ \
 			$(addprefix -P ,$(subst $\",,$(CONFIG_OF_REMOVE_PROPS)))
+
+# ASM offsets
+# ---------------------------------------------------------------------------
+
+# Default sed regexp - multiline due to syntax constraints
+define sed-offsets
+	"s:[[:space:]]*\.ascii[[:space:]]*\"\(.*\)\":\1:; \
+	/^->/{s:->#\(.*\):/* \1 */:; \
+	s:^->\([^ ]*\) [\$$#]*\([-0-9]*\) \(.*\):#define \1 \2 /* \3 */:; \
+	s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
+	s:->::; p;}"
+endef
+
+# 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"; \
+	 echo "/*"; \
+	 echo " * DO NOT MODIFY."; \
+	 echo " *"; \
+	 echo " * This file was generated by Kbuild"; \
+	 echo " */"; \
+	 echo ""; \
+	 sed -ne $(sed-offsets); \
+	 echo ""; \
+	 echo "#endif" )
+endef