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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 $(MODVERDIR)/
13# 2) modpost is then used to
14# 3) create one <module>.mod.c file pr. module
15# 4) create one Module.symvers file with CRC for all exported symbols
16# 5) compile all <module>.mod.c files
17# 6) final link of the module to a <module.ko> file
18
19# Step 3 is used to place certain information in the module's ELF
20# section, including information such as:
21# Version magic (see include/linux/vermagic.h for full details)
22# - Kernel release
23# - SMP is CONFIG_SMP
24# - PREEMPT is CONFIG_PREEMPT
25# - GCC Version
26# Module info
27# - Module version (MODULE_VERSION)
28# - Module alias'es (MODULE_ALIAS)
29# - Module license (MODULE_LICENSE)
30# - See include/linux/module.h for more details
31
32# Step 4 is solely used to allow module versioning in external modules,
33# where the CRC of each module is retrieved from the Module.symvers file.
34
35# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
36# symbols in the final module linking stage
37# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
38# This is solely useful to speed up test compiles
39PHONY := _modpost
40_modpost: __modpost
41
42include include/config/auto.conf
43include scripts/Kbuild.include
44
45# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
46ifneq ($(KBUILD_EXTMOD),)
47
48# set src + obj - they may be used when building the .mod.c file
49obj := $(KBUILD_EXTMOD)
50src := $(obj)
51
52# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
53include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
54 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
55endif
56
57include scripts/Makefile.lib
58
59kernelsymfile := $(objtree)/Module.symvers
60modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
61
62# Step 1), find all modules listed in $(MODVERDIR)/
63MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u
64__modules := $(shell $(MODLISTCMD))
65modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
66
67# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
68_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
69
70# Step 2), invoke modpost
71# Includes step 3,4
72modpost = scripts/mod/modpost \
73 $(if $(CONFIG_MODVERSIONS),-m) \
74 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
75 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
76 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
77 $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
78 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
79 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
80 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
81 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
82
83MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
84
85# If CONFIG_LTO_CLANG is enabled, .o files are either LLVM IR, or empty, so we
86# need to link them into actual objects before passing them to modpost
87modpost-ext = $(if $(CONFIG_LTO_CLANG),.lto,)
88
89ifdef CONFIG_LTO_CLANG
90quiet_cmd_cc_lto_link_modules = LD [M] $@
91cmd_cc_lto_link_modules = \
92 $(LD) $(ld_flags) -r -o $(@) \
93 $(shell [ -s $(@:$(modpost-ext).o=.o.symversions) ] && \
94 echo -T $(@:$(modpost-ext).o=.o.symversions)) \
95 --whole-archive $(filter-out FORCE,$^)
96
97$(modules:.ko=$(modpost-ext).o): %$(modpost-ext).o: %.o FORCE
98 $(call if_changed,cc_lto_link_modules)
99endif
100
101# We can go over command line length here, so be careful.
102quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
103 cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/$(modpost-ext)\.o/' | $(modpost) $(MODPOST_OPT) -s -T -
104
105PHONY += __modpost
106__modpost: $(modules:.ko=$(modpost-ext).o) FORCE
107 $(call cmd,modpost) $(wildcard vmlinux)
108
109quiet_cmd_kernel-mod = MODPOST $@
110 cmd_kernel-mod = $(modpost) $@
111
112vmlinux.o: FORCE
113 $(call cmd,kernel-mod)
114
115# Declare generated files as targets for modpost
116$(symverfile): __modpost ;
117$(modules:.ko=$(modpost-ext).mod.c): __modpost ;
118
119# Step 5), compile all *.mod.c files
120
121# modname is set to make c_flags define KBUILD_MODNAME
122modname = $(notdir $(@:.mod.o=))
123
124quiet_cmd_cc_o_c = CC $@
125 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
126 -c -o $@ $<
127
128$(modules:.ko=.mod.o): %.mod.o: %$(modpost-ext).mod.c FORCE
129 $(call if_changed_dep,cc_o_c)
130
131targets += $(modules:.ko=$(modpost-ext).mod.o)
132
133ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
134
135# Step 6), final link of the modules with optional arch pass after final link
136quiet_cmd_ld_ko_o = LD [M] $@
137
138ifdef CONFIG_LTO_CLANG
139 cmd_ld_ko_o = \
140 $(LD) -r $(LDFLAGS) \
141 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
142 $(shell [ -s $(@:.ko=.o.symversions) ] && \
143 echo -T $(@:.ko=.o.symversions)) \
144 -o $@ --whole-archive \
145 $(filter-out FORCE,$(^:$(modpost-ext).o=.o))
146
147 ifdef CONFIG_FTRACE_MCOUNT_RECORD
148 cmd_ld_ko_o += ; $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) $@
149 endif
150else
151 cmd_ld_ko_o = \
152 $(LD) -r $(LDFLAGS) \
153 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
154 -o $@ $(filter-out FORCE,$^) ; \
155 $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
156endif
157
158$(modules): %.ko: %$(modpost-ext).o %.mod.o FORCE
159 +$(call if_changed,ld_ko_o)
160
161targets += $(modules)
162
163
164# Add FORCE to the prequisites of a target to force it to be always rebuilt.
165# ---------------------------------------------------------------------------
166
167PHONY += FORCE
168
169FORCE:
170
171# Read all saved command lines and dependencies for the $(targets) we
172# may be building above, using $(if_changed{,_dep}). As an
173# optimization, we don't need to read them if the target does not
174# exist, we will rebuild anyway in that case.
175
176targets := $(wildcard $(sort $(targets)))
177cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
178
179ifneq ($(cmd_files),)
180 include $(cmd_files)
181endif
182
183
184# Declare the contents of the .PHONY variable as phony. We keep that
185# information in a variable se we can use it in if_changed and friends.
186
187.PHONY: $(PHONY)
188