17 files changed, 590 insertions, 187 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 557e725ab932..a6461ea411f7 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -37,6 +37,90 @@ include $(srctree)/scripts/Makefile.compiler
 include $(kbuild-file)
 include $(srctree)/scripts/Makefile.lib
 
+# flags that take effect in current and sub directories
+KBUILD_AFLAGS += $(subdir-asflags-y)
+KBUILD_CFLAGS += $(subdir-ccflags-y)
+KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
+
+# Figure out what we need to build from the various variables
+# ===========================================================================
+
+# When an object is listed to be built compiled-in and modular,
+# only build the compiled-in version
+obj-m := $(filter-out $(obj-y),$(obj-m))
+
+# Libraries are always collected in one lib file.
+# Filter out objects already built-in
+lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
+
+# Subdirectories we need to descend into
+subdir-ym := $(sort $(subdir-y) $(subdir-m) \
+			$(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m))))
+
+# Handle objects in subdirs:
+# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and
+#   foo/modules.order
+# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order
+#
+# Generate modules.order to determine modorder. Unfortunately, we don't have
+# information about ordering between -y and -m subdirs. Just put -y's first.
+
+ifdef need-modorder
+obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))
+else
+obj-m := $(filter-out %/, $(obj-m))
+endif
+
+ifdef need-builtin
+obj-y		:= $(patsubst %/, %/built-in.a, $(obj-y))
+else
+obj-y		:= $(filter-out %/, $(obj-y))
+endif
+
+# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
+suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
+# List composite targets that are constructed by combining other targets
+multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
+# List primitive targets that are compiled from source files
+real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
+
+# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
+multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
+multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)
+multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
+
+# Replace multi-part objects by their individual parts,
+# including built-in.a from subdirectories
+real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
+real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
+
+always-y += $(always-m)
+
+# hostprogs-always-y += foo
+# ... is a shorthand for
+# hostprogs += foo
+# always-y  += foo
+hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
+always-y += $(hostprogs-always-y) $(hostprogs-always-m)
+
+# userprogs-always-y is likewise.
+userprogs += $(userprogs-always-y) $(userprogs-always-m)
+always-y += $(userprogs-always-y) $(userprogs-always-m)
+
+# Add subdir path
+
+ifneq ($(obj),.)
+extra-y		:= $(addprefix $(obj)/, $(extra-y))
+always-y	:= $(addprefix $(obj)/, $(always-y))
+targets		:= $(addprefix $(obj)/, $(targets))
+obj-m		:= $(addprefix $(obj)/, $(obj-m))
+lib-y		:= $(addprefix $(obj)/, $(lib-y))
+real-obj-y	:= $(addprefix $(obj)/, $(real-obj-y))
+real-obj-m	:= $(addprefix $(obj)/, $(real-obj-m))
+multi-obj-m	:= $(addprefix $(obj)/, $(multi-obj-m))
+subdir-ym	:= $(addprefix $(obj)/, $(subdir-ym))
+endif
+
 ifndef obj
 $(warning kbuild: Makefile.build is included improperly)
 endif
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2b332645e0c2..1d581ba5df66 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -1,89 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-# flags that take effect in current and sub directories
-KBUILD_AFLAGS += $(subdir-asflags-y)
-KBUILD_CFLAGS += $(subdir-ccflags-y)
-KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
-
-# Figure out what we need to build from the various variables
-# ===========================================================================
-
-# When an object is listed to be built compiled-in and modular,
-# only build the compiled-in version
-obj-m := $(filter-out $(obj-y),$(obj-m))
-
-# Libraries are always collected in one lib file.
-# Filter out objects already built-in
-lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
-
-# Subdirectories we need to descend into
-subdir-ym := $(sort $(subdir-y) $(subdir-m) \
-			$(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m))))
-
-# Handle objects in subdirs:
-# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and
-#   foo/modules.order
-# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order
-#
-# Generate modules.order to determine modorder. Unfortunately, we don't have
-# information about ordering between -y and -m subdirs. Just put -y's first.
-
-ifdef need-modorder
-obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))
-else
-obj-m := $(filter-out %/, $(obj-m))
-endif
-
-ifdef need-builtin
-obj-y		:= $(patsubst %/, %/built-in.a, $(obj-y))
-else
-obj-y		:= $(filter-out %/, $(obj-y))
-endif
-
-# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
-suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
-# List composite targets that are constructed by combining other targets
-multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
-# List primitive targets that are compiled from source files
-real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
-
-# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
-multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
-multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)
-multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
-
-# Replace multi-part objects by their individual parts,
-# including built-in.a from subdirectories
-real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
-real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
-
-always-y += $(always-m)
-
-# hostprogs-always-y += foo
-# ... is a shorthand for
-# hostprogs += foo
-# always-y  += foo
-hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
-always-y += $(hostprogs-always-y) $(hostprogs-always-m)
-
-# userprogs-always-y is likewise.
-userprogs += $(userprogs-always-y) $(userprogs-always-m)
-always-y += $(userprogs-always-y) $(userprogs-always-m)
-
-# Add subdir path
-
-ifneq ($(obj),.)
-extra-y		:= $(addprefix $(obj)/,$(extra-y))
-always-y	:= $(addprefix $(obj)/,$(always-y))
-targets		:= $(addprefix $(obj)/,$(targets))
-obj-m		:= $(addprefix $(obj)/,$(obj-m))
-lib-y		:= $(addprefix $(obj)/,$(lib-y))
-real-obj-y	:= $(addprefix $(obj)/,$(real-obj-y))
-real-obj-m	:= $(addprefix $(obj)/,$(real-obj-m))
-multi-obj-m	:= $(addprefix $(obj)/, $(multi-obj-m))
-subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
-endif
-
 # Finds the multi-part object the current object will be linked into.
 # If the object belongs to two or more multi-part objects, list them all.
 modname-multi = $(sort $(foreach m,$(multi-obj-ym),\
diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index eed247d8abfc..13ea7bf1ae7d 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -228,12 +228,24 @@ static void process_fqn(struct die *cache, Dwarf_Die *die)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(accessibility)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(alignment)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(bit_size)
-DEFINE_PROCESS_UDATA_ATTRIBUTE(byte_size)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(encoding)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(data_bit_offset)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(data_member_location)
 DEFINE_PROCESS_UDATA_ATTRIBUTE(discr_value)
 
+static void process_byte_size_attr(struct die *cache, Dwarf_Die *die)
+{
+	Dwarf_Word value;
+	unsigned long override;
+
+	if (get_udata_attr(die, DW_AT_byte_size, &value)) {
+		if (stable && kabi_get_byte_size(cache->fqn, &override))
+			value = override;
+
+		process_fmt(cache, " byte_size(%" PRIu64 ")", value);
+	}
+}
+
 /* Match functions -- die_match_callback_t */
 #define DEFINE_MATCH(type)                                     \
 	static bool match_##type##_type(Dwarf_Die *die)        \
diff --git a/scripts/gendwarfksyms/examples/kabi.h b/scripts/gendwarfksyms/examples/kabi.h
index 97a5669b083d..170733a3fba4 100644
--- a/scripts/gendwarfksyms/examples/kabi.h
+++ b/scripts/gendwarfksyms/examples/kabi.h
@@ -37,11 +37,14 @@
 #define __stringify(x...) __stringify_1(x)
 #endif
 
-#define __KABI_RULE(hint, target, value)                             \
+#define ___KABI_RULE(hint, target, value)                            \
 	static const char __PASTE(__gendwarfksyms_rule_,             \
 				  __COUNTER__)[] __used __aligned(1) \
 		__section(".discard.gendwarfksyms.kabi_rules") =     \
-			"1\0" #hint "\0" #target "\0" #value
+			"1\0" #hint "\0" target "\0" value
+
+#define __KABI_RULE(hint, target, value) \
+	___KABI_RULE(hint, #target, #value)
 
 #define __KABI_NORMAL_SIZE_ALIGN(_orig, _new)                                             \
 	union {                                                                           \
@@ -90,6 +93,20 @@
 	__KABI_RULE(enumerator_value, fqn field, value)
 
 /*
+ * KABI_BYTE_SIZE(fqn, value)
+ *   Set the byte_size attribute for the struct/union/enum fqn to
+ *   value bytes.
+ */
+#define KABI_BYTE_SIZE(fqn, value) __KABI_RULE(byte_size, fqn, value)
+
+/*
+ * KABI_TYPE_STRING(type, str)
+ *   For the given type, override the type string used in symtypes
+ *   output and version calculation with str.
+ */
+#define KABI_TYPE_STRING(type, str) ___KABI_RULE(type_string, type, str)
+
+/*
  * KABI_RESERVE
  *   Reserve some "padding" in a structure for use by LTS backports.
  *   This is normally placed at the end of a structure.
diff --git a/scripts/gendwarfksyms/examples/kabi_ex.c b/scripts/gendwarfksyms/examples/kabi_ex.c
index 0b7ffd830541..1f799eb7c756 100644
--- a/scripts/gendwarfksyms/examples/kabi_ex.c
+++ b/scripts/gendwarfksyms/examples/kabi_ex.c
@@ -28,3 +28,10 @@ struct ex2c ex2c;
 struct ex3a ex3a;
 struct ex3b ex3b;
 struct ex3c ex3c;
+
+struct ex4a ex4a;
+
+struct ex5a ex5a;
+struct ex5b ex5b;
+
+int ex6a;
diff --git a/scripts/gendwarfksyms/examples/kabi_ex.h b/scripts/gendwarfksyms/examples/kabi_ex.h
index 1736e0f65208..785b211d9c58 100644
--- a/scripts/gendwarfksyms/examples/kabi_ex.h
+++ b/scripts/gendwarfksyms/examples/kabi_ex.h
@@ -21,6 +21,12 @@
  * 	./gendwarfksyms --stable --dump-dies \
  * 		examples/kabi_ex.o 2>&1 >/dev/null | \
  * 	FileCheck examples/kabi_ex.h --check-prefix=STABLE
+
+ * $ nm examples/kabi_ex.o | awk '{ print $NF }' | \
+ * 	./gendwarfksyms --stable --dump-versions \
+ * 		examples/kabi_ex.o 2>&1 >/dev/null | \
+ * 	sort | \
+ * 	FileCheck examples/kabi_ex.h --check-prefix=VERSIONS
  */
 
 #ifndef __KABI_EX_H__
@@ -170,7 +176,7 @@ struct ex2a {
 /*
  * STABLE:      variable structure_type ex2a {
  * STABLE-NEXT:   member base_type int byte_size(4) encoding(5) a data_member_location(0) ,
- * STABLE-NEXT:   member base_type [[ULONG:long unsigned int|unsigned long]] byte_size(8) encoding(7) b data_member_location(8)
+ * STABLE-NEXT:   member base_type [[ULONG]] byte_size(8) encoding(7) b data_member_location(8)
  * STABLE-NEXT:   member base_type int byte_size(4) encoding(5) c data_member_location(16) ,
  * STABLE-NEXT:   member base_type [[ULONG]] byte_size(8) encoding(7) d data_member_location(24)
  * STABLE-NEXT: } byte_size(32)
@@ -227,7 +233,7 @@ struct ex3a {
 
 /*
  * STABLE:      variable structure_type ex3a {
- * STABLE-NEXT:   member base_type [[ULONG:long unsigned int|unsigned long]] byte_size(8) encoding(7) a data_member_location(0)
+ * STABLE-NEXT:   member base_type [[ULONG]] byte_size(8) encoding(7) a data_member_location(0)
  * STABLE-NEXT:   member base_type [[ULONG]] byte_size(8) encoding(7) unused data_member_location(8)
  * STABLE-NEXT: } byte_size(16)
  */
@@ -260,4 +266,95 @@ _Static_assert(sizeof(struct ex3a) == sizeof(struct ex3c), "ex3a size doesn't ma
  * STABLE-NEXT: } byte_size(16)
  */
 
+/*
+ * Example: An ignored field added to an end of a partially opaque struct,
+ * while keeping the byte_size attribute unchanged.
+ */
+
+struct ex4a {
+	unsigned long a;
+	KABI_IGNORE(0, unsigned long b);
+};
+
+/*
+ * This may be safe if the structure allocation is managed by the core kernel
+ * and the layout remains unchanged except for appended new members.
+ */
+KABI_BYTE_SIZE(ex4a, 8);
+
+/*
+ * STABLE:      variable structure_type ex4a {
+ * STABLE-NEXT:   member base_type [[ULONG]] byte_size(8) encoding(7) a data_member_location(0)
+ * STABLE-NEXT: } byte_size(8)
+ */
+
+/*
+ * Example: A type string override.
+ */
+
+struct ex5a {
+	unsigned long a;
+};
+
+/*
+ * This may be safe if the structure is fully opaque to modules, even though
+ * its definition has inadvertently become part of the ABI.
+ */
+KABI_TYPE_STRING(
+	"s#ex5a",
+	"structure_type ex5a { member pointer_type { s#ex4a } byte_size(8) p data_member_location(0) } byte_size(8)");
+
+/*
+ * Make sure the fully expanded type string includes ex4a.
+ *
+ * VERSIONS:      ex5a variable structure_type ex5a {
+ * VERSIONS-SAME:   member pointer_type {
+ * VERSIONS-SAME:     structure_type ex4a {
+ * VERSIONS-SAME:       member base_type [[ULONG:long unsigned int|unsigned long]] byte_size(8) encoding(7) a data_member_location(0)
+ * VERSIONS-SAME:     } byte_size(8)
+ * VERSIONS-SAME:   } byte_size(8) p data_member_location(0)
+ * VERSIONS-SAME: } byte_size(8)
+ */
+
+/*
+ * Example: A type string definition for a non-existent type.
+ */
+
+struct ex5b {
+	unsigned long a;
+};
+
+/* Replace the type string for struct ex5b */
+KABI_TYPE_STRING(
+	"s#ex5b",
+	"structure_type ex5b { member pointer_type { s#ex5c } byte_size(8) p data_member_location(0) } byte_size(8)");
+
+/* Define a type string for a non-existent struct ex5c */
+KABI_TYPE_STRING(
+	"s#ex5c",
+	"structure_type ex5c { member base_type int byte_size(4) encoding(5) n data_member_location(0) } byte_size(8)");
+
+/*
+ * Make sure the fully expanded type string includes the definition for ex5c.
+ *
+ * VERSIONS:      ex5b variable structure_type ex5b {
+ * VERSIONS-SAME:   member pointer_type {
+ * VERSIONS-SAME:     structure_type ex5c {
+ * VERSIONS-SAME:       member base_type int byte_size(4) encoding(5) n data_member_location(0)
+ * VERSIONS-SAME:     } byte_size(8)
+ * VERSIONS-SAME:   } byte_size(8) p data_member_location(0)
+ * VERSIONS-SAME: } byte_size(8)
+ */
+
+/*
+ * Example: A type string override for a symbol.
+ */
+
+KABI_TYPE_STRING("ex6a", "variable s#ex5c");
+
+/*
+ * VERSIONS:      ex6a variable structure_type ex5c {
+ * VERSIONS-SAME:   member base_type int byte_size(4) encoding(5) n data_member_location(0)
+ * VERSIONS-SAME: } byte_size(8)
+ */
 #endif /* __KABI_EX_H__ */
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
index 2feec168bf73..7dd03ffe0c5c 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -287,10 +287,12 @@ void generate_symtypes_and_versions(FILE *file);
  * kabi.c
  */
 
+bool kabi_get_byte_size(const char *fqn, unsigned long *value);
 bool kabi_is_enumerator_ignored(const char *fqn, const char *field);
 bool kabi_get_enumerator_value(const char *fqn, const char *field,
 			       unsigned long *value);
 bool kabi_is_declonly(const char *fqn);
+bool kabi_get_type_string(const char *type, const char **str);
 
 void kabi_read_rules(int fd);
 void kabi_free(void);
diff --git a/scripts/gendwarfksyms/kabi.c b/scripts/gendwarfksyms/kabi.c
index 66f01fcd1607..b3ade713778f 100644
--- a/scripts/gendwarfksyms/kabi.c
+++ b/scripts/gendwarfksyms/kabi.c
@@ -54,11 +54,27 @@
  */
 #define KABI_RULE_TAG_ENUMERATOR_VALUE "enumerator_value"
 
+/*
+ * Rule: byte_size
+ * - For the fqn_field in the target field, set the byte_size
+ *   attribute to the value in the value field.
+ */
+#define KABI_RULE_TAG_BYTE_SIZE "byte_size"
+
+/*
+ * Rule: type_string
+ * - For the type reference in the fqn field, use the type string
+ *   in the value field.
+ */
+#define KABI_RULE_TAG_TYPE_STRING "type_string"
+
 enum kabi_rule_type {
 	KABI_RULE_TYPE_UNKNOWN,
 	KABI_RULE_TYPE_DECLONLY,
 	KABI_RULE_TYPE_ENUMERATOR_IGNORE,
 	KABI_RULE_TYPE_ENUMERATOR_VALUE,
+	KABI_RULE_TYPE_BYTE_SIZE,
+	KABI_RULE_TYPE_TYPE_STRING,
 };
 
 #define RULE_HASH_BITS 7
@@ -127,6 +143,14 @@ void kabi_read_rules(int fd)
 			.type = KABI_RULE_TYPE_ENUMERATOR_VALUE,
 			.tag = KABI_RULE_TAG_ENUMERATOR_VALUE,
 		},
+		{
+			.type = KABI_RULE_TYPE_BYTE_SIZE,
+			.tag = KABI_RULE_TAG_BYTE_SIZE,
+		},
+		{
+			.type = KABI_RULE_TYPE_TYPE_STRING,
+			.tag = KABI_RULE_TAG_TYPE_STRING,
+		},
 	};
 
 	if (!stable)
@@ -222,33 +246,55 @@ void kabi_read_rules(int fd)
 	check(elf_end(elf));
 }
 
-bool kabi_is_declonly(const char *fqn)
+static char *get_enumerator_target(const char *fqn, const char *field)
+{
+	char *target = NULL;
+
+	if (asprintf(&target, "%s %s", fqn, field) < 0)
+		error("asprintf failed for '%s %s'", fqn, field);
+
+	return target;
+}
+
+static struct rule *find_rule(enum kabi_rule_type type, const char *target)
 {
 	struct rule *rule;
 
 	if (!stable)
-		return false;
-	if (!fqn || !*fqn)
-		return false;
+		return NULL;
+	if (!target || !*target)
+		return NULL;
 
 	hash_for_each_possible(rules, rule, hash,
-			       rule_values_hash(KABI_RULE_TYPE_DECLONLY, fqn)) {
-		if (rule->type == KABI_RULE_TYPE_DECLONLY &&
-		    !strcmp(fqn, rule->target))
-			return true;
+			       rule_values_hash(type, target)) {
+		if (rule->type == type && !strcmp(target, rule->target))
+			return rule;
 	}
 
-	return false;
+	return NULL;
 }
 
-static char *get_enumerator_target(const char *fqn, const char *field)
+static struct rule *find_enumerator_rule(enum kabi_rule_type type,
+					 const char *fqn, const char *field)
 {
-	char *target = NULL;
+	struct rule *rule;
+	char *target;
 
-	if (asprintf(&target, "%s %s", fqn, field) < 0)
-		error("asprintf failed for '%s %s'", fqn, field);
+	if (!stable)
+		return NULL;
+	if (!fqn || !*fqn || !field || !*field)
+		return NULL;
 
-	return target;
+	target = get_enumerator_target(fqn, field);
+	rule = find_rule(type, target);
+
+	free(target);
+	return rule;
+}
+
+bool kabi_is_declonly(const char *fqn)
+{
+	return !!find_rule(KABI_RULE_TYPE_DECLONLY, fqn);
 }
 
 static unsigned long get_ulong_value(const char *value)
@@ -267,58 +313,49 @@ static unsigned long get_ulong_value(const char *value)
 
 bool kabi_is_enumerator_ignored(const char *fqn, const char *field)
 {
-	bool match = false;
-	struct rule *rule;
-	char *target;
-
-	if (!stable)
-		return false;
-	if (!fqn || !*fqn || !field || !*field)
-		return false;
+	return !!find_enumerator_rule(KABI_RULE_TYPE_ENUMERATOR_IGNORE, fqn,
+				      field);
+}
 
-	target = get_enumerator_target(fqn, field);
+bool kabi_get_enumerator_value(const char *fqn, const char *field,
+			       unsigned long *value)
+{
+	struct rule *rule;
 
-	hash_for_each_possible(
-		rules, rule, hash,
-		rule_values_hash(KABI_RULE_TYPE_ENUMERATOR_IGNORE, target)) {
-		if (rule->type == KABI_RULE_TYPE_ENUMERATOR_IGNORE &&
-		    !strcmp(target, rule->target)) {
-			match = true;
-			break;
-		}
+	rule = find_enumerator_rule(KABI_RULE_TYPE_ENUMERATOR_VALUE, fqn,
+				    field);
+	if (rule) {
+		*value = get_ulong_value(rule->value);
+		return true;
 	}
 
-	free(target);
-	return match;
+	return false;
 }
 
-bool kabi_get_enumerator_value(const char *fqn, const char *field,
-			       unsigned long *value)
+bool kabi_get_byte_size(const char *fqn, unsigned long *value)
 {
-	bool match = false;
 	struct rule *rule;
-	char *target;
 
-	if (!stable)
-		return false;
-	if (!fqn || !*fqn || !field || !*field)
-		return false;
+	rule = find_rule(KABI_RULE_TYPE_BYTE_SIZE, fqn);
+	if (rule) {
+		*value = get_ulong_value(rule->value);
+		return true;
+	}
 
-	target = get_enumerator_target(fqn, field);
+	return false;
+}
 
-	hash_for_each_possible(rules, rule, hash,
-			       rule_values_hash(KABI_RULE_TYPE_ENUMERATOR_VALUE,
-						target)) {
-		if (rule->type == KABI_RULE_TYPE_ENUMERATOR_VALUE &&
-		    !strcmp(target, rule->target)) {
-			*value = get_ulong_value(rule->value);
-			match = true;
-			break;
-		}
+bool kabi_get_type_string(const char *type, const char **str)
+{
+	struct rule *rule;
+
+	rule = find_rule(KABI_RULE_TYPE_TYPE_STRING, type);
+	if (rule) {
+		*str = rule->value;
+		return true;
 	}
 
-	free(target);
-	return match;
+	return false;
 }
 
 void kabi_free(void)
diff --git a/scripts/gendwarfksyms/types.c b/scripts/gendwarfksyms/types.c
index 6f37289104ff..39ce1770e463 100644
--- a/scripts/gendwarfksyms/types.c
+++ b/scripts/gendwarfksyms/types.c
@@ -100,7 +100,7 @@ static void type_expansion_append(struct type_expansion *type, const char *s,
 #define TYPE_HASH_BITS 12
 static HASHTABLE_DEFINE(type_map, 1 << TYPE_HASH_BITS);
 
-static int type_map_get(const char *name, struct type_expansion **res)
+static int __type_map_get(const char *name, struct type_expansion **res)
 {
 	struct type_expansion *e;
 
@@ -114,11 +114,12 @@ static int type_map_get(const char *name, struct type_expansion **res)
 	return -1;
 }
 
-static void type_map_add(const char *name, struct type_expansion *type)
+static struct type_expansion *type_map_add(const char *name,
+					   struct type_expansion *type)
 {
 	struct type_expansion *e;
 
-	if (type_map_get(name, &e)) {
+	if (__type_map_get(name, &e)) {
 		e = xmalloc(sizeof(struct type_expansion));
 		type_expansion_init(e);
 		e->name = xstrdup(name);
@@ -130,7 +131,7 @@ static void type_map_add(const char *name, struct type_expansion *type)
 	} else {
 		/* Use the longest available expansion */
 		if (type->len <= e->len)
-			return;
+			return e;
 
 		type_list_free(&e->expanded);
 
@@ -148,6 +149,34 @@ static void type_map_add(const char *name, struct type_expansion *type)
 		type_list_write(&e->expanded, stderr);
 		checkp(fputs("\n", stderr));
 	}
+
+	return e;
+}
+
+static void type_parse(const char *name, const char *str,
+		       struct type_expansion *type);
+
+static int type_map_get(const char *name, struct type_expansion **res)
+{
+	struct type_expansion type;
+	const char *override;
+
+	if (!__type_map_get(name, res))
+		return 0;
+
+	/*
+	 * If die_map didn't contain a type, we might still have
+	 * a type_string kABI rule that defines it.
+	 */
+	if (stable && kabi_get_type_string(name, &override)) {
+		type_expansion_init(&type);
+		type_parse(name, override, &type);
+		*res = type_map_add(name, &type);
+		type_expansion_free(&type);
+		return 0;
+	}
+
+	return -1;
 }
 
 static void type_map_write(FILE *file)
@@ -267,15 +296,18 @@ static char *get_type_name(struct die *cache)
 	return name;
 }
 
-static void __calculate_version(struct version *version, struct list_head *list)
+static void __calculate_version(struct version *version,
+				struct type_expansion *type)
 {
 	struct type_list_entry *entry;
 	struct type_expansion *e;
 
 	/* Calculate a CRC over an expanded type string */
-	list_for_each_entry(entry, list, list) {
+	list_for_each_entry(entry, &type->expanded, list) {
 		if (is_type_prefix(entry->str)) {
-			check(type_map_get(entry->str, &e));
+			if (type_map_get(entry->str, &e))
+				error("unknown type reference to '%s' when expanding '%s'",
+				      entry->str, type->name);
 
 			/*
 			 * It's sufficient to expand each type reference just
@@ -285,7 +317,7 @@ static void __calculate_version(struct version *version, struct list_head *list)
 				version_add(version, entry->str);
 			} else {
 				cache_mark_expanded(&expansion_cache, e);
-				__calculate_version(version, &e->expanded);
+				__calculate_version(version, e);
 			}
 		} else {
 			version_add(version, entry->str);
@@ -293,10 +325,11 @@ static void __calculate_version(struct version *version, struct list_head *list)
 	}
 }
 
-static void calculate_version(struct version *version, struct list_head *list)
+static void calculate_version(struct version *version,
+			      struct type_expansion *type)
 {
 	version_init(version);
-	__calculate_version(version, list);
+	__calculate_version(version, type);
 	cache_free(&expansion_cache);
 }
 
@@ -372,9 +405,80 @@ static void type_expand(struct die *cache, struct type_expansion *type,
 	cache_free(&expansion_cache);
 }
 
+static void type_parse(const char *name, const char *str,
+		       struct type_expansion *type)
+{
+	char *fragment;
+	size_t start = 0;
+	size_t end;
+	size_t pos;
+
+	if (!*str)
+		error("empty type string override for '%s'", name);
+
+	type_expansion_init(type);
+
+	for (pos = 0; str[pos]; ++pos) {
+		bool empty;
+		char marker = ' ';
+
+		if (!is_type_prefix(&str[pos]))
+			continue;
+
+		end = pos + 2;
+
+		/*
+		 * Find the end of the type reference. If the type name contains
+		 * spaces, it must be in single quotes.
+		 */
+		if (str[end] == '\'') {
+			marker = '\'';
+			++end;
+		}
+		while (str[end] && str[end] != marker)
+			++end;
+
+		/* Check that we have a non-empty type name */
+		if (marker == '\'') {
+			if (str[end] != marker)
+				error("incomplete %c# type reference for '%s' (string : '%s')",
+				      str[pos], name, str);
+			empty = end == pos + 3;
+			++end;
+		} else {
+			empty = end == pos + 2;
+		}
+		if (empty)
+			error("empty %c# type name for '%s' (string: '%s')",
+			      str[pos], name, str);
+
+		/* Append the part of the string before the type reference */
+		if (pos > start) {
+			fragment = xstrndup(&str[start], pos - start);
+			type_expansion_append(type, fragment, fragment);
+		}
+
+		/*
+		 * Append the type reference -- note that if the reference
+		 * is invalid, i.e. points to a non-existent type, we will
+		 * print out an error when calculating versions.
+		 */
+		fragment = xstrndup(&str[pos], end - pos);
+		type_expansion_append(type, fragment, fragment);
+
+		start = end;
+		pos = end - 1;
+	}
+
+	/* Append the rest of the type string, if there's any left */
+	if (str[start])
+		type_expansion_append(type, &str[start], NULL);
+}
+
 static void expand_type(struct die *cache, void *arg)
 {
 	struct type_expansion type;
+	const char *override;
 	char *name;
 
 	if (cache->mapped)
@@ -399,9 +503,13 @@ static void expand_type(struct die *cache, void *arg)
 		return;
 
 	debug("%s", name);
-	type_expand(cache, &type, true);
-	type_map_add(name, &type);
 
+	if (stable && kabi_get_type_string(name, &override))
+		type_parse(name, override, &type);
+	else
+		type_expand(cache, &type, true);
+
+	type_map_add(name, &type);
 	type_expansion_free(&type);
 	free(name);
 }
@@ -410,6 +518,7 @@ static void expand_symbol(struct symbol *sym, void *arg)
 {
 	struct type_expansion type;
 	struct version version;
+	const char *override;
 	struct die *cache;
 
 	/*
@@ -423,11 +532,14 @@ static void expand_symbol(struct symbol *sym, void *arg)
 	if (__die_map_get(sym->die_addr, DIE_SYMBOL, &cache))
 		return; /* We'll warn about missing CRCs later. */
 
-	type_expand(cache, &type, false);
+	if (stable && kabi_get_type_string(sym->name, &override))
+		type_parse(sym->name, override, &type);
+	else
+		type_expand(cache, &type, false);
 
 	/* If the symbol already has a version, don't calculate it again. */
 	if (sym->state != SYMBOL_PROCESSED) {
-		calculate_version(&version, &type.expanded);
+		calculate_version(&version, &type);
 		symbol_set_crc(sym, version.crc);
 		debug("%s = %lx", sym->name, version.crc);
 
diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c
index 8b0d7ac73dbb..83e48670c2fc 100644
--- a/scripts/genksyms/genksyms.c
+++ b/scripts/genksyms/genksyms.c
@@ -181,13 +181,9 @@ static int is_unknown_symbol(struct symbol *sym)
 			strcmp(defn->string, "{") == 0);
 }
 
-static struct symbol *__add_symbol(const char *name, enum symbol_type type,
-			    struct string_list *defn, int is_extern,
-			    int is_reference)
+static struct string_list *process_enum(const char *name, enum symbol_type type,
+					struct string_list *defn)
 {
-	unsigned long h;
-	struct symbol *sym;
-	enum symbol_status status = STATUS_UNCHANGED;
 	/* The parser adds symbols in the order their declaration completes,
 	 * so it is safe to store the value of the previous enum constant in
 	 * a static variable.
@@ -216,7 +212,7 @@ static struct symbol *__add_symbol(const char *name, enum symbol_type type,
 				defn = mk_node(buf);
 			}
 		}
-	} else if (type == SYM_ENUM) {
+	} else {
 		free_list(last_enum_expr, NULL);
 		last_enum_expr = NULL;
 		enum_counter = 0;
@@ -225,6 +221,23 @@ static struct symbol *__add_symbol(const char *name, enum symbol_type type,
 			return NULL;
 	}
 
+	return defn;
+}
+
+static struct symbol *__add_symbol(const char *name, enum symbol_type type,
+			    struct string_list *defn, int is_extern,
+			    int is_reference)
+{
+	unsigned long h;
+	struct symbol *sym;
+	enum symbol_status status = STATUS_UNCHANGED;
+
+	if ((type == SYM_ENUM_CONST || type == SYM_ENUM) && !is_reference) {
+		defn = process_enum(name, type, defn);
+		if (defn == NULL)
+			return NULL;
+	}
+
 	h = crc32(name);
 	hash_for_each_possible(symbol_hashtable, sym, hnode, h) {
 		if (map_to_ns(sym->type) != map_to_ns(type) ||
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 21578dcd4292..fe2231e0e6a4 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -205,15 +205,26 @@ struct property {
 	for (st = sym->prop; st; st = st->next) \
 		if (st->text)
 
+enum menu_type {
+	M_CHOICE,  // "choice"
+	M_COMMENT, // "comment"
+	M_IF,      // "if"
+	M_MENU,    // "mainmenu", "menu", "menuconfig"
+	M_NORMAL,  // others, i.e., "config"
+};
+
 /*
  * 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.
  *
+ * @type: type of the menu entry
  * @choice_members: list of choice members with priority.
  */
 struct menu {
+	enum menu_type type;
+
 	/* The next menu node at the same level */
 	struct menu *next;
 
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index b8ebc3094a23..fbc907f75eac 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -81,7 +81,7 @@ void _menu_init(void);
 void menu_warn(const 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_add_entry(struct symbol *sym, enum menu_type type);
 void menu_add_dep(struct expr *dep);
 void menu_add_visibility(struct expr *dep);
 struct property *menu_add_prompt(enum prop_type type, const char *prompt,
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 6587ac86d0d5..7d48a692bd27 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -15,7 +15,7 @@
 
 static const char nohelp_text[] = "There is no help available for this option.";
 
-struct menu rootmenu;
+struct menu rootmenu = { .type = M_MENU };
 static struct menu **last_entry_ptr;
 
 /**
@@ -65,12 +65,13 @@ void _menu_init(void)
 	last_entry_ptr = &rootmenu.list;
 }
 
-void menu_add_entry(struct symbol *sym)
+void menu_add_entry(struct symbol *sym, enum menu_type type)
 {
 	struct menu *menu;
 
 	menu = xmalloc(sizeof(*menu));
 	memset(menu, 0, sizeof(*menu));
+	menu->type = type;
 	menu->sym = sym;
 	menu->parent = current_menu;
 	menu->filename = cur_filename;
diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
index 68372d3ff325..e9c3c664e925 100644
--- a/scripts/kconfig/parser.y
+++ b/scripts/kconfig/parser.y
@@ -139,7 +139,7 @@ stmt_list_in_choice:
 
 config_entry_start: T_CONFIG nonconst_symbol T_EOL
 {
-	menu_add_entry($2);
+	menu_add_entry($2, M_NORMAL);
 	printd(DEBUG_PARSE, "%s:%d:config %s\n", cur_filename, cur_lineno, $2->name);
 };
 
@@ -173,7 +173,7 @@ config_stmt: config_entry_start config_option_list
 
 menuconfig_entry_start: T_MENUCONFIG nonconst_symbol T_EOL
 {
-	menu_add_entry($2);
+	menu_add_entry($2, M_MENU);
 	printd(DEBUG_PARSE, "%s:%d:menuconfig %s\n", cur_filename, cur_lineno, $2->name);
 };
 
@@ -246,7 +246,7 @@ choice: T_CHOICE T_EOL
 {
 	struct symbol *sym = sym_lookup(NULL, 0);
 
-	menu_add_entry(sym);
+	menu_add_entry(sym, M_CHOICE);
 	menu_set_type(S_BOOLEAN);
 	INIT_LIST_HEAD(&current_entry->choice_members);
 
@@ -315,7 +315,7 @@ default:
 if_entry: T_IF expr T_EOL
 {
 	printd(DEBUG_PARSE, "%s:%d:if\n", cur_filename, cur_lineno);
-	menu_add_entry(NULL);
+	menu_add_entry(NULL, M_IF);
 	menu_add_dep($2);
 	$$ = menu_add_menu();
 };
@@ -338,7 +338,7 @@ if_stmt_in_choice: if_entry stmt_list_in_choice if_end
 
 menu: T_MENU T_WORD_QUOTE T_EOL
 {
-	menu_add_entry(NULL);
+	menu_add_entry(NULL, M_MENU);
 	menu_add_prompt(P_MENU, $2, NULL);
 	printd(DEBUG_PARSE, "%s:%d:menu\n", cur_filename, cur_lineno);
 };
@@ -376,7 +376,7 @@ source_stmt: T_SOURCE T_WORD_QUOTE T_EOL
 
 comment: T_COMMENT T_WORD_QUOTE T_EOL
 {
-	menu_add_entry(NULL);
+	menu_add_entry(NULL, M_COMMENT);
 	menu_add_prompt(P_COMMENT, $2, NULL);
 	printd(DEBUG_PARSE, "%s:%d:comment\n", cur_filename, cur_lineno);
 };
diff --git a/scripts/misc-check b/scripts/misc-check
index d40d5484e0c5..a74450e799d1 100755
--- a/scripts/misc-check
+++ b/scripts/misc-check
@@ -3,17 +3,65 @@
 
 set -e
 
-# Detect files that are tracked but ignored by git. This is checked only when
-# ${KBUILD_EXTRA_WARN} contains 1, git is installed, and the source tree is
-# tracked by git.
+# Detect files that are tracked but ignored by git.
 check_tracked_ignored_files () {
-	case "${KBUILD_EXTRA_WARN}" in
-	*1*) ;;
-	*) return;;
-	esac
-
-	git -C ${srctree:-.} ls-files -i -c --exclude-per-directory=.gitignore 2>/dev/null |
+	git -C "${srctree:-.}" ls-files -i -c --exclude-per-directory=.gitignore 2>/dev/null |
 		sed 's/$/: warning: ignored by one of the .gitignore files/' >&2
 }
 
+# Check for missing #include <linux/export.h>
+#
+# The rule for including <linux/export.h> is very simple:
+# Include <linux/export.h> only when you use EXPORT_SYMBOL(). That's it.
+#
+# However, some headers include <linux/export.h> even though they are completely
+# unrelated to EXPORT_SYMBOL().
+#
+# One example is include/linux/module.h. Please note <linux/module.h> and
+# <linux/export.h> are orthogonal. <linux/module.h> should be included by files
+# that can be compiled as modules. In other words, <linux/module.h> should be
+# included by EXPORT_SYMBOL consumers. In contrast, <linux/export.h> should be
+# included from EXPORT_SYMBOL providers, which may or may not be modular.
+# Hence, include/linux/module.h should *not* include <linux/export.h>.
+#
+# Another example is include/linux/linkage.h, which is completely unrelated to
+# EXPORT_SYMBOL(). Worse, it is included by most C files, which means, most C
+# files end up including <linux/export.h>, even though only some of them
+# actually export symbols. Hence, include/linux/linkage.h should *not* include
+# <linux/export.h>.
+#
+# Before fixing such headers, we must ensure that C files using EXPORT_SYMBOL()
+# include <linux/export.h> directly, since many C files currently rely on
+# <linux/export.h> being included indirectly (likely, via <linux/linkage> etc.).
+#
+# Therefore, this check.
+#
+# The problem is simple - the warned files use EXPORT_SYMBOL(), but do not
+# include <linux/export.h>. Please add #include <linux/export.h> to them.
+#
+# If the included headers are sorted alphabetically, please insert
+# <linux/export.h> in the appropriate position to maintain the sort order.
+# For this reason, this script only checks missing <linux/export.h>, but
+# does not automatically fix it.
+check_missing_include_linux_export_h () {
+
+	git -C "${srctree:-.}" grep --files-with-matches -E 'EXPORT_SYMBOL((_NS)?(_GPL)?|_GPL_FOR_MODULES)\(.*\)' \
+	    -- '*.[ch]' :^tools/ :^include/linux/export.h |
+	xargs -r git -C "${srctree:-.}" grep --files-without-match '#include[[:space:]]*<linux/export\.h>' |
+	xargs -r printf "%s: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing\n" >&2
+}
+
+# If you do not use EXPORT_SYMBOL(), please do not include <linux/export.h>.
+# Currently, this is checked for *.c files, but not for *.h files, because some
+# *.c files rely on <linux/export.h> being included indirectly.
+check_unnecessary_include_linux_export_h () {
+
+	git -C "${srctree:-.}" grep --files-with-matches '#include[[:space:]]*<linux/export\.h>' \
+	    -- '*.[c]' :^tools/ |
+	xargs -r git -C "${srctree:-.}" grep --files-without-match -E 'EXPORT_SYMBOL((_NS)?(_GPL)?|_GPL_FOR_MODULES)\(.*\)' |
+	xargs -r printf "%s: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present\n" >&2
+}
+
 check_tracked_ignored_files
+check_missing_include_linux_export_h
+check_unnecessary_include_linux_export_h
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index be89921d60b6..5ca7c268294e 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -28,6 +28,8 @@
 #include "modpost.h"
 #include "../../include/linux/license.h"
 
+#define MODULE_NS_PREFIX "module:"
+
 static bool module_enabled;
 /* Are we using CONFIG_MODVERSIONS? */
 static bool modversions;
@@ -1595,11 +1597,14 @@ static void read_symbols(const char *modname)
 			license = get_next_modinfo(&info, "license", license);
 		}
 
-		namespace = get_modinfo(&info, "import_ns");
-		while (namespace) {
+		for (namespace = get_modinfo(&info, "import_ns");
+		     namespace;
+		     namespace = get_next_modinfo(&info, "import_ns", namespace)) {
+			if (strstarts(namespace, MODULE_NS_PREFIX))
+				error("%s: explicitly importing namespace \"%s\" is not allowed.\n",
+				      mod->name, namespace);
+
 			add_namespace(&mod->imported_namespaces, namespace);
-			namespace = get_next_modinfo(&info, "import_ns",
-						     namespace);
 		}
 
 		if (!get_modinfo(&info, "description"))
@@ -1684,6 +1689,46 @@ void buf_write(struct buffer *buf, const char *s, int len)
 	buf->pos += len;
 }
 
+/**
+ * verify_module_namespace() - does @modname have access to this symbol's @namespace
+ * @namespace: export symbol namespace
+ * @modname: module name
+ *
+ * If @namespace is prefixed with "module:" to indicate it is a module namespace
+ * then test if @modname matches any of the comma separated patterns.
+ *
+ * The patterns only support tail-glob.
+ */
+static bool verify_module_namespace(const char *namespace, const char *modname)
+{
+	size_t len, modlen = strlen(modname);
+	const char *prefix = "module:";
+	const char *sep;
+	bool glob;
+
+	if (!strstarts(namespace, prefix))
+		return false;
+
+	for (namespace += strlen(prefix); *namespace; namespace = sep) {
+		sep = strchrnul(namespace, ',');
+		len = sep - namespace;
+
+		glob = false;
+		if (sep[-1] == '*') {
+			len--;
+			glob = true;
+		}
+
+		if (*sep)
+			sep++;
+
+		if (strncmp(namespace, modname, len) == 0 && (glob || len == modlen))
+			return true;
+	}
+
+	return false;
+}
+
 static void check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
@@ -1711,7 +1756,8 @@ static void check_exports(struct module *mod)
 
 		basename = get_basename(mod->name);
 
-		if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
+		if (!verify_module_namespace(exp->namespace, basename) &&
+		    !contains_namespace(&mod->imported_namespaces, exp->namespace)) {
 			modpost_log(!allow_missing_ns_imports,
 				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
 				    basename, exp->name, exp->namespace);
diff --git a/scripts/tags.sh b/scripts/tags.sh
index 98680e9cd7be..99ce427d9a69 100755
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -344,7 +344,7 @@ case "$1" in
 
 	"tags")
 		rm -f tags
-		xtags ctags
+		xtags ${CTAGS:-ctags}
 		remove_structs=y
 		;;