diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index a471ac72a7c..dfee322125d 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -1761,7 +1761,7 @@ The system can be re-made subsequently by just typing <code>make</code>.
     <code>CONFIG_STACK_POINTER</code>: The initial stack pointer
   </li>
   <li>
-    <code>CONFIG_PROC_STACK_SIZE</code>: The size of the initial stack
+    <code>CONFIG_IDLETHREAD_STACKSIZE</code>: The size of the initial stack
   </li>
   <li>
     <code>CONFIG_PTHREAD_STACK_MIN</code>: Minimum pthread stack size
diff --git a/arch/arm/src/common/up_assert.c b/arch/arm/src/common/up_assert.c
index ac6906c7090..294fce44c55 100644
--- a/arch/arm/src/common/up_assert.c
+++ b/arch/arm/src/common/up_assert.c
@@ -160,7 +160,7 @@ static void up_dumpstate(void)
   if (rtcb->pid == 0)
     {
       ustackbase = g_heapbase - 4;
-      ustacksize = CONFIG_PROC_STACK_SIZE;
+      ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
     {
diff --git a/arch/arm/src/common/up_head.S b/arch/arm/src/common/up_head.S
index 019872f4d7a..f2a6ca1db90 100644
--- a/arch/arm/src/common/up_head.S
+++ b/arch/arm/src/common/up_head.S
@@ -297,7 +297,7 @@ __start:
 	 * _sbss is the start of the BSS region (see ld.script)
 	 * _ebss is the end of the BSS regsion (see ld.script)
 	 * The idle task stack starts at the end of BSS and is
-	 * of size CONFIG_PROC_STACK_SIZE.  The heap continues
+	 * of size CONFIG_IDLETHREAD_STACKSIZE.  The heap continues
 	 * from there until the end of memory.  See g_heapbase
 	 * below.
 	 */
@@ -305,7 +305,7 @@ __start:
 .Linitparms:
 	.long	_sbss
 	.long	_ebss
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 	.size	.Lvstart, .-.Lvstart
 
 	/* This global variable is unsigned long g_heapbase and is
@@ -318,7 +318,7 @@ __start:
 	.globl	g_heapbase
 	.type	g_heapbase, object
 g_heapbase:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
 	.size	g_heapbase, .-g_heapbase
 	.end
 
diff --git a/arch/arm/src/common/up_nommuhead.S b/arch/arm/src/common/up_nommuhead.S
index 318afb1861e..953a8ffc222 100644
--- a/arch/arm/src/common/up_nommuhead.S
+++ b/arch/arm/src/common/up_nommuhead.S
@@ -132,14 +132,14 @@ __start:
 	 * _sbss is the start of the BSS region (see ld.script)
 	 * _ebss is the end of the BSS regsion (see ld.script)
 	 * The idle task stack starts at the end of BSS and is
-	 * of size CONFIG_PROC_STACK_SIZE.  The heap continues
+	 * of size CONFIG_IDLETHREAD_STACKSIZE.  The heap continues
 	 * from there until the end of memory.  See g_heapbase
 	 * below.
 	 */
 
 LC0:	.long	_sbss
 	.long	_ebss
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 
 #ifdef CONFIG_BOOT_FROM_FLASH
 LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
@@ -158,7 +158,7 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.globl	g_heapbase
 	.type	g_heapbase, object
 g_heapbase:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
 	.size	g_heapbase, .-g_heapbase
 
 	.end
diff --git a/arch/arm/src/lpc214x/lpc214x_head.S b/arch/arm/src/lpc214x/lpc214x_head.S
index 9f90113fc8c..140f33e74c2 100644
--- a/arch/arm/src/lpc214x/lpc214x_head.S
+++ b/arch/arm/src/lpc214x/lpc214x_head.S
@@ -592,14 +592,14 @@ __start:
 	 * _sbss is the start of the BSS region (see ld.script)
 	 * _ebss is the end of the BSS regsion (see ld.script)
 	 * The idle task stack starts at the end of BSS and is
-	 * of size CONFIG_PROC_STACK_SIZE.  The heap continues
+	 * of size CONFIG_IDLETHREAD_STACKSIZE.  The heap continues
 	 * from there until the end of memory.  See g_heapbase
 	 * below.
 	 */
 
 LC0:	.long	_sbss
 	.long	_ebss
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 
 #ifdef CONFIG_BOOT_FROM_FLASH
 LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
@@ -618,7 +618,7 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.globl	g_heapbase
 	.type	g_heapbase, object
 g_heapbase:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
 	.size	g_heapbase, .-g_heapbase
 
 	.end
diff --git a/arch/arm/src/str71x/str71x_head.S b/arch/arm/src/str71x/str71x_head.S
index 9965f8c69e4..72c08abcf08 100644
--- a/arch/arm/src/str71x/str71x_head.S
+++ b/arch/arm/src/str71x/str71x_head.S
@@ -592,14 +592,14 @@ dtor_end:
 	 * _sbss is the start of the BSS region (see ld.script)
 	 * _ebss is the end of the BSS regsion (see ld.script)
 	 * The idle task stack starts at the end of BSS and is
-	 * of size CONFIG_PROC_STACK_SIZE.  The heap continues
+	 * of size CONFIG_IDLETHREAD_STACKSIZE.  The heap continues
 	 * from there until the end of memory.  See g_heapbase
 	 * below.
 	 */
 
 LC0:	.long	_sbss
 	.long	_ebss
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 
 #ifdef CONFIG_BOOT_FROM_FLASH
 LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
@@ -618,7 +618,7 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.globl	g_heapbase
 	.type	g_heapbase, object
 g_heapbase:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
 	.size	g_heapbase, .-g_heapbase
 
 	.end
diff --git a/arch/sh/src/common/up_assert.c b/arch/sh/src/common/up_assert.c
index cef369dc709..f4a1bc080fe 100644
--- a/arch/sh/src/common/up_assert.c
+++ b/arch/sh/src/common/up_assert.c
@@ -170,7 +170,7 @@ static void up_dumpstate(void)
   if (rtcb->pid == 0)
     {
       ustackbase = g_heapbase - 4;
-      ustacksize = CONFIG_PROC_STACK_SIZE;
+      ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
     {
diff --git a/arch/sh/src/sh1/sh1_head.S b/arch/sh/src/sh1/sh1_head.S
index 155723f5463..61f14443d5a 100644
--- a/arch/sh/src/sh1/sh1_head.S
+++ b/arch/sh/src/sh1/sh1_head.S
@@ -192,9 +192,9 @@ __vector_table:
 	 */
 
 	.long	__start		/* 0-1: Power-on reset (hard, NMI high) PC & SP */
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 	.long	__start		/* 2-3: Manual reset (soft, NMI low) PC & SP */
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 
 	.rept SH1_NCMN_VECTORS-4
 	.long	_up_invalid_handler
@@ -358,7 +358,7 @@ __start:
 	
 	.align 2
 .Lstack:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE-4
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE-4
 .Lwcr1:
 	.long	0x5ffffa2
 .Lbcr:
@@ -517,7 +517,7 @@ __start0:
 	.globl	_g_heapbase
 	.type	_g_heapbase, object
 _g_heapbase:
-	.long	_ebss+CONFIG_PROC_STACK_SIZE
+	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
 	.size	_g_heapbase, .-_g_heapbase
 
 	.end
diff --git a/arch/z80/src/Makefile.sdcc b/arch/z80/src/Makefile.sdcc
index 840087e3041..cf7ae9dfe03 100644
--- a/arch/z80/src/Makefile.sdcc
+++ b/arch/z80/src/Makefile.sdcc
@@ -110,7 +110,7 @@ up_mem.h:
 	@echo "#include <nuttx/config.h>" >>up_mem.h
 	@echo "" >>up_mem.h
 	@echo "#define CONFIG_STACK_END   $(CONFIG_DRAM_SIZE)" >> up_mem.h
-	@echo "#define CONFIG_STACK_BASE  (CONFIG_STACK_END - $(CONFIG_PROC_STACK_SIZE))" >> up_mem.h
+	@echo "#define CONFIG_STACK_BASE  (CONFIG_STACK_END - $(CONFIG_IDLETHREAD_STACKSIZE))" >> up_mem.h
 	@echo "#define CONFIG_HEAP1_END   CONFIG_STACK_BASE" >> up_mem.h
 	@echo "#define CONFIG_HEAP1_BASE  $(HEAP_BASE)" >> up_mem.h
 	@echo "" >>up_mem.h
@@ -125,8 +125,8 @@ else
 	@echo "	CONFIG_COMPILER	== 0" >> asm_mem.h
 endif
 	@echo "	CONFIG_STACK_END	== ($(CONFIG_DRAM_SIZE) - 1)" >> asm_mem.h
-	@echo "	CONFIG_STACK_BASE	== (CONFIG_STACK_END - $(CONFIG_PROC_STACK_SIZE))" >> asm_mem.h
-	@echo "	CONFIG_HEAP1_END	== (CONFIG_STACK_END - $(CONFIG_PROC_STACK_SIZE) - 1)" >> asm_mem.h
+	@echo "	CONFIG_STACK_BASE	== (CONFIG_STACK_END - $(CONFIG_IDLETHREAD_STACKSIZE))" >> asm_mem.h
+	@echo "	CONFIG_HEAP1_END	== (CONFIG_STACK_END - $(CONFIG_IDLETHREAD_STACKSIZE) - 1)" >> asm_mem.h
 	@echo "	CONFIG_HEAP1_BASE	== $(HEAP_BASE)" >> asm_mem.h
 
 # Combine all objects in this directory into a library
diff --git a/arch/z80/src/ez80/up_mem.h b/arch/z80/src/ez80/up_mem.h
index 7de938ff645..6031d398561 100644
--- a/arch/z80/src/ez80/up_mem.h
+++ b/arch/z80/src/ez80/up_mem.h
@@ -62,7 +62,7 @@
 
 #ifndef CONFIG_HEAP1_END
    extern unsigned long _stack;
-#  define CONFIG_HEAP1_END (((uint24)&_stack) - CONFIG_PROC_STACK_SIZE)
+#  define CONFIG_HEAP1_END (((uint24)&_stack) - CONFIG_IDLETHREAD_STACKSIZE)
 #endif
 
 /************************************************************************************
diff --git a/arch/z80/src/z8/up_mem.h b/arch/z80/src/z8/up_mem.h
index 72362edcb65..822af3f71eb 100644
--- a/arch/z80/src/z8/up_mem.h
+++ b/arch/z80/src/z8/up_mem.h
@@ -62,7 +62,7 @@
 
 #ifndef CONFIG_HEAP1_END
    extern far unsigned long far_stacktop;
-#  define CONFIG_HEAP1_END (((uint16)&far_stacktop) - CONFIG_PROC_STACK_SIZE + 1)
+#  define CONFIG_HEAP1_END (((uint16)&far_stacktop) - CONFIG_IDLETHREAD_STACKSIZE + 1)
 #endif
 
 /************************************************************************************
diff --git a/configs/README.txt b/configs/README.txt
index 123a9017149..9f4985aa56b 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 d0a4f82f537..629f5005946 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 5b3a0e6658f..86a734a8123 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 e85364d7b5d..bc684fb6b92 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 a45f91fb7f1..9ff2dc7676a 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 4e3c7232c36..dd5a72ae001 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 227677ba0e5..cfb6220960b 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 12d3f8fc7a1..4ff5bb089e3 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 00d56de48e1..bc5a8fb3a59 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 9c31667b0e9..1aacbfb74ae 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 fbbac16558c..82a1cc5c1f0 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 3ea1441f3f8..f6f0b199b98 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 bf927317c1b..993539e5c03 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 a22aeebd6b5..c1bbf523aca 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 2d6ac291da9..ba014b65ef5 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 017c7e36682..1d651edf603 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 0d629c2e197..385468debb6 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 280f61239b2..9851067d189 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 1ebb03bfc0e..d18ef215c2b 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 df04db1edc2..2f694020817 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 6cc39f2b29d..72ee3a69b03 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 577b762a503..8f2d00bee77 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 a75275f6a53..f6e491f48cd 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 76a3fa6dd6f..5e174b50030 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 60c78c99e8c..c713a60f47c 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 6c619ed6bd3..f9167cc8125 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 3f6160bc652..cc52ee44c2d 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 803064b7a25..95d718d391a 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 8b927a451b5..f70a9ef1fa6 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 2335829533b..af5d25dae65 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 8c5621b982d..41707a6db1e 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 4b10b5f607b..432a0a6d846 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 e091eb1d583..335924315e5 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 0f255536a39..dc8c2753379 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 c55e59aab66..9ed7d973cf4 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=
diff --git a/sched/os_start.c b/sched/os_start.c
index 07705b5f42b..414cbbe05f2 100644
--- a/sched/os_start.c
+++ b/sched/os_start.c
@@ -430,7 +430,7 @@ void os_start(void)
   sdbg("Starting init thread\n");
 #ifndef CONFIG_CUSTOM_STACK
   init_taskid = task_create("init", SCHED_PRIORITY_DEFAULT,
-                            CONFIG_PROC_STACK_SIZE,
+                            CONFIG_IDLETHREAD_STACKSIZE,
                             (main_t)user_start, (const char **)NULL);
 #else
   init_taskid = task_create("init", SCHED_PRIORITY_DEFAULT,