kbuild: sync top Makefile with Linux 3.18-rc1

Since Linux 3.15, relative path feature and related fixes,
cleanups have been merged to the top Makefile.

The relative path feature looks stable enough, so let's import it
to U-Boot along with various cleanups.

Commits imported from Linux (some need adjustment) are:

[1] commit 7e1c04779efd by Michal Marek
  kbuild: Use relative path for $(objtree)

[2] commit 890676c65d69 by Michal Marek
  kbuild: Use relative path when building in the source tree

[3] commit 9da0763bdd82 by Michal Marek
  kbuild: Use relative path when building in a subdir of the source tree

[4] commit c2e28dc975ea by Michal Marek
  kbuild: Print the name of the build directory

[5] commit 066b7ed95580 by Michal Marek
  kbuild: Do not print the build directory with make -s

[6] commit 3f1d9a6cec01 by Michal Marek
  kbuild: make -s should be used with kernelrelease/kernelversion/image_name

[7] commit 7ff525712acf by Masahiro Yamada
  kbuild: fake the "Entering directory ..." message more simply

[8] commit 745a254322c8 by Masahiro Yamada
  kbuild: use $(Q) for sub-make target

[9] commit aa55c8e2f7a3 by Masahiro Yamada
  kbuild: handle C=... and M=... after entering into build directory

[10] commit ab7474ea5361 by Borislav Petkov
  Kbuild: Ignore GREP_OPTIONS env variable

To use relative path feature, tools/Makefile and scripts/Makefile.autoconf
must be tweaked.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

1 files changed, 96 insertions, 90 deletions

diff --git a/Makefile b/Makefile
index b7624c5..ef67e9d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,3 @@
-#
-# (C) Copyright 2000-2013
-# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
-#
-# SPDX-License-Identifier:	GPL-2.0+
-#
-
 VERSION = 2014
 PATCHLEVEL = 10
 SUBLEVEL =
@@ -17,11 +10,9 @@ NAME =
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
 
-# Do not:
-# o  use make's built-in rules and variables
-#    (this increases performance and avoids hard-to-debug behaviour);
-# o  print "Entering directory ...";
-MAKEFLAGS += -rR --no-print-directory
+# Do not use make's built-in rules and variables
+# (this increases performance and avoids hard-to-debug behaviour);
+MAKEFLAGS += -rR
 
 # Avoid funny character set dependencies
 unexport LC_ALL
@@ -29,6 +20,9 @@ LC_COLLATE=C
 LC_NUMERIC=C
 export LC_COLLATE LC_NUMERIC
 
+# Avoid interference with shell env settings
+unexport GREP_OPTIONS
+
 # We are using a recursive build, so we need to do a little thinking
 # to get the ordering right.
 #
@@ -45,6 +39,29 @@ export LC_COLLATE LC_NUMERIC
 # descending is started. They are now explicitly listed as the
 # prepare rule.
 
+# Beautify output
+# ---------------------------------------------------------------------------
+#
+# Normally, we echo the whole command before executing it. By making
+# that echo $($(quiet)$(cmd)), we now have the possibility to set
+# $(quiet) to choose other forms of output instead, e.g.
+#
+#         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
+#         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
+#
+# If $(quiet) is empty, the whole command will be printed.
+# If it is set to "quiet_", only the short version will be printed.
+# If it is set to "silent_", nothing will be printed at all, since
+# the variable $(silent_cmd_cc_o_c) doesn't exist.
+#
+# A simple variant is to prefix commands with $(Q) - that's useful
+# for commands that shall be hidden in non-verbose mode.
+#
+#	$(Q)ln $@ :<
+#
+# If KBUILD_VERBOSE equals 0 then the above command will be hidden.
+# If KBUILD_VERBOSE equals 1 then the above command is displayed.
+#
 # To put more focus on warnings, be less verbose as default
 # Use 'make V=1' to see the full commands
 
@@ -55,33 +72,28 @@ ifndef KBUILD_VERBOSE
   KBUILD_VERBOSE = 0
 endif
 
-# Call a source code checker (by default, "sparse") as part of the
-# C compilation.
-#
-# Use 'make C=1' to enable checking of only re-compiled files.
-# Use 'make C=2' to enable checking of *all* source files, regardless
-# of whether they are re-compiled or not.
-#
-# See the file "Documentation/sparse.txt" for more details, including
-# where to get the "sparse" utility.
+ifeq ($(KBUILD_VERBOSE),1)
+  quiet =
+  Q =
+else
+  quiet=quiet_
+  Q = @
+endif
 
-ifeq ("$(origin C)", "command line")
-  KBUILD_CHECKSRC = $(C)
+# If the user is running make -s (silent mode), suppress echoing of
+# commands
+
+ifneq ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
+ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
+  quiet=silent_
 endif
-ifndef KBUILD_CHECKSRC
-  KBUILD_CHECKSRC = 0
+else					# make-3.8x
+ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
+  quiet=silent_
 endif
-
-# Use make M=dir to specify directory of external module to build
-# Old syntax make ... SUBDIRS=$PWD is still supported
-# Setting the environment variable KBUILD_EXTMOD take precedence
-ifdef SUBDIRS
-  KBUILD_EXTMOD ?= $(SUBDIRS)
 endif
 
-ifeq ("$(origin M)", "command line")
-  KBUILD_EXTMOD := $(M)
-endif
+export quiet Q KBUILD_VERBOSE
 
 # kbuild supports saving output files in a separate directory.
 # To locate output files in a separate directory two syntaxes are supported.
@@ -98,7 +110,6 @@ endif
 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
 # variable.
 
-
 # KBUILD_SRC is set on invocation of make in OBJ directory
 # KBUILD_SRC is not intended to be used by the regular user (for now)
 ifeq ($(KBUILD_SRC),)
@@ -131,10 +142,8 @@ $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 	@:
 
 sub-make: FORCE
-	$(if $(KBUILD_VERBOSE:1=),@)$(MAKE) -C $(KBUILD_OUTPUT) \
-	KBUILD_SRC=$(CURDIR) \
-	KBUILD_EXTMOD="$(KBUILD_EXTMOD)" -f $(CURDIR)/Makefile \
-	$(filter-out _all sub-make,$(MAKECMDGOALS))
+	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
+	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
 
 # Leave processing to above invocation of make
 skip-makefile := 1
@@ -144,6 +153,39 @@ endif # ifeq ($(KBUILD_SRC),)
 # We process the rest of the Makefile if this is the final invocation of make
 ifeq ($(skip-makefile),)
 
+# Do not print "Entering directory ...",
+# but we want to display it when entering to the output directory
+# so that IDEs/editors are able to understand relative filenames.
+MAKEFLAGS += --no-print-directory
+
+# Call a source code checker (by default, "sparse") as part of the
+# C compilation.
+#
+# Use 'make C=1' to enable checking of only re-compiled files.
+# Use 'make C=2' to enable checking of *all* source files, regardless
+# of whether they are re-compiled or not.
+#
+# See the file "Documentation/sparse.txt" for more details, including
+# where to get the "sparse" utility.
+
+ifeq ("$(origin C)", "command line")
+  KBUILD_CHECKSRC = $(C)
+endif
+ifndef KBUILD_CHECKSRC
+  KBUILD_CHECKSRC = 0
+endif
+
+# Use make M=dir to specify directory of external module to build
+# Old syntax make ... SUBDIRS=$PWD is still supported
+# Setting the environment variable KBUILD_EXTMOD take precedence
+ifdef SUBDIRS
+  KBUILD_EXTMOD ?= $(SUBDIRS)
+endif
+
+ifeq ("$(origin M)", "command line")
+  KBUILD_EXTMOD := $(M)
+endif
+
 # If building an external module we do not care about the all: rule
 # but instead _all depend on modules
 PHONY += all
@@ -153,8 +195,18 @@ else
 _all: modules
 endif
 
-srctree		:= $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR))
-objtree		:= $(CURDIR)
+ifeq ($(KBUILD_SRC),)
+        # building in the source tree
+        srctree := .
+else
+        ifeq ($(KBUILD_SRC)/,$(dir $(CURDIR)))
+                # building in a subdirectory of the source tree
+                srctree := ..
+        else
+                srctree := $(KBUILD_SRC)
+        endif
+endif
+objtree		:= .
 src		:= $(srctree)
 obj		:= $(objtree)
 
@@ -262,52 +314,6 @@ endif
 export KBUILD_MODULES KBUILD_BUILTIN
 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
 
-# Beautify output
-# ---------------------------------------------------------------------------
-#
-# Normally, we echo the whole command before executing it. By making
-# that echo $($(quiet)$(cmd)), we now have the possibility to set
-# $(quiet) to choose other forms of output instead, e.g.
-#
-#         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
-#         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
-#
-# If $(quiet) is empty, the whole command will be printed.
-# If it is set to "quiet_", only the short version will be printed.
-# If it is set to "silent_", nothing will be printed at all, since
-# the variable $(silent_cmd_cc_o_c) doesn't exist.
-#
-# A simple variant is to prefix commands with $(Q) - that's useful
-# for commands that shall be hidden in non-verbose mode.
-#
-#	$(Q)ln $@ :<
-#
-# If KBUILD_VERBOSE equals 0 then the above command will be hidden.
-# If KBUILD_VERBOSE equals 1 then the above command is displayed.
-
-ifeq ($(KBUILD_VERBOSE),1)
-  quiet =
-  Q =
-else
-  quiet=quiet_
-  Q = @
-endif
-
-# If the user is running make -s (silent mode), suppress echoing of
-# commands
-
-ifneq ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
-ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
-  quiet=silent_
-endif
-else					# make-3.8x
-ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
-  quiet=silent_
-endif
-endif
-
-export quiet Q KBUILD_VERBOSE
-
 # Look for make include files relative to root of kernel src
 MAKEFLAGS += --include-dir=$(srctree)
 
@@ -1308,7 +1314,7 @@ help:
 	@echo  ''
 	@echo  'Other generic targets:'
 	@echo  '  all		  - Build all necessary images depending on configuration'
-	@echo  '  u-boot	  - Build the bare u-boot'
+	@echo  '* u-boot	  - Build the bare u-boot'
 	@echo  '  dir/            - Build all files in dir and below'
 	@echo  '  dir/file.[oisS] - Build specified target only'
 	@echo  '  dir/file.lst    - Build specified mixed source/assembly target only'
@@ -1316,8 +1322,8 @@ help:
 	@echo  '  tags/ctags	  - Generate ctags file for editors'
 	@echo  '  etags		  - Generate etags file for editors'
 	@echo  '  cscope	  - Generate cscope index'
-	@echo  '  ubootrelease	  - Output the release version string'
-	@echo  '  ubootversion	  - Output the version stored in Makefile'
+	@echo  '  ubootrelease	  - Output the release version string (use with make -s)'
+	@echo  '  ubootversion	  - Output the version stored in Makefile (use with make -s)'
 	@echo  ''
 	@echo  'Static analysers'
 	@echo  '  checkstack      - Generate a list of stack hogs'