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Date:   Mon, 19 Dec 2022 13:18:55 -0600
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Subject: [PATCH v8 9/9] build: Add modules.builtin.alias
From:   Allen Webb <allenwebb@google.com>
To:     "linux-modules@vger.kernel.org" <linux-modules@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     Luis Chamberlain <mcgrof@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Allen Webb <allenwebb@google.com>
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Precedence: bulk

Generate modules.builtin.alias using modpost and install it with the
modules.

Signed-off-by: Allen Webb <allenwebb@google.com>
---
 .gitignore               |  1 +
 Makefile                 |  1 +
 scripts/Makefile.modpost | 17 ++++++++++++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index 47229f98b327b..40a90bca89641 100644
--- a/.gitignore
+++ b/.gitignore
@@ -67,6 +67,7 @@ modules.order
 /System.map
 /Module.markers
 /modules.builtin
+/modules.builtin.alias
 /modules.builtin.modinfo
 /modules.nsdeps
 
diff --git a/Makefile b/Makefile
index 78525ebea8762..572f364f40538 100644
--- a/Makefile
+++ b/Makefile
@@ -1558,6 +1558,7 @@ __modinst_pre:
 	fi
 	@sed 's:^:kernel/:' modules.order > $(MODLIB)/modules.order
 	@cp -f modules.builtin $(MODLIB)/
+	@cp -f modules.builtin.alias $(MODLIB)/
 	@cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/
 
 endif # CONFIG_MODULES
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index e41dee64d429c..94c1d66c7769a 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -15,6 +15,7 @@
 # 2) modpost is then used to
 # 3)  create one <module>.mod.c file per module
 # 4)  create one Module.symvers file with CRC for all exported symbols
+# 5)  create modules.builtin.alias the aliases for built-in modules
 
 # Step 3 is used to place certain information in the module's ELF
 # section, including information such as:
@@ -51,6 +52,21 @@ ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
 modpost-args += -n
 endif
 
+vmlinux.o-if-present := $(wildcard vmlinux.o)
+ifneq ($(vmlinux.o-if-present),)
+output-builtin.alias := modules.builtin.alias
+modpost-args += -b .modules.builtin.alias.in
+.modules.builtin.alias.in: $(output-symdump)
+	@# Building $(output-symdump) generates .modules.builtin.alias.in as a
+	@# side effect.
+	@[ -e $@ ] || $(MODPOST) -b .modules.builtin.alias.in $(vmlinux.o-if-present)
+
+$(output-builtin.alias): .modules.builtin.alias.in
+	sort -o $@ $^
+
+__modpost: $(output-builtin.alias)
+endif
+
 ifeq ($(KBUILD_EXTMOD),)
 
 # Generate the list of in-tree objects in vmlinux
@@ -78,7 +94,6 @@ targets += .vmlinux.objs
 .vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,vmlinux_objs)
 
-vmlinux.o-if-present := $(wildcard vmlinux.o)
 output-symdump := vmlinux.symvers
 
 ifdef KBUILD_MODULES
-- 
2.37.3