1 # SPDX-License-Identifier: GPL-2.0
2 # ===========================================================================
3 # Module versions
4 # ===========================================================================
5 #
6 # Stage one of module building created the following:
7 # a) The individual .o files used for the module
8 # b) A <module>.o file which is the .o files above linked together
9 # c) A <module>.mod file, listing the name of the preliminary <module>.o file,
10 # plus all .o files
11 # d) modules.order, which lists all the modules
12
13 # Stage 2 is handled by this file and does the following
14 # 1) Find all modules listed in modules.order
15 # 2) modpost is then used to
16 # 3) create one <module>.mod.c file per module
17 # 4) create one Module.symvers file with CRC for all exported symbols
18
19 # Step 3 is used to place certain information in the module's ELF
20 # section, including information such as:
21 # Version magic (see include/linux/vermagic.h for full details)
22 # - Kernel release
23 # - SMP is CONFIG_SMP
24 # - PREEMPT is CONFIG_PREEMPT[_RT]
25 # - GCC Version
26 # Module info
27 # - Module version (MODULE_VERSION)
28 # - Module alias'es (MODULE_ALIAS)
29 # - Module license (MODULE_LICENSE)
30 # - See include/linux/module.h for more details
31
32 # Step 4 is solely used to allow module versioning in external modules,
33 # where the CRC of each module is retrieved from the Module.symvers file.
34
35 PHONY := __modpost
36 __modpost:
37
38 include include/config/auto.conf
39 include $(srctree)/scripts/Kbuild.include
40
41 MODPOST = scripts/mod/modpost
42
43 modpost-args = \
44 $(if $(CONFIG_MODULES),-M) \
45 $(if $(CONFIG_MODVERSIONS),-m) \
46 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
47 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
48 $(if $(KBUILD_MODPOST_WARN),-w) \
49 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
50 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
51 $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \
52 -o $@
53
54 modpost-deps := $(MODPOST)
55
56 # 'make -i -k' ignores compile errors, and builds as many modules as possible.
57 ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
58 modpost-args += -n
59 endif
60
61 # Read out modules.order to pass in modpost.
62 # Otherwise, allmodconfig would fail with "Argument list too long".
63 ifdef KBUILD_MODULES
64 modpost-args += -T $(MODORDER)
65 modpost-deps += $(MODORDER)
66 endif
67
68 ifeq ($(KBUILD_EXTMOD),)
69
70 # Generate the list of in-tree objects in vmlinux
71 # ---------------------------------------------------------------------------
72
73 # This is used to retrieve symbol versions generated by genksyms.
74 ifdef CONFIG_MODVERSIONS
75 vmlinux.symvers Module.symvers: .vmlinux.objs
76 endif
77
78 # Ignore libgcc.a
79 # Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
80 # from the toolchain, but there is no EXPORT_SYMBOL in it.
81
82 quiet_cmd_vmlinux_objs = GEN $@
83 cmd_vmlinux_objs = \
84 for f in $(real-prereqs); do \
85 case $${f} in \
86 *libgcc.a) ;; \
87 *) $(AR) t $${f} ;; \
88 esac \
89 done > $@
90
91 targets += .vmlinux.objs
92 .vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
93 $(call if_changed,vmlinux_objs)
94
95 ifdef CONFIG_TRIM_UNUSED_KSYMS
96 ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
97 ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(if $(wildcard $(ksym-wl)),,$(srctree)/))$(ksym-wl)
98 modpost-args += -t $(addprefix -u , $(ksym-wl))
99 modpost-deps += $(ksym-wl)
100 endif
101
102 ifeq ($(wildcard vmlinux.o),)
103 missing-input := vmlinux.o
104 output-symdump := modules-only.symvers
105 else
106 modpost-args += vmlinux.o
107 modpost-deps += vmlinux.o
108 output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
109 endif
110
111 else
112
113 # set src + obj - they may be used in the modules's Makefile
114 obj := $(KBUILD_EXTMOD)
115 src := $(if $(VPATH),$(VPATH)/)$(obj)
116
117 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
118 include $(kbuild-file)
119
120 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
121
122 ifeq ($(wildcard Module.symvers),)
123 missing-input := Module.symvers
124 else
125 modpost-args += -i Module.symvers
126 modpost-deps += Module.symvers
127 endif
128
129 modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
130
131 endif # ($(KBUILD_EXTMOD),)
132
133 quiet_cmd_modpost = MODPOST $@
134 cmd_modpost = \
135 $(if $(missing-input), \
136 echo >&2 "WARNING: $(missing-input) is missing."; \
137 echo >&2 " Modules may not have dependencies or modversions."; \
138 echo >&2 " You may get many unresolved symbol errors."; \
139 echo >&2 " You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \
140 echo >&2 " if you want to proceed at your own risk.";) \
141 $(MODPOST) $(modpost-args)
142
143 targets += $(output-symdump)
144 $(output-symdump): $(modpost-deps) FORCE
145 $(call if_changed,modpost)
146
147 __modpost: $(output-symdump)
148 PHONY += FORCE
149 FORCE:
150
151 existing-targets := $(wildcard $(sort $(targets)))
152
153 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
154
155 .PHONY: $(PHONY)
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