From 551559e13af1ccd19d0525cb2b0f308905170647 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 7 Dec 2007 21:04:30 +0900 Subject: [PATCH] kbuild: implement modules.order 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 Acked-by: Greg Kroah-Hartman Cc: Bill Nottingham Cc: Rusty Russell Cc: Kay Sievers Cc: Jon Masters Signed-off-by: Sam Ravnborg --- Makefile | 8 +++++++- scripts/Makefile.build | 17 ++++++++++++++++- scripts/Makefile.lib | 6 ++++++ 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 344defd0f918..f8d1fd525e17 100644 --- a/Makefile +++ b/Makefile @@ -1021,9 +1021,14 @@ ifdef CONFIG_MODULES all: modules # Build modules +# +# A module can be listed more than once in obj-m resulting in +# duplicate lines in modules.order files. Those are removed +# using awk while concatenating to the final file. PHONY += modules modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) + $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order @echo ' Building modules, stage 2.'; $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost @@ -1051,6 +1056,7 @@ _modinst_: rm -f $(MODLIB)/build ; \ ln -s $(objtree) $(MODLIB)/build ; \ fi + @cp -f $(objtree)/modules.order $(MODLIB)/ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst # This depmod is only for convenience to give the initial @@ -1110,7 +1116,7 @@ clean: archclean $(clean-dirs) @find . $(RCS_FIND_IGNORE) \ \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \ - -o -name '*.symtypes' \) \ + -o -name '*.symtypes' -o -name 'modules.order' \) \ -type f -print | xargs rm -f # mrproper - Delete all generated files, including .config diff --git a/scripts/Makefile.build b/scripts/Makefile.build index de9836eee8bb..db38ef465a63 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -83,10 +83,12 @@ ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(lib-target)),) builtin-target := $(obj)/built-in.o endif +modorder-target := $(obj)/modules.order + # We keep a list of all modules in $(MODVERDIR) __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ - $(if $(KBUILD_MODULES),$(obj-m)) \ + $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \ $(subdir-ym) $(always) @: @@ -275,6 +277,19 @@ $(builtin-target): $(obj-y) FORCE targets += $(builtin-target) endif # builtin-target +# +# Rule to create modules.order file +# +# Create commands to either record .ko file or cat modules.order from +# a subdirectory +modorder-cmds = \ + $(foreach m, $(modorder), \ + $(if $(filter %/modules.order, $m), \ + cat $m;, echo kernel/$m;)) + +$(modorder-target): $(subdir-ym) FORCE + $(Q)(cat /dev/null; $(modorder-cmds)) > $@ + # # Rule to compile a set of .o files into one .a file # diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 3c5e88bfecf1..8e440233c27d 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -25,6 +25,11 @@ lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m))) # o if we encounter foo/ in $(obj-m), remove it from $(obj-m) # and add the directory to the list of dirs to descend into: $(subdir-m) +# Determine modorder. +# Unfortunately, we don't have information about ordering between -y +# and -m subdirs. Just put -y's first. +modorder := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m:.o=.ko)) + __subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y))) subdir-y += $(__subdir-y) __subdir-m := $(patsubst %/,%,$(filter %/, $(obj-m))) @@ -64,6 +69,7 @@ real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y) extra-y := $(addprefix $(obj)/,$(extra-y)) always := $(addprefix $(obj)/,$(always)) targets := $(addprefix $(obj)/,$(targets)) +modorder := $(addprefix $(obj)/,$(modorder)) obj-y := $(addprefix $(obj)/,$(obj-y)) obj-m := $(addprefix $(obj)/,$(obj-m)) lib-y := $(addprefix $(obj)/,$(lib-y)) -- 2.30.2