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54a702f705
GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.
Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped
A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.
.SECONDARY
Prerequisites of this special target are treated as intermediate
files but are never automatically deleted.
.PRECIOUS
When make is interrupted during execution, it may delete the target
file it is updating if the file was modified since make started.
If you mark the file as precious, make will never delete the file
if interrupted.
Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.
The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.
Another difference is that .PRECIOUS works with pattern rules whereas
.SECONDARY does not.
.PRECIOUS: $(obj)/%.lex.c
works, but
.SECONDARY: $(obj)/%.lex.c
has no effect. However, for the reason above, I do not want to use
.PRECIOUS which could cause obscure build breakage.
The targets specified as .SECONDARY must be explicit. $(targets)
contains all targets that need to include .*.cmd files. So, the
intermediates you want to keep are mostly in there. Therefore, mark
$(targets) as .SECONDARY. It means primary targets are also marked
as .SECONDARY, but I do not see any drawback for this.
I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This
will make Kbuild search for non-existing .*.cmd files, but this is
not a noticeable performance issue.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Frank Rowand <frowand.list@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
148 lines
4.5 KiB
Makefile
148 lines
4.5 KiB
Makefile
#
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# Building vDSO images for sparc.
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#
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KBUILD_CFLAGS += $(DISABLE_LTO)
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VDSO64-$(CONFIG_SPARC64) := y
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VDSOCOMPAT-$(CONFIG_COMPAT) := y
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# files to link into the vdso
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vobjs-y := vdso-note.o vclock_gettime.o
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# files to link into kernel
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obj-y += vma.o
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# vDSO images to build
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vdso_img-$(VDSO64-y) += 64
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vdso_img-$(VDSOCOMPAT-y) += 32
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vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
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$(obj)/vdso.o: $(obj)/vdso.so
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targets += vdso.lds $(vobjs-y)
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# Build the vDSO image C files and link them in.
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vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
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vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
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vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
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obj-y += $(vdso_img_objs)
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targets += $(vdso_img_cfiles)
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targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
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export CPPFLAGS_vdso.lds += -P -C
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VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
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-Wl,--no-undefined \
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-Wl,-z,max-page-size=8192 -Wl,-z,common-page-size=8192 \
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$(DISABLE_LTO)
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$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
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$(call if_changed,vdso)
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include
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hostprogs-y += vdso2c
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quiet_cmd_vdso2c = VDSO2C $@
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define cmd_vdso2c
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$(obj)/vdso2c $< $(<:%.dbg=%) $@
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endef
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$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
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$(call if_changed,vdso2c)
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#
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# Don't omit frame pointers for ease of userspace debugging, but do
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# optimize sibling calls.
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#
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CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables \
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-m64 -ffixed-g2 -ffixed-g3 -fcall-used-g4 -fcall-used-g5 -ffixed-g6 \
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-ffixed-g7 $(filter -g%,$(KBUILD_CFLAGS)) \
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$(call cc-option, -fno-stack-protector) -fno-omit-frame-pointer \
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-foptimize-sibling-calls -DBUILD_VDSO
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$(vobjs): KBUILD_CFLAGS += $(CFL)
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#
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# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
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#
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CFLAGS_REMOVE_vdso-note.o = -pg
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CFLAGS_REMOVE_vclock_gettime.o = -pg
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$(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg
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$(call if_changed,objcopy)
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CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf32_sparc,-soname=linux-gate.so.1
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#This makes sure the $(obj) subdirectory exists even though vdso32/
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#is not a kbuild sub-make subdirectory
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override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
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targets += vdso32/vdso32.lds
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targets += vdso32/vdso-note.o
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targets += vdso32/vclock_gettime.o
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KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
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$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(obj)/vdso32.so.dbg: asflags-$(CONFIG_SPARC64) += -m32
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KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
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KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic -mno-app-regs -ffixed-g7
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KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
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KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
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KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
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KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
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KBUILD_CFLAGS_32 += -mv8plus
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$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(obj)/vdso32.so.dbg: FORCE \
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$(obj)/vdso32/vdso32.lds \
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$(obj)/vdso32/vclock_gettime.o \
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$(obj)/vdso32/vdso-note.o
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$(call if_changed,vdso)
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#
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# The DSO images are built using a special linker script.
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#
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quiet_cmd_vdso = VDSO $@
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cmd_vdso = $(CC) -nostdlib -o $@ \
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$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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-Wl,-T,$(filter %.lds,$^) $(filter %.o,$^)
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VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
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$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic
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GCOV_PROFILE := n
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#
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# Install the unstripped copies of vdso*.so. If our toolchain supports
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# build-id, install .build-id links as well.
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#
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quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
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define cmd_vdso_install
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cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
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if readelf -n $< |grep -q 'Build ID'; then \
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buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
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first=`echo $$buildid | cut -b-2`; \
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last=`echo $$buildid | cut -b3-`; \
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mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
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ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
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fi
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endef
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vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
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$(MODLIB)/vdso: FORCE
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@mkdir -p $(MODLIB)/vdso
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$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE
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$(call cmd,vdso_install)
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PHONY += vdso_install $(vdso_img_insttargets)
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vdso_install: $(vdso_img_insttargets) FORCE
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