Merge patch series "Add generated modalias to modules.builtin.modinfo"

Alexey Gladkov says:

The modules.builtin.modinfo file is used by userspace (kmod to be specific) to
get information about builtin modules. Among other information about the module,
information about module aliases is stored. This is very important to determine
that a particular modalias will be handled by a module that is inside the
kernel.

There are several mechanisms for creating modalias for modules:

The first is to explicitly specify the MODULE_ALIAS of the macro. In this case,
the aliases go into the '.modinfo' section of the module if it is compiled
separately or into vmlinux.o if it is builtin into the kernel.

The second is the use of MODULE_DEVICE_TABLE followed by the use of the
modpost utility. In this case, vmlinux.o no longer has this information and
does not get it into modules.builtin.modinfo.

For example:

$ modinfo pci:v00008086d0000A36Dsv00001043sd00008694bc0Csc03i30
modinfo: ERROR: Module pci:v00008086d0000A36Dsv00001043sd00008694bc0Csc03i30 not found.

$ modinfo xhci_pci
name:           xhci_pci
filename:       (builtin)
license:        GPL
file:           drivers/usb/host/xhci-pci
description:    xHCI PCI Host Controller Driver

The builtin module is missing alias "pci:v*d*sv*sd*bc0Csc03i30*" which will be
generated by modpost if the module is built separately.

To fix this it is necessary to add the generated by modpost modalias to
modules.builtin.modinfo. Fortunately modpost already generates .vmlinux.export.c
for exported symbols. It is possible to add `.modinfo` for builtin modules and
modify the build system so that `.modinfo` section is extracted from the
intermediate vmlinux after modpost is executed.

Link: https://patch.msgid.link/cover.1758182101.git.legion@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

12 files changed, 131 insertions, 78 deletions

diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 1c606dfa595d..feecf1a6ddb4 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -209,6 +209,11 @@ SECTIONS
 	. = ALIGN(PAGE_SIZE);
 	_end = . ;
 
+	/* Debugging sections.	*/
+	STABS_DEBUG
+	DWARF_DEBUG
+	ELF_DETAILS
+
 	/*
 	 * uncompressed image info used by the decompressor
 	 * it should match struct vmlinux_info
@@ -239,11 +244,6 @@ SECTIONS
 #endif
 	} :NONE
 
-	/* Debugging sections.	*/
-	STABS_DEBUG
-	DWARF_DEBUG
-	ELF_DETAILS
-
 	/*
 	 * Make sure that the .got.plt is either completely empty or it
 	 * contains only the three reserved double words.
diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c
index 1f100270cd38..82597bd96525 100644
--- a/drivers/scsi/BusLogic.c
+++ b/drivers/scsi/BusLogic.c
@@ -3715,7 +3715,6 @@ static void __exit blogic_exit(void)
 
 __setup("BusLogic=", blogic_setup);
 
-#ifdef MODULE
 /*static const struct pci_device_id blogic_pci_tbl[] = {
 	{ PCI_VENDOR_ID_BUSLOGIC, PCI_DEVICE_ID_BUSLOGIC_MULTIMASTER,
 	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
@@ -3725,13 +3724,12 @@ __setup("BusLogic=", blogic_setup);
 	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
 	{ }
 };*/
-static const struct pci_device_id blogic_pci_tbl[] = {
+static const struct pci_device_id blogic_pci_tbl[] __maybe_unused = {
 	{PCI_DEVICE(PCI_VENDOR_ID_BUSLOGIC, PCI_DEVICE_ID_BUSLOGIC_MULTIMASTER)},
 	{PCI_DEVICE(PCI_VENDOR_ID_BUSLOGIC, PCI_DEVICE_ID_BUSLOGIC_MULTIMASTER_NC)},
 	{PCI_DEVICE(PCI_VENDOR_ID_BUSLOGIC, PCI_DEVICE_ID_BUSLOGIC_FLASHPOINT)},
 	{0, },
 };
-#endif
 MODULE_DEVICE_TABLE(pci, blogic_pci_tbl);
 
 module_init(blogic_init);
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ae2d2359b79e..cfa63860dfd4 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -831,6 +831,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
 
 /* Required sections not related to debugging. */
 #define ELF_DETAILS							\
+		.modinfo : { *(.modinfo) }				\
 		.comment 0 : { *(.comment) }				\
 		.symtab 0 : { *(.symtab) }				\
 		.strtab 0 : { *(.strtab) }				\
@@ -1044,7 +1045,6 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
 	*(.discard.*)							\
 	*(.export_symbol)						\
 	*(.no_trim_symbol)						\
-	*(.modinfo)							\
 	/* ld.bfd warns about .gnu.version* even when not emitted */	\
 	*(.gnu.version*)						\
 
diff --git a/include/linux/module.h b/include/linux/module.h
index 3319a5269d28..e135cc79acee 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -244,14 +244,22 @@ struct module_kobject *lookup_or_create_module_kobject(const char *name);
 /* What your module does. */
 #define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description)
 
-#ifdef MODULE
+/*
+ * Format: __mod_device_table__kmod_<modname>__<type>__<name>
+ * Parts of the string `__kmod_` and `__` are used as delimiters when parsing
+ * a symbol in file2alias.c
+ */
+#define __mod_device_table(type, name)	\
+	__PASTE(__mod_device_table__,	\
+	__PASTE(__KBUILD_MODNAME,	\
+	__PASTE(__,			\
+	__PASTE(type,			\
+	__PASTE(__, name)))))
+
 /* Creates an alias so file2alias.c can find device table. */
 #define MODULE_DEVICE_TABLE(type, name)					\
-static typeof(name) __mod_device_table__##type##__##name		\
+static typeof(name) __mod_device_table(type, name)			\
   __attribute__ ((used, alias(__stringify(name))))
-#else  /* !MODULE */
-#define MODULE_DEVICE_TABLE(type, name)
-#endif
 
 /* Version of form [<epoch>:]<version>[-<extra-version>].
  * Or for CVS/RCS ID version, everything but the number is stripped.
diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs
index 70d57814ff79..62c42da12e9d 100644
--- a/rust/kernel/device_id.rs
+++ b/rust/kernel/device_id.rs
@@ -195,10 +195,10 @@ macro_rules! module_device_table {
     ($table_type: literal, $module_table_name:ident, $table_name:ident) => {
         #[rustfmt::skip]
         #[export_name =
-            concat!("__mod_device_table__", $table_type,
-                    "__", module_path!(),
-                    "_", line!(),
-                    "_", stringify!($table_name))
+            concat!("__mod_device_table__", line!(),
+                    "__kmod_", module_path!(),
+                    "__", $table_type,
+                    "__", stringify!($table_name))
         ]
         static $module_table_name: [::core::mem::MaybeUninit<u8>; $table_name.raw_ids().size()] =
             unsafe { ::core::mem::transmute_copy($table_name.raw_ids()) };
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index b64862dc6f08..7c6ae9886f8f 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -9,20 +9,6 @@ include $(srctree)/scripts/Makefile.lib
 
 targets :=
 
-ifdef CONFIG_ARCH_VMLINUX_NEEDS_RELOCS
-vmlinux-final := vmlinux.unstripped
-
-quiet_cmd_strip_relocs = RSTRIP  $@
-      cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' --remove-section=!'.rel*.dyn' $< $@
-
-vmlinux: $(vmlinux-final) FORCE
-	$(call if_changed,strip_relocs)
-
-targets += vmlinux
-else
-vmlinux-final := vmlinux
-endif
-
 %.o: %.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
@@ -61,19 +47,14 @@ targets += .builtin-dtbs-list
 
 ifdef CONFIG_GENERIC_BUILTIN_DTB
 targets += .builtin-dtbs.S .builtin-dtbs.o
-$(vmlinux-final): .builtin-dtbs.o
+vmlinux.unstripped: .builtin-dtbs.o
 endif
 
-# vmlinux
+# vmlinux.unstripped
 # ---------------------------------------------------------------------------
 
-ifdef CONFIG_MODULES
-targets += .vmlinux.export.o
-$(vmlinux-final): .vmlinux.export.o
-endif
-
 ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
-$(vmlinux-final): arch/$(SRCARCH)/tools/vmlinux.arch.o
+vmlinux.unstripped: arch/$(SRCARCH)/tools/vmlinux.arch.o
 
 arch/$(SRCARCH)/tools/vmlinux.arch.o: vmlinux.o FORCE
 	$(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools $@
@@ -86,17 +67,61 @@ cmd_link_vmlinux =							\
 	$< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)" "$@";	\
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
-targets += $(vmlinux-final)
-$(vmlinux-final): scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
+targets += vmlinux.unstripped .vmlinux.export.o
+vmlinux.unstripped: scripts/link-vmlinux.sh vmlinux.o .vmlinux.export.o $(KBUILD_LDS) FORCE
 	+$(call if_changed_dep,link_vmlinux)
 ifdef CONFIG_DEBUG_INFO_BTF
-$(vmlinux-final): $(RESOLVE_BTFIDS)
+vmlinux.unstripped: $(RESOLVE_BTFIDS)
 endif
 
 ifdef CONFIG_BUILDTIME_TABLE_SORT
-$(vmlinux-final): scripts/sorttable
+vmlinux.unstripped: scripts/sorttable
 endif
 
+# vmlinux
+# ---------------------------------------------------------------------------
+
+remove-section-y                                   := .modinfo
+remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*'
+
+remove-symbols := -w --strip-symbol='__mod_device_table__*'
+
+# To avoid warnings: "empty loadable segment detected at ..." from GNU objcopy,
+# it is necessary to remove the PT_LOAD flag from the segment.
+quiet_cmd_strip_relocs = OBJCOPY $@
+      cmd_strip_relocs = $(OBJCOPY) $(patsubst %,--set-section-flags %=noload,$(remove-section-y)) $< $@; \
+                         $(OBJCOPY) $(addprefix --remove-section=,$(remove-section-y)) $(remove-symbols) $@
+
+targets += vmlinux
+vmlinux: vmlinux.unstripped FORCE
+	$(call if_changed,strip_relocs)
+
+# modules.builtin.modinfo
+# ---------------------------------------------------------------------------
+
+OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
+
+targets += modules.builtin.modinfo
+modules.builtin.modinfo: vmlinux.unstripped FORCE
+	$(call if_changed,objcopy)
+
+# modules.builtin
+# ---------------------------------------------------------------------------
+
+__default: modules.builtin
+
+# The second line aids cases where multiple modules share the same object.
+
+quiet_cmd_modules_builtin = GEN     $@
+      cmd_modules_builtin = \
+	tr '\0' '\n' < $< | \
+	sed -n 's/^[[:alnum:]:_]*\.file=//p' | \
+	tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$$/.ko/' > $@
+
+targets += modules.builtin
+modules.builtin: modules.builtin.modinfo FORCE
+	$(call if_changed,modules_builtin)
+
 # modules.builtin.ranges
 # ---------------------------------------------------------------------------
 ifdef CONFIG_BUILTIN_MODULE_RANGES
@@ -110,7 +135,7 @@ modules.builtin.ranges: $(srctree)/scripts/generate_builtin_ranges.awk \
 			modules.builtin vmlinux.map vmlinux.o.map FORCE
 	$(call if_changed,modules_builtin_ranges)
 
-vmlinux.map: $(vmlinux-final)
+vmlinux.map: vmlinux.unstripped
 	@:
 
 endif
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index b024ffb3e201..23c8751285d7 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 PHONY := __default
-__default: vmlinux.o modules.builtin.modinfo modules.builtin
+__default: vmlinux.o
 
 include include/config/auto.conf
 include $(srctree)/scripts/Kbuild.include
@@ -73,30 +73,6 @@ vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 
 targets += vmlinux.o
 
-# modules.builtin.modinfo
-# ---------------------------------------------------------------------------
-
-OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
-
-targets += modules.builtin.modinfo
-modules.builtin.modinfo: vmlinux.o FORCE
-	$(call if_changed,objcopy)
-
-# modules.builtin
-# ---------------------------------------------------------------------------
-
-# The second line aids cases where multiple modules share the same object.
-
-quiet_cmd_modules_builtin = GEN     $@
-      cmd_modules_builtin = \
-	tr '\0' '\n' < $< | \
-	sed -n 's/^[[:alnum:]:_]*\.file=//p' | \
-	tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$$/.ko/' > $@
-
-targets += modules.builtin
-modules.builtin: modules.builtin.modinfo FORCE
-	$(call if_changed,modules_builtin)
-
 # Add FORCE to the prerequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
 
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 51367c2bfc21..433849ff7529 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -73,10 +73,7 @@ vmlinux_link()
 		objs="${objs} .builtin-dtbs.o"
 	fi
 
-	if is_enabled CONFIG_MODULES; then
-		objs="${objs} .vmlinux.export.o"
-	fi
-
+	objs="${objs} .vmlinux.export.o"
 	objs="${objs} init/version-timestamp.o"
 
 	if [ "${SRCARCH}" = "um" ]; then
diff --git a/scripts/mksysmap b/scripts/mksysmap
index 3accbdb269ac..c4531eacde20 100755
--- a/scripts/mksysmap
+++ b/scripts/mksysmap
@@ -59,6 +59,9 @@
 # EXPORT_SYMBOL (namespace)
 / __kstrtabns_/d
 
+# MODULE_DEVICE_TABLE (symbol name)
+/ __mod_device_table__/d
+
 # ---------------------------------------------------------------------------
 # Ignored suffixes
 #  (do not forget '$' after each pattern)
@@ -79,6 +82,9 @@
 / _SDA_BASE_$/d
 / _SDA2_BASE_$/d
 
+# MODULE_INFO()
+/ __UNIQUE_ID_modinfo[0-9]*$/d
+
 # ---------------------------------------------------------------------------
 # Ignored patterns
 #  (symbols that contain the pattern are ignored)
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 00586119a25b..7da9735e7ab3 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1476,8 +1476,8 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 {
 	void *symval;
 	char *zeros = NULL;
-	const char *type, *name;
-	size_t typelen;
+	const char *type, *name, *modname;
+	size_t typelen, modnamelen;
 	static const char *prefix = "__mod_device_table__";
 
 	/* We're looking for a section relative symbol */
@@ -1488,10 +1488,20 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 	if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
 		return;
 
-	/* All our symbols are of form __mod_device_table__<type>__<name>. */
+	/* All our symbols are of form __mod_device_table__kmod_<modname>__<type>__<name>. */
 	if (!strstarts(symname, prefix))
 		return;
-	type = symname + strlen(prefix);
+
+	modname = strstr(symname, "__kmod_");
+	if (!modname)
+		return;
+	modname += strlen("__kmod_");
+
+	type = strstr(modname, "__");
+	if (!type)
+		return;
+	modnamelen = type - modname;
+	type += strlen("__");
 
 	name = strstr(type, "__");
 	if (!name)
@@ -1517,5 +1527,21 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 		}
 	}
 
+	if (mod->is_vmlinux) {
+		struct module_alias *alias;
+
+		/*
+		 * If this is vmlinux, record the name of the builtin module.
+		 * Traverse the linked list in the reverse order, and set the
+		 * builtin_modname unless it has already been set in the
+		 * previous call.
+		 */
+		list_for_each_entry_reverse(alias, &mod->aliases, node) {
+			if (alias->builtin_modname)
+				break;
+			alias->builtin_modname = xstrndup(modname, modnamelen);
+		}
+	}
+
 	free(zeros);
 }
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 5ca7c268294e..47c8aa2a6939 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2067,11 +2067,26 @@ static void write_if_changed(struct buffer *b, const char *fname)
 static void write_vmlinux_export_c_file(struct module *mod)
 {
 	struct buffer buf = { };
+	struct module_alias *alias, *next;
 
 	buf_printf(&buf,
 		   "#include <linux/export-internal.h>\n");
 
 	add_exported_symbols(&buf, mod);
+
+	buf_printf(&buf,
+		   "#include <linux/module.h>\n"
+		   "#undef __MODULE_INFO_PREFIX\n"
+		   "#define __MODULE_INFO_PREFIX\n");
+
+	list_for_each_entry_safe(alias, next, &mod->aliases, node) {
+		buf_printf(&buf, "MODULE_INFO(%s.alias, \"%s\");\n",
+			   alias->builtin_modname, alias->str);
+		list_del(&alias->node);
+		free(alias->builtin_modname);
+		free(alias);
+	}
+
 	write_if_changed(&buf, ".vmlinux.export.c");
 	free(buf.p);
 }
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 9133e4c3803f..2aecb8f25c87 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -99,10 +99,12 @@ buf_write(struct buffer *buf, const char *s, int len);
  * struct module_alias - auto-generated MODULE_ALIAS()
  *
  * @node: linked to module::aliases
+ * @modname: name of the builtin module (only for vmlinux)
  * @str: a string for MODULE_ALIAS()
  */
 struct module_alias {
 	struct list_head node;
+	char *builtin_modname;
 	char str[];
 };