| 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 in $(MODVERDIR)/, listing the name of the |
| 10 | # the preliminary <module>.o file, plus all .o files |
| 11 | |
| 12 | # Stage 2 is handled by this file and does the following |
| 13 | # 1) Find all modules from the files listed in $(MODVERDIR)/ |
| 14 | # 2) modpost is then used to |
| 15 | # 3) create one <module>.mod.c file pr. module |
| 16 | # 4) create one Module.symvers file with CRC for all exported symbols |
| 17 | # 5) compile all <module>.mod.c files |
| 18 | # 6) final link of the module to a <module.ko> file |
| 19 | |
| 20 | # Step 3 is used to place certain information in the module's ELF |
| 21 | # section, including information such as: |
| 22 | # Version magic (see include/linux/vermagic.h for full details) |
| 23 | # - Kernel release |
| 24 | # - SMP is CONFIG_SMP |
| 25 | # - PREEMPT is CONFIG_PREEMPT |
| 26 | # - GCC Version |
| 27 | # Module info |
| 28 | # - Module version (MODULE_VERSION) |
| 29 | # - Module alias'es (MODULE_ALIAS) |
| 30 | # - Module license (MODULE_LICENSE) |
| 31 | # - See include/linux/module.h for more details |
| 32 | |
| 33 | # Step 4 is solely used to allow module versioning in external modules, |
| 34 | # where the CRC of each module is retrieved from the Module.symvers file. |
| 35 | |
| 36 | # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined |
| 37 | # symbols in the final module linking stage |
| 38 | # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. |
| 39 | # This is solely useful to speed up test compiles |
| 40 | PHONY := _modpost |
| 41 | _modpost: __modpost |
| 42 | |
| 43 | include include/config/auto.conf |
| 44 | include scripts/Kbuild.include |
| 45 | |
| 46 | # When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info |
| 47 | ifneq ($(KBUILD_EXTMOD),) |
| 48 | |
| 49 | # set src + obj - they may be used when building the .mod.c file |
| 50 | obj := $(KBUILD_EXTMOD) |
| 51 | src := $(obj) |
| 52 | |
| 53 | # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS |
| 54 | include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ |
| 55 | $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) |
| 56 | endif |
| 57 | |
| 58 | include scripts/Makefile.lib |
| 59 | |
| 60 | kernelsymfile := $(objtree)/Module.symvers |
| 61 | modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers |
| 62 | |
| 63 | # Step 1), find all modules listed in $(MODVERDIR)/ |
| 64 | MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u |
| 65 | __modules := $(shell $(MODLISTCMD)) |
| 66 | modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o))) |
| 67 | |
| 68 | # Stop after building .o files if NOFINAL is set. Makes compile tests quicker |
| 69 | _modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules)) |
| 70 | |
| 71 | # Step 2), invoke modpost |
| 72 | # Includes step 3,4 |
| 73 | modpost = scripts/mod/modpost \ |
| 74 | $(if $(CONFIG_MODVERSIONS),-m) \ |
| 75 | $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \ |
| 76 | $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ |
| 77 | $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ |
| 78 | $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \ |
| 79 | $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ |
| 80 | $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ |
| 81 | $(if $(KBUILD_MODPOST_WARN),-w) |
| 82 | |
| 83 | MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS))) |
| 84 | |
| 85 | # We can go over command line length here, so be careful. |
| 86 | quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules |
| 87 | cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T - |
| 88 | |
| 89 | PHONY += __modpost |
| 90 | __modpost: $(modules:.ko=.o) FORCE |
| 91 | $(call cmd,modpost) $(wildcard vmlinux) |
| 92 | |
| 93 | quiet_cmd_kernel-mod = MODPOST $@ |
| 94 | cmd_kernel-mod = $(modpost) $@ |
| 95 | |
| 96 | vmlinux.o: FORCE |
| 97 | $(call cmd,kernel-mod) |
| 98 | |
| 99 | # Declare generated files as targets for modpost |
| 100 | $(modules:.ko=.mod.c): __modpost ; |
| 101 | |
| 102 | |
| 103 | # Step 5), compile all *.mod.c files |
| 104 | |
| 105 | # modname is set to make c_flags define KBUILD_MODNAME |
| 106 | modname = $(notdir $(@:.mod.o=)) |
| 107 | |
| 108 | quiet_cmd_cc_o_c = CC $@ |
| 109 | cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \ |
| 110 | -c -o $@ $< |
| 111 | |
| 112 | $(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE |
| 113 | $(call if_changed_dep,cc_o_c) |
| 114 | |
| 115 | targets += $(modules:.ko=.mod.o) |
| 116 | |
| 117 | ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) |
| 118 | |
| 119 | # Step 6), final link of the modules with optional arch pass after final link |
| 120 | quiet_cmd_ld_ko_o = LD [M] $@ |
| 121 | cmd_ld_ko_o = \ |
| 122 | $(LD) -r $(KBUILD_LDFLAGS) \ |
| 123 | $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ |
| 124 | -o $@ $(real-prereqs) ; \ |
| 125 | $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) |
| 126 | |
| 127 | $(modules): %.ko :%.o %.mod.o FORCE |
| 128 | +$(call if_changed,ld_ko_o) |
| 129 | |
| 130 | targets += $(modules) |
| 131 | |
| 132 | |
| 133 | # Add FORCE to the prequisites of a target to force it to be always rebuilt. |
| 134 | # --------------------------------------------------------------------------- |
| 135 | |
| 136 | PHONY += FORCE |
| 137 | |
| 138 | FORCE: |
| 139 | |
| 140 | # Read all saved command lines and dependencies for the $(targets) we |
| 141 | # may be building above, using $(if_changed{,_dep}). As an |
| 142 | # optimization, we don't need to read them if the target does not |
| 143 | # exist, we will rebuild anyway in that case. |
| 144 | |
| 145 | cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd)) |
| 146 | |
| 147 | ifneq ($(cmd_files),) |
| 148 | include $(cmd_files) |
| 149 | endif |
| 150 | |
| 151 | .PHONY: $(PHONY) |