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# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
36# This is solely useful to speed up test compiles
37
38PHONY := __modpost
39__modpost:
40
41include include/config/auto.conf
42include $(srctree)/scripts/Kbuild.include
43
44# for mod-prelink-ext
45include $(srctree)/scripts/Makefile.lib
46
47MODPOST = scripts/mod/modpost								\
48	$(if $(CONFIG_MODVERSIONS),-m)							\
49	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\
50	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)					\
51	-o $@
52
53ifdef MODPOST_VMLINUX
54
55quiet_cmd_modpost = MODPOST $@
56      cmd_modpost = $(MODPOST) $<
57
58vmlinux.symvers: vmlinux.o
59	$(call cmd,modpost)
60
61__modpost: vmlinux.symvers
62
63else
64
65ifeq ($(KBUILD_EXTMOD),)
66
67input-symdump := vmlinux.symvers
68output-symdump := modules-only.symvers
69
70quiet_cmd_cat = GEN     $@
71      cmd_cat = cat $(real-prereqs) > $@
72
73ifneq ($(wildcard vmlinux.symvers),)
74
75__modpost: Module.symvers
76Module.symvers: vmlinux.symvers modules-only.symvers FORCE
77	$(call if_changed,cat)
78
79targets += Module.symvers
80
81endif
82
83else
84
85# set src + obj - they may be used in the modules's Makefile
86obj := $(KBUILD_EXTMOD)
87src := $(obj)
88
89# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
90include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
91             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
92
93# modpost option for external modules
94MODPOST += -e
95
96input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
97output-symdump := $(KBUILD_EXTMOD)/Module.symvers
98
99endif
100
101existing-input-symdump := $(wildcard $(input-symdump))
102
103# modpost options for modules (both in-kernel and external)
104MODPOST += \
105	$(addprefix -i ,$(existing-input-symdump)) \
106	$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
107	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
108
109# 'make -i -k' ignores compile errors, and builds as many modules as possible.
110ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
111MODPOST += -n
112endif
113
114# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
115VPATH :=
116$(input-symdump):
117	@echo >&2 'WARNING: Symbol version dump "$@" is missing.'
118	@echo >&2 '         Modules may not have dependencies or modversions.'
119	@echo >&2 '         You may get many unresolved symbol warnings.'
120
121modules := $(sort $(shell cat $(MODORDER)))
122
123# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
124ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),)
125MODPOST += -w
126endif
127
128# Read out modules.order to pass in modpost.
129# Otherwise, allmodconfig would fail with "Argument list too long".
130quiet_cmd_modpost = MODPOST $@
131      cmd_modpost = sed 's/\.ko$$/$(mod-prelink-ext)\.o/' $< | $(MODPOST) -T -
132
133$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(mod-prelink-ext).o) FORCE
134	$(call if_changed,modpost)
135
136targets += $(output-symdump)
137
138__modpost: $(output-symdump)
139ifneq ($(KBUILD_MODPOST_NOFINAL),1)
140	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
141endif
142
143PHONY += FORCE
144FORCE:
145
146existing-targets := $(wildcard $(sort $(targets)))
147
148-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
149
150endif
151
152.PHONY: $(PHONY)
153