Revert "ANDROID: Revert "Merge tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux""

This reverts commit 3fde1dfb00.

Revert to the upstream version by reinstating the original
modules-for-v5.4 merge.

Bug: 142892219
Bug: 144336692
Change-Id: I3871c67dd3cba0a5b9b2e1a87be8653a14cb9de5
Signed-off-by: Matthias Maennich <maennich@google.com>

.gitignore

@@ -32,6 +32,7 @@
 *.lzo
 *.mod
 *.mod.c
+*.ns_deps
 *.o
 *.o.*
 *.patch

Documentation/kbuild/modules.rst

@@ -470,9 +470,12 @@ build.
 
 	The syntax of the Module.symvers file is::
 
-		<CRC>	    <Symbol>	       <module>
+	<CRC>       <Symbol>          <Namespace>  <Module>                         <Export Type>
 
-		0x2d036834  scsi_remove_host   drivers/scsi/scsi_mod
+	0xe1cc2a05  usb_stor_suspend  USB_STORAGE  drivers/usb/storage/usb-storage  EXPORT_SYMBOL_GPL
+
+	The fields are separated by tabs and values may be empty (e.g.
+	if no namespace is defined for an exported symbol).
 
 	For a kernel build without CONFIG_MODVERSIONS enabled, the CRC
 	would read 0x00000000.

Documentation/kernel-hacking/hacking.rst

@@ -594,6 +594,24 @@ internal implementation issue, and not really an interface. Some
 maintainers and developers may however require EXPORT_SYMBOL_GPL()
 when adding any new APIs or functionality.
 
+:c:func:`EXPORT_SYMBOL_NS()`
+----------------------------
+
+Defined in ``include/linux/export.h``
+
+This is the variant of `EXPORT_SYMBOL()` that allows specifying a symbol
+namespace. Symbol Namespaces are documented in
+``Documentation/kbuild/namespaces.rst``.
+
+:c:func:`EXPORT_SYMBOL_NS_GPL()`
+--------------------------------
+
+Defined in ``include/linux/export.h``
+
+This is the variant of `EXPORT_SYMBOL_GPL()` that allows specifying a symbol
+namespace. Symbol Namespaces are documented in
+``Documentation/kbuild/namespaces.rst``.
+
 Routines and Conventions
 ========================
 

Makefile

@@ -1481,6 +1481,9 @@ help:
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  ''
+	@echo  'Tools:'
+	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
+	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest       - Build and run kernel selftest (run as root)'
 	@echo  '                    Build, install, and boot kernel before'
@@ -1662,7 +1665,7 @@ clean: $(clean-dirs)
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
 		-o -name '*.dwo' -o -name '*.lst' \
-		-o -name '*.su' -o -name '*.mod' \
+		-o -name '*.su' -o -name '*.mod' -o -name '*.ns_deps' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
@@ -1680,6 +1683,15 @@ quiet_cmd_tags = GEN     $@
 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)
 
+# Script to generate missing namespace dependencies
+# ---------------------------------------------------------------------------
+
+PHONY += nsdeps
+
+nsdeps: modules
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------
 

arch/m68k/include/asm/export.h

@@ -1,3 +1,2 @@
-#define KSYM_ALIGN 2
 #define KCRC_ALIGN 2
 #include <asm-generic/export.h>

drivers/usb/storage/Makefile

@@ -8,6 +8,8 @@
 
 ccflags-y := -I $(srctree)/drivers/scsi
 
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=USB_STORAGE
+
 obj-$(CONFIG_USB_UAS)		+= uas.o
 obj-$(CONFIG_USB_STORAGE)	+= usb-storage.o
 

drivers/usb/storage/alauda.c

@@ -36,6 +36,7 @@
 MODULE_DESCRIPTION("Driver for Alauda-based card readers");
 MODULE_AUTHOR("Daniel Drake <dsd@gentoo.org>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 /*
  * Status bytes

drivers/usb/storage/cypress_atacb.c

@@ -22,6 +22,7 @@
 MODULE_DESCRIPTION("SAT support for Cypress USB/ATA bridges with ATACB");
 MODULE_AUTHOR("Matthieu Castet <castet.matthieu@free.fr>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 /*
  * The table of devices

drivers/usb/storage/datafab.c

@@ -54,6 +54,7 @@
 MODULE_DESCRIPTION("Driver for Datafab USB Compact Flash reader");
 MODULE_AUTHOR("Jimmie Mayfield <mayfield+datafab@sackheads.org>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 struct datafab_info {
 	unsigned long   sectors;	/* total sector count */

drivers/usb/storage/ene_ub6250.c

@@ -26,6 +26,7 @@
 
 MODULE_DESCRIPTION("Driver for ENE UB6250 reader");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 MODULE_FIRMWARE(SD_INIT1_FIRMWARE);
 MODULE_FIRMWARE(SD_INIT2_FIRMWARE);
 MODULE_FIRMWARE(SD_RW_FIRMWARE);

drivers/usb/storage/freecom.c

@@ -29,6 +29,7 @@
 MODULE_DESCRIPTION("Driver for Freecom USB/IDE adaptor");
 MODULE_AUTHOR("David Brown <usb-storage@davidb.org>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 #ifdef CONFIG_USB_STORAGE_DEBUG
 static void pdump(struct us_data *us, void *ibuffer, int length);

drivers/usb/storage/isd200.c

@@ -53,6 +53,7 @@
 MODULE_DESCRIPTION("Driver for In-System Design, Inc. ISD200 ASIC");
 MODULE_AUTHOR("Björn Stenberg <bjorn@haxx.se>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 static int isd200_Initialization(struct us_data *us);
 

drivers/usb/storage/jumpshot.c

@@ -51,6 +51,7 @@
 MODULE_DESCRIPTION("Driver for Lexar \"Jumpshot\" Compact Flash reader");
 MODULE_AUTHOR("Jimmie Mayfield <mayfield+usb@sackheads.org>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 /*
  * The table of devices

drivers/usb/storage/karma.c

@@ -23,6 +23,7 @@
 MODULE_DESCRIPTION("Driver for Rio Karma");
 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>, Keith Bennett <keith@mcs.st-and.ac.uk>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 #define RIO_PREFIX "RIOP\x00"
 #define RIO_PREFIX_LEN 5

drivers/usb/storage/onetouch.c

@@ -25,6 +25,7 @@
 MODULE_DESCRIPTION("Maxtor USB OneTouch hard drive button driver");
 MODULE_AUTHOR("Nick Sillik <n.sillik@temple.edu>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 #define ONETOUCH_PKT_LEN        0x02
 #define ONETOUCH_BUTTON         KEY_PROG1

drivers/usb/storage/realtek_cr.c

@@ -35,6 +35,7 @@
 MODULE_DESCRIPTION("Driver for Realtek USB Card Reader");
 MODULE_AUTHOR("wwang <wei_wang@realsil.com.cn>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 static int auto_delink_en = 1;
 module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);

drivers/usb/storage/sddr09.c

@@ -47,6 +47,7 @@
 MODULE_DESCRIPTION("Driver for SanDisk SDDR-09 SmartMedia reader");
 MODULE_AUTHOR("Andries Brouwer <aeb@cwi.nl>, Robert Baruch <autophile@starband.net>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 static int usb_stor_sddr09_dpcm_init(struct us_data *us);
 static int sddr09_transport(struct scsi_cmnd *srb, struct us_data *us);

drivers/usb/storage/sddr55.c

@@ -29,6 +29,7 @@
 MODULE_DESCRIPTION("Driver for SanDisk SDDR-55 SmartMedia reader");
 MODULE_AUTHOR("Simon Munton");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 /*
  * The table of devices

drivers/usb/storage/shuttle_usbat.c

@@ -48,6 +48,7 @@
 MODULE_DESCRIPTION("Driver for SCM Microsystems (a.k.a. Shuttle) USB-ATAPI cable");
 MODULE_AUTHOR("Daniel Drake <dsd@gentoo.org>, Robert Baruch <autophile@starband.net>");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 
 /* Supported device types */
 #define USBAT_DEV_HP8200	0x01

drivers/usb/storage/uas.c

@@ -1199,5 +1199,6 @@ static struct usb_driver uas_driver = {
 module_usb_driver(uas_driver);
 
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
 MODULE_AUTHOR(
 	"Hans de Goede <hdegoede@redhat.com>, Matthew Wilcox and Sarah Sharp");

include/asm-generic/export.h

@@ -4,14 +4,12 @@
 #ifndef KSYM_FUNC
 #define KSYM_FUNC(x) x
 #endif
-#ifdef CONFIG_64BIT
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-#ifndef KSYM_ALIGN
+#define KSYM_ALIGN 4
-#define KSYM_ALIGN 8
+#elif defined(CONFIG_64BIT)
-#endif
+#define KSYM_ALIGN 8
-#else
+#else
-#ifndef KSYM_ALIGN
 #define KSYM_ALIGN 4
-#endif
 #endif
 #ifndef KCRC_ALIGN
 #define KCRC_ALIGN 4
@@ -19,11 +17,11 @@
 
 .macro __put, val, name
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-	.long	\val - ., \name - .
+	.long	\val - ., \name - ., 0
 #elif defined(CONFIG_64BIT)
-	.quad	\val, \name
+	.quad	\val, \name, 0
 #else
-	.long	\val, \name
+	.long	\val, \name, 0
 #endif
 .endm
 
@@ -57,7 +55,6 @@ __kcrctab_\name:
 #endif
 #endif
 .endm
-#undef __put
 
 #if defined(CONFIG_TRIM_UNUSED_KSYMS)
 

include/linux/export.h

@@ -18,6 +18,8 @@ extern struct module __this_module;
 #define THIS_MODULE ((struct module *)0)
 #endif
 
+#define NS_SEPARATOR "."
+
 #ifdef CONFIG_MODVERSIONS
 /* Mark the CRC weak since genksyms apparently decides not to
  * generate a checksums for some symbols */
@@ -26,13 +28,13 @@ extern struct module __this_module;
 	asm("	.section \"___kcrctab" sec "+" #sym "\", \"a\"	\n"	\
 	    "	.weak	__crc_" #sym "				\n"	\
 	    "	.long	__crc_" #sym " - .			\n"	\
-	    "	.previous					\n");
+	    "	.previous					\n")
 #else
 #define __CRC_SYMBOL(sym, sec)						\
 	asm("	.section \"___kcrctab" sec "+" #sym "\", \"a\"	\n"	\
 	    "	.weak	__crc_" #sym "				\n"	\
 	    "	.long	__crc_" #sym "				\n"	\
-	    "	.previous					\n");
+	    "	.previous					\n")
 #endif
 #else
 #define __CRC_SYMBOL(sym, sec)
@@ -46,44 +48,77 @@ extern struct module __this_module;
  * absolute relocations that require runtime processing on relocatable
  * kernels.
  */
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns)				\
+	__ADDRESSABLE(sym)						\
+	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
+	    "	.balign	4					\n"	\
+	    "__ksymtab_" #ns NS_SEPARATOR #sym ":		\n"	\
+	    "	.long	" #sym "- .				\n"	\
+	    "	.long	__kstrtab_" #sym "- .			\n"	\
+	    "	.long	__kstrtabns_" #sym "- .			\n"	\
+	    "	.previous					\n")
+
 #define __KSYMTAB_ENTRY(sym, sec)					\
 	__ADDRESSABLE(sym)						\
 	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
-	    "	.balign	8					\n"	\
+	    "	.balign 4					\n"	\
 	    "__ksymtab_" #sym ":				\n"	\
 	    "	.long	" #sym "- .				\n"	\
 	    "	.long	__kstrtab_" #sym "- .			\n"	\
+	    "	.long	0					\n"	\
 	    "	.previous					\n")
 
 struct kernel_symbol {
 	int value_offset;
 	int name_offset;
+	int namespace_offset;
 };
 #else
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns)				\
+	static const struct kernel_symbol __ksymtab_##sym##__##ns	\
+	asm("__ksymtab_" #ns NS_SEPARATOR #sym)				\
+	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
+	__aligned(sizeof(void *))					\
+	= { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }
+
 #define __KSYMTAB_ENTRY(sym, sec)					\
 	static const struct kernel_symbol __ksymtab_##sym		\
+	asm("__ksymtab_" #sym)						\
 	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
-	= { (unsigned long)&sym, __kstrtab_##sym }
+	__aligned(sizeof(void *))					\
+	= { (unsigned long)&sym, __kstrtab_##sym, NULL }
 
 struct kernel_symbol {
 	unsigned long value;
 	const char *name;
+	const char *namespace;
 };
 #endif
 
 #ifdef __GENKSYMS__
 
-#define ___EXPORT_SYMBOL(sym, sec)	__GENKSYMS_EXPORT_SYMBOL(sym)
+#define ___EXPORT_SYMBOL(sym,sec)	__GENKSYMS_EXPORT_SYMBOL(sym)
+#define ___EXPORT_SYMBOL_NS(sym,sec,ns)	__GENKSYMS_EXPORT_SYMBOL(sym)
 
 #else
 
-/* For every exported symbol, place a struct in the __ksymtab section */
+#define ___export_symbol_common(sym, sec)				\
-#define ___EXPORT_SYMBOL(sym, sec)					\
 	extern typeof(sym) sym;						\
-	__CRC_SYMBOL(sym, sec)						\
+	__CRC_SYMBOL(sym, sec);						\
 	static const char __kstrtab_##sym[]				\
 	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
-	= #sym;								\
+	= #sym								\
+
+/* For every exported symbol, place a struct in the __ksymtab section */
+#define ___EXPORT_SYMBOL_NS(sym, sec, ns)				\
+	___export_symbol_common(sym, sec);				\
+	static const char __kstrtabns_##sym[]				\
+	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
+	= #ns;								\
+	__KSYMTAB_ENTRY_NS(sym, sec, ns)
+
+#define ___EXPORT_SYMBOL(sym, sec)					\
+	___export_symbol_common(sym, sec);				\
 	__KSYMTAB_ENTRY(sym, sec)
 
 #endif
@@ -95,6 +130,7 @@ struct kernel_symbol {
  * be reused in other execution contexts such as the UEFI stub or the
  * decompressor.
  */
+#define __EXPORT_SYMBOL_NS(sym, sec, ns)
 #define __EXPORT_SYMBOL(sym, sec)
 
 #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
@@ -121,15 +157,35 @@ struct kernel_symbol {
 #define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
 #define __cond_export_sym_0(sym, sec) /* nothing */
 
+#define __EXPORT_SYMBOL_NS(sym, sec, ns)				\
+	__ksym_marker(sym);						\
+	__cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
+#define __cond_export_ns_sym(sym, sec, ns, conf)			\
+	___cond_export_ns_sym(sym, sec, ns, conf)
+#define ___cond_export_ns_sym(sym, sec, ns, enabled)			\
+	__cond_export_ns_sym_##enabled(sym, sec, ns)
+#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
+#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */
+
 #else
 
-#define __EXPORT_SYMBOL(sym, sec)	___EXPORT_SYMBOL(sym, sec)
+#define __EXPORT_SYMBOL_NS(sym,sec,ns)	___EXPORT_SYMBOL_NS(sym,sec,ns)
+#define __EXPORT_SYMBOL(sym,sec)	___EXPORT_SYMBOL(sym,sec)
 
 #endif /* CONFIG_MODULES */
 
+#ifdef DEFAULT_SYMBOL_NAMESPACE
+#undef __EXPORT_SYMBOL
+#define __EXPORT_SYMBOL(sym, sec)				\
+	__EXPORT_SYMBOL_NS(sym, sec, DEFAULT_SYMBOL_NAMESPACE)
+#endif
+
 #define EXPORT_SYMBOL(sym)		__EXPORT_SYMBOL(sym, "")
 #define EXPORT_SYMBOL_GPL(sym)		__EXPORT_SYMBOL(sym, "_gpl")
 #define EXPORT_SYMBOL_GPL_FUTURE(sym)	__EXPORT_SYMBOL(sym, "_gpl_future")
+#define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL_NS(sym, "", ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL_NS(sym, "_gpl", ns)
+
 #ifdef CONFIG_UNUSED_SYMBOLS
 #define EXPORT_UNUSED_SYMBOL(sym)	__EXPORT_SYMBOL(sym, "_unused")
 #define EXPORT_UNUSED_SYMBOL_GPL(sym)	__EXPORT_SYMBOL(sym, "_unused_gpl")

init/Kconfig

@@ -2051,8 +2051,7 @@ config MODULE_SRCVERSION_ALL
 
 config MODULE_SIG
 	bool "Module signature verification"
-	depends on MODULES
+	select MODULE_SIG_FORMAT
-	select SYSTEM_DATA_VERIFICATION
 	help
 	  Check modules for valid signatures upon load: the signature
 	  is simply appended to the module. For more information see
@@ -2133,7 +2132,6 @@ config MODULE_SIG_HASH
 
 config MODULE_COMPRESS
 	bool "Compress modules on installation"
-	depends on MODULES
 	help
 
 	  Compresses kernel modules when 'make modules_install' is run; gzip or
@@ -2169,9 +2167,38 @@ config MODULE_COMPRESS_XZ
 
 endchoice
 
+config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+	bool "Allow loading of modules with missing namespace imports"
+	help
+	  Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
+	  a namespace. A module that makes use of a symbol exported with such a
+	  namespace is required to import the namespace via MODULE_IMPORT_NS().
+	  There is no technical reason to enforce correct namespace imports,
+	  but it creates consistency between symbols defining namespaces and
+	  users importing namespaces they make use of. This option relaxes this
+	  requirement and lifts the enforcement when loading a module.
+
+	  If unsure, say N.
+
+config UNUSED_SYMBOLS
+	bool "Enable unused/obsolete exported symbols"
+	default y if X86
+	help
+	  Unused but exported symbols make the kernel needlessly bigger.  For
+	  that reason most of these unused exports will soon be removed.  This
+	  option is provided temporarily to provide a transition period in case
+	  some external kernel module needs one of these symbols anyway. If you
+	  encounter such a case in your module, consider if you are actually
+	  using the right API.  (rationale: since nobody in the kernel is using
+	  this in a module, there is a pretty good chance it's actually the
+	  wrong interface to use).  If you really need the symbol, please send a
+	  mail to the linux kernel mailing list mentioning the symbol and why
+	  you really need it, and what the merge plan to the mainline kernel for
+	  your module is.
+
 config TRIM_UNUSED_KSYMS
 	bool "Trim unused exported kernel symbols"
-	depends on MODULES && !UNUSED_SYMBOLS
+	depends on !UNUSED_SYMBOLS
 	help
 	  The kernel and some modules make many symbols available for
 	  other modules to use via EXPORT_SYMBOL() and variants. Depending

kernel/module.c

@@ -545,12 +545,20 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
 #endif
 }
 
-static int cmp_name(const void *va, const void *vb)
+static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
 {
-	const char *a;
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-	const struct kernel_symbol *b;
+	if (!sym->namespace_offset)
-	a = va; b = vb;
+		return NULL;
-	return strcmp(a, kernel_symbol_name(b));
+	return offset_to_ptr(&sym->namespace_offset);
+#else
+	return sym->namespace;
+#endif
+}
+
+static int cmp_name(const void *name, const void *sym)
+{
+	return strcmp(name, kernel_symbol_name(sym));
 }
 
 static bool find_exported_symbol_in_section(const struct symsearch *syms,
@@ -1380,6 +1388,41 @@ static inline int same_magic(const char *amagic, const char *bmagic,
 }
 #endif /* CONFIG_MODVERSIONS */
 
+static char *get_modinfo(const struct load_info *info, const char *tag);
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+			      char *prev);
+
+static int verify_namespace_is_imported(const struct load_info *info,
+					const struct kernel_symbol *sym,
+					struct module *mod)
+{
+	const char *namespace;
+	char *imported_namespace;
+
+	namespace = kernel_symbol_namespace(sym);
+	if (namespace) {
+		imported_namespace = get_modinfo(info, "import_ns");
+		while (imported_namespace) {
+			if (strcmp(namespace, imported_namespace) == 0)
+				return 0;
+			imported_namespace = get_next_modinfo(
+				info, "import_ns", imported_namespace);
+		}
+#ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+		pr_warn(
+#else
+		pr_err(
+#endif
+			"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
+			mod->name, kernel_symbol_name(sym), namespace);
+#ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+		return -EINVAL;
+#endif
+	}
+	return 0;
+}
+
+
 /* Resolve a symbol for this module.  I.e. if we find one, record usage. */
 static const struct kernel_symbol *resolve_symbol(struct module *mod,
 						  const struct load_info *info,
@@ -1408,6 +1451,12 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 		goto getname;
 	}
 
+	err = verify_namespace_is_imported(info, sym, mod);
+	if (err) {
+		sym = ERR_PTR(err);
+		goto getname;
+	}
+
 	err = ref_module(mod, owner);
 	if (err) {
 		sym = ERR_PTR(err);
@@ -2482,7 +2531,8 @@ static char *next_string(char *string, unsigned long *secsize)
 	return string;
 }
 
-static char *get_modinfo(struct load_info *info, const char *tag)
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+			      char *prev)
 {
 	char *p;
 	unsigned int taglen = strlen(tag);
@@ -2493,13 +2543,25 @@ static char *get_modinfo(struct load_info *info, const char *tag)
 	 * get_modinfo() calls made before rewrite_section_headers()
 	 * must use sh_offset, as sh_addr isn't set!
 	 */
-	for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {
+	char *modinfo = (char *)info->hdr + infosec->sh_offset;
+
+	if (prev) {
+		size -= prev - modinfo;
+		modinfo = next_string(prev, &size);
+	}
+
+	for (p = modinfo; p; p = next_string(p, &size)) {
 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 			return p + taglen + 1;
 	}
 	return NULL;
 }
 
+static char *get_modinfo(const struct load_info *info, const char *tag)
+{
+	return get_next_modinfo(info, tag, NULL);
+}
+
 static void setup_modinfo(struct module *mod, struct load_info *info)
 {
 	struct module_attribute *attr;

lib/Kconfig.debug

@@ -277,22 +277,6 @@ config READABLE_ASM
           to keep kernel developers who have to stare a lot at assembler listings
           sane.
 
-config UNUSED_SYMBOLS
-	bool "Enable unused/obsolete exported symbols"
-	default y if X86
-	help
-	  Unused but exported symbols make the kernel needlessly bigger.  For
-	  that reason most of these unused exports will soon be removed.  This
-	  option is provided temporarily to provide a transition period in case
-	  some external kernel module needs one of these symbols anyway. If you
-	  encounter such a case in your module, consider if you are actually
-	  using the right API.  (rationale: since nobody in the kernel is using
-	  this in a module, there is a pretty good chance it's actually the
-	  wrong interface to use).  If you really need the symbol, please send a
-	  mail to the linux kernel mailing list mentioning the symbol and why
-	  you really need it, and what the merge plan to the mainline kernel for
-	  your module is.
-
 config DEBUG_FS
 	bool "Debug Filesystem"
 	help

scripts/Makefile.modpost

@@ -54,7 +54,8 @@ MODPOST = scripts/mod/modpost						\
 	$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS)))	\
 	$(if $(KBUILD_EXTMOD),-o $(modulesymfile))			\
 	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)			\
-	$(if $(KBUILD_MODPOST_WARN),-w)
+	$(if $(KBUILD_MODPOST_WARN),-w)					\
+	$(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
 
 ifdef MODPOST_VMLINUX
 
@@ -95,6 +96,8 @@ ifneq ($(KBUILD_MODPOST_NOFINAL),1)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
 endif
 
+nsdeps: __modpost
+
 endif
 
 .PHONY: $(PHONY)

scripts/export_report.pl

@@ -94,7 +94,7 @@ if (defined $opt{'o'}) {
 #
 while ( <$module_symvers> ) {
 	chomp;
-	my (undef, $symbol, $module, $gpl) = split;
+	my (undef, $symbol, $namespace, $module, $gpl) = split('\t');
 	$SYMBOL { $symbol } =  [ $module , "0" , $symbol, $gpl];
 }
 close($module_symvers);

scripts/mod/modpost.c

@@ -38,6 +38,8 @@ static int sec_mismatch_count = 0;
 static int sec_mismatch_fatal = 0;
 /* ignore missing files */
 static int ignore_missing_files;
+/* write namespace dependencies */
+static int write_namespace_deps;
 
 enum export {
 	export_plain,      export_unused,     export_gpl,
@@ -164,6 +166,7 @@ struct symbol {
 	struct module *module;
 	unsigned int crc;
 	int crc_valid;
+	char *namespace;
 	unsigned int weak:1;
 	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 	unsigned int kernel:1;     /* 1 if symbol is from kernel
@@ -235,6 +238,37 @@ static struct symbol *find_symbol(const char *name)
 	return NULL;
 }
 
+static bool contains_namespace(struct namespace_list *list,
+			       const char *namespace)
+{
+	struct namespace_list *ns_entry;
+
+	for (ns_entry = list; ns_entry != NULL; ns_entry = ns_entry->next)
+		if (strcmp(ns_entry->namespace, namespace) == 0)
+			return true;
+
+	return false;
+}
+
+static void add_namespace(struct namespace_list **list, const char *namespace)
+{
+	struct namespace_list *ns_entry;
+
+	if (!contains_namespace(*list, namespace)) {
+		ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
+					 strlen(namespace) + 1));
+		strcpy(ns_entry->namespace, namespace);
+		ns_entry->next = *list;
+		*list = ns_entry;
+	}
+}
+
+static bool module_imports_namespace(struct module *module,
+				     const char *namespace)
+{
+	return contains_namespace(module->imported_namespaces, namespace);
+}
+
 static const struct {
 	const char *str;
 	enum export export;
@@ -314,12 +348,26 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 		return export_unknown;
 }
 
+static char *sym_extract_namespace(const char **symname)
+{
+	char *namespace = NULL;
+	char *ns_separator;
+
+	ns_separator = strchr(*symname, '.');
+	if (ns_separator) {
+		namespace = NOFAIL(strndup(*symname, ns_separator - *symname));
+		*symname = ns_separator + 1;
+	}
+
+	return namespace;
+}
+
 /**
  * Add an exported symbol - it may have already been added without a
  * CRC, in this case just update the CRC
  **/
-static struct symbol *sym_add_exported(const char *name, struct module *mod,
+static struct symbol *sym_add_exported(const char *name, const char *namespace,
-				       enum export export)
+				       struct module *mod, enum export export)
 {
 	struct symbol *s = find_symbol(name);
 
@@ -327,15 +375,16 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod,
 		s = new_symbol(name, mod, export);
 	} else {
 		if (!s->preloaded) {
-			warn("%s: '%s' exported twice. Previous export "
+			warn("%s: '%s' exported twice. Previous export was in %s%s\n",
-			     "was in %s%s\n", mod->name, name,
+			     mod->name, name, s->module->name,
-			     s->module->name,
+			     is_vmlinux(s->module->name) ? "" : ".ko");
-			     is_vmlinux(s->module->name) ?"":".ko");
 		} else {
 			/* In case Module.symvers was out of date */
 			s->module = mod;
 		}
 	}
+	free(s->namespace);
+	s->namespace = namespace ? strdup(namespace) : NULL;
 	s->preloaded = 0;
 	s->vmlinux   = is_vmlinux(mod->name);
 	s->kernel    = 0;
@@ -626,6 +675,8 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 	unsigned int crc;
 	enum export export;
 	bool is_crc = false;
+	const char *name;
+	char *namespace;
 
 	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 	    strstarts(symname, "__ksymtab"))
@@ -697,8 +748,10 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 	default:
 		/* All exported symbols */
 		if (strstarts(symname, "__ksymtab_")) {
-			sym_add_exported(symname + strlen("__ksymtab_"), mod,
+			name = symname + strlen("__ksymtab_");
-					export);
+			namespace = sym_extract_namespace(&name);
+			sym_add_exported(name, namespace, mod, export);
+			free(namespace);
 		}
 		if (strcmp(symname, "init_module") == 0)
 			mod->has_init = 1;
@@ -1949,6 +2002,7 @@ static void read_symbols(const char *modname)
 	const char *symname;
 	char *version;
 	char *license;
+	char *namespace;
 	struct module *mod;
 	struct elf_info info = { };
 	Elf_Sym *sym;
@@ -1980,6 +2034,12 @@ static void read_symbols(const char *modname)
 		license = get_next_modinfo(&info, "license", license);
 	}
 
+	namespace = get_modinfo(&info, "import_ns");
+	while (namespace) {
+		add_namespace(&mod->imported_namespaces, namespace);
+		namespace = get_next_modinfo(&info, "import_ns", namespace);
+	}
+
 	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
 		symname = remove_dot(info.strtab + sym->st_name);
 
@@ -2139,6 +2199,18 @@ static int check_exports(struct module *mod)
 			basename++;
 		else
 			basename = mod->name;
+
+		if (exp->namespace && exp->namespace[0]) {
+			add_namespace(&mod->required_namespaces,
+				      exp->namespace);
+
+			if (!write_namespace_deps &&
+			    !module_imports_namespace(mod, exp->namespace)) {
+				warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
+				     basename, exp->name, exp->namespace);
+			}
+		}
+
 		if (!mod->gpl_compatible)
 			check_for_gpl_usage(exp->export, basename, exp->name);
 		check_for_unused(exp->export, basename, exp->name);
@@ -2358,7 +2430,7 @@ static void read_dump(const char *fname, unsigned int kernel)
 		return;
 
 	while ((line = get_next_line(&pos, file, size))) {
-		char *symname, *modname, *d, *export, *end;
+		char *symname, *namespace, *modname, *d, *export, *end;
 		unsigned int crc;
 		struct module *mod;
 		struct symbol *s;
@@ -2366,7 +2438,10 @@ static void read_dump(const char *fname, unsigned int kernel)
 		if (!(symname = strchr(line, '\t')))
 			goto fail;
 		*symname++ = '\0';
-		if (!(modname = strchr(symname, '\t')))
+		if (!(namespace = strchr(symname, '\t')))
+			goto fail;
+		*namespace++ = '\0';
+		if (!(modname = strchr(namespace, '\t')))
 			goto fail;
 		*modname++ = '\0';
 		if ((export = strchr(modname, '\t')) != NULL)
@@ -2383,7 +2458,8 @@ static void read_dump(const char *fname, unsigned int kernel)
 			mod = new_module(modname);
 			mod->skip = 1;
 		}
-		s = sym_add_exported(symname, mod, export_no(export));
+		s = sym_add_exported(symname, namespace, mod,
+				     export_no(export));
 		s->kernel    = kernel;
 		s->preloaded = 1;
 		s->is_static = 0;
@@ -2413,16 +2489,20 @@ static void write_dump(const char *fname)
 {
 	struct buffer buf = { };
 	struct symbol *symbol;
+	const char *namespace;
 	int n;
 
 	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
 		symbol = symbolhash[n];
 		while (symbol) {
-			if (dump_sym(symbol))
+			if (dump_sym(symbol)) {
-				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
+				namespace = symbol->namespace;
-					symbol->crc, symbol->name,
+				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
-					symbol->module->name,
+					   symbol->crc, symbol->name,
-					export_str(symbol->export));
+					   namespace ? namespace : "",
+					   symbol->module->name,
+					   export_str(symbol->export));
+			}
 			symbol = symbol->next;
 		}
 	}
@@ -2430,6 +2510,31 @@ static void write_dump(const char *fname)
 	free(buf.p);
 }
 
+static void write_namespace_deps_files(void)
+{
+	struct module *mod;
+	struct namespace_list *ns;
+	struct buffer ns_deps_buf = {};
+
+	for (mod = modules; mod; mod = mod->next) {
+		char fname[PATH_MAX];
+
+		if (mod->skip)
+			continue;
+
+		ns_deps_buf.pos = 0;
+
+		for (ns = mod->required_namespaces; ns; ns = ns->next)
+			buf_printf(&ns_deps_buf, "%s\n", ns->namespace);
+
+		if (ns_deps_buf.pos == 0)
+			continue;
+
+		sprintf(fname, "%s.ns_deps", mod->name);
+		write_if_changed(&ns_deps_buf, fname);
+	}
+}
+
 struct ext_sym_list {
 	struct ext_sym_list *next;
 	const char *file;
@@ -2447,7 +2552,7 @@ int main(int argc, char **argv)
 	struct ext_sym_list *extsym_iter;
 	struct ext_sym_list *extsym_start = NULL;
 
-	while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awE")) != -1) {
+	while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awEd")) != -1) {
 		switch (opt) {
 		case 'i':
 			kernel_read = optarg;
@@ -2488,6 +2593,9 @@ int main(int argc, char **argv)
 		case 'E':
 			sec_mismatch_fatal = 1;
 			break;
+		case 'd':
+			write_namespace_deps = 1;
+			break;
 		default:
 			exit(1);
 		}
@@ -2522,6 +2630,9 @@ int main(int argc, char **argv)
 
 		err |= check_modname_len(mod);
 		err |= check_exports(mod);
+		if (write_namespace_deps)
+			continue;
+
 		add_header(&buf, mod);
 		add_intree_flag(&buf, !external_module);
 		add_retpoline(&buf);
@@ -2534,6 +2645,12 @@ int main(int argc, char **argv)
 		sprintf(fname, "%s.mod.c", mod->name);
 		write_if_changed(&buf, fname);
 	}
+
+	if (write_namespace_deps) {
+		write_namespace_deps_files();
+		return 0;
+	}
+
 	if (dump_write)
 		write_dump(dump_write);
 	if (sec_mismatch_count && sec_mismatch_fatal)

scripts/mod/modpost.h

@@ -109,6 +109,11 @@ buf_printf(struct buffer *buf, const char *fmt, ...);
 void
 buf_write(struct buffer *buf, const char *s, int len);
 
+struct namespace_list {
+	struct namespace_list *next;
+	char namespace[0];
+};
+
 struct module {
 	struct module *next;
 	const char *name;
@@ -121,6 +126,10 @@ struct module {
 	struct buffer dev_table_buf;
 	char	     srcversion[25];
 	int is_dot_o;
+	// Required namespace dependencies
+	struct namespace_list *required_namespaces;
+	// Actual imported namespaces
+	struct namespace_list *imported_namespaces;
 };
 
 struct elf_info {