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
35# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
36# symbols in the final module linking stage
37# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
38# This is solely usefull to speed up test compiles
39PHONY := _modpost
40_modpost: __modpost
41
42include include/config/auto.conf
43include scripts/Kbuild.include
44include scripts/Makefile.lib
45
46kernelsymfile := $(objtree)/Module.symvers
47modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
48
49# Step 1), find all modules listed in $(MODVERDIR)/
50__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
51modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
52
53# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
54_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
55
56
57# Step 2), invoke modpost
58#  Includes step 3,4
59quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
60      cmd_modpost = scripts/mod/modpost            \
61        $(if $(CONFIG_MODVERSIONS),-m)             \
62	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)  \
63	$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
64	$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
65	$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
66	$(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
67
68PHONY += __modpost
69__modpost: $(modules:.ko=.o) FORCE
70	$(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
71
72quiet_cmd_kernel-mod = MODPOST $@
73      cmd_kernel-mod = $(cmd_modpost) $(KBUILD_VMLINUX_OBJS)
74
75PHONY += vmlinux
76vmlinux: FORCE
77	$(call cmd,kernel-mod)
78
79# Declare generated files as targets for modpost
80$(symverfile):         __modpost ;
81$(modules:.ko=.mod.c): __modpost ;
82
83
84# Step 5), compile all *.mod.c files
85
86# modname is set to make c_flags define KBUILD_MODNAME
87modname = $(notdir $(@:.mod.o=))
88
89quiet_cmd_cc_o_c = CC      $@
90      cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)	\
91		   -c -o $@ $<
92
93$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
94	$(call if_changed_dep,cc_o_c)
95
96targets += $(modules:.ko=.mod.o)
97
98# Step 6), final link of the modules
99quiet_cmd_ld_ko_o = LD [M]  $@
100      cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@		\
101			  $(filter-out FORCE,$^)
102
103$(modules): %.ko :%.o %.mod.o FORCE
104	$(call if_changed,ld_ko_o)
105
106targets += $(modules)
107
108
109# Add FORCE to the prequisites of a target to force it to be always rebuilt.
110# ---------------------------------------------------------------------------
111
112PHONY += FORCE
113
114FORCE:
115
116# Read all saved command lines and dependencies for the $(targets) we
117# may be building above, using $(if_changed{,_dep}). As an
118# optimization, we don't need to read them if the target does not
119# exist, we will rebuild anyway in that case.
120
121targets := $(wildcard $(sort $(targets)))
122cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
123
124ifneq ($(cmd_files),)
125  include $(cmd_files)
126endif
127
128
129# Declare the contents of the .PHONY variable as phony.  We keep that
130# information in a variable se we can use it in if_changed and friends.
131
132.PHONY: $(PHONY)
133