xref: /openbmc/linux/scripts/Makefile.modpost (revision cb481993) 
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 pr. module
17# 4)  create one Module.symvers file with CRC for all exported symbols
18# 5) compile all <module>.mod.c files
19# 6) final link of the module to a <module.ko> file
20
21# Step 3 is used to place certain information in the module's ELF
22# section, including information such as:
23#   Version magic (see include/linux/vermagic.h for full details)
24#     - Kernel release
25#     - SMP is CONFIG_SMP
26#     - PREEMPT is CONFIG_PREEMPT
27#     - GCC Version
28#   Module info
29#     - Module version (MODULE_VERSION)
30#     - Module alias'es (MODULE_ALIAS)
31#     - Module license (MODULE_LICENSE)
32#     - See include/linux/module.h for more details
33
34# Step 4 is solely used to allow module versioning in external modules,
35# where the CRC of each module is retrieved from the Module.symvers file.
36
37# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
38# symbols in the final module linking stage
39# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
40# This is solely useful to speed up test compiles
41PHONY := _modpost
42_modpost: __modpost
43
44include include/config/auto.conf
45include scripts/Kbuild.include
46
47# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
48ifneq ($(KBUILD_EXTMOD),)
49
50# set src + obj - they may be used when building the .mod.c file
51obj := $(KBUILD_EXTMOD)
52src := $(obj)
53
54# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
55include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
56             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
57endif
58
59include scripts/Makefile.lib
60
61kernelsymfile := $(objtree)/Module.symvers
62modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
63
64modorder := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)modules.order
65
66# Step 1), find all modules listed in modules.order
67ifdef CONFIG_MODULES
68modules := $(sort $(shell cat $(modorder)))
69endif
70
71# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
72_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
73
74# Step 2), invoke modpost
75#  Includes step 3,4
76modpost = scripts/mod/modpost                    \
77 $(if $(CONFIG_MODVERSIONS),-m)                  \
78 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
79 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
80 $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
81 $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
82 $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
83 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)  \
84 $(if $(KBUILD_MODPOST_WARN),-w)
85
86MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
87
88# We can go over command line length here, so be careful.
89quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
90      cmd_modpost = sed 's/ko$$/o/' $(modorder) | $(modpost) $(MODPOST_OPT) -s -T -
91
92PHONY += __modpost
93__modpost: $(modules:.ko=.o) FORCE
94	$(call cmd,modpost) $(wildcard vmlinux)
95
96quiet_cmd_kernel-mod = MODPOST $@
97      cmd_kernel-mod = $(modpost) $@
98
99vmlinux.o: FORCE
100	$(call cmd,kernel-mod)
101
102# Declare generated files as targets for modpost
103$(modules:.ko=.mod.c): __modpost ;
104
105
106# Step 5), compile all *.mod.c files
107
108# modname is set to make c_flags define KBUILD_MODNAME
109modname = $(notdir $(@:.mod.o=))
110
111quiet_cmd_cc_o_c = CC      $@
112      cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
113		   -c -o $@ $<
114
115$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
116	$(call if_changed_dep,cc_o_c)
117
118targets += $(modules:.ko=.mod.o)
119
120ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
121
122# Step 6), final link of the modules with optional arch pass after final link
123quiet_cmd_ld_ko_o = LD [M]  $@
124      cmd_ld_ko_o =                                                     \
125	$(LD) -r $(KBUILD_LDFLAGS)                                      \
126                 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)             \
127                 -o $@ $(real-prereqs) ;                                \
128	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
129
130$(modules): %.ko :%.o %.mod.o FORCE
131	+$(call if_changed,ld_ko_o)
132
133targets += $(modules)
134
135
136# Add FORCE to the prequisites of a target to force it to be always rebuilt.
137# ---------------------------------------------------------------------------
138
139PHONY += FORCE
140
141FORCE:
142
143# Read all saved command lines and dependencies for the $(targets) we
144# may be building above, using $(if_changed{,_dep}). As an
145# optimization, we don't need to read them if the target does not
146# exist, we will rebuild anyway in that case.
147
148existing-targets := $(wildcard $(sort $(targets)))
149
150-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
151
152.PHONY: $(PHONY)
153