1 files changed, 87 insertions, 0 deletions
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
new file mode 100644
index 000000000000..3c97a1564947
--- /dev/null
+++ b/scripts/Makefile.vmlinux_o
@@ -0,0 +1,87 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+PHONY := __default
+__default: vmlinux.o
+
+include include/config/auto.conf
+include $(srctree)/scripts/Kbuild.include
+
+# for objtool
+include $(srctree)/scripts/Makefile.lib
+
+# Generate a linker script to ensure correct ordering of initcalls for Clang LTO
+# ---------------------------------------------------------------------------
+
+quiet_cmd_gen_initcalls_lds = GEN     $@
+      cmd_gen_initcalls_lds = \
+	$(PYTHON3) $(srctree)/scripts/jobserver-exec \
+	$(PERL) $(real-prereqs) > $@
+
+.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
+		$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+	$(call if_changed,gen_initcalls_lds)
+
+targets := .tmp_initcalls.lds
+
+ifdef CONFIG_LTO_CLANG
+initcalls-lds := .tmp_initcalls.lds
+endif
+
+# objtool for vmlinux.o
+# ---------------------------------------------------------------------------
+#
+# For LTO and IBT, objtool doesn't run on individual translation units.
+# Run everything on vmlinux instead.
+
+objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
+
+# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled.
+#
+# Add some more flags as needed.
+# --no-unreachable and --link might be added twice, but it is fine.
+#
+# Expand objtool_args to a simple variable to avoid circular reference.
+
+objtool_args := \
+	$(if $(delay-objtool),$(objtool_args)) \
+	$(if $(CONFIG_NOINSTR_VALIDATION), --noinstr) \
+	$(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \
+	--link
+
+# Link of vmlinux.o used for section mismatch analysis
+# ---------------------------------------------------------------------------
+
+quiet_cmd_ld_vmlinux.o = LD      $@
+      cmd_ld_vmlinux.o = \
+	$(LD) ${KBUILD_LDFLAGS} -r -o $@ \
+	$(addprefix -T , $(initcalls-lds)) \
+	--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
+	--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
+	$(cmd_objtool)
+
+define rule_ld_vmlinux.o
+	$(call cmd_and_savecmd,ld_vmlinux.o)
+	$(call cmd,gen_objtooldep)
+endef
+
+vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+	$(call if_changed_rule,ld_vmlinux.o)
+
+targets += vmlinux.o
+
+# Add FORCE to the prequisites of a target to force it to be always rebuilt.
+# ---------------------------------------------------------------------------
+
+PHONY += FORCE
+FORCE:
+
+# Read all saved command lines and dependencies for the $(targets) we
+# may be building above, using $(if_changed{,_dep}). As an
+# optimization, we don't need to read them if the target does not
+# exist, we will rebuild anyway in that case.
+
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+.PHONY: $(PHONY)