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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 per module
17# 4) create one Module.symvers file with CRC for all exported symbols
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[_RT]
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
35PHONY := __modpost
36__modpost:
37
38include include/config/auto.conf
39include $(srctree)/scripts/Kbuild.include
40
41MODPOST = scripts/mod/modpost
42
43modpost-args = \
44 $(if $(CONFIG_MODULES),-M) \
45 $(if $(CONFIG_MODVERSIONS),-m) \
46 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
47 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
48 $(if $(KBUILD_MODPOST_WARN),-w) \
49 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
50 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
51 $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \
52 -o $@
53
54modpost-deps := $(MODPOST)
55
56# 'make -i -k' ignores compile errors, and builds as many modules as possible.
57ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
58modpost-args += -n
59endif
60
61# Read out modules.order to pass in modpost.
62# Otherwise, allmodconfig would fail with "Argument list too long".
63ifdef KBUILD_MODULES
64modpost-args += -T $(MODORDER)
65modpost-deps += $(MODORDER)
66endif
67
68ifeq ($(KBUILD_EXTMOD),)
69
70# Generate the list of in-tree objects in vmlinux
71# ---------------------------------------------------------------------------
72
73# This is used to retrieve symbol versions generated by genksyms.
74ifdef CONFIG_MODVERSIONS
75vmlinux.symvers Module.symvers: .vmlinux.objs
76endif
77
78# Ignore libgcc.a
79# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
80# from the toolchain, but there is no EXPORT_SYMBOL in it.
81
82quiet_cmd_vmlinux_objs = GEN $@
83 cmd_vmlinux_objs = \
84 for f in $(real-prereqs); do \
85 case $${f} in \
86 *libgcc.a) ;; \
87 *) $(AR) t $${f} ;; \
88 esac \
89 done > $@
90
91targets += .vmlinux.objs
92.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
93 $(call if_changed,vmlinux_objs)
94
95ifdef CONFIG_TRIM_UNUSED_KSYMS
96ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
97ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl)
98modpost-args += -t $(addprefix -u , $(ksym-wl))
99modpost-deps += $(ksym-wl)
100endif
101
102ifeq ($(wildcard vmlinux.o),)
103missing-input := vmlinux.o
104output-symdump := modules-only.symvers
105else
106modpost-args += vmlinux.o
107modpost-deps += vmlinux.o
108output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
109endif
110
111else
112
113# set src + obj - they may be used in the modules's Makefile
114obj := $(KBUILD_EXTMOD)
115src := $(obj)
116
117# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
118include $(kbuild-file)
119
120output-symdump := $(KBUILD_EXTMOD)/Module.symvers
121
122ifeq ($(wildcard Module.symvers),)
123missing-input := Module.symvers
124else
125modpost-args += -i Module.symvers
126modpost-deps += Module.symvers
127endif
128
129modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
130
131endif # ($(KBUILD_EXTMOD),)
132
133quiet_cmd_modpost = MODPOST $@
134 cmd_modpost = \
135 $(if $(missing-input), \
136 echo >&2 "WARNING: $(missing-input) is missing."; \
137 echo >&2 " Modules may not have dependencies or modversions."; \
138 echo >&2 " You may get many unresolved symbol errors."; \
139 echo >&2 " You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \
140 echo >&2 " if you want to proceed at your own risk.";) \
141 $(MODPOST) $(modpost-args)
142
143targets += $(output-symdump)
144$(output-symdump): $(modpost-deps) FORCE
145 $(call if_changed,modpost)
146
147__modpost: $(output-symdump)
148PHONY += FORCE
149FORCE:
150
151existing-targets := $(wildcard $(sort $(targets)))
152
153-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
154
155.PHONY: $(PHONY)
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
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[_RT]
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_NOFINAL can be set to skip the final link of modules.
36# This is solely useful to speed up test compiles
37
38PHONY := __modpost
39__modpost:
40
41include include/config/auto.conf
42include $(srctree)/scripts/Kbuild.include
43
44# for ld_flags
45include $(srctree)/scripts/Makefile.lib
46
47MODPOST = scripts/mod/modpost \
48 $(if $(CONFIG_MODVERSIONS),-m) \
49 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
50 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
51 -o $@
52
53ifdef MODPOST_VMLINUX
54
55quiet_cmd_modpost = MODPOST $@
56 cmd_modpost = $(MODPOST) $<
57
58vmlinux.symvers: __KEEPMAKEFILEO__B.o
59 $(call cmd,modpost)
60
61__modpost: vmlinux.symvers
62
63else
64
65ifeq ($(KBUILD_EXTMOD),)
66
67input-symdump := vmlinux.symvers
68output-symdump := modules-only.symvers
69
70quiet_cmd_cat = GEN $@
71 cmd_cat = cat $(real-prereqs) > $@
72
73ifneq ($(wildcard vmlinux.symvers),)
74
75__modpost: Module.symvers
76Module.symvers: vmlinux.symvers modules-only.symvers FORCE
77 $(call if_changed,cat)
78
79targets += Module.symvers
80
81endif
82
83else
84
85# set src + obj - they may be used in the modules's Makefile
86obj := $(KBUILD_EXTMOD)
87src := $(obj)
88
89# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
90include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
91 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
92
93# modpost option for external modules
94MODPOST += -e
95
96input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
97output-symdump := $(KBUILD_EXTMOD)/Module.symvers
98
99endif
100
101existing-input-symdump := $(wildcard $(input-symdump))
102
103# modpost options for modules (both in-kernel and external)
104MODPOST += \
105 $(addprefix -i ,$(existing-input-symdump)) \
106 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
107 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
108
109# 'make -i -k' ignores compile errors, and builds as many modules as possible.
110ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
111MODPOST += -n
112endif
113
114# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
115VPATH :=
116$(input-symdump):
117 @echo >&2 'WARNING: Symbol version dump "$@" is missing.'
118 @echo >&2 ' Modules may not have dependencies or modversions.'
119 @echo >&2 ' You may get many unresolved symbol warnings.'
120
121ifdef CONFIG_LTO_CLANG
122# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run
123# LTO to compile them into native code before running modpost
124prelink-ext := .lto
125
126quiet_cmd_cc_lto_link_modules = LTO [M] $@
127cmd_cc_lto_link_modules = \
128 $(LD) $(ld_flags) -r -o $@ \
129 $(shell [ -s $(@:.lto.o=.o.symversions) ] && \
130 echo -T $(@:.lto.o=.o.symversions)) \
131 --whole-archive $^
132
133%.lto.o: %.o
134 $(call if_changed,cc_lto_link_modules)
135endif
136
137modules := $(sort $(shell cat $(MODORDER)))
138
139# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
140ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),)
141MODPOST += -w
142endif
143
144# Read out modules.order to pass in modpost.
145# Otherwise, allmodconfig would fail with "Argument list too long".
146quiet_cmd_modpost = MODPOST $@
147 cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T -
148
149$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE
150 $(call if_changed,modpost)
151
152targets += $(output-symdump)
153
154__modpost: $(output-symdump)
155ifneq ($(KBUILD_MODPOST_NOFINAL),1)
156 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
157endif
158
159PHONY += FORCE
160FORCE:
161
162existing-targets := $(wildcard $(sort $(targets)))
163
164-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
165
166endif
167
168.PHONY: $(PHONY)