kbuild: link of vmlinux moved to a script

Move the final link of vmlinux to a script to improve
readability and maintainability of the code.

The Makefile fragments used to link vmlinux has over the
years seen far too many changes and the logic had become
hard to follow.

As the process by nature is serialized there was
nothing gained including this in the Makefile.

"um" has special link requirments - and the
only way to handle this was to hard-code the linking
of "um" in the script.
This was better than trying to modularize it only for the
benefit of "um" anyway.

The shell script has been improved after input from:
Arnaud Lacombe <lacombar@gmail.com>
Nick Bowler <nbowler@elliptictech.com>

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Arnaud Lacombe <lacombar@gmail.com>
Cc: Nick Bowler <nbowler@elliptictech.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This commit is contained in:
Sam Ravnborg
2012-05-05 10:18:41 +02:00
committed by Michal Marek
parent 9569857051
commit 1f2bfbd00e
3 changed files with 225 additions and 212 deletions
+12 -203
View File
@@ -337,7 +337,6 @@ AWK = awk
GENKSYMS = scripts/genksyms/genksyms
INSTALLKERNEL := installkernel
DEPMOD = /sbin/depmod
KALLSYMS = scripts/kallsyms
PERL = perl
CHECK = sparse
@@ -723,191 +722,21 @@ libs-y1 := $(patsubst %/, %/lib.a, $(libs-y))
libs-y2 := $(patsubst %/, %/built-in.o, $(libs-y))
libs-y := $(libs-y1) $(libs-y2)
# externally visible symbols
# Externally visible symbols (used by link-vmlinux.sh)
export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y)
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
export LDFLAGS_vmlinux
# Build vmlinux
# ---------------------------------------------------------------------------
# vmlinux is built from the objects selected by $(vmlinux-init) and
# $(vmlinux-main). Most are built-in.o files from top-level directories
# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
# Ordering when linking is important, and $(vmlinux-init) must be first.
#
# vmlinux
# ^
# |
# +-< $(vmlinux-init)
# | +--< init/version.o + more
# |
# +--< $(vmlinux-main)
# | +--< driver/built-in.o mm/built-in.o + more
# |
# +-< kallsyms.o (see description in CONFIG_KALLSYMS section)
#
# vmlinux version (uname -v) cannot be updated during normal
# descending-into-subdirs phase since we do not yet know if we need to
# update vmlinux.
# Therefore this step is delayed until just before final link of vmlinux -
# except in the kallsyms case where it is done just before adding the
# symbols to the kernel.
#
# System.map is generated to document addresses of all kernel symbols
vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
vmlinux-init := $(head-y) $(init-y)
vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
vmlinux-all := $(vmlinux-init) $(vmlinux-main)
vmlinux-lds := arch/$(SRCARCH)/kernel/vmlinux.lds
# Final link of vmlinux
cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux)
quiet_cmd_link-vmlinux = LINK $@
# Rule to link vmlinux - also used during CONFIG_KALLSYMS
# May be overridden by arch/$(ARCH)/Makefile
quiet_cmd_vmlinux__ ?= LD $@
cmd_vmlinux__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \
-T $(vmlinux-lds) $(vmlinux-init) \
--start-group $(vmlinux-main) --end-group \
$(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o FORCE ,$^)
# Generate new vmlinux version
quiet_cmd_vmlinux_version = GEN .version
cmd_vmlinux_version = set -e; \
if [ ! -r .version ]; then \
rm -f .version; \
echo 1 >.version; \
else \
mv .version .old_version; \
expr 0$$(cat .old_version) + 1 >.version; \
fi; \
$(MAKE) $(build)=init
# Generate System.map
quiet_cmd_sysmap = SYSMAP
cmd_sysmap = $(CONFIG_SHELL) $(srctree)/scripts/mksysmap
# Link of vmlinux
# If CONFIG_KALLSYMS is set .version is already updated
# Generate System.map and verify that the content is consistent
# Use + in front of the vmlinux_version rule to silent warning with make -j2
# First command is ':' to allow us to use + in front of the rule
define rule_vmlinux__
:
$(if $(CONFIG_KALLSYMS),,+$(call cmd,vmlinux_version))
$(call cmd,vmlinux__)
$(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
$(Q)$(if $($(quiet)cmd_sysmap), \
echo ' $($(quiet)cmd_sysmap) System.map' &&) \
$(cmd_sysmap) $@ System.map; \
if [ $$? -ne 0 ]; then \
rm -f $@; \
/bin/false; \
fi;
$(verify_kallsyms)
endef
ifdef CONFIG_KALLSYMS
# Generate section listing all symbols and add it into vmlinux $(kallsyms.o)
# It's a three stage process:
# o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
# empty
# Running kallsyms on that gives us .tmp_kallsyms1.o with
# the right size - vmlinux version (uname -v) is updated during this step
# o .tmp_vmlinux2 now has a __kallsyms section of the right size,
# but due to the added section, some addresses have shifted.
# From here, we generate a correct .tmp_kallsyms2.o
# o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
# o Verify that the System.map from vmlinux matches the map from
# .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
# o If 'make KALLSYMS_EXTRA_PASS=1" was used, do an extra pass using
# .tmp_vmlinux3 and .tmp_kallsyms3.o. This is only meant as a
# temporary bypass to allow the kernel to be built while the
# maintainers work out what went wrong with kallsyms.
last_kallsyms := 2
ifdef KALLSYMS_EXTRA_PASS
ifneq ($(KALLSYMS_EXTRA_PASS),0)
last_kallsyms := 3
endif
endif
kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
define verify_kallsyms
$(Q)$(if $($(quiet)cmd_sysmap), \
echo ' $($(quiet)cmd_sysmap) .tmp_System.map' &&) \
$(cmd_sysmap) .tmp_vmlinux$(last_kallsyms) .tmp_System.map
$(Q)cmp -s System.map .tmp_System.map || \
(echo Inconsistent kallsyms data; \
echo This is a bug - please report about it; \
echo Try "make KALLSYMS_EXTRA_PASS=1" as a workaround; \
rm .tmp_kallsyms* ; /bin/false )
endef
# Update vmlinux version before link
# Use + in front of this rule to silent warning about make -j1
# First command is ':' to allow us to use + in front of this rule
cmd_ksym_ld = $(cmd_vmlinux__)
define rule_ksym_ld
:
+$(call cmd,vmlinux_version)
$(call cmd,vmlinux__)
$(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
endef
# Generate .S file with all kernel symbols
quiet_cmd_kallsyms = KSYM $@
cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
$(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@
.tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
$(call if_changed_dep,as_o_S)
.tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
$(call cmd,kallsyms)
# .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
.tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
$(call if_changed_rule,ksym_ld)
.tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
$(call if_changed,vmlinux__)
.tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
$(call if_changed,vmlinux__)
# Needs to visit scripts/ before $(KALLSYMS) can be used.
$(KALLSYMS): scripts ;
# Generate some data for debugging strange kallsyms problems
debug_kallsyms: .tmp_map$(last_kallsyms)
.tmp_map%: .tmp_vmlinux% FORCE
($(OBJDUMP) -h $< | $(AWK) '/^ +[0-9]/{print $$4 " 0 " $$2}'; $(NM) $<) | sort > $@
.tmp_map3: .tmp_map2
.tmp_map2: .tmp_map1
endif # ifdef CONFIG_KALLSYMS
# Do modpost on a prelinked vmlinux. The finally linked vmlinux has
# relevant sections renamed as per the linker script.
quiet_cmd_vmlinux-modpost = LD $@
cmd_vmlinux-modpost = $(LD) $(LDFLAGS) -r -o $@ \
$(vmlinux-init) --start-group $(vmlinux-main) --end-group \
$(filter-out $(vmlinux-init) $(vmlinux-main) FORCE ,$^)
define rule_vmlinux-modpost
:
+$(call cmd,vmlinux-modpost)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
$(Q)echo 'cmd_$@ := $(cmd_vmlinux-modpost)' > $(dot-target).cmd
endef
# vmlinux image - including updated kernel symbols
vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
# Include targets which we want to
# execute if the rest of the kernel build went well.
vmlinux: scripts/link-vmlinux.sh $(vmlinux-deps) FORCE
ifdef CONFIG_HEADERS_CHECK
$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
endif
@@ -917,22 +746,11 @@ endif
ifdef CONFIG_BUILD_DOCSRC
$(Q)$(MAKE) $(build)=Documentation
endif
$(call vmlinux-modpost)
$(call if_changed_rule,vmlinux__)
$(Q)rm -f .old_version
# build vmlinux.o first to catch section mismatch errors early
ifdef CONFIG_KALLSYMS
.tmp_vmlinux1: vmlinux.o
endif
modpost-init := $(filter-out init/built-in.o, $(vmlinux-init))
vmlinux.o: $(modpost-init) $(vmlinux-main) FORCE
$(call if_changed_rule,vmlinux-modpost)
+$(call if_changed,link-vmlinux)
# The actual objects are generated when descending,
# make sure no implicit rule kicks in
$(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
$(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
# Handle descending into subdirectories listed in $(vmlinux-dirs)
# Preset locale variables to speed up the build process. Limit locale
@@ -1156,8 +974,6 @@ endif # CONFIG_MODULES
# Directories & files removed with 'make clean'
CLEAN_DIRS += $(MODVERDIR)
CLEAN_FILES += vmlinux System.map \
.tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
# Directories & files removed with 'make mrproper'
MRPROPER_DIRS += include/config usr/include include/generated \
@@ -1403,6 +1219,7 @@ scripts: ;
endif # KBUILD_EXTMOD
clean: $(clean-dirs)
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean
$(call cmd,rmdirs)
$(call cmd,rmfiles)
@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
@@ -1536,14 +1353,6 @@ quiet_cmd_depmod = DEPMOD $(KERNELRELEASE)
cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
$(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
$(KBUILD_AFLAGS_KERNEL) \
$(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CPPFLAGS) \
$(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
quiet_cmd_as_o_S = AS $@
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
# read all saved command lines
targets := $(wildcard $(sort $(targets)))