20 files changed, 548 insertions, 5065 deletions

diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst
index 63066db39910..af5a437198d0 100644
--- a/Documentation/admin-guide/README.rst
+++ b/Documentation/admin-guide/README.rst
@@ -170,11 +170,6 @@ Configuring the kernel
                         your existing ./.config file and asking about
                         new config symbols.
 
-     "make silentoldconfig"
-                        Like above, but avoids cluttering the screen
-                        with questions already answered.
-                        Additionally updates the dependencies.
-
      "make olddefconfig"
                         Like above, but sets new symbols to their default
                         values without prompting.
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 560beaef5a7c..81cdb528ad46 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -32,6 +32,8 @@ you probably needn't concern yourself with isdn4k-utils.
 GNU C                  3.2              gcc --version
 GNU make               3.81             make --version
 binutils               2.20             ld -v
+flex                   2.5.35           flex --version
+bison                  2.0              bison --version
 util-linux             2.10o            fdformat --version
 module-init-tools      0.9.10           depmod -V
 e2fsprogs              1.41.4           e2fsck -V
@@ -79,6 +81,19 @@ The build system has, as of 4.13, switched to using thin archives (`ar T`)
 rather than incremental linking (`ld -r`) for built-in.o intermediate steps.
 This requires binutils 2.20 or newer.
 
+Flex
+----
+
+Since Linux 4.16, the build system generates lexical analyzers
+during build.  This requires flex 2.5.35 or later.
+
+
+Bison
+-----
+
+Since Linux 4.16, the build system generates parsers
+during build.  This requires bison 2.0 or later.
+
 Perl
 ----
 
@@ -333,6 +348,16 @@ Binutils
 
 - <https://www.kernel.org/pub/linux/devel/binutils/>
 
+Flex
+----
+
+- <https://github.com/westes/flex/releases>
+
+Bison
+-----
+
+- <ftp://ftp.gnu.org/gnu/bison/>
+
 OpenSSL
 -------
 
diff --git a/Makefile b/Makefile
index c8b8e902d5a4..11aff0f9e105 100644
--- a/Makefile
+++ b/Makefile
@@ -377,6 +377,8 @@ NM		= $(CROSS_COMPILE)nm
 STRIP		= $(CROSS_COMPILE)strip
 OBJCOPY		= $(CROSS_COMPILE)objcopy
 OBJDUMP		= $(CROSS_COMPILE)objdump
+LEX		= flex
+YACC		= bison
 AWK		= awk
 GENKSYMS	= scripts/genksyms/genksyms
 INSTALLKERNEL  := installkernel
@@ -428,7 +430,7 @@ GCC_PLUGINS_CFLAGS :=
 
 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP HOSTLDFLAGS HOST_LOADLIBES
-export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
+export MAKE LEX YACC AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 6047ed4e8a3d..3098410abad8 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -113,7 +113,7 @@ config EFI_CAPSULE_LOADER
 	  Most users should say N.
 
 config EFI_CAPSULE_QUIRK_QUARK_CSH
-	boolean "Add support for Quark capsules with non-standard headers"
+	bool "Add support for Quark capsules with non-standard headers"
 	depends on X86 && !64BIT
 	select EFI_CAPSULE_LOADER
 	default y
diff --git a/drivers/staging/rtlwifi/Kconfig b/drivers/staging/rtlwifi/Kconfig
index b6b03950987b..7b4276f5c41f 100644
--- a/drivers/staging/rtlwifi/Kconfig
+++ b/drivers/staging/rtlwifi/Kconfig
@@ -7,6 +7,6 @@ config R8822BE
 	wireless network adapters.
 
 config RTLWIFI_DEBUG_ST
-	boolean
+	bool
 	depends on R8822BE
 	default y
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 7dee1da83e2a..5fdc1a19b02c 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -186,39 +186,49 @@ $(foreach m, $(notdir $1), \
 	$(addprefix $(obj)/, $(foreach s, $3, $($(m:%$(strip $2)=%$(s)))))))
 endef
 
-ifdef REGENERATE_PARSERS
-
 # LEX
 # ---------------------------------------------------------------------------
-LEX_PREFIX = $(if $(LEX_PREFIX_${baseprereq}),$(LEX_PREFIX_${baseprereq}),yy)
-
 quiet_cmd_flex = LEX     $@
-      cmd_flex = flex -o$@ -L -P $(LEX_PREFIX) $<
+      cmd_flex = $(LEX) -o$@ -L $<
 
+ifdef REGENERATE_PARSERS
 .PRECIOUS: $(src)/%.lex.c_shipped
 $(src)/%.lex.c_shipped: $(src)/%.l
 	$(call cmd,flex)
+endif
+
+.PRECIOUS: $(obj)/%.lex.c
+$(filter %.lex.c,$(targets)): $(obj)/%.lex.c: $(src)/%.l FORCE
+	$(call if_changed,flex)
 
 # YACC
 # ---------------------------------------------------------------------------
-YACC_PREFIX = $(if $(YACC_PREFIX_${baseprereq}),$(YACC_PREFIX_${baseprereq}),yy)
-
 quiet_cmd_bison = YACC    $@
-      cmd_bison = bison -o$@ -t -l -p $(YACC_PREFIX) $<
+      cmd_bison = $(YACC) -o$@ -t -l $<
 
+ifdef REGENERATE_PARSERS
 .PRECIOUS: $(src)/%.tab.c_shipped
 $(src)/%.tab.c_shipped: $(src)/%.y
 	$(call cmd,bison)
+endif
+
+.PRECIOUS: $(obj)/%.tab.c
+$(filter %.tab.c,$(targets)): $(obj)/%.tab.c: $(src)/%.y FORCE
+	$(call if_changed,bison)
 
 quiet_cmd_bison_h = YACC    $@
       cmd_bison_h = bison -o/dev/null --defines=$@ -t -l -p $(YACC_PREFIX) $<
 
+ifdef REGENERATE_PARSERS
 .PRECIOUS: $(src)/%.tab.h_shipped
 $(src)/%.tab.h_shipped: $(src)/%.y
 	$(call cmd,bison_h)
-
 endif
 
+.PRECIOUS: $(obj)/%.tab.h
+$(filter %.tab.h,$(targets)): $(obj)/%.tab.h: $(src)/%.y FORCE
+	$(call if_changed,bison_h)
+
 # Shipped files
 # ===========================================================================
 
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index 297c1bf35140..cb3ec53a7c29 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -34,6 +34,8 @@ config: $(obj)/conf
 nconfig: $(obj)/nconf
 	$< $(silent) $(Kconfig)
 
+# This has become an internal implementation detail and is now deprecated
+# for external use.
 silentoldconfig: $(obj)/conf
 	$(Q)mkdir -p include/config include/generated
 	$(Q)test -e include/generated/autoksyms.h || \
@@ -92,6 +94,8 @@ PHONY += oldnoconfig savedefconfig defconfig
 # 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."
 
 savedefconfig: $(obj)/conf
 	$< $(silent) --$@=defconfig $(Kconfig)
@@ -142,7 +146,6 @@ help:
 	@echo  '  oldconfig	  - Update current config utilising a provided .config as base'
 	@echo  '  localmodconfig  - Update current config disabling modules not loaded'
 	@echo  '  localyesconfig  - Update current config converting local mods to core'
-	@echo  '  silentoldconfig - Same as oldconfig, but quietly, additionally update deps'
 	@echo  '  defconfig	  - New config with default from ARCH supplied defconfig'
 	@echo  '  savedefconfig   - Save current config as ./defconfig (minimal config)'
 	@echo  '  allnoconfig	  - New config where all options are answered with no'
@@ -151,8 +154,8 @@ help:
 	@echo  '  alldefconfig    - New config with all symbols set to default'
 	@echo  '  randconfig	  - New config with random answer to all options'
 	@echo  '  listnewconfig   - List new options'
-	@echo  '  olddefconfig	  - Same as silentoldconfig but sets new symbols to their'
-	@echo  '                    default value'
+	@echo  '  olddefconfig	  - Same as oldconfig but sets new symbols to their'
+	@echo  '                    default value without prompting'
 	@echo  '  kvmconfig	  - Enable additional options for kvm guest kernel support'
 	@echo  '  xenconfig       - Enable additional options for xen dom0 and guest kernel support'
 	@echo  '  tinyconfig	  - Configure the tiniest possible kernel'
@@ -191,6 +194,7 @@ gconf-objs	:= gconf.o zconf.tab.o
 
 hostprogs-y := conf nconf mconf kxgettext qconf gconf
 
+targets		+= zconf.tab.c zconf.lex.c
 clean-files	:= qconf.moc .tmp_qtcheck .tmp_gtkcheck
 clean-files	+= zconf.tab.c zconf.lex.c gconf.glade.h
 clean-files     += config.pot linux.pot
@@ -205,14 +209,12 @@ always := dochecklxdialog
 
 # Add environment specific flags
 HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCC) $(HOSTCFLAGS))
+HOST_EXTRACXXFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCXX) $(HOSTCXXFLAGS))
 
 # generated files seem to need this to find local include files
 HOSTCFLAGS_zconf.lex.o	:= -I$(src)
 HOSTCFLAGS_zconf.tab.o	:= -I$(src)
 
-LEX_PREFIX_zconf	:= zconf
-YACC_PREFIX_zconf	:= zconf
-
 HOSTLOADLIBES_qconf	= $(KC_QT_LIBS)
 HOSTCXXFLAGS_qconf.o	= $(KC_QT_CFLAGS)
 
diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 866369f10ff8..307bc3f7b945 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -20,7 +20,6 @@
 
 static void conf(struct menu *menu);
 static void check_conf(struct menu *menu);
-static void xfgets(char *str, int size, FILE *in);
 
 enum input_mode {
 	oldaskconfig,
@@ -35,7 +34,8 @@ enum input_mode {
 	savedefconfig,
 	listnewconfig,
 	olddefconfig,
-} input_mode = oldaskconfig;
+};
+static enum input_mode input_mode = oldaskconfig;
 
 static int indent = 1;
 static int tty_stdio;
@@ -82,6 +82,13 @@ static void check_stdin(void)
 	}
 }
 
+/* Helper function to facilitate fgets() by Jean Sacren. */
+static void xfgets(char *str, int size, FILE *in)
+{
+	if (!fgets(str, size, in))
+		fprintf(stderr, "\nError in reading or end of file.\n");
+}
+
 static int conf_askvalue(struct symbol *sym, const char *def)
 {
 	enum symbol_type type = sym_get_type(sym);
@@ -477,8 +484,9 @@ static void conf_usage(const char *progname)
 	printf("  --listnewconfig         List new options\n");
 	printf("  --oldaskconfig          Start a new configuration using a line-oriented program\n");
 	printf("  --oldconfig             Update a configuration using a provided .config as base\n");
-	printf("  --silentoldconfig       Same as oldconfig, but quietly, additionally update deps\n");
-	printf("  --olddefconfig          Same as silentoldconfig but sets new symbols to their default value\n");
+	printf("  --silentoldconfig       Similar to oldconfig but generates configuration in\n"
+	       "                          include/{generated/,config/} (oldconfig used to be more verbose)\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");
@@ -712,12 +720,3 @@ int main(int ac, char **av)
 	}
 	return 0;
 }
-
-/*
- * Helper function to facilitate fgets() by Jean Sacren.
- */
-void xfgets(char *str, int size, FILE *in)
-{
-	if (fgets(str, size, in) == NULL)
-		fprintf(stderr, "\nError in reading or end of file.\n");
-}
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 297b079ae4d9..f7927391de30 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -28,7 +28,7 @@ static void conf_message(const char *fmt, ...)
 	__attribute__ ((format (printf, 1, 2)));
 
 static const char *conf_filename;
-static int conf_lineno, conf_warnings, conf_unsaved;
+static int conf_lineno, conf_warnings;
 
 const char conf_defname[] = "arch/$ARCH/defconfig";
 
@@ -290,7 +290,6 @@ load:
 	conf_filename = name;
 	conf_lineno = 0;
 	conf_warnings = 0;
-	conf_unsaved = 0;
 
 	def_flags = SYMBOL_DEF << def;
 	for_all_symbols(i, sym) {
@@ -409,6 +408,7 @@ setsym:
 int conf_read(const char *name)
 {
 	struct symbol *sym;
+	int conf_unsaved = 0;
 	int i;
 
 	sym_set_change_count(0);
@@ -1123,7 +1123,7 @@ void set_all_choice_values(struct symbol *csym)
 bool conf_set_all_new_symbols(enum conf_def_mode mode)
 {
 	struct symbol *sym, *csym;
-	int i, cnt, pby, pty, ptm;	/* pby: probability of boolean  = y
+	int i, cnt, pby, pty, ptm;	/* pby: probability of bool     = y
 					 * pty: probability of tristate = y
 					 * ptm: probability of tristate = m
 					 */
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index 8cee597d33a5..2ba332b3fed7 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -113,7 +113,7 @@ void expr_free(struct expr *e)
 		break;
 	case E_NOT:
 		expr_free(e->left.expr);
-		return;
+		break;
 	case E_EQUAL:
 	case E_GEQ:
 	case E_GTH:
@@ -138,8 +138,18 @@ static int trans_count;
 #define e1 (*ep1)
 #define e2 (*ep2)
 
+/*
+ * expr_eliminate_eq() helper.
+ *
+ * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
+ * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
+ * against all other leaves. Two equal leaves are both replaced with either 'y'
+ * or 'n' as appropriate for 'type', to be eliminated later.
+ */
 static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
 {
+	/* Recurse down to leaves */
+
 	if (e1->type == type) {
 		__expr_eliminate_eq(type, &e1->left.expr, &e2);
 		__expr_eliminate_eq(type, &e1->right.expr, &e2);
@@ -150,12 +160,18 @@ static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct e
 		__expr_eliminate_eq(type, &e1, &e2->right.expr);
 		return;
 	}
+
+	/* e1 and e2 are leaves. Compare them. */
+
 	if (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
 	    e1->left.sym == e2->left.sym &&
 	    (e1->left.sym == &symbol_yes || e1->left.sym == &symbol_no))
 		return;
 	if (!expr_eq(e1, e2))
 		return;
+
+	/* e1 and e2 are equal leaves. Prepare them for elimination. */
+
 	trans_count++;
 	expr_free(e1); expr_free(e2);
 	switch (type) {
@@ -172,6 +188,35 @@ static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct e
 	}
 }
 
+/*
+ * Rewrites the expressions 'ep1' and 'ep2' to remove operands common to both.
+ * Example reductions:
+ *
+ *	ep1: A && B           ->  ep1: y
+ *	ep2: A && B && C      ->  ep2: C
+ *
+ *	ep1: A || B           ->  ep1: n
+ *	ep2: A || B || C      ->  ep2: C
+ *
+ *	ep1: A && (B && FOO)  ->  ep1: FOO
+ *	ep2: (BAR && B) && A  ->  ep2: BAR
+ *
+ *	ep1: A && (B || C)    ->  ep1: y
+ *	ep2: (C || B) && A    ->  ep2: y
+ *
+ * Comparisons are done between all operands at the same "level" of && or ||.
+ * For example, in the expression 'e1 && (e2 || e3) && (e4 || e5)', the
+ * following operands will be compared:
+ *
+ *	- 'e1', 'e2 || e3', and 'e4 || e5', against each other
+ *	- e2 against e3
+ *	- e4 against e5
+ *
+ * Parentheses are irrelevant within a single level. 'e1 && (e2 && e3)' and
+ * '(e1 && e2) && e3' are both a single level.
+ *
+ * See __expr_eliminate_eq() as well.
+ */
 void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
 {
 	if (!e1 || !e2)
@@ -197,6 +242,12 @@ void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
 #undef e1
 #undef e2
 
+/*
+ * Returns true if 'e1' and 'e2' are equal, after minor simplification. Two
+ * &&/|| expressions are considered equal if every operand in one expression
+ * equals some operand in the other (operands do not need to appear in the same
+ * order), recursively.
+ */
 static int expr_eq(struct expr *e1, struct expr *e2)
 {
 	int res, old_count;
@@ -243,6 +294,17 @@ static int expr_eq(struct expr *e1, struct expr *e2)
 	return 0;
 }
 
+/*
+ * Recursively performs the following simplifications in-place (as well as the
+ * corresponding simplifications with swapped operands):
+ *
+ *	expr && n  ->  n
+ *	expr && y  ->  expr
+ *	expr || n  ->  expr
+ *	expr || y  ->  y
+ *
+ * Returns the optimized expression.
+ */
 static struct expr *expr_eliminate_yn(struct expr *e)
 {
 	struct expr *tmp;
@@ -516,12 +578,21 @@ static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
 	return NULL;
 }
 
+/*
+ * expr_eliminate_dups() helper.
+ *
+ * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
+ * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
+ * against all other leaves to look for simplifications.
+ */
 static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct expr **ep2)
 {
 #define e1 (*ep1)
 #define e2 (*ep2)
 	struct expr *tmp;
 
+	/* Recurse down to leaves */
+
 	if (e1->type == type) {
 		expr_eliminate_dups1(type, &e1->left.expr, &e2);
 		expr_eliminate_dups1(type, &e1->right.expr, &e2);
@@ -532,6 +603,9 @@ static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct
 		expr_eliminate_dups1(type, &e1, &e2->right.expr);
 		return;
 	}
+
+	/* e1 and e2 are leaves. Compare and process them. */
+
 	if (e1 == e2)
 		return;
 
@@ -568,6 +642,17 @@ static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct
 #undef e2
 }
 
+/*
+ * Rewrites 'e' in-place to remove ("join") duplicate and other redundant
+ * operands.
+ *
+ * Example simplifications:
+ *
+ *	A || B || A    ->  A || B
+ *	A && B && A=y  ->  A=y && B
+ *
+ * Returns the deduplicated expression.
+ */
 struct expr *expr_eliminate_dups(struct expr *e)
 {
 	int oldcount;
@@ -584,6 +669,7 @@ struct expr *expr_eliminate_dups(struct expr *e)
 			;
 		}
 		if (!trans_count)
+			/* No simplifications done in this pass. We're done */
 			break;
 		e = expr_eliminate_yn(e);
 	}
@@ -591,6 +677,12 @@ struct expr *expr_eliminate_dups(struct expr *e)
 	return e;
 }
 
+/*
+ * Performs various simplifications involving logical operators and
+ * comparisons.
+ *
+ * Allocates and returns a new expression.
+ */
 struct expr *expr_transform(struct expr *e)
 {
 	struct expr *tmp;
@@ -805,6 +897,20 @@ bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
  	return false;
 }
 
+/*
+ * Inserts explicit comparisons of type 'type' to symbol 'sym' into the
+ * expression 'e'.
+ *
+ * Examples transformations for type == E_UNEQUAL, sym == &symbol_no:
+ *
+ *	A              ->  A!=n
+ *	!A             ->  A=n
+ *	A && B         ->  !(A=n || B=n)
+ *	A || B         ->  !(A=n && B=n)
+ *	A && (B || C)  ->  !(A=n || (B=n && C=n))
+ *
+ * Allocates and returns a new expression.
+ */
 struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
 {
 	struct expr *e1, *e2;
@@ -1073,7 +1179,7 @@ struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2)
 	return expr_get_leftmost_symbol(ret);
 }
 
-void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
+static void __expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken, bool revdep)
 {
 	if (!e) {
 		fn(data, NULL, "y");
@@ -1128,9 +1234,14 @@ void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *
 		fn(data, e->right.sym, e->right.sym->name);
 		break;
 	case E_OR:
-		expr_print(e->left.expr, fn, data, E_OR);
-		fn(data, NULL, " || ");
-		expr_print(e->right.expr, fn, data, E_OR);
+		if (revdep && e->left.expr->type != E_OR)
+			fn(data, NULL, "\n  - ");
+		__expr_print(e->left.expr, fn, data, E_OR, revdep);
+		if (revdep)
+			fn(data, NULL, "\n  - ");
+		else
+			fn(data, NULL, " || ");
+		__expr_print(e->right.expr, fn, data, E_OR, revdep);
 		break;
 	case E_AND:
 		expr_print(e->left.expr, fn, data, E_AND);
@@ -1163,6 +1274,11 @@ void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *
 		fn(data, NULL, ")");
 }
 
+void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
+{
+	__expr_print(e, fn, data, prevtoken, false);
+}
+
 static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
 {
 	xfwrite(str, strlen(str), 1, data);
@@ -1207,3 +1323,13 @@ void expr_gstr_print(struct expr *e, struct gstr *gs)
 {
 	expr_print(e, expr_print_gstr_helper, gs, E_NONE);
 }
+
+/*
+ * Transform the top level "||" tokens into newlines and prepend each
+ * line with a minus. This makes expressions much easier to read.
+ * Suitable for reverse dependency expressions.
+ */
+void expr_gstr_print_revdep(struct expr *e, struct gstr *gs)
+{
+	__expr_print(e, expr_print_gstr_helper, gs, E_NONE, true);
+}
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index a73f762c48d6..c16e82e302a2 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -74,17 +74,60 @@ enum {
 	S_DEF_COUNT
 };
 
+/*
+ * Represents a configuration symbol.
+ *
+ * Choices are represented as a special kind of symbol and have the
+ * SYMBOL_CHOICE bit set in 'flags'.
+ */
 struct symbol {
+	/* The next symbol in the same bucket in the symbol hash table */
 	struct symbol *next;
+
+	/* The name of the symbol, e.g. "FOO" for 'config FOO' */
 	char *name;
+
+	/* S_BOOLEAN, S_TRISTATE, ... */
 	enum symbol_type type;
+
+	/*
+	 * The calculated value of the symbol. The SYMBOL_VALID bit is set in
+	 * 'flags' when this is up to date. Note that this value might differ
+	 * from the user value set in e.g. a .config file, due to visibility.
+	 */
 	struct symbol_value curr;
+
+	/*
+	 * Values for the symbol provided from outside. def[S_DEF_USER] holds
+	 * the .config value.
+	 */
 	struct symbol_value def[S_DEF_COUNT];
+
+	/*
+	 * An upper bound on the tristate value the user can set for the symbol
+	 * if it is a boolean or tristate. Calculated from prompt dependencies,
+	 * which also inherit dependencies from enclosing menus, choices, and
+	 * ifs. If 'n', the user value will be ignored.
+	 *
+	 * Symbols lacking prompts always have visibility 'n'.
+	 */
 	tristate visible;
+
+	/* SYMBOL_* flags */
 	int flags;
+
+	/* List of properties. See prop_type. */
 	struct property *prop;
+
+	/* Dependencies from enclosing menus, choices, and ifs */
 	struct expr_value dir_dep;
+
+	/* Reverse dependencies through being selected by other symbols */
 	struct expr_value rev_dep;
+
+	/*
+	 * "Weak" reverse dependencies through being implied by other symbols
+	 */
 	struct expr_value implied;
 };
 
@@ -133,7 +176,7 @@ enum prop_type {
 	P_UNKNOWN,
 	P_PROMPT,   /* prompt "foo prompt" or "BAZ Value" */
 	P_COMMENT,  /* text associated with a comment */
-	P_MENU,     /* prompt associated with a menuconfig option */
+	P_MENU,     /* prompt associated with a menu or menuconfig symbol */
 	P_DEFAULT,  /* default y */
 	P_CHOICE,   /* choice value */
 	P_SELECT,   /* select BAR */
@@ -166,22 +209,67 @@ struct property {
 	for (st = sym->prop; st; st = st->next) \
 		if (st->text)
 
+/*
+ * Represents a node in the menu tree, as seen in e.g. menuconfig (though used
+ * for all front ends). Each symbol, menu, etc. defined in the Kconfig files
+ * gets a node. A symbol defined in multiple locations gets one node at each
+ * location.
+ */
 struct menu {
+	/* The next menu node at the same level */
 	struct menu *next;
+
+	/* The parent menu node, corresponding to e.g. a menu or choice */
 	struct menu *parent;
+
+	/* The first child menu node, for e.g. menus and choices */
 	struct menu *list;
+
+	/*
+	 * The symbol associated with the menu node. Choices are implemented as
+	 * a special kind of symbol. NULL for menus, comments, and ifs.
+	 */
 	struct symbol *sym;
+
+	/*
+	 * The prompt associated with the node. This holds the prompt for a
+	 * symbol as well as the text for a menu or comment, along with the
+	 * type (P_PROMPT, P_MENU, etc.)
+	 */
 	struct property *prompt;
+
+	/*
+	 * 'visible if' dependencies. If more than one is given, they will be
+	 * ANDed together.
+	 */
 	struct expr *visibility;
+
+	/*
+	 * Ordinary dependencies from e.g. 'depends on' and 'if', ANDed
+	 * together
+	 */
 	struct expr *dep;
+
+	/* MENU_* flags */
 	unsigned int flags;
+
+	/* Any help text associated with the node */
 	char *help;
+
+	/* The location where the menu node appears in the Kconfig files */
 	struct file *file;
 	int lineno;
+
+	/* For use by front ends that need to store auxiliary data */
 	void *data;
 };
 
+/*
+ * Set on a menu node when the corresponding symbol changes state in some way.
+ * Can be checked by front ends.
+ */
 #define MENU_CHANGED		0x0001
+
 #define MENU_ROOT		0x0002
 
 struct jump_key {
@@ -222,6 +310,7 @@ struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2);
 void expr_fprint(struct expr *e, FILE *out);
 struct gstr; /* forward */
 void expr_gstr_print(struct expr *e, struct gstr *gs);
+void expr_gstr_print_revdep(struct expr *e, struct gstr *gs);
 
 static inline int expr_is_yes(struct expr *e)
 {
diff --git a/scripts/kconfig/kconf_id.c b/scripts/kconfig/kconf_id.c
index 5abbc728fbc4..3ea9c5f9f730 100644
--- a/scripts/kconfig/kconf_id.c
+++ b/scripts/kconfig/kconf_id.c
@@ -20,7 +20,6 @@ static struct kconf_id kconf_id_array[] = {
 	{ "tristate",		T_TYPE,			TF_COMMAND, S_TRISTATE },
 	{ "def_tristate",	T_DEFAULT,		TF_COMMAND, S_TRISTATE },
 	{ "bool",		T_TYPE,			TF_COMMAND, S_BOOLEAN },
-	{ "boolean",		T_TYPE,			TF_COMMAND, S_BOOLEAN },
 	{ "def_bool",		T_DEFAULT,		TF_COMMAND, S_BOOLEAN },
 	{ "int",		T_TYPE,			TF_COMMAND, S_INT },
 	{ "hex",		T_TYPE,			TF_COMMAND, S_HEX },
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index cdcbe43e87b3..16cb62b92650 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -100,7 +100,6 @@ void menu_warn(struct menu *menu, const char *fmt, ...);
 struct menu *menu_add_menu(void);
 void menu_end_menu(void);
 void menu_add_entry(struct symbol *sym);
-void menu_end_entry(void);
 void menu_add_dep(struct expr *dep);
 void menu_add_visibility(struct expr *dep);
 struct property *menu_add_prompt(enum prop_type type, char *prompt, struct expr *dep);
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index 315ce2c7cb9d..c829be8bb19f 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -246,7 +246,7 @@ search_help[] = N_(
 	"  Selected by: BAR [=n]\n"
 	"-----------------------------------------------------------------\n"
 	"o The line 'Type:' shows the type of the configuration option for\n"
-	"  this symbol (boolean, tristate, string, ...)\n"
+	"  this symbol (bool, tristate, string, ...)\n"
 	"o The line 'Prompt:' shows the text used in the menu structure for\n"
 	"  this symbol\n"
 	"o The 'Defined at' line tells at what file / line number the symbol\n"
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index e9357931b47d..99222855544c 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -62,13 +62,8 @@ void menu_add_entry(struct symbol *sym)
 		menu_add_symbol(P_SYMBOL, sym, NULL);
 }
 
-void menu_end_entry(void)
-{
-}
-
 struct menu *menu_add_menu(void)
 {
-	menu_end_entry();
 	last_entry_ptr = &current_entry->list;
 	return current_menu = current_entry;
 }
@@ -79,19 +74,23 @@ void menu_end_menu(void)
 	current_menu = current_menu->parent;
 }
 
-static struct expr *menu_check_dep(struct expr *e)
+/*
+ * Rewrites 'm' to 'm' && MODULES, so that it evaluates to 'n' when running
+ * without modules
+ */
+static struct expr *rewrite_m(struct expr *e)
 {
 	if (!e)
 		return e;
 
 	switch (e->type) {
 	case E_NOT:
-		e->left.expr = menu_check_dep(e->left.expr);
+		e->left.expr = rewrite_m(e->left.expr);
 		break;
 	case E_OR:
 	case E_AND:
-		e->left.expr = menu_check_dep(e->left.expr);
-		e->right.expr = menu_check_dep(e->right.expr);
+		e->left.expr = rewrite_m(e->left.expr);
+		e->right.expr = rewrite_m(e->right.expr);
 		break;
 	case E_SYMBOL:
 		/* change 'm' into 'm' && MODULES */
@@ -106,7 +105,7 @@ static struct expr *menu_check_dep(struct expr *e)
 
 void menu_add_dep(struct expr *dep)
 {
-	current_entry->dep = expr_alloc_and(current_entry->dep, menu_check_dep(dep));
+	current_entry->dep = expr_alloc_and(current_entry->dep, dep);
 }
 
 void menu_set_type(int type)
@@ -131,7 +130,7 @@ static struct property *menu_add_prop(enum prop_type type, char *prompt, struct
 
 	prop->menu = current_entry;
 	prop->expr = expr;
-	prop->visible.expr = menu_check_dep(dep);
+	prop->visible.expr = dep;
 
 	if (prompt) {
 		if (isspace(*prompt)) {
@@ -252,6 +251,16 @@ static void sym_check_prop(struct symbol *sym)
 					    "'%s': number is invalid",
 					    sym->name);
 			}
+			if (sym_is_choice(sym)) {
+				struct property *choice_prop =
+					sym_get_choice_prop(sym2);
+
+				if (!choice_prop ||
+				    prop_get_symbol(choice_prop) != sym)
+					prop_warn(prop,
+						  "choice default symbol '%s' is not contained in the choice",
+						  sym2->name);
+			}
 			break;
 		case P_SELECT:
 		case P_IMPLY:
@@ -260,13 +269,13 @@ static void sym_check_prop(struct symbol *sym)
 			if (sym->type != S_BOOLEAN && sym->type != S_TRISTATE)
 				prop_warn(prop,
 				    "config symbol '%s' uses %s, but is "
-				    "not boolean or tristate", sym->name, use);
+				    "not bool or tristate", sym->name, use);
 			else if (sym2->type != S_UNKNOWN &&
 				 sym2->type != S_BOOLEAN &&
 				 sym2->type != S_TRISTATE)
 				prop_warn(prop,
 				    "'%s' has wrong type. '%s' only "
-				    "accept arguments of boolean and "
+				    "accept arguments of bool and "
 				    "tristate type", sym2->name, use);
 			break;
 		case P_RANGE:
@@ -292,6 +301,11 @@ void menu_finalize(struct menu *parent)