diff --git a/repos/base-fiasco/etc/specs.conf b/repos/base-fiasco/etc/specs.conf
index eafd6189f..0f422868a 100644
--- a/repos/base-fiasco/etc/specs.conf
+++ b/repos/base-fiasco/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode fiasco x86_32 vesa pci ps2 framebuffer
+SPECS += fiasco x86_32
diff --git a/repos/base-foc/etc/specs.conf b/repos/base-foc/etc/specs.conf
index b78640192..f5ae8ffc5 100644
--- a/repos/base-foc/etc/specs.conf
+++ b/repos/base-foc/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode foc
+SPECS += foc
diff --git a/repos/base-foc/lib/mk/kernel-foc.inc b/repos/base-foc/lib/mk/kernel-foc.inc
index 420c4186d..53b2d7bff 100644
--- a/repos/base-foc/lib/mk/kernel-foc.inc
+++ b/repos/base-foc/lib/mk/kernel-foc.inc
@@ -4,6 +4,9 @@ FOC_SRC      := $(call select_from_ports,foc)/src/kernel/foc/kernel/fiasco
 
 KERNEL_BUILD_OUTPUT_FILTER = 2>&1 | sed "s/^/      [fiasco.oc]  /"
 
+MAKEOVERRIDES := $(filter-out KERNEL=%,$(MAKEOVERRIDES))
+unexport KERNEL
+
 $(FOC_BUILD_DIR):
 	$(VERBOSE_MK) $(MAKE) SYSTEM_TARGET="$(CROSS_DEV_PREFIX)" \
 	                      $(VERBOSE_DIR) -C $(FOC_SRC) BUILDDIR=$@ \
diff --git a/repos/base-linux/etc/specs.conf b/repos/base-linux/etc/specs.conf
index e6290e022..b8df884c8 100644
--- a/repos/base-linux/etc/specs.conf
+++ b/repos/base-linux/etc/specs.conf
@@ -1,23 +1 @@
-
-SPECS += genode linux sdl
-
-#
-# Detect host CPU architecture
-#
-UNAME_MACHINE := $(shell uname -m)
-
-ifeq ($(UNAME_MACHINE),i686)
-SPECS += x86_32
-endif
-
-ifeq ($(UNAME_MACHINE),x86_64)
-SPECS += x86_64
-endif
-
-ifeq ($(UNAME_MACHINE),armv6l)
-SPECS += arm_v6
-endif
-
-ifeq ($(UNAME_MACHINE),armv7l)
-SPECS += arm_v7a
-endif
+SPECS += linux sdl
diff --git a/repos/base-nova/etc/specs.conf b/repos/base-nova/etc/specs.conf
index 07749c890..cdc01511c 100644
--- a/repos/base-nova/etc/specs.conf
+++ b/repos/base-nova/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode nova vesa acpi pci ps2 framebuffer
+SPECS += nova acpi
diff --git a/repos/base-okl4/etc/specs.conf b/repos/base-okl4/etc/specs.conf
index 901c175a4..8da465ec4 100644
--- a/repos/base-okl4/etc/specs.conf
+++ b/repos/base-okl4/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode okl4 x86_32 vesa pci ps2 framebuffer
+SPECS += okl4 x86_32
diff --git a/repos/base-pistachio/etc/specs.conf b/repos/base-pistachio/etc/specs.conf
index 9b6966ecc..e069f3e0f 100644
--- a/repos/base-pistachio/etc/specs.conf
+++ b/repos/base-pistachio/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode pistachio x86_32 vesa pci ps2 framebuffer
+SPECS += pistachio x86_32
diff --git a/repos/base-sel4/etc/specs.conf b/repos/base-sel4/etc/specs.conf
index adfa3ddba..92a508fb1 100644
--- a/repos/base-sel4/etc/specs.conf
+++ b/repos/base-sel4/etc/specs.conf
@@ -1 +1 @@
-SPECS += genode sel4 vesa acpi pci ps2 framebuffer
+SPECS += sel4 acpi
diff --git a/repos/base/mk/spec/x86.mk b/repos/base/mk/spec/x86.mk
new file mode 100644
index 000000000..62bce4396
--- /dev/null
+++ b/repos/base/mk/spec/x86.mk
@@ -0,0 +1,3 @@
+ifeq ($(filter $(SPECS),linux),)
+SPECS += vesa pci ps2 framebuffer usb
+endif
diff --git a/repos/base/mk/spec/x86_32.mk b/repos/base/mk/spec/x86_32.mk
index 5c40d463c..c35cc0c63 100644
--- a/repos/base/mk/spec/x86_32.mk
+++ b/repos/base/mk/spec/x86_32.mk
@@ -17,3 +17,4 @@ LD_MARCH ?= -melf_i386
 AS_MARCH ?= -march=i686 --32
 
 include $(call select_from_repositories,mk/spec/32bit.mk)
+include $(call select_from_repositories,mk/spec/x86.mk)
diff --git a/repos/base/mk/spec/x86_64.mk b/repos/base/mk/spec/x86_64.mk
index 8e7bfc65b..dd7507ec0 100644
--- a/repos/base/mk/spec/x86_64.mk
+++ b/repos/base/mk/spec/x86_64.mk
@@ -20,5 +20,5 @@ CC_MARCH ?= -m64
 #
 LD_MARCH ?= -melf_x86_64
 
-
 include $(call select_from_repositories,mk/spec/64bit.mk)
+include $(call select_from_repositories,mk/spec/x86.mk)
diff --git a/repos/ports/lib/mk/spec/hw_x86_64_muen/virtualbox-hwaccl.mk b/repos/ports/lib/mk/spec/muen/virtualbox-hwaccl.mk
similarity index 100%
rename from repos/ports/lib/mk/spec/hw_x86_64_muen/virtualbox-hwaccl.mk
rename to repos/ports/lib/mk/spec/muen/virtualbox-hwaccl.mk
diff --git a/tool/builddir/etc/README b/tool/builddir/build.conf/README
similarity index 100%
rename from tool/builddir/etc/README
rename to tool/builddir/build.conf/README
diff --git a/tool/builddir/etc/build.conf.foc_arndale b/tool/builddir/build.conf/foc_arndale
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_arndale
rename to tool/builddir/build.conf/foc_arndale
diff --git a/tool/builddir/etc/build.conf.foc_imx53 b/tool/builddir/build.conf/foc_imx53
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_imx53
rename to tool/builddir/build.conf/foc_imx53
diff --git a/tool/builddir/etc/build.conf.foc_odroid_x2 b/tool/builddir/build.conf/foc_odroid_x2
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_odroid_x2
rename to tool/builddir/build.conf/foc_odroid_x2
diff --git a/tool/builddir/etc/build.conf.foc_panda b/tool/builddir/build.conf/foc_panda
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_panda
rename to tool/builddir/build.conf/foc_panda
diff --git a/tool/builddir/etc/build.conf.foc_pbxa9 b/tool/builddir/build.conf/foc_pbxa9
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_pbxa9
rename to tool/builddir/build.conf/foc_pbxa9
diff --git a/tool/builddir/etc/build.conf.foc_rpi b/tool/builddir/build.conf/foc_rpi
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_rpi
rename to tool/builddir/build.conf/foc_rpi
diff --git a/tool/builddir/etc/build.conf.foc_x86_32 b/tool/builddir/build.conf/foc_x86_32
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_x86_32
rename to tool/builddir/build.conf/foc_x86_32
diff --git a/tool/builddir/etc/build.conf.foc_x86_64 b/tool/builddir/build.conf/foc_x86_64
similarity index 100%
rename from tool/builddir/etc/build.conf.foc_x86_64
rename to tool/builddir/build.conf/foc_x86_64
diff --git a/tool/builddir/build.conf/make_j b/tool/builddir/build.conf/make_j
new file mode 100644
index 000000000..3a36a2629
--- /dev/null
+++ b/tool/builddir/build.conf/make_j
@@ -0,0 +1,3 @@
+# enable parallel build
+#MAKE += -j4
+
diff --git a/tool/builddir/build.conf/qemu_opt_arm b/tool/builddir/build.conf/qemu_opt_arm
new file mode 100644
index 000000000..f0a44519f
--- /dev/null
+++ b/tool/builddir/build.conf/qemu_opt_arm
@@ -0,0 +1,14 @@
+
+##
+## Qemu arguments, effective when using the run tool's 'power_on/qemu' back end
+##
+
+# enable GDB stub
+#QEMU_OPT += -s
+
+# use time-tested graphics backend
+QEMU_OPT += -display sdl
+
+# add kernel-specific Qemu arguments
+QEMU_OPT += $(QEMU_OPT(${KERNEL})}
+
diff --git a/tool/builddir/build.conf/qemu_opt_x86 b/tool/builddir/build.conf/qemu_opt_x86
new file mode 100644
index 000000000..e784260d8
--- /dev/null
+++ b/tool/builddir/build.conf/qemu_opt_x86
@@ -0,0 +1,20 @@
+
+##
+## Qemu arguments, effective when using the run tool's 'power_on/qemu' back end
+##
+
+# enable GDB stub
+#QEMU_OPT += -s
+
+# prevent Qemu from using KVM
+QEMU_OPT += -no-kvm
+
+# use time-tested graphics backend
+QEMU_OPT += -display sdl
+
+# use machine model that supports nested virtualization
+QEMU_OPT(nova) += -cpu core2duo
+
+# add kernel-specific Qemu arguments
+QEMU_OPT += $(QEMU_OPT(${KERNEL})}
+
diff --git a/tool/builddir/etc/build.conf.optional b/tool/builddir/build.conf/repos
similarity index 66%
rename from tool/builddir/etc/build.conf.optional
rename to tool/builddir/build.conf/repos
index 0d2c55174..10c9ed41f 100644
--- a/tool/builddir/etc/build.conf.optional
+++ b/tool/builddir/build.conf/repos
@@ -1,4 +1,22 @@
 
+##
+## Kernel-specific repository
+##
+
+ifdef KERNEL
+REPOSITORIES += $(GENODE_DIR)/repos/base-$(KERNEL)
+endif
+
+
+##
+## Repositories needed for the default demo scenario
+##
+
+REPOSITORIES += $(GENODE_DIR)/repos/base
+REPOSITORIES += $(GENODE_DIR)/repos/os
+REPOSITORIES += $(GENODE_DIR)/repos/demo
+
+
 ##
 ## Optional repositories
 ##
@@ -36,9 +54,11 @@
 #REPOSITORIES += $(GENODE_DIR)/repos/gems
 
 #
-# Genode world repository
+# Collection of community-maintained components
 #
-# Collection of community-maintained components available at
-# https://github.com/genodelabs/genode-world.git
+# Please follow the instructions provided at:
+#
+#   https://github.com/genodelabs/genode-world
 #
 #REPOSITORIES += $(GENODE_DIR)/repos/world
+
diff --git a/tool/builddir/etc/build.conf.drivers_x86 b/tool/builddir/build.conf/repos_x86
similarity index 100%
rename from tool/builddir/etc/build.conf.drivers_x86
rename to tool/builddir/build.conf/repos_x86
index 16e4c0490..027c92cf8 100644
--- a/tool/builddir/etc/build.conf.drivers_x86
+++ b/tool/builddir/build.conf/repos_x86
@@ -1,4 +1,3 @@
-
 #
 # Drivers ported from the OpenBSD
 #
@@ -8,3 +7,4 @@
 # Drivers ported from iPXE
 #
 #REPOSITORIES += $(GENODE_DIR)/repos/dde_ipxe
+
diff --git a/tool/builddir/build.conf/run b/tool/builddir/build.conf/run
new file mode 100644
index 000000000..0b49e7324
--- /dev/null
+++ b/tool/builddir/build.conf/run
@@ -0,0 +1,5 @@
+
+##
+## Run-tool configuration
+##
+
diff --git a/tool/builddir/build.conf/run_boot_dir b/tool/builddir/build.conf/run_boot_dir
new file mode 100644
index 000000000..41964376f
--- /dev/null
+++ b/tool/builddir/build.conf/run_boot_dir
@@ -0,0 +1,4 @@
+ifdef KERNEL
+RUN_OPT += ${KERNEL_RUN_OPT(${KERNEL})} --include boot_dir/$(KERNEL)
+endif
+
diff --git a/tool/builddir/build.conf/run_kernel_fiasco b/tool/builddir/build.conf/run_kernel_fiasco
new file mode 100644
index 000000000..2c90892cb
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_fiasco
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= fiasco
+
diff --git a/tool/builddir/build.conf/run_kernel_foc b/tool/builddir/build.conf/run_kernel_foc
new file mode 100644
index 000000000..8fb8e38b7
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_foc
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= foc
+
diff --git a/tool/builddir/build.conf/run_kernel_hw b/tool/builddir/build.conf/run_kernel_hw
new file mode 100644
index 000000000..3c0c84a75
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_hw
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= hw
+
diff --git a/tool/builddir/build.conf/run_kernel_hw_foc b/tool/builddir/build.conf/run_kernel_hw_foc
new file mode 100644
index 000000000..5b0d5b474
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_hw_foc
@@ -0,0 +1,3 @@
+# kernel to use (hw or foc)
+KERNEL ?= hw
+
diff --git a/tool/builddir/etc/build.conf.linux_arm b/tool/builddir/build.conf/run_kernel_linux
similarity index 75%
rename from tool/builddir/etc/build.conf.linux_arm
rename to tool/builddir/build.conf/run_kernel_linux
index 31f20c5d0..e9e5bd52c 100644
--- a/tool/builddir/etc/build.conf.linux_arm
+++ b/tool/builddir/build.conf/run_kernel_linux
@@ -1,4 +1,6 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-linux
+# kernel to use
+KERNEL ?= linux
+
 
 ##
 ## Kernel-specific run tool configuration
@@ -6,3 +8,4 @@ REPOSITORIES  = $(GENODE_DIR)/repos/base-linux
 
 RUN_OPT = --include boot_dir/linux \
           --include power_on/linux --include log/linux
+
diff --git a/tool/builddir/build.conf/run_kernel_nova b/tool/builddir/build.conf/run_kernel_nova
new file mode 100644
index 000000000..a6f19dda8
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_nova
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= nova
+
diff --git a/tool/builddir/build.conf/run_kernel_okl4 b/tool/builddir/build.conf/run_kernel_okl4
new file mode 100644
index 000000000..d4e3bd71a
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_okl4
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= okl4
+
diff --git a/tool/builddir/build.conf/run_kernel_pistachio b/tool/builddir/build.conf/run_kernel_pistachio
new file mode 100644
index 000000000..0cfdb95bc
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_pistachio
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= pistachio
+
diff --git a/tool/builddir/build.conf/run_kernel_sel4 b/tool/builddir/build.conf/run_kernel_sel4
new file mode 100644
index 000000000..cd5b6cb5a
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_sel4
@@ -0,0 +1,3 @@
+# kernel to use
+KERNEL ?= sel4
+
diff --git a/tool/builddir/build.conf/run_kernel_x86_32 b/tool/builddir/build.conf/run_kernel_x86_32
new file mode 100644
index 000000000..59d9c117d
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_x86_32
@@ -0,0 +1,3 @@
+# kernel to use (nova, linux, sel4, foc, okl4, fiasco, or pistachio)
+#KERNEL ?= nova
+
diff --git a/tool/builddir/build.conf/run_kernel_x86_64 b/tool/builddir/build.conf/run_kernel_x86_64
new file mode 100644
index 000000000..d95dac441
--- /dev/null
+++ b/tool/builddir/build.conf/run_kernel_x86_64
@@ -0,0 +1,3 @@
+# kernel to use (nova, hw, linux, or foc)
+#KERNEL ?= nova
+
diff --git a/tool/builddir/build.conf/run_opt_arm_hw_foc b/tool/builddir/build.conf/run_opt_arm_hw_foc
new file mode 100644
index 000000000..b3e7f55b7
--- /dev/null
+++ b/tool/builddir/build.conf/run_opt_arm_hw_foc
@@ -0,0 +1,4 @@
+# local varible for run-tool arguments that depend on the used kernel
+KERNEL_RUN_OPT(hw)  := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(foc) := $(QEMU_RUN_OPT)
+
diff --git a/tool/builddir/build.conf/run_opt_hw b/tool/builddir/build.conf/run_opt_hw
new file mode 100644
index 000000000..3a20d1580
--- /dev/null
+++ b/tool/builddir/build.conf/run_opt_hw
@@ -0,0 +1,3 @@
+# local varible for run-tool arguments that depend on the used kernel
+KERNEL_RUN_OPT(hw) := $(QEMU_RUN_OPT)
+
diff --git a/tool/builddir/etc/build.conf.hw_x86_64_muen b/tool/builddir/build.conf/run_opt_muen
similarity index 89%
rename from tool/builddir/etc/build.conf.hw_x86_64_muen
rename to tool/builddir/build.conf/run_opt_muen
index 6b690bd36..cd73a4879 100644
--- a/tool/builddir/etc/build.conf.hw_x86_64_muen
+++ b/tool/builddir/build.conf/run_opt_muen
@@ -1,4 +1,3 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
 
 ##
 ## Kernel-specific run tool configuration
@@ -11,6 +10,7 @@ RUN_OPT = --include boot_dir/hw --include image/muen
 #
 # The specified file must be relative to the Muen policy directory or an
 # absolute path.
+#
 RUN_OPT += --image-muen-hardware platform/lenovo-t430s.xml
 
 #
@@ -28,13 +28,15 @@ RUN_OPT += --image-muen-spark-path /opt/spark
 #
 # The specified file must be relative to the Muen policy directory or an
 # absolute path.
+#
 RUN_OPT += --image-muen-system xml/genode-base_hw.xml
 
 #
 # Muen system components
 #
 # Available components are located in the Muen project directory 'components/'.
-RUN_OPT += --image-muen-components 'libdebuglog libmutime dbgserver sm tau0 time'
+#
+RUN_OPT += --image-muen-components 'dbgserver sm tau0 time'
 
 #
 # External Muen build
@@ -42,4 +44,6 @@ RUN_OPT += --image-muen-components 'libdebuglog libmutime dbgserver sm tau0 time
 # Specifies if the Muen kernel should be built automatically.
 # If the Muen system is built and integrated externally, i.e. outside
 # of the Genode build system, set this parameter to 1.
+#
 RUN_OPT += --image-muen-external-build 0
+
diff --git a/tool/builddir/build.conf/run_opt_spike b/tool/builddir/build.conf/run_opt_spike
new file mode 100644
index 000000000..6f73bf281
--- /dev/null
+++ b/tool/builddir/build.conf/run_opt_spike
@@ -0,0 +1,7 @@
+
+##
+## Run tool configuration
+##
+
+RUN_OPT = --include power_on/spike --include log/spike
+
diff --git a/tool/builddir/build.conf/run_opt_x86_32 b/tool/builddir/build.conf/run_opt_x86_32
new file mode 100644
index 000000000..b5a335919
--- /dev/null
+++ b/tool/builddir/build.conf/run_opt_x86_32
@@ -0,0 +1,9 @@
+# local varible for run-tool arguments that depend on the used kernel
+KERNEL_RUN_OPT(nova)      := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(sel4)      := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(foc)       := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(okl4)      := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(fiasco)    := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(pistachio) := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(linux)     := --include power_on/linux --include log/linux
+
diff --git a/tool/builddir/build.conf/run_opt_x86_64 b/tool/builddir/build.conf/run_opt_x86_64
new file mode 100644
index 000000000..e442a1db8
--- /dev/null
+++ b/tool/builddir/build.conf/run_opt_x86_64
@@ -0,0 +1,6 @@
+# local varible for run-tool arguments that depend on the used kernel
+KERNEL_RUN_OPT(nova)  := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(hw)    := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(foc)   := $(QEMU_RUN_OPT)
+KERNEL_RUN_OPT(linux) := --include power_on/linux --include log/linux
+
diff --git a/tool/builddir/build.conf/run_qemu b/tool/builddir/build.conf/run_qemu
new file mode 100644
index 000000000..0289dd9ff
--- /dev/null
+++ b/tool/builddir/build.conf/run_qemu
@@ -0,0 +1,3 @@
+# local variable for run-tool arguments used for running scenarios in Qemu
+QEMU_RUN_OPT := --include power_on/qemu  --include log/qemu
+
diff --git a/tool/builddir/build.conf/run_qemu_iso b/tool/builddir/build.conf/run_qemu_iso
new file mode 100644
index 000000000..8a83db7bf
--- /dev/null
+++ b/tool/builddir/build.conf/run_qemu_iso
@@ -0,0 +1,3 @@
+# local variable for run-tool arguments used for running scenarios in Qemu
+QEMU_RUN_OPT := --include power_on/qemu  --include log/qemu --include image/iso
+
diff --git a/tool/builddir/etc/build.conf.drivers_arm b/tool/builddir/etc/build.conf.drivers_arm
deleted file mode 100644
index 8b1378917..000000000
--- a/tool/builddir/etc/build.conf.drivers_arm
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/tool/builddir/etc/build.conf.fiasco_x86 b/tool/builddir/etc/build.conf.fiasco_x86
deleted file mode 100644
index 867afd040..000000000
--- a/tool/builddir/etc/build.conf.fiasco_x86
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-fiasco
-
-##
-## Kernel-specific run tool configuration
-##
-RUN_OPT = --include boot_dir/fiasco \
-          --include power_on/qemu --include log/qemu --include image/iso
diff --git a/tool/builddir/etc/build.conf.generic b/tool/builddir/etc/build.conf.generic
deleted file mode 100644
index cf9b838a7..000000000
--- a/tool/builddir/etc/build.conf.generic
+++ /dev/null
@@ -1,8 +0,0 @@
-
-##
-## Repositories needed for the default demo scenario
-##
-
-REPOSITORIES += $(GENODE_DIR)/repos/base
-REPOSITORIES += $(GENODE_DIR)/repos/os
-REPOSITORIES += $(GENODE_DIR)/repos/demo
diff --git a/tool/builddir/etc/build.conf.hw_arndale b/tool/builddir/etc/build.conf.hw_arndale
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_arndale
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_imx53_qsb b/tool/builddir/etc/build.conf.hw_imx53_qsb
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_imx53_qsb
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_imx53_qsb_tz b/tool/builddir/etc/build.conf.hw_imx53_qsb_tz
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_imx53_qsb_tz
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_odroid_xu b/tool/builddir/etc/build.conf.hw_odroid_xu
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_odroid_xu
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_panda b/tool/builddir/etc/build.conf.hw_panda
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_panda
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_pbxa9 b/tool/builddir/etc/build.conf.hw_pbxa9
deleted file mode 100644
index 3931f27d7..000000000
--- a/tool/builddir/etc/build.conf.hw_pbxa9
+++ /dev/null
@@ -1,8 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw \
-          --include power_on/qemu --include log/qemu
diff --git a/tool/builddir/etc/build.conf.hw_riscv b/tool/builddir/etc/build.conf.hw_riscv
deleted file mode 100644
index 16061703b..000000000
--- a/tool/builddir/etc/build.conf.hw_riscv
+++ /dev/null
@@ -1,9 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw \
-          --include power_on/spike --include log/spike
-
diff --git a/tool/builddir/etc/build.conf.hw_rpi b/tool/builddir/etc/build.conf.hw_rpi
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_rpi
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_usb_armory b/tool/builddir/etc/build.conf.hw_usb_armory
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_usb_armory
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_wand_quad b/tool/builddir/etc/build.conf.hw_wand_quad
deleted file mode 100644
index 38fdf9d89..000000000
--- a/tool/builddir/etc/build.conf.hw_wand_quad
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
diff --git a/tool/builddir/etc/build.conf.hw_x86_64 b/tool/builddir/etc/build.conf.hw_x86_64
deleted file mode 100644
index 54a3c309b..000000000
--- a/tool/builddir/etc/build.conf.hw_x86_64
+++ /dev/null
@@ -1,9 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw \
-          --include power_on/qemu --include log/qemu --include image/iso
-
diff --git a/tool/builddir/etc/build.conf.hw_zynq b/tool/builddir/etc/build.conf.hw_zynq
deleted file mode 100644
index ed5c31cf1..000000000
--- a/tool/builddir/etc/build.conf.hw_zynq
+++ /dev/null
@@ -1,13 +0,0 @@
-REPOSITORIES += $(GENODE_DIR)/repos/base-hw
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/hw
-
-## Set RUN_OPT to exectute this on Qemu
-RUN_OPT += --include power_on/qemu --include log/qemu
-
-## Set RUN_OPT to execute this on actual hardware.
-#RUN_OPT += --include image/uboot
diff --git a/tool/builddir/etc/build.conf.linux_x86 b/tool/builddir/etc/build.conf.linux_x86
deleted file mode 100644
index 31f20c5d0..000000000
--- a/tool/builddir/etc/build.conf.linux_x86
+++ /dev/null
@@ -1,8 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-linux
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/linux \
-          --include power_on/linux --include log/linux
diff --git a/tool/builddir/etc/build.conf.nova_x86_32 b/tool/builddir/etc/build.conf.nova_x86_32
deleted file mode 100644
index b66c30c94..000000000
--- a/tool/builddir/etc/build.conf.nova_x86_32
+++ /dev/null
@@ -1,13 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-nova
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/nova \
-          --include power_on/qemu --include log/qemu --include image/iso
-
-#
-# The current NOVA kernel build is optimized for Intel Core2 Duo.
-#
-QEMU_OPT     += -cpu core2duo
diff --git a/tool/builddir/etc/build.conf.nova_x86_64 b/tool/builddir/etc/build.conf.nova_x86_64
deleted file mode 100644
index b66c30c94..000000000
--- a/tool/builddir/etc/build.conf.nova_x86_64
+++ /dev/null
@@ -1,13 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-nova
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/nova \
-          --include power_on/qemu --include log/qemu --include image/iso
-
-#
-# The current NOVA kernel build is optimized for Intel Core2 Duo.
-#
-QEMU_OPT     += -cpu core2duo
diff --git a/tool/builddir/etc/build.conf.okl4_x86 b/tool/builddir/etc/build.conf.okl4_x86
deleted file mode 100644
index ace567cea..000000000
--- a/tool/builddir/etc/build.conf.okl4_x86
+++ /dev/null
@@ -1,8 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-okl4
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/okl4 \
-          --include power_on/qemu --include log/qemu --include image/iso
diff --git a/tool/builddir/etc/build.conf.pistachio_x86 b/tool/builddir/etc/build.conf.pistachio_x86
deleted file mode 100644
index 0928125d2..000000000
--- a/tool/builddir/etc/build.conf.pistachio_x86
+++ /dev/null
@@ -1,8 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-pistachio
-
-##
-## Kernel-specific run tool configuration
-##
-
-RUN_OPT = --include boot_dir/pistachio \
-          --include power_on/qemu --include log/qemu --include image/iso
diff --git a/tool/builddir/etc/build.conf.ports-foc b/tool/builddir/etc/build.conf.ports-foc
deleted file mode 100644
index 38880fe23..000000000
--- a/tool/builddir/etc/build.conf.ports-foc
+++ /dev/null
@@ -1,5 +0,0 @@
-
-#
-# Software ported specifically for Fiasco.OC, i.e., L4Linux
-#
-#REPOSITORIES += $(GENODE_DIR)/repos/ports-foc
diff --git a/tool/builddir/etc/build.conf.qemu_no_kvm b/tool/builddir/etc/build.conf.qemu_no_kvm
deleted file mode 100644
index 1d5eee058..000000000
--- a/tool/builddir/etc/build.conf.qemu_no_kvm
+++ /dev/null
@@ -1,10 +0,0 @@
-
-#
-# Prevent Qemu from using KVM
-#
-# Qemu version that come with major Linux distributions (i.e., Ubuntu) enable
-# KVM by default. To use Qemu without KVM, Qemu must be started with the
-# '-no-kvm' argument. However, if your Qemu version does not support this
-# argument, comment-out this line.
-#
-QEMU_OPT     += -no-kvm
diff --git a/tool/builddir/etc/build.conf.sel4_x86_32 b/tool/builddir/etc/build.conf.sel4_x86_32
deleted file mode 100644
index 6b0a50512..000000000
--- a/tool/builddir/etc/build.conf.sel4_x86_32
+++ /dev/null
@@ -1,7 +0,0 @@
-REPOSITORIES  = $(GENODE_DIR)/repos/base-sel4
-
-##
-## Kernel-specific run tool configuration
-##
-RUN_OPT = --include boot_dir/sel4 \
-          --include power_on/qemu --include log/qemu --include image/iso
diff --git a/tool/create_builddir b/tool/create_builddir
index b8cb23c8e..429924502 100755
--- a/tool/create_builddir
+++ b/tool/create_builddir
@@ -19,35 +19,53 @@ usage:
 	@echo "  create_builddir <platform> [BUILD_DIR=<build-dir>]"
 	@echo
 	@echo "  <platform>   can be:"
-	@echo "                  'linux_x86'"
-	@echo "                  'linux_arm'"
-	@echo "                  'fiasco_x86'"
-	@echo "                  'pistachio_x86'"
-	@echo "                  'okl4_x86'"
-	@echo "                  'nova_x86_32'"
-	@echo "                  'nova_x86_64'"
-	@echo "                  'hw_panda'"
-	@echo "                  'hw_pbxa9'"
-	@echo "                  'hw_imx53_qsb'"
-	@echo "                  'hw_imx53_qsb_tz'"
-	@echo "                  'hw_usb_armory'"
-	@echo "                  'hw_wand_quad'"
-	@echo "                  'hw_arndale'"
-	@echo "                  'hw_odroid_xu'"
-	@echo "                  'hw_rpi'"
-	@echo "                  'hw_zynq'"
-	@echo "                  'hw_x86_64'"
-	@echo "                  'hw_x86_64_muen'"
-	@echo "                  'hw_riscv'"
-	@echo "                  'foc_x86_32'"
-	@echo "                  'foc_x86_64'"
-	@echo "                  'foc_pbxa9'"
-	@echo "                  'foc_imx53'"
-	@echo "                  'foc_panda'"
-	@echo "                  'foc_arndale'"
-	@echo "                  'foc_rpi'"
-	@echo "                  'foc_odroid_x2'"
-	@echo "                  'sel4_x86_32'"
+	@echo "                  'x86_32'"
+	@echo "                  'x86_64'"
+	@echo "                  'panda'"
+	@echo "                  'pbxa9'"
+	@echo "                  'rpi'"
+	@echo "                  'arndale'"
+	@echo "                  'imx53_qsb'"
+	@echo "                  'imx53_qsb_tz'"
+	@echo "                  'usb_armory'"
+	@echo "                  'wand_quad'"
+	@echo "                  'odroid_xu'"
+	@echo "                  'odroid_x2'"
+	@echo "                  'zynq'"
+	@echo "                  'muen'"
+	@echo "                  'riscv_spike'"
+	@echo "                  'linux'"
+	@echo
+	@echo "  the following <platform> arguments are deprecated:"
+	@echo "                  'linux_x86'       (use 'linux')"
+	@echo "                  'linux_arm'       (use 'linux')"
+	@echo "                  'fiasco_x86'      (use 'x86_32')"
+	@echo "                  'okl4_x86'        (use 'x86_32')"
+	@echo "                  'pistachio_x86'   (use 'x86_32')"
+	@echo "                  'nova_x86_32'     (use 'x86_32')"
+	@echo "                  'nova_x86_64'     (use 'x86_64')"
+	@echo "                  'hw_x86_64'       (use 'x86_64')"
+	@echo "                  'foc_x86_32'      (use 'x86_32')"
+	@echo "                  'foc_x86_64'      (use 'x86_64')"
+	@echo "                  'sel4_x86_32'     (use 'x86_32')"
+	@echo "                  'hw_panda'        (use 'panda')"
+	@echo "                  'foc_panda'       (use 'panda')"
+	@echo "                  'hw_pbxa9'        (use 'pbxa9')"
+	@echo "                  'foc_pbxa9'       (use 'pbxa9')"
+	@echo "                  'hw_rpi'          (use 'rpi')"
+	@echo "                  'foc_rpi'         (use 'rpi')"
+	@echo "                  'hw_arndale'      (use 'arndale')"
+	@echo "                  'foc_arndale'     (use 'arndale')"
+	@echo "                  'hw_imx53_qsb'    (use 'imx53_qsb')"
+	@echo "                  'foc_imx53'       (use 'imx53_qsb')"
+	@echo "                  'hw_imx53_qsb_tz' (use 'imx53_qsb_tz')"
+	@echo "                  'hw_usb_armory'   (use 'usb_armory')"
+	@echo "                  'hw_wand_quad'    (use 'wand_quad')"
+	@echo "                  'hw_odroid_xu'    (use 'odroid_xu')"
+	@echo "                  'hw_zynq'         (use 'zynq')"
+	@echo "                  'hw_x86_64_muen'  (use 'muen')"
+	@echo "                  'hw_riscv'        (use 'riscv_spike')"
+	@echo "                  'foc_odroid_x2'   (use 'odroid_x2')"
 	@echo
 	@echo "  The definition of BUILD_DIR is optional. If specified,"
 	@echo "  <build-dir> is the location of the build directory to create."
@@ -94,183 +112,152 @@ else
 CONTRIB_ABS_DIR := $(abspath $(shell echo $(CONTRIB_DIR)))
 endif
 
-#
-# Generic build-directory preparation rules
-#
-BUILD_CONF          = $(GENODE_ABS_DIR)/tool/builddir/etc/build.conf
-BUILD_CONF_PLATFORM = $(BUILD_CONF).$(PLATFORM)
-
 $(BUILD_DIR)/etc:
 	@mkdir -p $@
 
-$(BUILD_DIR)/etc/build.conf:: $(BUILD_CONF_PLATFORM)
-	@echo "GENODE_DIR    = $(GENODE_ABS_DIR)" > $@
-	@echo 'BASE_DIR      = $$(GENODE_DIR)/repos/base' >> $@
-	@echo 'CONTRIB_DIR   = $(CONTRIB_ABS_DIR)' >> $@
+BUILD_CONF_X86_32 := run_qemu_iso run_opt_x86_32 run_boot_dir qemu_opt_x86 repos repos_x86
+BUILD_CONF_X86_64 := run_qemu_iso run_opt_x86_64 run_boot_dir qemu_opt_x86 repos repos_x86
+BUILD_CONF_PBXA9  := run_qemu run_opt_arm_hw_foc run_boot_dir qemu_opt_arm repos
 
-#
-# Supply -no-kvm argument to Qemu for kernels that are incompatible with KVM
-#
-ifeq ($(filter-out foc_x86_32 foc_x86_64 okl4_x86 nova_x86_32 nova_x86_64 pistachio_x86,$(PLATFORM)),)
-$(BUILD_DIR)/etc/build.conf::
-	@cat $(BUILD_CONF).qemu_no_kvm >> $@
-endif
+BUILD_CONF(x86_32) := run_kernel_x86_32 $(BUILD_CONF_X86_32)
+BUILD_CONF(x86_64) := run_kernel_x86_64 $(BUILD_CONF_X86_64)
+BUILD_CONF(pbxa9)  := run_kernel_hw_foc $(BUILD_CONF_PBXA9)
+BUILD_CONF(panda)        := run_kernel_hw_foc run_boot_dir repos
+BUILD_CONF(rpi)          := run_kernel_hw_foc run_boot_dir repos
+BUILD_CONF(arndale)      := run_kernel_hw_foc run_boot_dir repos
+BUILD_CONF(imx53_qsb)    := run_kernel_hw_foc run_boot_dir repos
+BUILD_CONF(imx53_qsb_tz) := run_kernel_hw     run_boot_dir repos
+BUILD_CONF(usb_armory)   := run_kernel_hw     run_boot_dir repos
+BUILD_CONF(wand_quad)    := run_kernel_hw     run_boot_dir repos
+BUILD_CONF(odroid_xu)    := run_kernel_hw     run_boot_dir repos
+BUILD_CONF(odroid_x2)    := run_kernel_foc    run_boot_dir repos
+BUILD_CONF(zynq)         := run_kernel_hw run_qemu run_opt_hw run_boot_dir qemu_opt_arm repos
+BUILD_CONF(muen)         := run_kernel_hw run_opt_muen        run_boot_dir repos
+BUILD_CONF(riscv_spike)  := run_kernel_hw run_opt_spike       run_boot_dir repos
+BUILD_CONF(linux)        := run_kernel_linux repos
 
-#
-# Add 'base-<platform>' and generic repositories
-#
-$(BUILD_DIR)/etc/build.conf:: $(BUILD_CONF_PLATFORM)
+# deprecated platforms, to be removed
+BUILD_CONF(linux_x86)       := run_kernel_linux repos
+BUILD_CONF(linux_arm)       := run_kernel_linux repos
+BUILD_CONF(fiasco_x86)      := run_kernel_fiasco    $(BUILD_CONF_X86_32)
+BUILD_CONF(okl4_x86)        := run_kernel_okl4      $(BUILD_CONF_X86_32)
+BUILD_CONF(pistachio_x86)   := run_kernel_pistachio $(BUILD_CONF_X86_32)
+BUILD_CONF(nova_x86_32)     := run_kernel_nova      $(BUILD_CONF_X86_32)
+BUILD_CONF(nova_x86_64)     := run_kernel_nova      $(BUILD_CONF_X86_64)
+BUILD_CONF(hw_x86_64)       := run_kernel_hw        $(BUILD_CONF_X86_64)
+BUILD_CONF(foc_x86_32)      := run_kernel_foc       $(BUILD_CONF_X86_32)
+BUILD_CONF(foc_x86_64)      := run_kernel_foc       $(BUILD_CONF_X86_64)
+BUILD_CONF(sel4_x86_32)     := run_kernel_sel4      $(BUILD_CONF_X86_32)
+BUILD_CONF(hw_panda)        := ${BUILD_CONF(panda)}
+BUILD_CONF(foc_panda)       := run_kernel_foc run_boot_dir repos
+BUILD_CONF(hw_pbxa9)        := ${BUILD_CONF(pbxa9)}
+BUILD_CONF(foc_pbxa9)       := run_kernel_foc $(BUILD_CONF_PBXA9)
+BUILD_CONF(hw_rpi)          := ${BUILD_CONF(rpi)}
+BUILD_CONF(foc_rpi)         := run_kernel_foc run_boot_dir repos
+BUILD_CONF(hw_arndale)      := ${BUILD_CONF(arndale)}
+BUILD_CONF(foc_arndale)     := run_kernel_foc run_boot_dir repos
+BUILD_CONF(hw_imx53_qsb)    := ${BUILD_CONF(imx53_qsb)}
+BUILD_CONF(foc_imx53)       := run_kernel_foc run_boot_dir repos
+BUILD_CONF(hw_imx53_qsb_tz) := ${BUILD_CONF(imx53_qsb_tz)}
+BUILD_CONF(hw_usb_armory)   := ${BUILD_CONF(usb_armory)}
+BUILD_CONF(hw_wand_quad)    := ${BUILD_CONF(wand_quad)}
+BUILD_CONF(hw_odroid_xu)    := ${BUILD_CONF(odroid_xu)}
+BUILD_CONF(hw_zynq)         := ${BUILD_CONF(zynq)}
+BUILD_CONF(hw_x86_64_muen)  := ${BUILD_CONF(muen)}
+BUILD_CONF(hw_riscv)        := ${BUILD_CONF(riscv_spike)}
+BUILD_CONF(foc_odroid_x2)   := ${BUILD_CONF(odroid_x2)}
+
+message: $(BUILD_DIR)/etc/build.conf
+$(BUILD_DIR)/etc/build.conf:
+	@echo "GENODE_DIR  := $(GENODE_ABS_DIR)" > $@
+	@echo 'BASE_DIR    := $$(GENODE_DIR)/repos/base' >> $@
+	@echo 'CONTRIB_DIR := $(CONTRIB_ABS_DIR)' >> $@
 	@echo >> $@
-	@echo "##" >> $@
-	@echo "## Kernel-specific base repository" >> $@
-	@echo "##" >> $@
-	@echo >> $@
-	@cat $< >> $@
-	@cat $(BUILD_CONF).generic >> $@
-
-#
-# Add optional repositories for all platforms
-#
-# Those repositories rely on Genode's libc or contain device drivers.
-# Both prerequisites are not available for hybrid Linux/Genode programs.
-#
-$(BUILD_DIR)/etc/build.conf::
-	@cat $(BUILD_CONF).optional >> $@
+	@for i in make_j run; do \
+		cat $(GENODE_DIR)/tool/builddir/build.conf/$$i; done >> $@
+	@for i in ${BUILD_CONF(${PLATFORM})}; do \
+		cat $(GENODE_DIR)/tool/builddir/build.conf/$$i; done >> $@
 
+message: $(BUILD_DIR)/Makefile
 $(BUILD_DIR)/Makefile:
 	@ln -sf $(GENODE_ABS_DIR)/tool/builddir/build.mk $@
 
+$(BUILD_DIR)/etc/build.conf: $(BUILD_DIR)/etc
+$(BUILD_DIR)/etc/specs.conf: $(BUILD_DIR)/etc
+
 #
-# Add 'ports-foc' repository to Fiasco.OC build directory
+# Detect host CPU architecture (needed for creating Linux build directory that
+# matches the host system)
 #
-ifeq ($(filter-out foc_x86_32 foc_imx53 foc_pbxa9 foc_panda foc_arndale foc_rpi foc_odroid_x2,$(PLATFORM)),)
-$(BUILD_DIR)/etc/build.conf::
-	@cat $(BUILD_CONF).ports-foc >> $@
+UNAME_MACHINE := $(shell uname -m)
+
+SPEC_ARCH(i686)   := x86_32
+SPEC_ARCH(x86_64) := x86_64
+SPEC_ARCH(armv6l) := armv_v6
+SPEC_ARCH(armv7l) := armv_v7
+
+HOST_SPEC_ARCH := ${SPEC_ARCH(${UNAME_MACHINE})}
+
+#
+# SPECS definitions
+#
+
+SPECS(x86_32)       := x86_32
+SPECS(x86_64)       := x86_64
+SPECS(pbxa9)        := pbxa9
+SPECS(panda)        := panda
+SPECS(rpi)          := rpi
+SPECS(arndale)      := arndale
+SPECS(imx53_qsb)    := imx53_qsb
+SPECS(imx53_qsb_tz) := imx53_qsb_tz
+SPECS(usb_armory)   := hw_usb_armory usb_armory
+SPECS(wand_quad)    := hw_wand_quad wand_quad
+SPECS(odroid_xu)    := hw_odroid_xu odroid_xu
+SPECS(odroid_x2)    := foc_odroid_x2 odroid_x2
+SPECS(zynq_qemu)    := hw_zynq zynq_qemu
+SPECS(muen)         := hw_x86_64_muen muen x86_64
+SPECS(riscv_spike)  := hw_riscv riscv
+SPECS(linux)        := $(HOST_SPEC_ARCH)
+
+# deprecated platforms
+SPECS(linux_x86)       := $(HOST_SPEC_ARCH)
+SPECS(linux_arm)       := $(HOST_SPEC_ARCH)
+SPECS(fiasco_x86)      :=
+SPECS(okl4_x86)        :=
+SPECS(pistachio_x86)   :=
+SPECS(nova_x86_32)     := nova_x86_32 x86_32 acpi
+SPECS(nova_x86_64)     := nova_x86_64 x86_64 acpi
+SPECS(hw_x86_64)       := hw_x86_64 x86_64 acpi
+SPECS(foc_x86_32)      := foc_x86_32 x86_32 acpi
+SPECS(foc_x86_64)      := foc_x86_64 x86_64 acpi
+SPECS(sel4_x86_32)     := sel4_x86_32 x86_32 acpi
+SPECS(hw_panda)        := hw_panda panda perf_counter
+SPECS(foc_panda)       := foc_panda panda
+SPECS(hw_pbxa9)        := hw_pbxa9 pbxa9 perf_counter
+SPECS(foc_pbxa9)       := foc_pbxa9 pbxa9
+SPECS(hw_rpi)          := hw_rpi rpi perf_counter
+SPECS(foc_rpi)         := foc_rpi rpi
+SPECS(hw_arndale)      := hw_arndale arndale perf_counter
+SPECS(foc_arndale)     := foc_arndale arndale
+SPECS(hw_imx53_qsb)    := hw_imx53_qsb imx53_qsb perf_counter
+SPECS(foc_imx53)       := foc_imx53 imx53_qsb
+SPECS(hw_imx53_qsb_tz) := hw_imx53_qsb_tz imx53_qsb_tz perf_counter
+SPECS(hw_usb_armory)   := hw_usb_armory usb_armory perf_counter
+SPECS(hw_wand_quad)    := hw_wand_quad wand_quad perf_counter
+SPECS(hw_odroid_xu)    := hw_odroid_xu odroid_xu perf_counter
+SPECS(hw_zynq)         := hw_zynq zynq perf_counter zynq_qemu
+SPECS(hw_x86_64_muen)  := hw_x86_64_muen x86_64 muen
+SPECS(hw_riscv)        := hw_riscv riscv
+SPECS(foc_odroid_x2)   := foc_odroid_x2 odroid_x2
+
+ifneq (${SPECS(${PLATFORM})},)
+message: $(BUILD_DIR)/etc/specs.conf
+$(BUILD_DIR)/etc/specs.conf:
+	@echo "SPECS += ${SPECS(${PLATFORM})}" > $@
 endif
 
-#
-# Add x86 drivers repositories to x86 build directories
-#
-ifeq ($(filter-out foc_x86_32 foc_x86_64 okl4_x86 nova_x86_32 nova_x86_64 pistachio_x86 fiasco_x86 hw_x86_64 hw_x86_64_muen sel4_x86_32,$(PLATFORM)),)
-$(BUILD_DIR)/etc/build.conf::
-	@cat $(BUILD_CONF).drivers_x86 >> $@
-endif
-
-#
-# Add ARM drivers repositories to ARM build directories
-#
-ifeq ($(filter-out foc_panda foc_arndale hw_panda hw_arndale hw_odroid_xu foc_imx53 foc_rpi foc_odroid_x2,$(PLATFORM)),)
-$(BUILD_DIR)/etc/build.conf::
-	@cat $(BUILD_CONF).drivers_arm >> $@
-endif
-
-#
-# Generic platform dependencies
-#
-$(PLATFORM):: $(BUILD_DIR)/etc
-$(PLATFORM):: $(BUILD_DIR)/etc/build.conf
-$(PLATFORM):: $(BUILD_DIR)/Makefile
-
-#
-# Platform-specific dependencies
-#
-foc_x86_32::
-	@echo "SPECS  = genode foc_x86_32" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi"             >> $(BUILD_DIR)/etc/specs.conf
-
-foc_x86_64::
-	@echo "SPECS = genode foc_x86_64" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi"             >> $(BUILD_DIR)/etc/specs.conf
-
-nova_x86_32::
-	@echo "SPECS  = genode nova_x86_32" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi"              >> $(BUILD_DIR)/etc/specs.conf
-
-nova_x86_64::
-	@echo "SPECS = genode nova_x86_64" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi"             >> $(BUILD_DIR)/etc/specs.conf
-
-sel4_x86_32::
-	@echo "SPECS  = genode sel4_x86_32" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi"              >> $(BUILD_DIR)/etc/specs.conf
-
-foc_pbxa9::
-	@echo "SPECS = genode foc_pbxa9" > $(BUILD_DIR)/etc/specs.conf
-
-foc_panda::
-	@echo "SPECS = genode foc_panda" > $(BUILD_DIR)/etc/specs.conf
-
-foc_imx53::
-	@echo "SPECS = genode foc_imx53" > $(BUILD_DIR)/etc/specs.conf
-
-foc_arndale::
-	@echo "SPECS = genode foc_arndale" > $(BUILD_DIR)/etc/specs.conf
-
-foc_rpi::
-	@echo "SPECS = genode foc_rpi" > $(BUILD_DIR)/etc/specs.conf
-
-foc_odroid_x2::
-	@echo "SPECS = genode foc_odroid_x2" > $(BUILD_DIR)/etc/specs.conf
-
-#
-# On all other platforms, the performance counter is assumed to be active by
-# default. On HW, its activation is done by an optional core lib. To be
-# conform to the other platforms, opt it in by default and, e.g. for security
-# reasons, allow users to opt it out.
-#
-hw_pbxa9::
-	@echo "SPECS = genode hw_pbxa9" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_panda::
-	@echo "SPECS = genode hw_panda" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_imx53_qsb::
-	@echo "SPECS = genode hw_imx53_qsb" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_imx53_qsb_tz::
-	@echo "SPECS = genode hw_imx53_qsb_tz" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_usb_armory::
-	@echo "SPECS = genode hw_usb_armory" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_wand_quad::
-	@echo "SPECS = genode hw_wand_quad" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_arndale::
-	@echo "SPECS = genode hw_arndale" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_rpi::
-	@echo "SPECS = genode hw_rpi" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_zynq::
-	@echo "SPECS = genode hw_zynq" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-	@echo "## By default, hw_zynq is executed on Qemu" >> $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += zynq_qemu" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_odroid_xu::
-	@echo "SPECS = genode hw_odroid_xu" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += perf_counter" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_x86_64::
-	@echo "SPECS = genode hw_x86_64" > $(BUILD_DIR)/etc/specs.conf
-	@echo "SPECS += acpi" >> $(BUILD_DIR)/etc/specs.conf
-
-hw_x86_64_muen::
-	@echo "SPECS = genode hw_x86_64_muen" > $(BUILD_DIR)/etc/specs.conf
-
-hw_riscv::
-	@echo "SPECS = genode hw_riscv" > $(BUILD_DIR)/etc/specs.conf
-
-$(PLATFORM)::
+$(PLATFORM): message
+message:
 	@echo "Successfully created build directory at $(BUILD_DIR)."
 	@echo "Please adjust $(BUILD_DIR)/etc/build.conf according to your needs."