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 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 44MODPOST = scripts/mod/modpost \ 45 $(if $(CONFIG_MODVERSIONS),-m) \ 46 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 47 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 48 -o $@ 49 50ifdef MODPOST_VMLINUX 51 52quiet_cmd_modpost = MODPOST $@ 53 cmd_modpost = $(MODPOST) $< 54 55vmlinux.symvers: vmlinux.o 56 $(call cmd,modpost) 57 58__modpost: vmlinux.symvers 59 60# Generate the list of in-tree objects in vmlinux 61# --------------------------------------------------------------------------- 62 63# This is used to retrieve symbol versions generated by genksyms. 64ifdef CONFIG_MODVERSIONS 65vmlinux.symvers: .vmlinux.objs 66endif 67 68# Ignore libgcc.a 69# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a 70# from the toolchain, but there is no EXPORT_SYMBOL in it. 71 72quiet_cmd_vmlinux_objs = GEN $@ 73 cmd_vmlinux_objs = \ 74 for f in $(real-prereqs); do \ 75 case $${f} in \ 76 *libgcc.a) ;; \ 77 *.a) $(AR) t $${f} ;; \ 78 *) echo $${f} ;; \ 79 esac \ 80 done > $@ 81 82targets += .vmlinux.objs 83.vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE 84 $(call if_changed,vmlinux_objs) 85 86else 87 88ifeq ($(KBUILD_EXTMOD),) 89 90input-symdump := vmlinux.symvers 91output-symdump := modules-only.symvers 92 93quiet_cmd_cat = GEN $@ 94 cmd_cat = cat $(real-prereqs) > $@ 95 96ifneq ($(wildcard vmlinux.symvers),) 97 98__modpost: Module.symvers 99Module.symvers: vmlinux.symvers modules-only.symvers FORCE 100 $(call if_changed,cat) 101 102targets += Module.symvers 103 104endif 105 106else 107 108# set src + obj - they may be used in the modules's Makefile 109obj := $(KBUILD_EXTMOD) 110src := $(obj) 111 112# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 113include $(or $(wildcard $(src)/Kbuild), $(src)/Makefile) 114 115# modpost option for external modules 116MODPOST += -e 117 118input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS) 119output-symdump := $(KBUILD_EXTMOD)/Module.symvers 120 121endif 122 123existing-input-symdump := $(wildcard $(input-symdump)) 124 125# modpost options for modules (both in-kernel and external) 126MODPOST += \ 127 $(addprefix -i ,$(existing-input-symdump)) \ 128 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ 129 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) 130 131# 'make -i -k' ignores compile errors, and builds as many modules as possible. 132ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),) 133MODPOST += -n 134endif 135 136# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree). 137VPATH := 138$(input-symdump): 139 @echo >&2 'WARNING: Symbol version dump "$@" is missing.' 140 @echo >&2 ' Modules may not have dependencies or modversions.' 141 @echo >&2 ' You may get many unresolved symbol warnings.' 142 143# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols 144ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),) 145MODPOST += -w 146endif 147 148# Read out modules.order to pass in modpost. 149# Otherwise, allmodconfig would fail with "Argument list too long". 150quiet_cmd_modpost = MODPOST $@ 151 cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T - 152 153$(output-symdump): $(MODORDER) $(input-symdump) FORCE 154 $(call if_changed,modpost) 155 156targets += $(output-symdump) 157 158__modpost: $(output-symdump) 159ifneq ($(KBUILD_MODPOST_NOFINAL),1) 160 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal 161endif 162 163endif 164 165PHONY += FORCE 166FORCE: 167 168existing-targets := $(wildcard $(sort $(targets))) 169 170-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 171 172.PHONY: $(PHONY) 173