xref: /openbmc/linux/scripts/Makefile.modpost (revision 481461f5) 
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_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
54modpost-deps := $(MODPOST)
55
56# 'make -i -k' ignores compile errors, and builds as many modules as possible.
57ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
58modpost-args += -n
59endif
60
61# Read out modules.order to pass in modpost.
62# Otherwise, allmodconfig would fail with "Argument list too long".
63ifdef KBUILD_MODULES
64modpost-args += -T $(MODORDER)
65modpost-deps += $(MODORDER)
66endif
67
68ifeq ($(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.
74ifdef CONFIG_MODVERSIONS
75vmlinux.symvers Module.symvers: .vmlinux.objs
76endif
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
82quiet_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
91targets += .vmlinux.objs
92.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
93	$(call if_changed,vmlinux_objs)
94
95ifdef CONFIG_TRIM_UNUSED_KSYMS
96ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
97ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl)
98modpost-args += -t $(addprefix -u , $(ksym-wl))
99modpost-deps += $(ksym-wl)
100endif
101
102ifeq ($(wildcard vmlinux.o),)
103missing-input := vmlinux.o
104output-symdump := modules-only.symvers
105else
106modpost-args += vmlinux.o
107modpost-deps += vmlinux.o
108output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
109endif
110
111else
112
113# set src + obj - they may be used in the modules's Makefile
114obj := $(KBUILD_EXTMOD)
115src := $(obj)
116
117# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
118include $(kbuild-file)
119
120output-symdump := $(KBUILD_EXTMOD)/Module.symvers
121
122ifeq ($(wildcard Module.symvers),)
123missing-input := Module.symvers
124else
125modpost-args += -i Module.symvers
126modpost-deps += Module.symvers
127endif
128
129modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
130
131endif # ($(KBUILD_EXTMOD),)
132
133quiet_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
143targets += $(output-symdump)
144$(output-symdump): $(modpost-deps) FORCE
145	$(call if_changed,modpost)
146
147__modpost: $(output-symdump)
148PHONY += FORCE
149FORCE:
150
151existing-targets := $(wildcard $(sort $(targets)))
152
153-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
154
155.PHONY: $(PHONY)
156