kbuild: fix and refactor single target build
[linux-block.git] / scripts / Makefile.vmlinux_o
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1# SPDX-License-Identifier: GPL-2.0-only
2
3PHONY := __default
4__default: vmlinux.o
5
6include include/config/auto.conf
7include $(srctree)/scripts/Kbuild.include
8
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9# for objtool
10include $(srctree)/scripts/Makefile.lib
11
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12# Generate a linker script to ensure correct ordering of initcalls for Clang LTO
13# ---------------------------------------------------------------------------
14
15quiet_cmd_gen_initcalls_lds = GEN $@
16 cmd_gen_initcalls_lds = \
17 $(PYTHON3) $(srctree)/scripts/jobserver-exec \
18 $(PERL) $(real-prereqs) > $@
19
20.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
21 $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
22 $(call if_changed,gen_initcalls_lds)
23
24targets := .tmp_initcalls.lds
25
26ifdef CONFIG_LTO_CLANG
27initcalls-lds := .tmp_initcalls.lds
28endif
29
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30# objtool for vmlinux.o
31# ---------------------------------------------------------------------------
32#
33# For LTO and IBT, objtool doesn't run on individual translation units.
34# Run everything on vmlinux instead.
35
36objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
37
38# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled.
39#
40# Add some more flags as needed.
41# --no-unreachable and --link might be added twice, but it is fine.
42#
43# Expand objtool_args to a simple variable to avoid circular reference.
44
45objtool_args := \
46 $(if $(delay-objtool),$(objtool_args)) \
f43b9876 47 $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr $(if $(CONFIG_CPU_UNRET_ENTRY), --unret)) \
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48 $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \
49 --link
50
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51# Link of vmlinux.o used for section mismatch analysis
52# ---------------------------------------------------------------------------
53
54quiet_cmd_ld_vmlinux.o = LD $@
55 cmd_ld_vmlinux.o = \
56 $(LD) ${KBUILD_LDFLAGS} -r -o $@ \
57 $(addprefix -T , $(initcalls-lds)) \
58 --whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
59 --start-group $(KBUILD_VMLINUX_LIBS) --end-group \
b42d2306 60 $(cmd_objtool)
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61
62define rule_ld_vmlinux.o
63 $(call cmd_and_savecmd,ld_vmlinux.o)
b42d2306 64 $(call cmd,gen_objtooldep)
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65endef
66
67vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
68 $(call if_changed_rule,ld_vmlinux.o)
69
70targets += vmlinux.o
71
72# Add FORCE to the prequisites of a target to force it to be always rebuilt.
73# ---------------------------------------------------------------------------
74
75PHONY += FORCE
76FORCE:
77
78# Read all saved command lines and dependencies for the $(targets) we
79# may be building above, using $(if_changed{,_dep}). As an
80# optimization, we don't need to read them if the target does not
81# exist, we will rebuild anyway in that case.
82
83existing-targets := $(wildcard $(sort $(targets)))
84
85-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
86
87.PHONY: $(PHONY)