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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Tejun Heo](/assets/img/avatar_default.png)
When multiple built-in modules (especially drivers) provide the same capability, they're prioritized by link order specified by the order listed in Makefile. This implicit ordering is lost for loadable modules. When driver modules are loaded by udev, what comes first in modules.alias file is selected. However, the order in this file is indeterministic (depends on filesystem listing order of installed modules). This causes confusion. The solution is two-parted. This patch updates kbuild such that it generates and installs modules.order which contains the name of modules ordered according to Makefile. The second part is update to depmod such that it generates output files according to this file. Note that both obj-y and obj-m subdirs can contain modules and ordering information between those two are lost from beginning. Currently obj-y subdirs are put before obj-m subdirs. Sam Ravnborg cleaned up Makefile modifications and suggested using awk to remove duplicate lines from modules.order instead of using separate C program. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Bill Nottingham <notting@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Jon Masters <jonathan@jonmasters.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
175 lines
6.7 KiB
Makefile
175 lines
6.7 KiB
Makefile
# Backward compatibility
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asflags-y += $(EXTRA_AFLAGS)
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ccflags-y += $(EXTRA_CFLAGS)
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cppflags-y += $(EXTRA_CPPFLAGS)
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ldflags-y += $(EXTRA_LDFLAGS)
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# Figure out what we need to build from the various variables
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# ===========================================================================
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# When an object is listed to be built compiled-in and modular,
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# only build the compiled-in version
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obj-m := $(filter-out $(obj-y),$(obj-m))
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# Libraries are always collected in one lib file.
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# Filter out objects already built-in
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lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
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# Handle objects in subdirs
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# ---------------------------------------------------------------------------
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# o if we encounter foo/ in $(obj-y), replace it by foo/built-in.o
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# and add the directory to the list of dirs to descend into: $(subdir-y)
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# o if we encounter foo/ in $(obj-m), remove it from $(obj-m)
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# and add the directory to the list of dirs to descend into: $(subdir-m)
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# Determine modorder.
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# Unfortunately, we don't have information about ordering between -y
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# and -m subdirs. Just put -y's first.
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modorder := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m:.o=.ko))
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__subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y)))
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subdir-y += $(__subdir-y)
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__subdir-m := $(patsubst %/,%,$(filter %/, $(obj-m)))
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subdir-m += $(__subdir-m)
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obj-y := $(patsubst %/, %/built-in.o, $(obj-y))
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obj-m := $(filter-out %/, $(obj-m))
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# Subdirectories we need to descend into
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subdir-ym := $(sort $(subdir-y) $(subdir-m))
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# if $(foo-objs) exists, foo.o is a composite object
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multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
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multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
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multi-used := $(multi-used-y) $(multi-used-m)
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single-used-m := $(sort $(filter-out $(multi-used-m),$(obj-m)))
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# Build list of the parts of our composite objects, our composite
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# objects depend on those (obviously)
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multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)) $($(m:.o=-y)))
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multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)) $($(m:.o=-y)))
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multi-objs := $(multi-objs-y) $(multi-objs-m)
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# $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
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# tell kbuild to descend
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subdir-obj-y := $(filter %/built-in.o, $(obj-y))
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# $(obj-dirs) is a list of directories that contain object files
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obj-dirs := $(dir $(multi-objs) $(subdir-obj-y))
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# Replace multi-part objects by their individual parts, look at local dir only
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real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(extra-y)
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real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
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# Add subdir path
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extra-y := $(addprefix $(obj)/,$(extra-y))
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always := $(addprefix $(obj)/,$(always))
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targets := $(addprefix $(obj)/,$(targets))
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modorder := $(addprefix $(obj)/,$(modorder))
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obj-y := $(addprefix $(obj)/,$(obj-y))
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obj-m := $(addprefix $(obj)/,$(obj-m))
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lib-y := $(addprefix $(obj)/,$(lib-y))
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subdir-obj-y := $(addprefix $(obj)/,$(subdir-obj-y))
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real-objs-y := $(addprefix $(obj)/,$(real-objs-y))
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real-objs-m := $(addprefix $(obj)/,$(real-objs-m))
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single-used-m := $(addprefix $(obj)/,$(single-used-m))
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multi-used-y := $(addprefix $(obj)/,$(multi-used-y))
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multi-used-m := $(addprefix $(obj)/,$(multi-used-m))
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multi-objs-y := $(addprefix $(obj)/,$(multi-objs-y))
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multi-objs-m := $(addprefix $(obj)/,$(multi-objs-m))
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subdir-ym := $(addprefix $(obj)/,$(subdir-ym))
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obj-dirs := $(addprefix $(obj)/,$(obj-dirs))
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# These flags are needed for modversions and compiling, so we define them here
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# already
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# $(modname_flags) #defines KBUILD_MODNAME as the name of the module it will
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# end up in (or would, if it gets compiled in)
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# Note: It's possible that one object gets potentially linked into more
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# than one module. In that case KBUILD_MODNAME will be set to foo_bar,
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# where foo and bar are the name of the modules.
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name-fix = $(subst $(comma),_,$(subst -,_,$1))
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basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
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modname_flags = $(if $(filter 1,$(words $(modname))),\
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-D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
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_c_flags = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(basetarget).o)
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_a_flags = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(basetarget).o)
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_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
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# If building the kernel in a separate objtree expand all occurrences
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# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
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ifeq ($(KBUILD_SRC),)
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__c_flags = $(_c_flags)
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__a_flags = $(_a_flags)
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__cpp_flags = $(_cpp_flags)
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else
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# -I$(obj) locates generated .h files
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# $(call addtree,-I$(obj)) locates .h files in srctree, from generated .c files
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# and locates generated .h files
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# FIXME: Replace both with specific CFLAGS* statements in the makefiles
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__c_flags = $(call addtree,-I$(obj)) $(call flags,_c_flags)
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__a_flags = $(call flags,_a_flags)
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__cpp_flags = $(call flags,_cpp_flags)
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endif
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c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
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$(__c_flags) $(modkern_cflags) \
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-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
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a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
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$(__a_flags) $(modkern_aflags)
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cpp_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(__cpp_flags)
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ld_flags = $(LDFLAGS) $(ldflags-y)
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# Finds the multi-part object the current object will be linked into
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modname-multi = $(sort $(foreach m,$(multi-used),\
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$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))
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# Shipped files
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# ===========================================================================
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quiet_cmd_shipped = SHIPPED $@
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cmd_shipped = cat $< > $@
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$(obj)/%:: $(src)/%_shipped
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$(call cmd,shipped)
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# Commands useful for building a boot image
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# ===========================================================================
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#
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# Use as following:
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#
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# target: source(s) FORCE
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# $(if_changed,ld/objcopy/gzip)
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#
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# and add target to extra-y so that we know we have to
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# read in the saved command line
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# Linking
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# ---------------------------------------------------------------------------
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quiet_cmd_ld = LD $@
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cmd_ld = $(LD) $(LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F)) \
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$(filter-out FORCE,$^) -o $@
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# Objcopy
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# ---------------------------------------------------------------------------
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quiet_cmd_objcopy = OBJCOPY $@
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cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
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# Gzip
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# ---------------------------------------------------------------------------
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quiet_cmd_gzip = GZIP $@
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cmd_gzip = gzip -f -9 < $< > $@
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