kconfig / kbuild: Re-sync with Linux 4.20

Align Kconfig and Kbuild logic to Linux 4.20 release with minimal impact
on files outside of this scope.

Our previous Kconfig sync was done by commit 587e4a4 ("kconfig /
kbuild: Re-sync with Linux 4.19").

As part of this re-sync, a few related changes from previous Linux
releases were found to have been missed and merged in, and are not in
the following list.

The imported Linux commits are:

[From prior to v4.19]
b1e0d8b70fa3 kbuild: Fix gcc -x syntax
a4353898980c kconfig: add CC_IS_GCC and GCC_VERSION
469cb7376c06 kconfig: add CC_IS_CLANG and CLANG_VERSION

[From v4.19 to v4.20]
487c7c7702ab kbuild: prefix Makefile.dtbinst path with $(srctree) unconditionally
0d91bf584fe5 kbuild: remove old check for CFLAGS use
25815cf5ffec kbuild: hide most of targets when running config or mixed targets
00d78ab2ba75 kbuild: remove dead code in cmd_files calculation in top Makefile
23066c3f4e21 Compiler Attributes: enable -Wstringop-truncation on W=1 (gcc >= 8)
37c8a5fafa3b kbuild: consolidate Devicetree dtb build rules
80463f1b7bf9 kbuild: add --include-dir flag only for out-of-tree build
77ec0c20c7e0 kbuild: remove VERSION and PATCHLEVEL from $(objtree)/Makefile
74bc0c09b2da kbuild: remove user ID check in scripts/mkmakefile
4fd61277f662 kbuild: do not pass $(objtree) to scripts/mkmakefile
80d0dda3a4e5 kbuild: simplify command line creation in scripts/mkmakefile
fb073a4b473e kbuild: add -Wno-pointer-sign flag unconditionally
9df3e7a7d7d6 kbuild: add -Wno-unused-but-set-variable flag unconditionally
69ea912fda74 kbuild: remove unneeded link_multi_deps
7d0ea2524202 kbuild: use 'else ifeq' for checksrc to improve readability
04c459d20448 kconfig: remove oldnoconfig target
0085b4191f3e kconfig: remove silentoldconfig target
3f80babd9ca4 kbuild: remove unused cc-fullversion variable
2cd3faf87d2d merge_config.sh: Allow to define config prefix
076f421da5d4 kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
6bbe4385d035 kconfig: merge_config: avoid false positive matches from comment lines

[From post v4.20]
885480b08469 Makefile: Move -Wno-unused-but-set-variable out of GCC only block

There are a number of changes related to additional warnings as well as
being able to drop cc-name entirely that have been omitted for now as
additional work is required first.

Cc: Masahiro Yamada <[email protected]>
Signed-off-by: Tom Rini <[email protected]>

Kconfig

@@ -57,6 +57,21 @@ config LOCALVERSION_AUTO
 
 	  which is done within the script "scripts/setlocalversion".)
 
+config CC_IS_GCC
+	def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc)
+
+config GCC_VERSION
+	int
+	default $(shell,$(srctree)/scripts/gcc-version.sh -p $(CC) | sed 's/^0*//') if CC_IS_GCC
+	default 0
+
+config CC_IS_CLANG
+	def_bool $(success,$(CC) --version | head -n 1 | grep -q clang)
+
+config CLANG_VERSION
+	int
+	default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
+
 config CC_OPTIMIZE_FOR_SIZE
 	bool "Optimize for size"
 	default y

Makefile

@@ -12,10 +12,9 @@ NAME =
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
 
-# o Do not use make's built-in rules and variables
-#   (this increases performance and avoids hard-to-debug behaviour);
-# o Look for make include files relative to root of kernel src
-MAKEFLAGS += -rR --include-dir=$(CURDIR)
+# Do not use make's built-in rules and variables
+# (this increases performance and avoids hard-to-debug behaviour)
+MAKEFLAGS += -rR
 
 # Determine target architecture for the sandbox
 include include/host_arch.h
@@ -162,6 +161,13 @@ KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
 $(if $(KBUILD_OUTPUT),, \
      $(error failed to create output directory "$(saved-output)"))
 
+# Look for make include files relative to root of kernel src
+#
+# This does not become effective immediately because MAKEFLAGS is re-parsed
+# once after the Makefile is read.  It is OK since we are going to invoke
+# 'sub-make' below.
+MAKEFLAGS += --include-dir=$(CURDIR)
+
 PHONY += $(MAKECMDGOALS) sub-make
 
 $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
@@ -492,8 +498,7 @@ PHONY += outputmakefile
 outputmakefile:
 ifneq ($(KBUILD_SRC),)
 	$(Q)ln -fsn $(srctree) source
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
-	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
 endif
 
 # To make sure we do not include .config for any of the *config targets
@@ -572,7 +577,7 @@ else
 # Carefully list dependencies so we do not try to build scripts twice
 # in parallel
 PHONY += scripts
-scripts: scripts_basic include/config/auto.conf
+scripts: scripts_basic scripts_dtc include/config/auto.conf
 	$(Q)$(MAKE) $(build)=$(@)
 
 ifeq ($(dot-config),1)
@@ -709,6 +714,9 @@ KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector)
 endif
 KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks)
 
+# disable pointer signed / unsigned warnings in gcc 4.0
+KBUILD_CFLAGS += -Wno-pointer-sign
+
 # disable stringop warnings in gcc 8+
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
 
@@ -739,7 +747,7 @@ endif
 KBUILD_CFLAGS += $(call cc-option,-Wno-format-nonliteral)
 KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
 
-ifeq ($(cc-name),clang)
+ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
 KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
@@ -751,12 +759,11 @@ KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
 # See modpost pattern 2
 KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,)
 KBUILD_CFLAGS += $(call cc-option, -fcatch-undefined-behavior)
-else
+endif
 
 # These warnings generated too much noise in a regular build.
 # Use make W=1 to enable them (see scripts/Makefile.extrawarn)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
-endif
 
 # Prohibit date/time macros, which would make the build non-deterministic
 KBUILD_CFLAGS   += $(call cc-option,-Werror=date-time)
@@ -1946,6 +1953,35 @@ $(dt_h): $(srctree)/Makefile FORCE
 $(defaultenv_h): $(CONFIG_DEFAULT_ENV_FILE:"%"=%) FORCE
 	$(call filechk,defaultenv.h)
 
+# ---------------------------------------------------------------------------
+# Devicetree files
+
+ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/boot/dts/),)
+dtstree := arch/$(SRCARCH)/boot/dts
+endif
+
+ifneq ($(dtstree),)
+
+%.dtb: prepare3 scripts_dtc
+	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
+
+PHONY += dtbs dtbs_install
+dtbs: prepare3 scripts_dtc
+	$(Q)$(MAKE) $(build)=$(dtstree)
+
+dtbs_install:
+	$(Q)$(MAKE) $(dtbinst)=$(dtstree)
+
+ifdef CONFIG_OF_EARLY_FLATTREE
+all: dtbs
+endif
+
+endif
+
+PHONY += scripts_dtc
+scripts_dtc: scripts_basic
+	$(Q)$(MAKE) $(build)=scripts/dtc
+
 # ---------------------------------------------------------------------------
 quiet_cmd_cpp_lds = LDS     $@
 cmd_cpp_lds = $(CPP) -Wp,-MD,$(depfile) $(cpp_flags) $(LDPPFLAGS) \
@@ -2208,9 +2244,6 @@ PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS): scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=doc $@
 
-endif #ifeq ($(config-targets),1)
-endif #ifeq ($(mixed-targets),1)
-
 PHONY += checkstack ubootrelease ubootversion
 
 checkstack:
@@ -2298,13 +2331,15 @@ quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files))
 
 # read all saved command lines
 
-cmd_files := $(wildcard .*.cmd $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
+cmd_files := $(wildcard .*.cmd)
 
 ifneq ($(cmd_files),)
   $(cmd_files): ;	# Do not try to update included dependency files
   include $(cmd_files)
 endif
 
+endif    #ifeq ($(config-targets),1)
+endif    #ifeq ($(mixed-targets),1)
 endif	# skip-makefile
 
 PHONY += FORCE

scripts/Kbuild.include

@@ -142,10 +142,6 @@ cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo
 # cc-version
 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 
-# cc-fullversion
-cc-fullversion = $(shell $(CONFIG_SHELL) \
-	$(srctree)/scripts/gcc-version.sh -p $(CC))
-
 # cc-ifversion
 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4))
@@ -193,7 +189,7 @@ modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
 # Usage:
 # $(Q)$(MAKE) $(dtbinst)=dir
-dtbinst := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.dtbinst obj
+dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
 
 ###
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=

scripts/Makefile.build

@@ -48,9 +48,6 @@ include scripts/Makefile.uncmd_spl
 
 include scripts/Kbuild.include
 
-# For backward compatibility check that these variables do not change
-save-cflags := $(CFLAGS)
-
 # The filename Kbuild has precedence over Makefile
 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
@@ -61,13 +58,6 @@ asflags-y  += $(PLATFORM_CPPFLAGS)
 ccflags-y  += $(PLATFORM_CPPFLAGS)
 cppflags-y += $(PLATFORM_CPPFLAGS)
 
-# If the save-* variables changed error out
-ifeq ($(KBUILD_NOPEDANTIC),)
-        ifneq ("$(save-cflags)","$(CFLAGS)")
-                $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
-        endif
-endif
-
 include scripts/Makefile.lib
 
 # Do not include host rules unless needed
@@ -99,14 +89,12 @@ __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
 	@:
 
 # Linus' kernel sanity checking tool
-ifneq ($(KBUILD_CHECKSRC),0)
-  ifeq ($(KBUILD_CHECKSRC),2)
-    quiet_cmd_force_checksrc = CHECK   $<
-          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
-  else
-      quiet_cmd_checksrc     = CHECK   $<
-            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
-  endif
+ifeq ($(KBUILD_CHECKSRC),1)
+  quiet_cmd_checksrc       = CHECK   $<
+        cmd_checksrc       = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
+else ifeq ($(KBUILD_CHECKSRC),2)
+  quiet_cmd_force_checksrc = CHECK   $<
+        cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
 endif
 
 # Do section mismatch analysis for each module/built-in.o
@@ -369,21 +357,8 @@ $(lib-target): $(lib-y) FORCE
 targets += $(lib-target)
 endif
 
-#
-# Rule to link composite objects
-#
-#  Composite objects are specified in kbuild makefile as follows:
-#    <composite-object>-objs := <list of .o files>
-#  or
-#    <composite-object>-y    := <list of .o files>
-link_multi_deps =                     \
-$(filter $(addprefix $(obj)/,         \
-$($(subst $(obj)/,,$(@:.o=-objs)))    \
-$($(subst $(obj)/,,$(@:.o=-y)))), $^)
-
-
 quiet_cmd_link_multi-y = AR      $@
-cmd_link_multi-y = rm -f $@; $(AR) cDPrsT$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
+cmd_link_multi-y = rm -f $@; $(AR) cDPrsT$(KBUILD_ARFLAGS) $@ $(filter %.o,$^)
 
 quiet_cmd_link_multi-m = AR [M]  $@
 cmd_link_multi-m = $(cmd_link_multi-y)
@@ -394,7 +369,7 @@ $(call multi_depend, $(multi-used-y), .o, -objs -y)
 
 $(multi-used-m): FORCE
 	$(call if_changed,link_multi-m)
-	@{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
+	@{ echo $(@:.o=.ko); echo $(filter %.o,$^); } > $(MODVERDIR)/$(@F:.o=.mod)
 $(call multi_depend, $(multi-used-m), .o, -objs -y)
 
 targets += $(multi-used-y) $(multi-used-m)

scripts/Makefile.extrawarn

@@ -11,6 +11,8 @@
 # are not supported by all versions of the compiler
 # ==========================================================================
 
+KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
+
 ifeq ("$(origin W)", "command line")
   export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
 endif
@@ -25,7 +27,11 @@ warning-1 += $(call cc-option, -Wmissing-prototypes)
 warning-1 += -Wold-style-definition
 warning-1 += $(call cc-option, -Wmissing-include-dirs)
 warning-1 += $(call cc-option, -Wunused-but-set-variable)
+warning-1 += $(call cc-option, -Wunused-const-variable)
+warning-1 += $(call cc-option, -Wpacked-not-aligned)
+warning-1 += $(call cc-option, -Wstringop-truncation)
 warning-1 += $(call cc-disable-warning, missing-field-initializers)
+warning-1 += $(call cc-disable-warning, sign-compare)
 
 warning-2 := -Waggregate-return
 warning-2 += -Wcast-align
@@ -34,6 +40,9 @@ warning-2 += -Wnested-externs
 warning-2 += -Wshadow
 warning-2 += $(call cc-option, -Wlogical-op)
 warning-2 += $(call cc-option, -Wmissing-field-initializers)
+warning-2 += $(call cc-option, -Wsign-compare)
+warning-2 += $(call cc-option, -Wmaybe-uninitialized)
+warning-2 += $(call cc-option, -Wunused-macros)
 
 warning-3 := -Wbad-function-cast
 warning-3 += -Wcast-qual

scripts/Makefile.lib

@@ -320,7 +320,7 @@ quiet_cmd_dtc = DTC     $@
 # Bring in any U-Boot-specific include at the end of the file
 cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
 	(cat $<; $(if $(u_boot_dtsi),echo '$(pound)include "$(u_boot_dtsi)"')) > $(pre-tmp); \
-	$(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $(pre-tmp) ; \
+	$(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $(pre-tmp) ; \
 	$(DTC) -O dtb -o $@ -b 0 \
 		-i $(dir $<) $(DTC_FLAGS) \
 		-d $(depfile).dtc.tmp $(dtc-tmp) || \

scripts/clang-version.sh

@@ -0,0 +1,23 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# clang-version [-p] clang-command
+#
+# Prints the compiler version of `clang-command' in a canonical 4-digit form
+# such as `0500' for clang-5.0 etc.
+#
+# With the -p option, prints the patchlevel as well, for example `050001' for
+# clang-5.0.1 etc.
+#
+
+compiler="$*"
+
+if ! ( $compiler --version | grep -q clang) ; then
+	echo 0
+	exit 1
+fi
+
+MAJOR=$(echo __clang_major__ | $compiler -E -x c - | tail -n 1)
+MINOR=$(echo __clang_minor__ | $compiler -E -x c - | tail -n 1)
+PATCHLEVEL=$(echo __clang_patchlevel__ | $compiler -E -x c - | tail -n 1)
+printf "%d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL

scripts/gcc-version.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 #
 # gcc-version [-p] gcc-command
 #
@@ -22,10 +23,10 @@ if [ ${#compiler} -eq 0 ]; then
 	exit 1
 fi
 
-MAJOR=$(echo __GNUC__ | $compiler -E -xc - | tail -n 1)
-MINOR=$(echo __GNUC_MINOR__ | $compiler -E -xc - | tail -n 1)
+MAJOR=$(echo __GNUC__ | $compiler -E -x c - | tail -n 1)
+MINOR=$(echo __GNUC_MINOR__ | $compiler -E -x c - | tail -n 1)
 if [ "x$with_patchlevel" != "x" ] ; then
-	PATCHLEVEL=$(echo __GNUC_PATCHLEVEL__ | $compiler -E -xc - | tail -n 1)
+	PATCHLEVEL=$(echo __GNUC_PATCHLEVEL__ | $compiler -E -x c - | tail -n 1)
 	printf "%02d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL
 else
 	printf "%02d%02d\\n" $MAJOR $MINOR

scripts/kconfig/Makefile

@@ -74,21 +74,7 @@ PHONY += $(simple-targets)
 $(simple-targets): $(obj)/conf
 	$< $(silent) --$@ $(Kconfig)
 
-PHONY += oldnoconfig silentoldconfig savedefconfig defconfig
-
-# oldnoconfig is an alias of olddefconfig, because people already are dependent
-# on its behavior (sets new symbols to their default value but not 'n') with the
-# counter-intuitive name.
-oldnoconfig: olddefconfig
-	@echo "  WARNING: \"oldnoconfig\" target will be removed after Linux 4.19"
-	@echo "            Please use \"olddefconfig\" instead, which is an alias."
-
-# We do not expect manual invokcation of "silentoldcofig" (or "syncconfig").
-silentoldconfig: syncconfig
-	@echo "  WARNING: \"silentoldconfig\" has been renamed to \"syncconfig\""
-	@echo "            and is now an internal implementation detail."
-	@echo "            What you want is probably \"oldconfig\"."
-	@echo "            \"silentoldconfig\" will be removed after Linux 4.19"
+PHONY += savedefconfig defconfig
 
 savedefconfig: $(obj)/conf
 	$< $(silent) --$@=defconfig $(Kconfig)

scripts/kconfig/conf.c

@@ -460,12 +460,6 @@ static struct option long_opts[] = {
 	{"randconfig",      no_argument,       NULL, randconfig},
 	{"listnewconfig",   no_argument,       NULL, listnewconfig},
 	{"olddefconfig",    no_argument,       NULL, olddefconfig},
-	/*
-	 * oldnoconfig is an alias of olddefconfig, because people already
-	 * are dependent on its behavior(sets new symbols to their default
-	 * value but not 'n') with the counter-intuitive name.
-	 */
-	{"oldnoconfig",     no_argument,       NULL, olddefconfig},
 	{NULL, 0, NULL, 0}
 };
 
@@ -480,7 +474,6 @@ static void conf_usage(const char *progname)
 	printf("  --syncconfig            Similar to oldconfig but generates configuration in\n"
 	       "                          include/{generated/,config/}\n");
 	printf("  --olddefconfig          Same as oldconfig but sets new symbols to their default value\n");
-	printf("  --oldnoconfig           An alias of olddefconfig\n");
 	printf("  --defconfig <file>      New config with default defined in <file>\n");
 	printf("  --savedefconfig <file>  Save the minimal current configuration to <file>\n");
 	printf("  --allnoconfig           New config where all options are answered with no\n");