Factor out sparse tree makefile fragments and introduce hg-clone and

tarball methods in preparation for migrating away from the sparse tree
layout.

This re-introduces 14883:6568c1882af5 and 14862:98efd2e410ae plus
further fixes.

Also add makefile fragments to support building the paravirt ops tree
(make linux-2.6-paravirt-build).

Signed-off-by: Ian Campbell <ian.campbell@xensource.com>

12 files changed, 243 insertions, 129 deletions

diff --git a/buildconfigs/Rules.mk b/buildconfigs/Rules.mk
index ae61ea0095..49ef8fe21d 100644
--- a/buildconfigs/Rules.mk
+++ b/buildconfigs/Rules.mk
@@ -3,79 +3,9 @@ include Config.mk
 
 export DESTDIR
 
-# Choose the best mirror to download linux kernel
-KERNEL_REPO = http://www.kernel.org
-
 ALLKERNELS = $(patsubst buildconfigs/mk.%,%,$(wildcard buildconfigs/mk.*))
 ALLSPARSETREES = $(patsubst %-xen-sparse,%,$(wildcard *-xen-sparse))
 
-# Setup pristine search path
-PRISTINE_SRC_PATH	?= .:..
-vpath pristine-% $(PRISTINE_SRC_PATH)
-
-# Let XEN_TARGET_ARCH override ARCH.
-ifeq ($(XEN_TARGET_ARCH),x86_32)
-LINUX_ARCH	?= i386
-else
-LINUX_ARCH	?= $(XEN_TARGET_ARCH)
-endif
-
-# Expand Linux series to Linux version
-LINUX_SERIES	?= 2.6
-LINUX_VER	?= $(shell grep "^LINUX_VER " buildconfigs/mk.linux-2.6-xen | sed -e 's/.*=[ ]*//')
-
-# Setup Linux search path
-LINUX_SRC_PATH	?= .:..
-vpath linux-%.tar.bz2 $(LINUX_SRC_PATH)
-vpath patch-%.bz2 $(LINUX_SRC_PATH)
-
-# download a pristine Linux kernel tarball if there isn't one in LINUX_SRC_PATH
-linux-%.tar.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$*)).$(word 2,$(subst ., ,$*))
-linux-%.tar.bz2:
-	@echo "Cannot find $@ in path $(LINUX_SRC_PATH)"
-	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$@ -O./$@
-
-patch-%.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$(*F))).$(word 2,$(subst ., ,$(*F)))
-patch-%.bz2: override _LINUX_XDIR = $(if $(word 3,$(subst -, ,$(*F))),snapshots,testing)
-patch-%.bz2:
-	@echo "Cannot find $(@F) in path $(LINUX_SRC_PATH)"
-	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$(_LINUX_XDIR)/$(@F) -O./$@
-
-pristine-%: pristine-%/.valid-pristine
-	@true
-
-pristine-%/.valid-pristine: %.tar.bz2
-	rm -rf tmp-pristine-$* $(@D)
-	mkdir -p tmp-pristine-$*
-	tar -C tmp-pristine-$* -jxf $<
-	-@rm -f tmp-pristine-$*/pax_global_header
-	mv tmp-pristine-$*/* $(@D)
-	@rm -rf tmp-pristine-$*
-	touch $(@D)/.hgskip
-	touch $@ # update timestamp to avoid rebuild
-
-PATCHDIRS := $(wildcard patches/*-*)
-
-ifneq ($(PATCHDIRS),)
--include $(patsubst %,%/.makedep,$(PATCHDIRS))
-
-$(patsubst patches/%,patches/%/.makedep,$(PATCHDIRS)): patches/%/.makedep: 
-	@echo 'ref-$*/.valid-ref: $$(wildcard patches/$*/*.patch)' >$@
-
-ref-%/.valid-ref: pristine-%/.valid-pristine
-	set -e
-	rm -rf $(@D)
-	cp -al $(<D) $(@D)
-	if [ -d patches/$* ] ; then                                    \
-	    echo Applying patches from patches/$*... ;                 \
-	    for i in $$(cat patches/$*/series) ; do                    \
-	        echo ... $$i ;                                         \
-	        patch -d $(@D) -p1 --quiet <patches/$*/$$i || exit 1 ; \
-	     done ;                                                    \
-	fi
-	touch $@ # update timestamp to avoid rebuild
-endif
-
 %-install:
 	$(MAKE) -f buildconfigs/mk.$* build
 
@@ -101,32 +31,13 @@ endif
 %-clean:
 	$(MAKE) -f buildconfigs/mk.$* clean
 
-linux-2.6-xen.patch: ref-linux-$(LINUX_VER)/.valid-ref
-	rm -rf tmp-$@
-	cp -al $(<D) tmp-$@
-	( cd linux-2.6-xen-sparse && bash ./mkbuildtree ../tmp-$@ )	
-	diff -Nurp $(patsubst ref%,pristine%,$(<D)) tmp-$@ > $@ || true
-	rm -rf tmp-$@
-
-%-xen.patch: ref-%/.valid-ref
-	rm -rf tmp-$@
-	cp -al $(<D) tmp-$@
-	( cd $*-xen-sparse && bash ./mkbuildtree ../tmp-$@ )	
-	diff -Nurp $(patsubst ref%,pristine%,$(<D)) tmp-$@ > $@ || true
-	rm -rf tmp-$@
+%.patch:
+	$(MAKE) -f buildconfigs/mk.$* $@
 
 %-mrproper:
-	$(MAKE) -f buildconfigs/mk.$*-xen mrpropper
+	$(MAKE) -f buildconfigs/mk.$*-xen mrproper
 	rm -rf pristine-$(*)* ref-$(*)*
 	rm -rf $*-xen.patch
 
-.PHONY: config-update-pae
-config-update-pae:
-ifeq ($(XEN_TARGET_X86_PAE),y)
-	sed -e 's!^CONFIG_HIGHMEM4G=y$$!\# CONFIG_HIGHMEM4G is not set!;s!^\# CONFIG_HIGHMEM64G is not set$$!CONFIG_HIGHMEM64G=y!' $(CONFIG_FILE) > $(CONFIG_FILE)- && mv $(CONFIG_FILE)- $(CONFIG_FILE)
-else
-	grep '^CONFIG_HIGHMEM64G=y' $(CONFIG_FILE) >/dev/null && ( sed -e 's!^CONFIG_HIGHMEM64G=y$$!\# CONFIG_HIGHMEM64G is not set!;s!^\# CONFIG_HIGHMEM4G is not set$$!CONFIG_HIGHMEM4G=y!' $(CONFIG_FILE) > $(CONFIG_FILE)- && mv $(CONFIG_FILE)- $(CONFIG_FILE) ) || true
-endif
-
 # never delete any intermediate files.
 .SECONDARY:
diff --git a/buildconfigs/create_config.sh b/buildconfigs/create_config.sh
index 76b7a484fe..529b7fadcb 100644
--- a/buildconfigs/create_config.sh
+++ b/buildconfigs/create_config.sh
@@ -18,23 +18,26 @@ systype=$4
 # Start with initial config skeleton file, if any.
 # Derive from linux-defconfig_xen_x86_32 otherwise.
 #
-skeleton=buildconfigs/linux-defconfig_${extraversion}_${target_arch}${systype}
+skeleton=buildconfigs/linux-defconfig_${extraversion#-}_${target_arch}${systype}
 [ -r $skeleton ] || skeleton=buildconfigs/linux-defconfig_xen_x86_32
 [ -r $skeleton.local ] && skeleton=$skeleton.local
 cp $skeleton $config_file
 
+echo "Using $skeleton as base config"
 
 # Update
 #
 filter_template="s/^#\{0,1\} *\(CONFIG[^= ]*\).*/\/^#\\\{0,1\\\} *\1[= ].*\/d/p"
-config_dirs="buildconfigs/conf.linux buildconfigs/conf.linux-${target_arch} buildconfigs/conf.linux-${extraversion} buildconfigs/conf.linux-${target_arch}-${extraversion}"
+config_dirs="buildconfigs/conf.linux buildconfigs/conf.linux-${target_arch} buildconfigs/conf.linux${extraversion} buildconfigs/conf.linux-${target_arch}${extraversion}"
 
 for config_dir in $config_dirs
 do
     if [ -d $config_dir ]; then
+        echo "Processing $config_dir..." 1>&2
         # processing is done in alphanumeric order
         find $config_dir -type f | sort | while read update
         do
+            echo "   ... $update" 1>&2
             # create the filter rules in a temp file
             filter_rules=`mktemp -t xenupdateconf.XXXXXXXXXX`
             sed -n "${filter_template}" < $update > $filter_rules
diff --git a/buildconfigs/mk.linux-2.6-native b/buildconfigs/mk.linux-2.6-native
index c3ee13bdca..09ed18efde 100644
--- a/buildconfigs/mk.linux-2.6-native
+++ b/buildconfigs/mk.linux-2.6-native
@@ -1,4 +1,4 @@
-EXTRAVERSION = native
+EXTRAVERSION = -native
 IMAGE_TARGET = bzImage
 INSTALL_BOOT_PATH = $(DESTDIR)/boot
 include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/mk.linux-2.6-paravirt b/buildconfigs/mk.linux-2.6-paravirt
new file mode 100644
index 0000000000..1a0127733e
--- /dev/null
+++ b/buildconfigs/mk.linux-2.6-paravirt
@@ -0,0 +1,11 @@
+XEN_LINUX_SOURCE ?= tarball
+XEN_LINUX_MIRROR ?= http://xenbits.xensource.com/ext/paravirt_ops/
+LINUX_VER ?= 2.6-paravirt
+
+# This target currently only supports x86_32.
+XEN_TARGET_ARCH = x86_32
+IMAGE_TARGET ?= vmlinux bzImage
+
+EXTRAVERSION ?=
+
+include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/mk.linux-2.6-xen b/buildconfigs/mk.linux-2.6-xen
index bdc5e738ad..afd56b1397 100644
--- a/buildconfigs/mk.linux-2.6-xen
+++ b/buildconfigs/mk.linux-2.6-xen
@@ -1,21 +1,28 @@
 LINUX_SERIES = 2.6
-LINUX_VER    = 2.6.18
+LINUX_VER    ?= 2.6.18
 
-EXTRAVERSION ?= xen
+EXTRAVERSION ?= -xen
 
-LINUX_SRCDIR = linux-$(LINUX_VER)-xen
-LINUX_DIR    = build-linux-$(LINUX_VER)-$(EXTRAVERSION)_$(XEN_TARGET_ARCH)
+XEN_LINUX_SOURCE ?= sparse
 
-IMAGE_TARGET ?= vmlinuz
-INSTALL_BOOT_PATH ?= $(DESTDIR)
+# Let XEN_TARGET_ARCH override ARCH.
+ifeq ($(XEN_TARGET_ARCH),x86_32)
+LINUX_ARCH	?= i386
+else
+LINUX_ARCH	?= $(XEN_TARGET_ARCH)
+endif
 
-ifeq ($(XEN_TARGET_ARCH),ia64)
+LINUX_DIR     = build-linux-$(LINUX_VER)$(EXTRAVERSION)_$(XEN_TARGET_ARCH)
+
+IMAGE_TARGET ?= vmlinuz
 INSTALL_BOOT_PATH := $(DESTDIR)/boot
-endif
 
 LINUX_VER3  := $(LINUX_SERIES).$(word 3, $(subst ., ,$(LINUX_VER)))
 
-include buildconfigs/Rules.mk
+.PHONY: _build
+_build: build
+
+include buildconfigs/src.$(XEN_LINUX_SOURCE)
 
 # The real action starts here!
 .PHONY: build
@@ -28,31 +35,63 @@ build: $(LINUX_DIR)/include/linux/autoconf.h
 	mkdir -p $(INSTALL_BOOT_PATH)
 	$(MAKE) -C $(LINUX_DIR) ARCH=$(LINUX_ARCH) INSTALL_PATH=$(INSTALL_BOOT_PATH) install
 
-$(LINUX_SRCDIR)/.valid-src: ref-linux-$(LINUX_VER)/.valid-ref
-	rm -rf $(LINUX_SRCDIR)
-	cp -al $(<D) $(LINUX_SRCDIR)
-	# Apply arch-xen patches
-	( cd linux-$(LINUX_SERIES)-xen-sparse && \
-          LINUX_ARCH=$(LINUX_ARCH) bash ./mkbuildtree ../$(LINUX_SRCDIR) )
-	# Patch kernel Makefile to set EXTRAVERSION
-	( cd $(LINUX_SRCDIR) ; \
-	  sed -e 's,^EXTRAVERSION.*,&$$(XENGUEST),' \
-	      -e 's,^KERNELRELEASE,XENGUEST := $$(shell [ -r $$(objtree)/.xenguest ] \&\& cat $$(objtree)/.xenguest)\n&,' Makefile >Mk.tmp ; \
-	  rm -f Makefile ; mv Mk.tmp Makefile )
-	touch $@
-
+$(LINUX_DIR)/include/linux/autoconf.h: CONFIG_FILE=$(PWD)/$(LINUX_DIR)/.config
 $(LINUX_DIR)/include/linux/autoconf.h: $(LINUX_SRCDIR)/.valid-src
 	rm -rf $(LINUX_DIR)
 	mkdir -p $(LINUX_DIR)
-	# Re-use config from install dir if one exits else use default config
+	# Re-use config from install dir if one exists. Next try to use
+	# buildconfigs/create_config.sh is one is provided by the source
+	# tree. Finally attempt to use make defconfig.
+	set -e ; \
 	CONFIG_VERSION=$$(sed -ne 's/$$(XENGUEST)//; s/^EXTRAVERSION = //p' $(LINUX_SRCDIR)/Makefile); \
-	[ -r $(DESTDIR)/boot/config-$(LINUX_VER3)$$CONFIG_VERSION-$(EXTRAVERSION) ] && \
-	  cp $(DESTDIR)/boot/config-$(LINUX_VER3)$$CONFIG_VERSION-$(EXTRAVERSION) $(LINUX_DIR)/.config \
-	  || sh buildconfigs/create_config.sh $(LINUX_DIR)/.config $(EXTRAVERSION) $(XEN_TARGET_ARCH) $(XEN_SYSTYPE)
-	# See if we need to munge config to enable PAE
-	$(MAKE) CONFIG_FILE=$(LINUX_DIR)/.config -f buildconfigs/Rules.mk config-update-pae
-	echo "-$(EXTRAVERSION)" >$(LINUX_DIR)/.xenguest
+	if [ -r $(DESTDIR)/boot/config-$(LINUX_VER3)$$CONFIG_VERSION$(EXTRAVERSION) ] ; then \
+	  cp $(DESTDIR)/boot/config-$(LINUX_VER3)$$CONFIG_VERSION$(EXTRAVERSION) $(CONFIG_FILE) ; \
+        elif [ -e $(LINUX_SRCDIR)/buildconfigs/create_config.sh ] ; then \
+	  cd $(LINUX_SRCDIR) && sh buildconfigs/create_config.sh \
+		$(CONFIG_FILE) $(EXTRAVERSION) $(XEN_TARGET_ARCH) $(XEN_SYSTYPE) ; \
+          echo "Configured $(LINUX_DIR) using create_config.sh" ; \
+	elif $(MAKE) -C $(LINUX_SRCDIR) ARCH=$(LINUX_ARCH) defconfig O=$$(/bin/pwd)/$(LINUX_DIR) ; then \
+	  echo "Configured $(LINUX_DIR) using defconfig" ; \
+	else \
+          echo "No configuration method found for this kernel" ; \
+	fi
+ifeq ($(XEN_TARGET_ARCH),x86_32)
+ifeq ($(pae),y)
+	sed -e 's!^CONFIG_HIGHMEM4G=y$$!\# CONFIG_HIGHMEM4G is not set!;s!^\# CONFIG_HIGHMEM64G is not set$$!CONFIG_HIGHMEM64G=y!' $(CONFIG_FILE) > $(CONFIG_FILE)- && mv $(CONFIG_FILE)- $(CONFIG_FILE)
+else
+	grep '^CONFIG_HIGHMEM64G=y' $(CONFIG_FILE) >/dev/null && ( sed -e 's!^CONFIG_HIGHMEM64G=y$$!\# CONFIG_HIGHMEM64G is not set!;s!^\# CONFIG_HIGHMEM4G is not set$$!CONFIG_HIGHMEM4G=y!' $(CONFIG_FILE) > $(CONFIG_FILE)- && mv $(CONFIG_FILE)- $(CONFIG_FILE) ) || true
+endif
+endif
+ifneq ($(EXTRAVERSION),)
+	echo "$(EXTRAVERSION)" >$(LINUX_DIR)/localversion-xen
+endif
 	$(MAKE) -C $(LINUX_SRCDIR) ARCH=$(LINUX_ARCH) oldconfig O=$$(/bin/pwd)/$(LINUX_DIR)
+	@if [ ! -f $(LINUX_DIR)/Makefile ] ; then \
+	    echo "***********************************"; \
+	    echo "oldconfig did not create a Makefile"; \
+	    echo "Generating $(LINUX_DIR)/Makefile   "; \
+	    echo "***********************************"; \
+	    ( echo "# Automatically generated: don't edit"; \
+	      echo ""; \
+	      echo "VERSION = 2"; \
+	      echo "PATCHLEVEL = 6"; \
+	      echo ""; \
+	      echo "KERNELSRC    := $(PWD)/$(LINUX_SRCDIR)"; \
+	      echo "KERNELOUTPUT := $(PWD)/$(LINUX_DIR)"; \
+	      echo ""; \
+	      echo "MAKEFLAGS += --no-print-directory"; \
+	      echo ""; \
+	      echo ".PHONY: all \$$(MAKECMDGOALS)"; \
+	      echo ""; \
+	      echo "all:"; \
+	      echo "	\$$(MAKE) -C \$$(KERNELSRC) O=\$$(KERNELOUTPUT)"; \
+	      echo ""; \
+	      echo "Makefile:;"; \
+	      echo ""; \
+	      echo "\$$(filter-out all Makefile,\$$(MAKECMDGOALS)) %/:"; \
+	      echo "	\$$(MAKE) -C \$$(KERNELSRC) O=\$$(KERNELOUTPUT) \$$@"; \
+	    ) > $(LINUX_DIR)/Makefile ; \
+	fi
 
 .PHONY: prep
 prep: $(LINUX_DIR)/include/linux/autoconf.h
@@ -67,12 +106,11 @@ clean::
 	[ ! -d $(LINUX_DIR) ] || \
 		$(MAKE) -C $(LINUX_DIR) ARCH=$(LINUX_ARCH) clean
 
-
 .PHONY: delete
 delete: 
 	rm -rf tmp-linux-$(LINUX_VER) $(LINUX_DIR) 
 
-.PHONY: mrpropper
-mrpropper:
+.PHONY: mrproper
+mrproper:
 	rm -rf $(LINUX_SRCDIR)
 	rm -f linux-$(LINUX_VER).tar.bz2
diff --git a/buildconfigs/mk.linux-2.6-xen0 b/buildconfigs/mk.linux-2.6-xen0
index 604bc102a1..96a5712a83 100644
--- a/buildconfigs/mk.linux-2.6-xen0
+++ b/buildconfigs/mk.linux-2.6-xen0
@@ -1,2 +1,2 @@
-EXTRAVERSION = xen0
+EXTRAVERSION = -xen0
 include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/mk.linux-2.6-xenU b/buildconfigs/mk.linux-2.6-xenU
index fb2ded608d..02f3e0773b 100644
--- a/buildconfigs/mk.linux-2.6-xenU
+++ b/buildconfigs/mk.linux-2.6-xenU
@@ -1,2 +1,2 @@
-EXTRAVERSION = xenU
+EXTRAVERSION = -xenU
 include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/mk.linux-2.6.5-SLES-xen b/buildconfigs/mk.linux-2.6.5-SLES-xen
new file mode 100644
index 0000000000..693e89ca64
--- /dev/null
+++ b/buildconfigs/mk.linux-2.6.5-SLES-xen
@@ -0,0 +1,12 @@
+# This tree only supports PAE
+XEN_TARGET_ARCH = x86_32
+XEN_TARGET_X86_PAE = y
+
+EXTRAVERSION = -xen
+LINUX_VER = 2.6.5-SLES
+
+XEN_LINUX_SOURCE = hg-clone
+XEN_LINUX_HGREPO ?= http://xenbits.xensource.com/kernels/sles9x.hg
+XEN_LINUX_HGREV  ?= tip
+
+include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/mk.linux-2.6.9-RHEL-xen b/buildconfigs/mk.linux-2.6.9-RHEL-xen
new file mode 100644
index 0000000000..9b1a9b87a7
--- /dev/null
+++ b/buildconfigs/mk.linux-2.6.9-RHEL-xen
@@ -0,0 +1,12 @@
+# This tree only supports PAE
+XEN_TARGET_ARCH = x86_32
+XEN_TARGET_X86_PAE = y
+
+EXTRAVERSION = -xen
+LINUX_VER = 2.6.9-RHEL
+
+XEN_LINUX_SOURCE = hg-clone
+XEN_LINUX_HGREPO ?= http://xenbits.xensource.com/kernels/rhel4x.hg
+XEN_LINUX_HGREV  ?= tip
+
+include buildconfigs/mk.linux-2.6-xen
diff --git a/buildconfigs/src.hg-clone b/buildconfigs/src.hg-clone
new file mode 100644
index 0000000000..f387a95b6a
--- /dev/null
+++ b/buildconfigs/src.hg-clone
@@ -0,0 +1,26 @@
+# Main repository to clone.
+XEN_LINUX_HGREPO ?= http://xenbits.xensource.com/linux-$(LINUX_VER)-xen.hg
+
+# Set this to pull additional changesets from a second source.
+
+# This can be useful if you use a local mirror for XEN_LINUX_HGREPO
+# (to reduce time spent cloning) but still want to pull the very
+# latest changesets from xenbits.
+XEN_LINUX_HGUPDATES ?=
+
+# Set this to update to a particlar revision.
+XEN_LINUX_HGREV  ?=
+
+LINUX_SRCDIR ?= linux-$(LINUX_VER)-xen.hg
+
+$(LINUX_SRCDIR)/.valid-src:
+	if [ ! -d $(LINUX_SRCDIR) ] ; then \
+	    hg clone $(XEN_LINUX_HGREPO) $(LINUX_SRCDIR) ; \
+	fi
+	if [ -n "$(XEN_LINUX_HGUPDATES)" ] ; then \
+	    hg pull -R $(LINUX_SRCDIR) $(XEN_LINUX_HGUPDATES) ; \
+	fi
+	if [ -n "$(XEN_LINUX_HGREV)" ] ; then \
+	    hg update -R $(LINUX_SRCDIR) $(XEN_LINUX_HGREV) ; \
+	fi
+	touch $@
diff --git a/buildconfigs/src.sparse b/buildconfigs/src.sparse
new file mode 100644
index 0000000000..96a830050b
--- /dev/null
+++ b/buildconfigs/src.sparse
@@ -0,0 +1,76 @@
+# Choose the best mirror to download linux kernel
+KERNEL_REPO = http://www.kernel.org
+
+LINUX_SRCDIR ?= linux-$(LINUX_VER)-xen
+
+# Setup pristine search path
+PRISTINE_SRC_PATH	?= .:..
+vpath pristine-% $(PRISTINE_SRC_PATH)
+
+# Setup Linux search path
+LINUX_SRC_PATH	?= .:..
+vpath linux-%.tar.bz2 $(LINUX_SRC_PATH)
+vpath patch-%.bz2 $(LINUX_SRC_PATH)
+
+# download a pristine Linux kernel tarball if there isn't one in LINUX_SRC_PATH
+linux-%.tar.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$*)).$(word 2,$(subst ., ,$*))
+linux-%.tar.bz2:
+	@echo "Cannot find $@ in path $(LINUX_SRC_PATH)"
+	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$@ -O./$@
+
+patch-%.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$(*F))).$(word 2,$(subst ., ,$(*F)))
+patch-%.bz2: override _LINUX_XDIR = $(if $(word 3,$(subst -, ,$(*F))),snapshots,testing)
+patch-%.bz2:
+	@echo "Cannot find $(@F) in path $(LINUX_SRC_PATH)"
+	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$(_LINUX_XDIR)/$(@F) -O./$@
+
+pristine-%: pristine-%/.valid-pristine
+	@true
+
+pristine-%/.valid-pristine: %.tar.bz2
+	rm -rf tmp-pristine-$* $(@D)
+	mkdir -p tmp-pristine-$*
+	tar -C tmp-pristine-$* -jxf $<
+	-@rm -f tmp-pristine-$*/pax_global_header
+	mv tmp-pristine-$*/* $(@D)
+	@rm -rf tmp-pristine-$*
+	touch $(@D)/.hgskip
+	touch $@ # update timestamp to avoid rebuild
+
+PATCHDIRS := $(wildcard patches/*-*)
+
+ifneq ($(PATCHDIRS),)
+-include $(patsubst %,%/.makedep,$(PATCHDIRS))
+
+$(patsubst patches/%,patches/%/.makedep,$(PATCHDIRS)): patches/%/.makedep: 
+	@echo 'ref-$*/.valid-ref: $$(wildcard patches/$*/*.patch)' >$@
+
+ref-%/.valid-ref: pristine-%/.valid-pristine
+	set -e
+	rm -rf $(@D)
+	cp -al $(<D) $(@D)
+	if [ -d patches/$* ] ; then                                    \
+	    echo Applying patches from patches/$*... ;                 \
+	    for i in $$(cat patches/$*/series) ; do                    \
+	        echo ... $$i ;                                         \
+	        patch -d $(@D) -p1 --quiet <patches/$*/$$i || exit 1 ; \
+	     done ;                                                    \
+	fi
+	touch $@ # update timestamp to avoid rebuild
+endif
+
+$(LINUX_SRCDIR)/.valid-src: ref-linux-$(LINUX_VER)/.valid-ref
+	rm -rf $(LINUX_SRCDIR)
+	cp -al $(<D) $(LINUX_SRCDIR)
+	# Apply arch-xen patches
+	( cd linux-$(LINUX_SERIES)-xen-sparse && \
+          LINUX_ARCH=$(LINUX_ARCH) bash ./mkbuildtree ../$(LINUX_SRCDIR) )
+	( cd $(LINUX_SRCDIR) && [ -e buildconfigs ] || ln -s $(PWD)/buildconfigs buildconfigs )
+	touch $@
+
+linux-2.6-xen.patch: ref-linux-$(LINUX_VER)/.valid-ref
+	rm -rf tmp-$@
+	cp -al $(<D) tmp-$@
+	( cd linux-2.6-xen-sparse && bash ./mkbuildtree ../tmp-$@ )
+	diff -Nurp $(patsubst ref%,pristine%,$(<D)) tmp-$@ > $@ || true
+	rm -rf tmp-$@
diff --git a/buildconfigs/src.tarball b/buildconfigs/src.tarball
new file mode 100644
index 0000000000..35f0860479
--- /dev/null
+++ b/buildconfigs/src.tarball
@@ -0,0 +1,25 @@
+XEN_LINUX_MIRROR ?= http://www.kernel.org/pub/linux/kernel/v2.6/
+XEN_LINUX_TARBALL ?= linux-$(LINUX_VER)-xen.tar.bz2
+
+LINUX_SRCDIR ?= linux-$(LINUX_VER)
+
+# Setup Linux search path
+LINUX_SRC_PATH	?= .:..
+vpath linux-%.tar.bz2 $(LINUX_SRC_PATH)
+
+# download a pristine Linux kernel tarball if there isn't one in LINUX_SRC_PATH
+linux-%.tar.bz2:
+	@echo "Cannot find $@ in path $(LINUX_SRC_PATH)"
+	wget $(XEN_LINUX_MIRROR)/$@ -O./$@
+
+# XXX create a pristine tree for diff -Nurp convenience
+
+%/.valid-src: %.tar.bz2
+	rm -rf tmp-linux-$* $(@D)
+	mkdir -p tmp-linux-$*
+	tar -C tmp-linux-$* -jxf $<
+	-@rm -f tmp-linux-$*/pax_global_header
+	mv tmp-linux-$*/* $(@D)
+	@rm -rf tmp-linux-$*
+	touch $(@D)/.hgskip
+	touch $@ # update timestamp to avoid rebuild