Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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# 5) compile all <module>.mod.c files
19# 6) final link of the module to a <module.ko> file
20
21# Step 3 is used to place certain information in the module's ELF
22# section, including information such as:
23# Version magic (see include/linux/vermagic.h for full details)
24# - Kernel release
25# - SMP is CONFIG_SMP
26# - PREEMPT is CONFIG_PREEMPT
27# - GCC Version
28# Module info
29# - Module version (MODULE_VERSION)
30# - Module alias'es (MODULE_ALIAS)
31# - Module license (MODULE_LICENSE)
32# - See include/linux/module.h for more details
33
34# Step 4 is solely used to allow module versioning in external modules,
35# where the CRC of each module is retrieved from the Module.symvers file.
36
37# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
38# symbols in the final module linking stage
39# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
40# This is solely useful to speed up test compiles
41
42PHONY := __modpost
43__modpost:
44
45include include/config/auto.conf
46include scripts/Kbuild.include
47
48kernelsymfile := $(objtree)/Module.symvers
49modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
50
51MODPOST = scripts/mod/modpost \
52 $(if $(CONFIG_MODVERSIONS),-m) \
53 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
54 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
55 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
56 $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
57 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
58 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
59 $(if $(KBUILD_MODPOST_WARN),-w)
60
61ifdef MODPOST_VMLINUX
62
63__modpost: vmlinux.o
64
65quiet_cmd_modpost = MODPOST $@
66 cmd_modpost = $(MODPOST) $@
67
68PHONY += vmlinux.o
69vmlinux.o:
70 $(call cmd,modpost)
71
72else
73
74# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
75ifneq ($(KBUILD_EXTMOD),)
76
77# set src + obj - they may be used when building the .mod.c file
78obj := $(KBUILD_EXTMOD)
79src := $(obj)
80
81# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
82include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
83 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
84endif
85
86include scripts/Makefile.lib
87
88modorder := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)modules.order
89
90# find all modules listed in modules.order
91modules := $(sort $(shell cat $(modorder)))
92
93# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
94__modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
95 @:
96
97MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - $(wildcard vmlinux)
98
99# We can go over command line length here, so be careful.
100quiet_cmd_modpost = MODPOST $(words $(modules)) modules
101 cmd_modpost = sed 's/ko$$/o/' $(modorder) | $(MODPOST)
102
103PHONY += modules-modpost
104modules-modpost:
105 $(call cmd,modpost)
106
107# Declare generated files as targets for modpost
108$(modules:.ko=.mod.c): modules-modpost
109
110# Step 5), compile all *.mod.c files
111
112# modname is set to make c_flags define KBUILD_MODNAME
113modname = $(notdir $(@:.mod.o=))
114
115quiet_cmd_cc_o_c = CC $@
116 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
117 -c -o $@ $<
118
119$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
120 $(call if_changed_dep,cc_o_c)
121
122targets += $(modules:.ko=.mod.o)
123
124ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
125
126# Step 6), final link of the modules with optional arch pass after final link
127quiet_cmd_ld_ko_o = LD [M] $@
128 cmd_ld_ko_o = \
129 $(LD) -r $(KBUILD_LDFLAGS) \
130 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
131 -o $@ $(real-prereqs) ; \
132 $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
133
134$(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
152existing-targets := $(wildcard $(sort $(targets)))
153
154-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
155
156endif
157
158.PHONY: $(PHONY)