xref: /openbmc/linux/scripts/Makefile.modpost (revision ef4290e6) 
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_NSDEPS),-d $(MODULES_NSDEPS))					\
48	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)	\
49	-o $@
50
51modpost-deps := $(MODPOST)
52
53# 'make -i -k' ignores compile errors, and builds as many modules as possible.
54ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
55modpost-args += -n
56endif
57
58ifeq ($(KBUILD_EXTMOD),)
59
60# Generate the list of in-tree objects in vmlinux
61# ---------------------------------------------------------------------------
62
63# This is used to retrieve symbol versions generated by genksyms.
64ifdef CONFIG_MODVERSIONS
65vmlinux.symvers Module.symvers: .vmlinux.objs
66endif
67
68# Ignore libgcc.a
69# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
70# from the toolchain, but there is no EXPORT_SYMBOL in it.
71
72quiet_cmd_vmlinux_objs = GEN     $@
73      cmd_vmlinux_objs =		\
74	for f in $(real-prereqs); do	\
75		case $${f} in		\
76		*libgcc.a) ;;		\
77		*) $(AR) t $${f} ;;	\
78		esac			\
79	done > $@
80
81targets += .vmlinux.objs
82.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
83	$(call if_changed,vmlinux_objs)
84
85ifeq ($(wildcard vmlinux.o),)
86missing-input := vmlinux.o
87output-symdump := modules-only.symvers
88else
89modpost-args += vmlinux.o
90modpost-deps += vmlinux.o
91output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
92endif
93
94else
95
96# set src + obj - they may be used in the modules's Makefile
97obj := $(KBUILD_EXTMOD)
98src := $(obj)
99
100# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
101include $(kbuild-file)
102
103output-symdump := $(KBUILD_EXTMOD)/Module.symvers
104
105ifeq ($(wildcard Module.symvers),)
106missing-input := Module.symvers
107else
108modpost-args += -i Module.symvers
109modpost-deps += Module.symvers
110endif
111
112modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
113
114endif # ($(KBUILD_EXTMOD),)
115
116ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)
117modpost-args += -w
118endif
119
120ifdef KBUILD_MODULES
121modpost-args += -T $(MODORDER)
122modpost-deps += $(MODORDER)
123endif
124
125# Read out modules.order to pass in modpost.
126# Otherwise, allmodconfig would fail with "Argument list too long".
127quiet_cmd_modpost = MODPOST $@
128      cmd_modpost = \
129	$(if $(missing-input), \
130		echo >&2 "WARNING: $(missing-input) is missing."; \
131		echo >&2 "         Modules may not have dependencies or modversions."; \
132		echo >&2 "         You may get many unresolved symbol warnings.";) \
133	$(MODPOST) $(modpost-args)
134
135targets += $(output-symdump)
136$(output-symdump): $(modpost-deps) FORCE
137	$(call if_changed,modpost)
138
139__modpost: $(output-symdump)
140PHONY += FORCE
141FORCE:
142
143existing-targets := $(wildcard $(sort $(targets)))
144
145-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
146
147.PHONY: $(PHONY)
148