xref: /openbmc/linux/scripts/Makefile.modpost (revision 732a675a) 
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 $(MODVERDIR)/
13# 2) modpost is then used to
14# 3)  create one <module>.mod.c file pr. module
15# 4)  create one Module.symvers file with CRC for all exported symbols
16# 4a) [CONFIG_MARKERS] create one Module.markers file listing defined markers
17# 5) compile all <module>.mod.c files
18# 6) final link of the module to a <module.ko> file
19
20# Step 3 is used to place certain information in the module's ELF
21# section, including information such as:
22#   Version magic (see include/vermagic.h for full details)
23#     - Kernel release
24#     - SMP is CONFIG_SMP
25#     - PREEMPT is CONFIG_PREEMPT
26#     - GCC Version
27#   Module info
28#     - Module version (MODULE_VERSION)
29#     - Module alias'es (MODULE_ALIAS)
30#     - Module license (MODULE_LICENSE)
31#     - See include/linux/module.h for more details
32
33# Step 4 is solely used to allow module versioning in external modules,
34# where the CRC of each module is retrieved from the Module.symers file.
35
36# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
37# symbols in the final module linking stage
38# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
39# This is solely usefull to speed up test compiles
40PHONY := _modpost
41_modpost: __modpost
42
43include include/config/auto.conf
44include scripts/Kbuild.include
45
46# When building external modules load the Kbuild file to retreive EXTRA_SYMBOLS info
47ifneq ($(KBUILD_EXTMOD),)
48
49# set src + obj - they may be used when building the .mod.c file
50obj := $(KBUILD_EXTMOD)
51src := $(obj)
52
53# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
54include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
55             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
56endif
57
58include scripts/Makefile.lib
59
60kernelsymfile := $(objtree)/Module.symvers
61modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
62kernelmarkersfile := $(objtree)/Module.markers
63modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
64
65markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
66
67# Step 1), find all modules listed in $(MODVERDIR)/
68__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
69modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
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
74ifneq ($(KBUILD_BUILDHOST),$(ARCH))
75        cross_build := 1
76endif
77
78# Step 2), invoke modpost
79#  Includes step 3,4
80modpost = scripts/mod/modpost                    \
81 $(if $(CONFIG_MODVERSIONS),-m)                  \
82 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
83 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
84 $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
85 $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(EXTRA_SYMBOLS))) \
86 $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
87 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
88 $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
89 $(if $(CONFIG_MARKERS),-M $(markersfile))	 \
90 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
91 $(if $(cross_build),-c)
92
93quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
94      cmd_modpost = $(modpost) -s
95
96PHONY += __modpost
97__modpost: $(modules:.ko=.o) FORCE
98	$(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
99
100quiet_cmd_kernel-mod = MODPOST $@
101      cmd_kernel-mod = $(modpost) $@
102
103vmlinux.o: FORCE
104	$(call cmd,kernel-mod)
105
106# Declare generated files as targets for modpost
107$(symverfile):         __modpost ;
108$(modules:.ko=.mod.c): __modpost ;
109
110ifdef CONFIG_MARKERS
111$(markersfile):	       __modpost ;
112endif
113
114
115# Step 5), compile all *.mod.c files
116
117# modname is set to make c_flags define KBUILD_MODNAME
118modname = $(notdir $(@:.mod.o=))
119
120quiet_cmd_cc_o_c = CC      $@
121      cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)	\
122		   -c -o $@ $<
123
124$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
125	$(call if_changed_dep,cc_o_c)
126
127targets += $(modules:.ko=.mod.o)
128
129# Step 6), final link of the modules
130quiet_cmd_ld_ko_o = LD [M]  $@
131      cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@		\
132			  $(filter-out FORCE,$^)
133
134$(modules): %.ko :%.o %.mod.o FORCE
135	$(call if_changed,ld_ko_o)
136
137targets += $(modules)
138
139
140# Add FORCE to the prequisites of a target to force it to be always rebuilt.
141# ---------------------------------------------------------------------------
142
143PHONY += FORCE
144
145FORCE:
146
147# Read all saved command lines and dependencies for the $(targets) we
148# may be building above, using $(if_changed{,_dep}). As an
149# optimization, we don't need to read them if the target does not
150# exist, we will rebuild anyway in that case.
151
152targets := $(wildcard $(sort $(targets)))
153cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
154
155ifneq ($(cmd_files),)
156  include $(cmd_files)
157endif
158
159
160# Declare the contents of the .PHONY variable as phony.  We keep that
161# information in a variable se we can use it in if_changed and friends.
162
163.PHONY: $(PHONY)
164