Revert "kbuild: simplify vmlinux link stage"

This reverts commit a7815807f749669d3e06529b2d448390f2ef0f9d.

4 files changed, 212 insertions, 161 deletions

diff --git a/Makefile b/Makefile
index cd0b71c648ca..9904722275e3 100644
--- a/Makefile
+++ b/Makefile
@@ -631,32 +631,172 @@ libs-y1		:= $(patsubst %/, %/lib.a, $(libs-y))
 libs-y2		:= $(patsubst %/, %/built-in.o, $(libs-y))
 libs-y		:= $(libs-y1) $(libs-y2)
 
-#
 # Build vmlinux
-#
 # ---------------------------------------------------------------------------
-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
+# 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-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;
+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.
+
+kallsyms.o := .tmp_kallsyms2.o
+
+# 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) > $@
 
-vmlinux-deps := $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
-vmlinux-deps += $(KBUILD_VMLINUX_LDS)
+.tmp_kallsyms1.o .tmp_kallsyms2.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__)
+
+# Needs to visit scripts/ before $(KALLSYMS) can be used.
+$(KALLSYMS): scripts ;
+
+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-deps)
+vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
 ifdef CONFIG_HEADERS_CHECK
 	$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 endif
 ifdef CONFIG_SAMPLES
 	$(Q)$(MAKE) $(build)=samples
 endif
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh
+	$(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)
 
-# The actual objects are generated when descending,
+# The actual objects are generated when descending, 
 # make sure no implicit rule kicks in
-$(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
+$(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(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 06cbc09f988f..dbeab15e7bb7 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) += -rpath /lib -rpath /usr/lib
+LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib
 
 CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) \
 	$(call cc-option, -fno-stack-protector,) \
@@ -117,8 +117,19 @@ CPPFLAGS_vmlinux.lds = -U$(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.
-LDFLAGS_vmlinux := $(LINK-y) --wrap malloc --wrap free --wrap calloc
-KBUILD_VMLINUX_EXTRA := -lutil
+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
 
 # 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/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
deleted file mode 100644
index b9ecff5c0de3..000000000000
--- a/scripts/link-vmlinux.sh
+++ /dev/null
@@ -1,145 +0,0 @@
-# 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
new file mode 100644
index 000000000000..6e133a0bae7a
--- /dev/null
+++ b/scripts/mksysmap
@@ -0,0 +1,45 @@
+#!/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
+