kbuild: create *.mod with full directory path and remove MODVERDIR
While descending directories, Kbuild produces objects for modules, but do not link final *.ko files; it is done in the modpost. To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR) for every module it is building. Some post-processing steps read the necessary information from *.mod files. This avoids descending into directories again. This mechanism was introduced in 2003 or so. Later, commit551559e13a("kbuild: implement modules.order") added modules.order. So, we can simply read it out to know all the modules with directory paths. This is easier than parsing the first line of *.mod files. $(MODVERDIR) has a flat directory structure, that is, *.mod files are named only with base names. This is based on the assumption that the module name is unique across the tree. This assumption is really fragile. Stephen Rothwell reported a race condition caused by a module name conflict: https://lkml.org/lkml/2019/5/13/991 In parallel building, two different threads could write to the same $(MODVERDIR)/*.mod simultaneously. Non-unique module names are the source of all kind of troubles, hence commit3a48a91901("kbuild: check uniqueness of module names") introduced a new checker script. However, it is still fragile in the build system point of view because this race happens before scripts/modules-check.sh is invoked. If it happens again, the modpost will emit unclear error messages. To fix this issue completely, create *.mod with full directory path so that two threads never attempt to write to the same file. $(MODVERDIR) is no longer needed. Since modules with directory paths are listed in modules.order, Kbuild is still able to find *.mod files without additional descending. I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y, it occurs not only in the modpost stage, but also during directory descending, where sumversion.c may parse stale *.mod files. It would emit 'No such file or directory' warning when an object consisting a module is renamed, or when a single-obj module is turned into a multi-obj module or vice versa. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicolas Pitre <nico@fluxnic.net>
This commit is contained in:
Masahiro Yamada
parent
7deb55f571
commit
b7dca6dd1e
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@ -30,6 +30,7 @@
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*.lz4
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*.lzma
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*.lzo
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*.mod
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*.mod.c
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*.o
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*.o.*
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@ -30,6 +30,7 @@
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*.lzo
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*.mo
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*.moc
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*.mod
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*.mod.c
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*.o
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*.o.*
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20
Makefile
20
Makefile
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@ -486,11 +486,6 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
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export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
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export KBUILD_ARFLAGS
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# When compiling out-of-tree modules, put MODVERDIR in the module
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# tree rather than in the kernel tree. The kernel tree might
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# even be read-only.
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export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
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# Files to ignore in find ... statements
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export RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o \
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@ -1029,8 +1024,8 @@ vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
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# Recurse until adjust_autoksyms.sh is satisfied
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PHONY += autoksyms_recursive
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autoksyms_recursive: $(vmlinux-deps)
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ifdef CONFIG_TRIM_UNUSED_KSYMS
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autoksyms_recursive: $(vmlinux-deps) modules.order
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$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
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"$(MAKE) -f $(srctree)/Makefile vmlinux"
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endif
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@ -1113,7 +1108,6 @@ endif
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prepare1: prepare3 outputmakefile asm-generic $(version_h) $(autoksyms_h) \
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include/generated/utsrelease.h
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$(cmd_crmodverdir)
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archprepare: archheaders archscripts prepare1 scripts
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@ -1371,7 +1365,7 @@ endif # CONFIG_MODULES
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# make distclean Remove editor backup files, patch leftover files and the like
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# Directories & files removed with 'make clean'
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CLEAN_DIRS += $(MODVERDIR) include/ksym
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CLEAN_DIRS += include/ksym
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CLEAN_FILES += modules.builtin.modinfo
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# Directories & files removed with 'make mrproper'
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@ -1641,7 +1635,6 @@ PHONY += $(clean-dirs) clean
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$(clean-dirs):
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$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
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clean: rm-dirs := $(MODVERDIR)
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clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
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PHONY += help
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@ -1655,8 +1648,6 @@ help:
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@echo ''
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PHONY += prepare
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prepare:
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$(cmd_crmodverdir)
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endif # KBUILD_EXTMOD
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clean: $(clean-dirs)
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@ -1667,7 +1658,7 @@ clean: $(clean-dirs)
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-o -name '*.ko.*' \
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-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
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-o -name '*.dwo' -o -name '*.lst' \
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-o -name '*.su' \
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-o -name '*.su' -o -name '*.mod' \
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-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
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-o -name '*.lex.c' -o -name '*.tab.[ch]' \
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-o -name '*.asn1.[ch]' \
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@ -1794,11 +1785,6 @@ quiet_cmd_depmod = DEPMOD $(KERNELRELEASE)
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cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
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$(KERNELRELEASE)
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# Create temporary dir for module support files
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# clean it up only when building all modules
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cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
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$(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
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# read saved command lines for existing targets
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existing-targets := $(wildcard $(sort $(targets)))
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@ -353,23 +353,13 @@ config DEBUG_SECTION_MISMATCH
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which results in the code/data being placed in specific sections.
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The section mismatch analysis is always performed after a full
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kernel build, and enabling this option causes the following
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additional steps to occur:
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additional step to occur:
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- Add the option -fno-inline-functions-called-once to gcc commands.
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When inlining a function annotated with __init in a non-init
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function, we would lose the section information and thus
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the analysis would not catch the illegal reference.
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This option tells gcc to inline less (but it does result in
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a larger kernel).
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- Run the section mismatch analysis for each module/built-in.a file.
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When we run the section mismatch analysis on vmlinux.o, we
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lose valuable information about where the mismatch was
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introduced.
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Running the analysis for each module/built-in.a file
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tells where the mismatch happens much closer to the
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source. The drawback is that the same mismatch is
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reported at least twice.
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- Enable verbose reporting from modpost in order to help resolve
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the section mismatches that are reported.
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config SECTION_MISMATCH_WARN_ONLY
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bool "Make section mismatch errors non-fatal"
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@ -67,8 +67,6 @@ ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
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modorder-target := $(obj)/modules.order
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endif
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# We keep a list of all modules in $(MODVERDIR)
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__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
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$(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
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$(subdir-ym) $(always)
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@ -87,11 +85,6 @@ ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
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cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
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endif
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# Do section mismatch analysis for each module/built-in.a
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ifdef CONFIG_DEBUG_SECTION_MISMATCH
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cmd_secanalysis = ; scripts/mod/modpost $@
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endif
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# Compile C sources (.c)
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# ---------------------------------------------------------------------------
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@ -278,13 +271,11 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
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$(call cmd,force_checksrc)
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$(call if_changed_rule,cc_o_c)
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# Single-part modules are special since we need to mark them in $(MODVERDIR)
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$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
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$(call cmd,force_checksrc)
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$(call if_changed_rule,cc_o_c)
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@{ echo $(@:.o=.ko); echo $@; \
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$(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
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$(cmd_undef_syms); } > $(patsubst %.o,%.mod,$@)
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quiet_cmd_cc_lst_c = MKLST $@
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cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
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@ -461,12 +452,12 @@ endif
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# module is turned into a multi object module, $^ will contain header file
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# dependencies recorded in the .*.cmd file.
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quiet_cmd_link_multi-m = LD [M] $@
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cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis)
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cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
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$(multi-used-m): FORCE
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$(call if_changed,link_multi-m)
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@{ echo $(@:.o=.ko); echo $(filter %.o,$^); \
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$(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
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$(cmd_undef_syms); } > $(patsubst %.o,%.mod,$@)
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$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
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targets += $(multi-used-m)
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@ -6,8 +6,8 @@
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# Stage one of module building created the following:
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# a) The individual .o files used for the module
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# b) A <module>.o file which is the .o files above linked together
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# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
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# the preliminary <module>.o file, plus all .o files
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# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
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# plus all .o files
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# d) modules.order, which lists all the modules
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# Stage 2 is handled by this file and does the following
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@ -8,8 +8,7 @@
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#
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# Create/update the include/generated/autoksyms.h file from the list
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# of all module's needed symbols as recorded on the third line of
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# .tmp_versions/*.mod files.
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# of all module's needed symbols as recorded on the third line of *.mod files.
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#
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# For each symbol being added or removed, the corresponding dependency
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# file's timestamp is updated to force a rebuild of the affected source
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@ -47,13 +46,10 @@ cat > "$new_ksyms_file" << EOT
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*/
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EOT
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[ "$(ls -A "$MODVERDIR")" ] &&
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for mod in "$MODVERDIR"/*.mod; do
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sed -n -e '3{s/ /\n/g;/^$/!p;}' "$mod"
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done | sort -u |
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while read sym; do
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echo "#define __KSYM_${sym} 1"
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done >> "$new_ksyms_file"
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sed 's/ko$/mod/' modules.order |
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xargs -n1 sed -n -e '3{s/ /\n/g;/^$/!p;}' -- |
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sort -u |
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sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$new_ksyms_file"
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# Special case for modversions (see modpost.c)
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if [ -n "$CONFIG_MODVERSIONS" ]; then
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@ -396,21 +396,11 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
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unsigned long len;
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struct md4_ctx md;
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char *sources, *end, *fname;
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const char *basename;
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char filelist[PATH_MAX + 1];
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char *modverdir = getenv("MODVERDIR");
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if (!modverdir)
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modverdir = ".";
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/* Source files for module are in .tmp_versions/modname.mod,
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after the first line. */
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if (strrchr(modname, '/'))
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basename = strrchr(modname, '/') + 1;
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else
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basename = modname;
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snprintf(filelist, sizeof(filelist), "%s/%.*s.mod", modverdir,
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(int) strlen(basename) - 2, basename);
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/* objects for a module are listed in the second line of *.mod file. */
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snprintf(filelist, sizeof(filelist), "%.*smod",
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(int)strlen(modname) - 1, modname);
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file = grab_file(filelist, &len);
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if (!file)
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@ -29,7 +29,7 @@ fi
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PROVIDES="$PROVIDES kernel-$KERNELRELEASE"
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__KERNELRELEASE=$(echo $KERNELRELEASE | sed -e "s/-/_/g")
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EXCLUDES="$RCS_TAR_IGNORE --exclude=.tmp_versions --exclude=*vmlinux* \
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EXCLUDES="$RCS_TAR_IGNORE --exclude=*vmlinux* --exclude=*.mod \
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--exclude=*.o --exclude=*.ko --exclude=*.cmd --exclude=Documentation \
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--exclude=.config.old --exclude=.missing-syscalls.d --exclude=*.s"
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@ -12,8 +12,8 @@ default:
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$(MAKE) -C $(KDIR) M=$(CURDIR)
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clean:
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- rm -rf *.o *.ko .tmp-versions .*.cmd .*.mod.* *.mod.c
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- rm -rf .tmp_versions* Module.symvers modules.order
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- rm -rf *.o *.ko .*.cmd .*.mod.* *.mod.c
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- rm -rf Module.symvers modules.order
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install: default
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install -d $(KMISC)
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