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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
35PHONY := __modpost
36__modpost:
37
38include include/config/auto.conf
39include $(srctree)/scripts/Kbuild.include
40
41MODPOST = scripts/mod/modpost
42
43modpost-args = \
44 $(if $(CONFIG_MODVERSIONS),-m) \
45 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
46 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
47 $(if $(KBUILD_MODPOST_WARN),-w) \
48 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
49 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
50 $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \
51 -o $@
52
53modpost-deps := $(MODPOST)
54
55# 'make -i -k' ignores compile errors, and builds as many modules as possible.
56ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
57modpost-args += -n
58endif
59
60# Read out modules.order to pass in modpost.
61# Otherwise, allmodconfig would fail with "Argument list too long".
62ifdef KBUILD_MODULES
63modpost-args += -T $(MODORDER)
64modpost-deps += $(MODORDER)
65endif
66
67ifeq ($(KBUILD_EXTMOD),)
68
69# Generate the list of in-tree objects in vmlinux
70# ---------------------------------------------------------------------------
71
72# This is used to retrieve symbol versions generated by genksyms.
73ifdef CONFIG_MODVERSIONS
74vmlinux.symvers Module.symvers: .vmlinux.objs
75endif
76
77# Ignore libgcc.a
78# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
79# from the toolchain, but there is no EXPORT_SYMBOL in it.
80
81quiet_cmd_vmlinux_objs = GEN $@
82 cmd_vmlinux_objs = \
83 for f in $(real-prereqs); do \
84 case $${f} in \
85 *libgcc.a) ;; \
86 *) $(AR) t $${f} ;; \
87 esac \
88 done > $@
89
90targets += .vmlinux.objs
91.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
92 $(call if_changed,vmlinux_objs)
93
94ifdef CONFIG_TRIM_UNUSED_KSYMS
95ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
96ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl)
97modpost-args += -t $(addprefix -u , $(ksym-wl))
98modpost-deps += $(ksym-wl)
99endif
100
101ifeq ($(wildcard vmlinux.o),)
102missing-input := vmlinux.o
103output-symdump := modules-only.symvers
104else
105modpost-args += vmlinux.o
106modpost-deps += vmlinux.o
107output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
108endif
109
110else
111
112# set src + obj - they may be used in the modules's Makefile
113obj := $(KBUILD_EXTMOD)
114src := $(obj)
115
116# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
117include $(kbuild-file)
118
119output-symdump := $(KBUILD_EXTMOD)/Module.symvers
120
121ifeq ($(wildcard Module.symvers),)
122missing-input := Module.symvers
123else
124modpost-args += -i Module.symvers
125modpost-deps += Module.symvers
126endif
127
128modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
129
130endif # ($(KBUILD_EXTMOD),)
131
132quiet_cmd_modpost = MODPOST $@
133 cmd_modpost = \
134 $(if $(missing-input), \
135 echo >&2 "WARNING: $(missing-input) is missing."; \
136 echo >&2 " Modules may not have dependencies or modversions."; \
137 echo >&2 " You may get many unresolved symbol errors."; \
138 echo >&2 " You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \
139 echo >&2 " if you want to proceed at your own risk.";) \
140 $(MODPOST) $(modpost-args)
141
142targets += $(output-symdump)
143$(output-symdump): $(modpost-deps) FORCE
144 $(call if_changed,modpost)
145
146__modpost: $(output-symdump)
147PHONY += FORCE
148FORCE:
149
150existing-targets := $(wildcard $(sort $(targets)))
151
152-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
153
154.PHONY: $(PHONY)