diff --git a/configs/README.txt b/configs/README.txt
index 123a901714..9f4985aa56 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -369,7 +369,7 @@ defconfig -- This is a configuration file similar to the Linux
 		CONFIG_BOOT_FROM_FLASH - Some configurations support XIP
 		  operation from FLASH.
 		CONFIG_STACK_POINTER - The initial stack pointer
-		CONFIG_PROC_STACK_SIZE - The size of the initial stack
+		CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 		CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 		CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 		CONFIG_HEAP_BASE - The beginning of the heap
diff --git a/configs/c5471evm/defconfig b/configs/c5471evm/defconfig
index d0a4f82f53..629f500594 100644
--- a/configs/c5471evm/defconfig
+++ b/configs/c5471evm/defconfig
@@ -373,7 +373,7 @@ CONFIG_NET_C5471_BASET10=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -382,7 +382,7 @@ CONFIG_NET_C5471_BASET10=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/c5471evm/dhcpconfig b/configs/c5471evm/dhcpconfig
index 5b3a0e6658..86a734a812 100644
--- a/configs/c5471evm/dhcpconfig
+++ b/configs/c5471evm/dhcpconfig
@@ -373,7 +373,7 @@ CONFIG_NET_C5471_BASET10=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -382,7 +382,7 @@ CONFIG_NET_C5471_BASET10=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/c5471evm/netconfig b/configs/c5471evm/netconfig
index e85364d7b5..bc684fb6b9 100644
--- a/configs/c5471evm/netconfig
+++ b/configs/c5471evm/netconfig
@@ -373,7 +373,7 @@ CONFIG_NET_C5471_BASET10=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -382,7 +382,7 @@ CONFIG_NET_C5471_BASET10=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/c5471evm/nshconfig b/configs/c5471evm/nshconfig
index a45f91fb7f..9ff2dc7676 100644
--- a/configs/c5471evm/nshconfig
+++ b/configs/c5471evm/nshconfig
@@ -373,7 +373,7 @@ CONFIG_NET_C5471_BASET10=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -382,7 +382,7 @@ CONFIG_NET_C5471_BASET10=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/ez80f910200kitg/ostest/defconfig b/configs/ez80f910200kitg/ostest/defconfig
index 4e3c7232c3..dd5a72ae00 100644
--- a/configs/ez80f910200kitg/ostest/defconfig
+++ b/configs/ez80f910200kitg/ostest/defconfig
@@ -345,7 +345,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -353,7 +353,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=256
+CONFIG_IDLETHREAD_STACKSIZE=256
 CONFIG_PTHREAD_STACK_MIN=128
 CONFIG_PTHREAD_STACK_DEFAULT=256
 CONFIG_HEAP_SIZE=
diff --git a/configs/m68332evb/defconfig b/configs/m68332evb/defconfig
index 227677ba0e..cfb6220960 100644
--- a/configs/m68332evb/defconfig
+++ b/configs/m68332evb/defconfig
@@ -323,7 +323,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #   operation from FLASH.
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -331,7 +331,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/mcu123-lpc214x/nsh/defconfig b/configs/mcu123-lpc214x/nsh/defconfig
index 12d3f8fc7a..4ff5bb089e 100644
--- a/configs/mcu123-lpc214x/nsh/defconfig
+++ b/configs/mcu123-lpc214x/nsh/defconfig
@@ -554,7 +554,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -563,7 +563,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 CONFIG_BOOT_FROM_FLASH=y
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=2048
+CONFIG_IDLETHREAD_STACKSIZE=2048
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=2048
 CONFIG_HEAP_BASE=
diff --git a/configs/mcu123-lpc214x/ostest/defconfig b/configs/mcu123-lpc214x/ostest/defconfig
index 00d56de48e..bc5a8fb3a5 100644
--- a/configs/mcu123-lpc214x/ostest/defconfig
+++ b/configs/mcu123-lpc214x/ostest/defconfig
@@ -549,7 +549,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -558,7 +558,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 CONFIG_BOOT_FROM_FLASH=y
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=2048
+CONFIG_IDLETHREAD_STACKSIZE=2048
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=2048
 CONFIG_HEAP_BASE=
diff --git a/configs/mcu123-lpc214x/usbserial/defconfig b/configs/mcu123-lpc214x/usbserial/defconfig
index 9c31667b0e..1aacbfb74a 100644
--- a/configs/mcu123-lpc214x/usbserial/defconfig
+++ b/configs/mcu123-lpc214x/usbserial/defconfig
@@ -566,7 +566,7 @@ CONFIG_EXAMPLES_USBSERIAL_ONLYBIG=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -575,7 +575,7 @@ CONFIG_EXAMPLES_USBSERIAL_ONLYBIG=n
 CONFIG_BOOT_FROM_FLASH=y
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=2048
+CONFIG_IDLETHREAD_STACKSIZE=2048
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=2048
 CONFIG_HEAP_BASE=
diff --git a/configs/mcu123-lpc214x/usbstorage/defconfig b/configs/mcu123-lpc214x/usbstorage/defconfig
index fbbac16558..82a1cc5c1f 100644
--- a/configs/mcu123-lpc214x/usbstorage/defconfig
+++ b/configs/mcu123-lpc214x/usbstorage/defconfig
@@ -609,7 +609,7 @@ CONFIG_EXAMPLES_USBSTRG_TRACEINTERRUPTS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -618,7 +618,7 @@ CONFIG_EXAMPLES_USBSTRG_TRACEINTERRUPTS=n
 CONFIG_BOOT_FROM_FLASH=y
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=2048
+CONFIG_IDLETHREAD_STACKSIZE=2048
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=2048
 CONFIG_HEAP_BASE=
diff --git a/configs/ntosd-dm320/nettest/defconfig b/configs/ntosd-dm320/nettest/defconfig
index 3ea1441f3f..f6f0b199b9 100644
--- a/configs/ntosd-dm320/nettest/defconfig
+++ b/configs/ntosd-dm320/nettest/defconfig
@@ -485,7 +485,7 @@ CONFIG_DM9X_ETRANS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -494,7 +494,7 @@ CONFIG_DM9X_ETRANS=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/ntosd-dm320/nsh/defconfig b/configs/ntosd-dm320/nsh/defconfig
index bf927317c1..993539e5c0 100644
--- a/configs/ntosd-dm320/nsh/defconfig
+++ b/configs/ntosd-dm320/nsh/defconfig
@@ -547,7 +547,7 @@ CONFIG_DM9X_ETRANS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -556,7 +556,7 @@ CONFIG_DM9X_ETRANS=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/ntosd-dm320/ostest/defconfig b/configs/ntosd-dm320/ostest/defconfig
index a22aeebd6b..c1bbf523ac 100644
--- a/configs/ntosd-dm320/ostest/defconfig
+++ b/configs/ntosd-dm320/ostest/defconfig
@@ -479,7 +479,7 @@ CONFIG_DM9X_ETRANS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -488,7 +488,7 @@ CONFIG_DM9X_ETRANS=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/ntosd-dm320/udp/defconfig b/configs/ntosd-dm320/udp/defconfig
index 2d6ac291da..ba014b65ef 100644
--- a/configs/ntosd-dm320/udp/defconfig
+++ b/configs/ntosd-dm320/udp/defconfig
@@ -493,7 +493,7 @@ CONFIG_DM9X_ETRANS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -502,7 +502,7 @@ CONFIG_DM9X_ETRANS=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/ntosd-dm320/uip/defconfig b/configs/ntosd-dm320/uip/defconfig
index 017c7e3668..1d651edf60 100644
--- a/configs/ntosd-dm320/uip/defconfig
+++ b/configs/ntosd-dm320/uip/defconfig
@@ -485,7 +485,7 @@ CONFIG_DM9X_ETRANS=n
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -494,7 +494,7 @@ CONFIG_DM9X_ETRANS=n
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_BASE=
diff --git a/configs/olimex-strp711/ostest/defconfig b/configs/olimex-strp711/ostest/defconfig
index 0d629c2e19..385468debb 100644
--- a/configs/olimex-strp711/ostest/defconfig
+++ b/configs/olimex-strp711/ostest/defconfig
@@ -616,7 +616,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -625,7 +625,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 CONFIG_BOOT_FROM_FLASH=y
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=2048
+CONFIG_IDLETHREAD_STACKSIZE=2048
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=2048
 CONFIG_HEAP_BASE=
diff --git a/configs/pjrc-8051/defconfig b/configs/pjrc-8051/defconfig
index 280f61239b..9851067d18 100644
--- a/configs/pjrc-8051/defconfig
+++ b/configs/pjrc-8051/defconfig
@@ -321,7 +321,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -329,7 +329,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=y
-CONFIG_PROC_STACK_SIZE=
+CONFIG_IDLETHREAD_STACKSIZE=
 CONFIG_PTHREAD_STACK_MIN=
 CONFIG_PTHREAD_STACK_DEFAULT=
 CONFIG_HEAP_BASE=
diff --git a/configs/sim/mount/defconfig b/configs/sim/mount/defconfig
index 1ebb03bfc0..d18ef215c2 100644
--- a/configs/sim/mount/defconfig
+++ b/configs/sim/mount/defconfig
@@ -329,7 +329,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -337,7 +337,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_IDLETHREAD_STACKSIZE=0x00001000
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=8192
 CONFIG_HEAP_BASE=
diff --git a/configs/sim/nettest/defconfig b/configs/sim/nettest/defconfig
index df04db1edc..2f69402081 100644
--- a/configs/sim/nettest/defconfig
+++ b/configs/sim/nettest/defconfig
@@ -328,7 +328,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -336,7 +336,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_IDLETHREAD_STACKSIZE=0x00001000
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=8192
 CONFIG_HEAP_BASE=
diff --git a/configs/sim/nsh/defconfig b/configs/sim/nsh/defconfig
index 6cc39f2b29..72ee3a69b0 100644
--- a/configs/sim/nsh/defconfig
+++ b/configs/sim/nsh/defconfig
@@ -372,7 +372,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -380,7 +380,7 @@ CONFIG_EXAMPLES_MOUNT_DEVNAME="/dev/ram0"
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_IDLETHREAD_STACKSIZE=0x00001000
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=8192
 CONFIG_HEAP_BASE=
diff --git a/configs/sim/ostest/defconfig b/configs/sim/ostest/defconfig
index 577b762a50..8f2d00bee7 100644
--- a/configs/sim/ostest/defconfig
+++ b/configs/sim/ostest/defconfig
@@ -323,7 +323,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -331,7 +331,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_IDLETHREAD_STACKSIZE=0x00001000
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=8192
 CONFIG_HEAP_BASE=
diff --git a/configs/sim/pashello/defconfig b/configs/sim/pashello/defconfig
index a75275f6a5..f6e491f48c 100644
--- a/configs/sim/pashello/defconfig
+++ b/configs/sim/pashello/defconfig
@@ -317,7 +317,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -325,7 +325,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_IDLETHREAD_STACKSIZE=0x00001000
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=8192
 CONFIG_HEAP_BASE=
diff --git a/configs/us7032evb1/nsh/defconfig b/configs/us7032evb1/nsh/defconfig
index 76a3fa6dd6..5e174b5003 100644
--- a/configs/us7032evb1/nsh/defconfig
+++ b/configs/us7032evb1/nsh/defconfig
@@ -545,7 +545,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -554,7 +554,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_BASE=
diff --git a/configs/us7032evb1/ostest/defconfig b/configs/us7032evb1/ostest/defconfig
index 60c78c99e8..c713a60f47 100644
--- a/configs/us7032evb1/ostest/defconfig
+++ b/configs/us7032evb1/ostest/defconfig
@@ -545,7 +545,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer (arm7tdmi only)
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -554,7 +554,7 @@ CONFIG_EXAMPLES_NSH_MMCSDMINOR=0
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
 CONFIG_STACK_POINTER=
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_BASE=
diff --git a/configs/xtrs/nsh/defconfig b/configs/xtrs/nsh/defconfig
index 6c619ed6bd..f9167cc812 100644
--- a/configs/xtrs/nsh/defconfig
+++ b/configs/xtrs/nsh/defconfig
@@ -360,7 +360,7 @@ CONFIG_EXAMPLES_NSH_FATMOUNTPT=/tmp
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -368,7 +368,7 @@ CONFIG_EXAMPLES_NSH_FATMOUNTPT=/tmp
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/xtrs/ostest/defconfig b/configs/xtrs/ostest/defconfig
index 3f6160bc65..cc52ee44c2 100644
--- a/configs/xtrs/ostest/defconfig
+++ b/configs/xtrs/ostest/defconfig
@@ -317,7 +317,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -325,7 +325,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/xtrs/pashello/defconfig b/configs/xtrs/pashello/defconfig
index 803064b7a2..95d718d391 100644
--- a/configs/xtrs/pashello/defconfig
+++ b/configs/xtrs/pashello/defconfig
@@ -317,7 +317,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -325,7 +325,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/z16f2800100zcog/ostest/defconfig b/configs/z16f2800100zcog/ostest/defconfig
index 8b927a451b..f70a9ef1fa 100644
--- a/configs/z16f2800100zcog/ostest/defconfig
+++ b/configs/z16f2800100zcog/ostest/defconfig
@@ -343,7 +343,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -351,7 +351,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_SIZE=
diff --git a/configs/z16f2800100zcog/pashello/defconfig b/configs/z16f2800100zcog/pashello/defconfig
index 2335829533..af5d25dae6 100644
--- a/configs/z16f2800100zcog/pashello/defconfig
+++ b/configs/z16f2800100zcog/pashello/defconfig
@@ -343,7 +343,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -351,7 +351,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=4096
+CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=4096
 CONFIG_HEAP_SIZE=
diff --git a/configs/z80sim/nsh/defconfig b/configs/z80sim/nsh/defconfig
index 8c5621b982..41707a6db1 100644
--- a/configs/z80sim/nsh/defconfig
+++ b/configs/z80sim/nsh/defconfig
@@ -350,7 +350,7 @@ CONFIG_EXAMPLES_NSH_FATMOUNTPT=/tmp
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -358,7 +358,7 @@ CONFIG_EXAMPLES_NSH_FATMOUNTPT=/tmp
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/z80sim/ostest/defconfig b/configs/z80sim/ostest/defconfig
index 4b10b5f607..432a0a6d84 100644
--- a/configs/z80sim/ostest/defconfig
+++ b/configs/z80sim/ostest/defconfig
@@ -307,7 +307,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -315,7 +315,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/z80sim/pashello/defconfig b/configs/z80sim/pashello/defconfig
index e091eb1d58..335924315e 100644
--- a/configs/z80sim/pashello/defconfig
+++ b/configs/z80sim/pashello/defconfig
@@ -307,7 +307,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -315,7 +315,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=1024
+CONFIG_IDLETHREAD_STACKSIZE=1024
 CONFIG_PTHREAD_STACK_MIN=256
 CONFIG_PTHREAD_STACK_DEFAULT=1024
 CONFIG_HEAP_SIZE=
diff --git a/configs/z8encore000zco/ostest/defconfig b/configs/z8encore000zco/ostest/defconfig
index 0f255536a3..dc8c275337 100644
--- a/configs/z8encore000zco/ostest/defconfig
+++ b/configs/z8encore000zco/ostest/defconfig
@@ -346,7 +346,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -354,7 +354,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=256
+CONFIG_IDLETHREAD_STACKSIZE=256
 CONFIG_PTHREAD_STACK_MIN=128
 CONFIG_PTHREAD_STACK_DEFAULT=256
 CONFIG_HEAP_SIZE=
diff --git a/configs/z8f64200100kit/ostest/defconfig b/configs/z8f64200100kit/ostest/defconfig
index c55e59aab6..9ed7d973cf 100644
--- a/configs/z8f64200100kit/ostest/defconfig
+++ b/configs/z8f64200100kit/ostest/defconfig
@@ -346,7 +346,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 # CONFIG_CUSTOM_STACK - The up_ implementation will handle
 #   all stack operations outside of the nuttx model.
 # CONFIG_STACK_POINTER - The initial stack pointer
-# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_IDLETHREAD_STACKSIZE - The size of the initial stack
 # CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
 # CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
 # CONFIG_HEAP_BASE - The beginning of the heap
@@ -354,7 +354,7 @@ CONFIG_EXAMPLES_NSH_NETMASK=(255<<24|255<<16|255<<8|0)
 #
 CONFIG_BOOT_FROM_FLASH=n
 CONFIG_CUSTOM_STACK=n
-CONFIG_PROC_STACK_SIZE=256
+CONFIG_IDLETHREAD_STACKSIZE=256
 CONFIG_PTHREAD_STACK_MIN=128
 CONFIG_PTHREAD_STACK_DEFAULT=256
 CONFIG_HEAP_SIZE=