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Message-ID: <20080610190307.GA15983@uranus.ravnborg.org>
Date: Tue, 10 Jun 2008 21:03:07 +0200
From: Sam Ravnborg <sam@...nborg.org>
To: Jeff Dike <jdike@...toit.com>
Cc: linux-kbuild <linux-kbuild@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: kbuild breaks um - fails to find util when linking
Hi Jeff.
In an attempt to make the final link of vmlinux
readable/hackable I have broken um build.
um used a special rule so it could use gcc as linker.
With my changes we need to use ld to link vmlinux and
ld now fails to locate util.
I hope you have a clue why. I tried various things but
did not find out why ld cannot locate util.
I have appended a combinded diff of the relvant two patches
including my um/Makefile changes.
I would really like to fix um and fold the fix into my
tree.
You can use "make V=3" to see the exact command used in the
link phase.
Thanks,
Sam
diff --git a/Makefile b/Makefile
index 2b95120..6a14c95 100644
--- a/Makefile
+++ b/Makefile
@@ -626,206 +626,32 @@ libs-y1 := $(patsubst %/, %/lib.a, $(libs-y))
libs-y2 := $(patsubst %/, %/built-in.o, $(libs-y))
libs-y := $(libs-y1) $(libs-y2)
-# 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.
+# Build vmlinux
#
-# System.map is generated to document addresses of all kernel symbols
-
-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
-export KBUILD_VMLINUX_OBJS := $(vmlinux-all)
-
-# Rule to link vmlinux - also used during CONFIG_KALLSYMS
-# May be overridden by arch/$(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 $(kallsyms.o)
-# It's a three stage process:
-# o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
-# empty
-# Running kallsyms on that gives us .tmp_kallsyms1.o with
-# the right size - vmlinux version (uname -v) is updated during this step
-# o .tmp_vmlinux2 now has a __kallsyms section of the right size,
-# but due to the added section, some addresses have shifted.
-# From here, we generate a correct .tmp_kallsyms2.o
-# o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
-# o Verify that the System.map from vmlinux matches the map from
-# .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
-# o If CONFIG_KALLSYMS_EXTRA_PASS is set, do an extra pass using
-# .tmp_vmlinux3 and .tmp_kallsyms3.o. This is only meant as a
-# temporary bypass to allow the kernel to be built while the
-# maintainers work out what went wrong with kallsyms.
-
-ifdef CONFIG_KALLSYMS_EXTRA_PASS
-last_kallsyms := 3
-else
-last_kallsyms := 2
-endif
-
-kallsyms.o := .tmp_kallsyms$(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 Try setting CONFIG_KALLSYMS_EXTRA_PASS; \
- 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
+# ---------------------------------------------------------------------------
+export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
+export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y)
+export KBUILD_VMLINUX_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
+export KBUILD_VMLINUX_EXTRA
+export LDFLAGS_vmlinux
-# 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-deps := $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
+vmlinux-deps += $(KBUILD_VMLINUX_LDS)
# vmlinux image - including updated kernel symbols
-vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
+vmlinux: $(vmlinux-deps)
ifdef CONFIG_HEADERS_CHECK
$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
endif
ifdef CONFIG_SAMPLES
$(Q)$(MAKE) $(build)=samples
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)
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh
-# The actual objects are generated when descending,
+# The actual objects are generated when descending,
# make sure no implicit rule kicks in
-$(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
diff --git a/arch/um/Makefile b/arch/um/Makefile
index dbeab15..06cbc09 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -104,7 +104,7 @@ archprepare: $(ARCH_SYMLINKS) $(ARCH_DIR)/include/user_constants.h
prepare: $(ARCH_DIR)/include/kern_constants.h
LINK-$(CONFIG_LD_SCRIPT_STATIC) += -static
-LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib
+LINK-$(CONFIG_LD_SCRIPT_DYN) += -rpath /lib -rpath /usr/lib
CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) \
$(call cc-option, -fno-stack-protector,) \
@@ -117,19 +117,8 @@ CPPFLAGS_vmlinux.lds = -U$(SUBARCH) -DSTART=$(START) -DELF_ARCH=$(ELF_ARCH) \
-DELF_FORMAT="$(ELF_FORMAT)" -DKERNEL_STACK_SIZE=$(STACK_SIZE)
# The wrappers will select whether using "malloc" or the kernel allocator.
-LINK_WRAPS = -Wl,--wrap,malloc -Wl,--wrap,free -Wl,--wrap,calloc
-
-LD_FLAGS_CMDLINE = $(foreach opt,$(LDFLAGS),-Wl,$(opt))
-
-CFLAGS_vmlinux := $(LINK-y) $(LINK_WRAPS) $(LD_FLAGS_CMDLINE)
-define cmd_vmlinux__
- $(CC) $(CFLAGS_vmlinux) -o $@ \
- -Wl,-T,$(vmlinux-lds) $(vmlinux-init) \
- -Wl,--start-group $(vmlinux-main) -Wl,--end-group \
- -lutil \
- $(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o \
- FORCE ,$^) ; rm -f linux
-endef
+LDFLAGS_vmlinux := $(LINK-y) --wrap malloc --wrap free --wrap calloc
+KBUILD_VMLINUX_EXTRA := -lutil
# When cleaning we don't include .config, so we don't include
# TT or skas makefiles and don't clean skas_ptregs.h.
diff --git a/init/Kconfig b/init/Kconfig
index 6199d11..5fc1067 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -588,18 +588,6 @@ config KALLSYMS_ALL
Say N.
-config KALLSYMS_EXTRA_PASS
- bool "Do an extra kallsyms pass"
- depends on KALLSYMS
- help
- If kallsyms is not working correctly, the build will fail with
- inconsistent kallsyms data. If that occurs, log a bug report and
- turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
- Always say N here unless you find a bug in kallsyms, which must be
- reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
- you wait for kallsyms to be fixed.
-
-
config HOTPLUG
bool "Support for hot-pluggable devices" if EMBEDDED
default y
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
new file mode 100644
index 0000000..b9ecff5
--- /dev/null
+++ b/scripts/link-vmlinux.sh
@@ -0,0 +1,145 @@
+# Build vmlinux
+# ---------------------------------------------------------------------------
+# vmlinux is built from the objects selected by $(KBUILD_VMLINUX_INIT) and
+# $(KBUILD_VMLINUX_MAIN). Most are built-in.o files from top-level directories
+# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
+# Ordering when linking is important, and $(KBUILD_VMLINUX_INIT) must be first.
+#
+# vmlinux
+# ^
+# |
+# +-< $(KBUILD_VMLINUX_INIT)
+# | +--< init/version.o + more
+# |
+# +--< $(KBUILD_VMLINUX_MAIN)
+# | +--< driver/built-in.o mm/built-in.o + more
+# |
+# +-< $(KBUILD_VMLINUX_EXTRA)
+#
+# vmlinux version (uname -v) cannot be updated during normal
+# descending-into-subdirs phase since we do not yet know if we need to
+# update vmlinux.
+#
+# System.map is generated to document addresses of all kernel symbols
+
+
+# We need access to CONFIG_ symbols
+source .config
+# Error out on error
+set -e
+# USe "make V=3" to debug this script
+if [ "${KBUILD_VERBOSE}" = "3" ]; then
+ set -x
+fi
+
+MAKE=make
+# Override MAKEFLAGS to avoid parrallel builds
+MAKEFLAGS='--no-print-directory -Rr --include-dir=$(srctree)'
+# Delete output files in case of error
+trap cleanup SIGHUP SIGINT SIGQUIT SIGTERM ERR
+cleanup()
+{
+ rm -f vmlinux.o
+ rm -f .old_version
+ rm -f .tmp_vmlinux*
+ rm -f .tmp_kallsyms*
+ rm -f vmlinux
+ rm -f .tmp_System.map
+ rm -f System.map
+}
+# non-verbose output
+tell()
+{
+ printf " %-7s %s\n" $1 $2
+}
+
+#####
+# Generate System.map
+
+# $NM produces the following output:
+# f0081e80 T alloc_vfsmnt
+
+# The second row specify the type of the symbol:
+# A = Absolute
+# B = Uninitialised data (.bss)
+# C = Comon symbol
+# D = Initialised data
+# G = Initialised data for small objects
+# I = Indirect reference to another symbol
+# N = Debugging symbol
+# R = Read only
+# S = Uninitialised data for small objects
+# T = Text code symbol
+# U = Undefined symbol
+# V = Weak symbol
+# W = Weak symbol
+# Corresponding small letters are local symbols
+
+# For System.map filter away:
+# a - local absolute symbols
+# N = Debugging symbol
+# U - undefined global symbols
+# w - local weak symbols
+
+# readprofile starts reading symbols when _stext is found, and
+# continue until it finds a symbol which is not either of 'T', 't',
+# 'W' or 'w'. __crc_ are 'A' and placed in the middle
+# so we just ignore them to let readprofile continue to work.
+# (At least sparc64 has __crc_ in the middle).
+mksysmap()
+{
+ $NM -n $1 | grep -v '\( [aNUw] \)\|\(__crc_\)\|\( \$[adt]\)'
+}
+
+# link vmlinux.o
+tell LD vmlinux.o
+${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -r -o vmlinux.o \
+ ${KBUILD_VMLINUX_INIT} \
+ --start-group ${KBUILD_VMLINUX_MAIN} --end-group \
+ ${KBUILD_VMLINUX_EXTRA}
+
+# modpost vmlinux.o
+${MAKE} -f ${srctree}/scripts/Makefile.modpost vmlinux.o
+
+# Update version
+tell GEN .version
+if [ ! -r .version ]; then
+ rm -f .version;
+ echo 1 >.version;
+else
+ mv .version .old_version;
+ expr 0$(cat .old_version) + 1 >.version;
+fi;
+
+# final build of init/
+${MAKE} -f ${srctree}/scripts/Makefile.build obj=init
+
+VMLINUX=vmlinux
+if [ "${CONFIG_KALLSYMS}" = "y" ]; then
+ VMLINUX=.tmp_vmlinux
+fi
+
+# First stage of fully linked vmlinux
+tell LD ${VMLINUX}
+${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${VMLINUX} \
+ -T ${KBUILD_VMLINUX_LDS} vmlinux.o
+
+if [ "${CONFIG_KALLSYMS}" = "y" ]; then
+
+ # Do an extra pass to link in kallsyms data
+ ${NM} -n .tmp_vmlinux | scripts/kallsyms > .tmp_kallsyms.S
+ ${CC} ${KBUILD_AFLAGS} ${KBUILD_CPPFLAGS} -c -o .tmp_kallsyms.o \
+ .tmp_kallsyms.S
+ # link in kalll symbols
+ tell LD vmlinux
+ ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o vmlinux \
+ -T ${KBUILD_VMLINUX_LDS} vmlinux.o .tmp_kallsyms.o
+fi
+
+tell SYSMAP System.map
+mksysmap vmlinux > System.map
+
+# We made a new kernel - delete old version file
+rm -f .old_version
+
+
diff --git a/scripts/mksysmap b/scripts/mksysmap
deleted file mode 100644
index 6e133a0..0000000
--- a/scripts/mksysmap
+++ /dev/null
@@ -1,45 +0,0 @@
-#!/bin/sh -x
-# Based on the vmlinux file create the System.map file
-# System.map is used by module-init tools and some debugging
-# tools to retrieve the actual addresses of symbols in the kernel.
-#
-# Usage
-# mksysmap vmlinux System.map
-
-
-#####
-# Generate System.map (actual filename passed as second argument)
-
-# $NM produces the following output:
-# f0081e80 T alloc_vfsmnt
-
-# The second row specify the type of the symbol:
-# A = Absolute
-# B = Uninitialised data (.bss)
-# C = Comon symbol
-# D = Initialised data
-# G = Initialised data for small objects
-# I = Indirect reference to another symbol
-# N = Debugging symbol
-# R = Read only
-# S = Uninitialised data for small objects
-# T = Text code symbol
-# U = Undefined symbol
-# V = Weak symbol
-# W = Weak symbol
-# Corresponding small letters are local symbols
-
-# For System.map filter away:
-# a - local absolute symbols
-# U - undefined global symbols
-# N - debugging symbols
-# w - local weak symbols
-
-# readprofile starts reading symbols when _stext is found, and
-# continue until it finds a symbol which is not either of 'T', 't',
-# 'W' or 'w'. __crc_ are 'A' and placed in the middle
-# so we just ignore them to let readprofile continue to work.
-# (At least sparc64 has __crc_ in the middle).
-
-$NM -n $1 | grep -v '\( [aNUw] \)\|\(__crc_\)\|\( \$[adt]\)' > $2
-
--
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