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kbuild: unify two modpost invocations

Currently, modpost is executed twice; first for vmlinux, second for modules. This commit merges them. Current build flow ================== 1) build obj-y and obj-m objects 2) link vmlinux.o 3) modpost for vmlinux 4) link vmlinux 5) modpost for modules 6) link modules (*.ko) The build steps 1) through 6) are serialized, that is, modules are built after vmlinux. You do not get benefits of parallel builds when scripts/link-vmlinux.sh is being run. New build flow ============== 1) build obj-y and obj-m objects 2) link vmlinux.o 3) modpost for vmlinux and modules 4a) link vmlinux 4b) link modules (*.ko) In the new build flow, modpost is invoked just once. vmlinux and modules are built in parallel. One exception is CONFIG_DEBUG_INFO_BTF_MODULES=y, where modules depend on vmlinux.

Masahiro Yamada committed 4 years ago

Commit f73edc81 parent 9c5a0ac4 files · +54 −76Browse files

Unified · Split

4 files
  1. Makefile +25 −7
  2. scripts/Makefile.modfinal +1 −1
  3. scripts/Makefile.modpost +28 −65
  4. scripts/link-vmlinux.sh +0 −3
Makefile+25−7
@@ -1150,7 +1150,7 @@ cmd_link-vmlinux = \ · 1149 unmodified lines
11501150 $(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \
11511151 $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
11521152
1153−vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
1153+vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) modpost FORCE
11541154 +$(call if_changed_dep,link-vmlinux)
11551155
11561156 targets := vmlinux
@@ -1426,7 +1426,13 @@ endif · 269 unmodified lines
14261426 # Build modules
14271427 #
14281428
1429−modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_prepare
1429+# *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFOBTF_MODULES
1430+# is an exception.
1431+ifdef CONFIG_DEBUG_INFO_BTF_MODULES
1432+modules: vmlinux
1433+endif
1434+
1435+modules: modules_prepare
14301436
14311437 # Target to prepare building external modules
14321438 modules_prepare: prepare
@@ -1739,8 +1745,12 @@ ifdef CONFIG_MODULES · 306 unmodified lines
17391745 $(MODORDER): $(build-dir)
17401746 @:
17411747
1742−modules: modules_check
1743− $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1748+# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
1749+# This is solely useful to speed up test compiles.
1750+modules: modpost
1751+ifneq ($(KBUILD_MODPOST_NOFINAL),1)
1752+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
1753+endif
17441754
17451755 PHONY += modules_check
17461756 modules_check: $(MODORDER)
@@ -1771,6 +1781,11 @@ KBUILD_MODULES := · 24 unmodified lines
17711781
17721782 endif # CONFIG_MODULES
17731783
1784+PHONY += modpost
1785+modpost: $(if $(single-build),, $(if $(KBUILD_BUILTIN), vmlinux.o)) \
1786+ $(if $(KBUILD_MODULES), modules_check)
1787+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1788+
17741789 # Single targets
17751790 # ---------------------------------------------------------------------------
17761791 # To build individual files in subdirectories, you can do like this:
@@ -1790,16 +1805,19 @@ single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS))) · 13 unmodified lines
17901805 single-no-ko := $(filter-out $(single-ko), $(MAKECMDGOALS)) \
17911806 $(foreach x, o mod, $(patsubst %.ko, %.$x, $(single-ko)))
17921807
1793−$(single-ko): single_modpost
1808+$(single-ko): single_modules
17941809 @:
17951810 $(single-no-ko): $(build-dir)
17961811 @:
17971812
17981813 # Remove MODORDER when done because it is not the real one.
1799−PHONY += single_modpost
1800−single_modpost: $(single-no-ko) modules_prepare
1814+PHONY += single_modules
1815+single_modules: $(single-no-ko) modules_prepare
18011816 $(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$m;) } > $(MODORDER)
18021817 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1818+ifneq ($(KBUILD_MODPOST_NOFINAL),1)
1819+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
1820+endif
18031821 $(Q)rm -f $(MODORDER)
18041822
18051823 single-goals := $(addprefix $(build-dir)/, $(single-no-ko))
scripts/Makefile.modfinal+1−1
@@ -55,7 +55,7 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ · 54 unmodified lines
5555 printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
5656
5757 # Re-generate module BTFs if either module's .ko or vmlinux changed
58−$(modules): %.ko: %.o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE
58+$(modules): %.ko: %.o %.mod.o scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),vmlinux) FORCE
5959 +$(call if_changed_except,ld_ko_o,vmlinux)
6060 ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6161 +$(if $(newer-prereqs),$(call cmd,btf_ko))
scripts/Makefile.modpost+28−65
@@ -32,9 +32,6 @@ · 31 unmodified lines
3232 # Step 4 is solely used to allow module versioning in external modules,
3333 # where the CRC of each module is retrieved from the Module.symvers file.
3434
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−
3835 PHONY := __modpost
3936 __modpost:
4037
@@ -45,24 +42,23 @@ MODPOST = scripts/mod/modpost \ · 4 unmodified lines
4542 $(if $(CONFIG_MODVERSIONS),-m) \
4643 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
4744 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
45+ $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
46+ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
4847 -o $@
4948
50−ifdef MODPOST_VMLINUX
51−
52−quiet_cmd_modpost = MODPOST $@
53− cmd_modpost = $(MODPOST) $<
54−
55−vmlinux.symvers: vmlinux.o
56− $(call cmd,modpost)
49+# 'make -i -k' ignores compile errors, and builds as many modules as possible.
50+ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
51+MODPOST += -n
52+endif
5753
58−__modpost: vmlinux.symvers
54+ifeq ($(KBUILD_EXTMOD),)
5955
6056 # Generate the list of in-tree objects in vmlinux
6157 # ---------------------------------------------------------------------------
6258
6359 # This is used to retrieve symbol versions generated by genksyms.
6460 ifdef CONFIG_MODVERSIONS
65−vmlinux.symvers: .vmlinux.objs
61+vmlinux.symvers Module.symvers: .vmlinux.objs
6662 endif
6763
6864 # Ignore libgcc.a
@@ -83,24 +79,12 @@ targets += .vmlinux.objs · 14 unmodified lines
8379 .vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
8480 $(call if_changed,vmlinux_objs)
8581
86−else
87−
88−ifeq ($(KBUILD_EXTMOD),)
89−
90−input-symdump := vmlinux.symvers
91−output-symdump := modules-only.symvers
92−
93−quiet_cmd_cat = GEN $@
94− cmd_cat = cat $(real-prereqs) > $@
95−
96−ifneq ($(wildcard vmlinux.symvers),)
97−
98−__modpost: Module.symvers
99−Module.symvers: vmlinux.symvers modules-only.symvers FORCE
100− $(call if_changed,cat)
101−
102−targets += Module.symvers
82+vmlinux.o-if-present := $(wildcard vmlinux.o)
83+output-symdump := vmlinux.symvers
10384
85+ifdef KBUILD_MODULES
86+output-symdump := $(if $(vmlinux.o-if-present), Module.symvers, modules-only.symvers)
87+missing-input := $(filter-out $(vmlinux.o-if-present),vmlinux.o)
10488 endif
10589
10690 else
@@ -112,56 +96,35 @@ src := $(obj) · 5 unmodified lines
11296 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
11397 include $(or $(wildcard $(src)/Kbuild), $(src)/Makefile)
11498
115−# modpost option for external modules
116−MODPOST += -e
117−
118−input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
99+module.symvers-if-present := $(wildcard Module.symvers)
119100 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
101+missing-input := $(filter-out $(module.symvers-if-present), Module.symvers)
120102
121−endif
122−
123−existing-input-symdump := $(wildcard $(input-symdump))
124−
125−# modpost options for modules (both in-kernel and external)
126−MODPOST += \
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.
132−ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
133−MODPOST += -n
134−endif
103+MODPOST += -e $(addprefix -i ,$(module.symvers-if-present) $(KBUILD_EXTRA_SYMBOLS))
135104
136−# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
137−VPATH :=
138−$(input-symdump):
139− @echo >&2 'WARNING: Symbol version dump "$@" is missing.'
140− @echo >&2 ' Modules may not have dependencies or modversions.'
141− @echo >&2 ' You may get many unresolved symbol warnings.'
105+endif # ($(KBUILD_EXTMOD),)
142106
143−# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
144−ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),)
107+ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)
145108 MODPOST += -w
146109 endif
147110
111+modorder-if-needed := $(if $(KBUILD_MODULES), $(MODORDER))
112+
148113 # Read out modules.order to pass in modpost.
149114 # Otherwise, allmodconfig would fail with "Argument list too long".
150115 quiet_cmd_modpost = MODPOST $@
151− cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T -
152−
153−$(output-symdump): $(MODORDER) $(input-symdump) FORCE
154− $(call if_changed,modpost)
116+ cmd_modpost = \
117+ $(if $(missing-input), \
118+ echo >&2 "WARNING: $(missing-input) is missing."; \
119+ echo >&2 " Modules may not have dependencies or modversions."; \
120+ echo >&2 " You may get many unresolved symbol warnings.";) \
121+ sed 's/ko$$/o/' $(or $(modorder-if-needed), /dev/null) | $(MODPOST) $(vmlinux.o-if-present) -T -
155122
156123 targets += $(output-symdump)
124+$(output-symdump): $(modorder-if-needed) $(vmlinux.o-if-present) $(moudle.symvers-if-present) FORCE
125+ $(call if_changed,modpost)
157126
158127 __modpost: $(output-symdump)
159−ifneq ($(KBUILD_MODPOST_NOFINAL),1)
160− $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
161−endif
162−
163−endif
164−
165128 PHONY += FORCE
166129 FORCE:
167130
scripts/link-vmlinux.sh+0−3
@@ -214,9 +214,6 @@ if [ "$1" = "clean" ]; then · 213 unmodified lines
214214 exit 0
215215 fi
216216
217−# modpost vmlinux.o to check for section mismatches
218−${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
219−
220217 info MODINFO modules.builtin.modinfo
221218 ${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
222219 info GEN modules.builtin