xref: /linux-6.15/scripts/Makefile.modpost (revision 12715d20) 
1# ===========================================================================
2# Module versions
3# ===========================================================================
4#
5# Stage one of module building created the following:
6# a) The individual .o files used for the module
7# b) A <module>.o file which is the .o files above linked together
8# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
9#    the preliminary <module>.o file, plus all .o files
10
11# Stage 2 is handled by this file and does the following
12# 1) Find all modules from the files listed in $(MODVERDIR)/
13# 2) modpost is then used to
14# 3)  create one <module>.mod.c file pr. module
15# 4)  create one Module.symvers file with CRC for all exported symbols
16# 5) compile all <module>.mod.c files
17# 6) final link of the module to a <module.ko> file
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/vermagic.h for full details)
22#     - Kernel release
23#     - SMP is CONFIG_SMP
24#     - PREEMPT is CONFIG_PREEMPT
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.symers file.
34
35PHONY := _modpost
36_modpost: __modpost
37
38include include/config/auto.conf
39include scripts/Kbuild.include
40include scripts/Makefile.lib
41
42kernelsymfile := $(objtree)/Module.symvers
43modulesymfile := $(KBUILD_EXTMOD)/Module.symvers
44
45# Step 1), find all modules listed in $(MODVERDIR)/
46__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
47modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
48
49_modpost: $(modules)
50
51
52# Step 2), invoke modpost
53#  Includes step 3,4
54quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
55      cmd_modpost = scripts/mod/modpost            \
56        $(if $(CONFIG_MODVERSIONS),-m)             \
57	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)  \
58	$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
59	$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
60	$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
61	$(wildcard vmlinux) $(filter-out FORCE,$^)
62
63PHONY += __modpost
64__modpost: $(modules:.ko=.o) FORCE
65	$(call cmd,modpost)
66
67quiet_cmd_kernel-mod = MODPOST $@
68      cmd_kernel-mod = $(cmd_modpost)
69
70vmlinux: FORCE
71	$(call cmd,kernel-mod)
72
73# Declare generated files as targets for modpost
74$(symverfile):         __modpost ;
75$(modules:.ko=.mod.c): __modpost ;
76
77
78# Step 5), compile all *.mod.c files
79
80# modname is set to make c_flags define KBUILD_MODNAME
81modname = $(notdir $(@:.mod.o=))
82
83quiet_cmd_cc_o_c = CC      $@
84      cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)	\
85		   -c -o $@ $<
86
87$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
88	$(call if_changed_dep,cc_o_c)
89
90targets += $(modules:.ko=.mod.o)
91
92# Step 6), final link of the modules
93quiet_cmd_ld_ko_o = LD [M]  $@
94      cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ 		\
95			  $(filter-out FORCE,$^)
96
97$(modules): %.ko :%.o %.mod.o FORCE
98	$(call if_changed,ld_ko_o)
99
100targets += $(modules)
101
102
103# Add FORCE to the prequisites of a target to force it to be always rebuilt.
104# ---------------------------------------------------------------------------
105
106PHONY += FORCE
107
108FORCE:
109
110# Read all saved command lines and dependencies for the $(targets) we
111# may be building above, using $(if_changed{,_dep}). As an
112# optimization, we don't need to read them if the target does not
113# exist, we will rebuild anyway in that case.
114
115targets := $(wildcard $(sort $(targets)))
116cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
117
118ifneq ($(cmd_files),)
119  include $(cmd_files)
120endif
121
122
123# Declare the contents of the .PHONY variable as phony.  We keep that
124# information in a variable se we can use it in if_changed and friends.
125
126.PHONY: $(PHONY)
127