diff --git a/arch/arm/src/arm/up_assert.c b/arch/arm/src/arm/up_assert.c
index d97aba5ea3..e5bf00d6ee 100644
--- a/arch/arm/src/arm/up_assert.c
+++ b/arch/arm/src/arm/up_assert.c
@@ -174,7 +174,7 @@ static void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/arm/src/arm/up_head.S b/arch/arm/src/arm/up_head.S
index 46efd87725..ef911d0b66 100644
--- a/arch/arm/src/arm/up_head.S
+++ b/arch/arm/src/arm/up_head.S
@@ -610,7 +610,7 @@ __start:
 	 *
 	 * The idle task stack starts at the end of BSS and is of size
 	 * CONFIG_IDLETHREAD_STACKSIZE.  The heap continues from there until the
-	 * end of memory.  See g_heapbase below.
+	 * end of memory.  See g_idle_topstack below.
 	 */
 
 .Linitparms:
@@ -645,17 +645,17 @@ __start:
 
 	 /* Data section variables */
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to .Linitparms
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	.end
 
diff --git a/arch/arm/src/arm/up_nommuhead.S b/arch/arm/src/arm/up_nommuhead.S
index aac95b73a4..e3f5a94e68 100644
--- a/arch/arm/src/arm/up_nommuhead.S
+++ b/arch/arm/src/arm/up_nommuhead.S
@@ -135,7 +135,7 @@ __start:
 	 * _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_IDLETHREAD_STACKSIZE.  The heap continues
-	 * from there until the end of memory.  See g_heapbase
+	 * from there until the end of memory.  See g_idle_topstack
 	 * below.
 	 */
 
@@ -150,18 +150,18 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 #endif
 	.size	__start, .-__start
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to LCO
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
 
diff --git a/arch/arm/src/armv6-m/up_assert.c b/arch/arm/src/armv6-m/up_assert.c
index 15ba1f53f7..de5e5f6a12 100644
--- a/arch/arm/src/armv6-m/up_assert.c
+++ b/arch/arm/src/armv6-m/up_assert.c
@@ -181,7 +181,7 @@ static void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/arm/src/armv7-m/mpu.h b/arch/arm/src/armv7-m/mpu.h
index 74bfe7a9ed..7e2e6bb77c 100644
--- a/arch/arm/src/armv7-m/mpu.h
+++ b/arch/arm/src/armv7-m/mpu.h
@@ -66,7 +66,7 @@
 /* MPU Type Register Bit Definitions */
 
 #define MPU_TYPE_SEPARATE       (1 << 0) /* Bit 0: 0:unified or 1:separate memory maps */
-#define MPU_TYPE_DREGION_SHIFT  (8)      /* Bits 8-15: Number MPU data regsion */
+#define MPU_TYPE_DREGION_SHIFT  (8)      /* Bits 8-15: Number MPU data regions */
 #define MPU_TYPE_DREGION_MASK   (0xff << MPU_TYPE_DREGION_SHIFT)
 #define MPU_TYPE_IREGION_SHIFT  (16)     /* Bits 16-23: Number MPU instruction regions */
 #define MPU_TYPE_IREGION_MASK   (0xff << MPU_TYPE_IREGION_SHIFT)
@@ -104,11 +104,11 @@
 #  define MPU_RASR_SRD_5        (0x20 << MPU_RASR_SRD_SHIFT)
 #  define MPU_RASR_SRD_6        (0x40 << MPU_RASR_SRD_SHIFT)
 #  define MPU_RASR_SRD_7        (0x80 << MPU_RASR_SRD_SHIFT)
-#define MPU_RASR_ATTR_SHIFT     (21)      /* Bits 19-21: TEX Address Permisson */
-#define MPU_RASR_ATTR__MASK     (7 << MPU_RASR_ATTR_SHIFT)
-#define MPU_RASR_S              (1 << 18) /* Bit 18: Shareable */
-#define MPU_RASR_C              (1 << 17) /* Bit 17: Cacheable */
 #define MPU_RASR_B              (1 << 16) /* Bit 16: Bufferable */
+#define MPU_RASR_C              (1 << 17) /* Bit 17: Cacheable */
+#define MPU_RASR_S              (1 << 18) /* Bit 18: Shareable */
+#define MPU_RASR_ATTR_SHIFT     (19)      /* Bits 19-21: TEX Address Permisson */
+#define MPU_RASR_ATTR_MASK      (7 << MPU_RASR_ATTR_SHIFT)
 #define MPU_RASR_AP_SHIFT       (24)      /* Bits 24-26: Access permission */
 #define MPU_RASR_AP_MASK        (7 << MPU_RASR_AP_SHIFT)
 #  define MPU_RASR_AP_NONO      (0 << MPU_RASR_AP_SHIFT) /* P:None U:None */
diff --git a/arch/arm/src/armv7-m/up_assert.c b/arch/arm/src/armv7-m/up_assert.c
index 394c6858f4..a4a58639ca 100644
--- a/arch/arm/src/armv7-m/up_assert.c
+++ b/arch/arm/src/armv7-m/up_assert.c
@@ -180,7 +180,7 @@ static void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/arm/src/common/up_allocateheap.c b/arch/arm/src/common/up_allocateheap.c
index 12cbfcfa8e..617bffd2e3 100644
--- a/arch/arm/src/common/up_allocateheap.c
+++ b/arch/arm/src/common/up_allocateheap.c
@@ -82,6 +82,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/arm/src/common/up_internal.h b/arch/arm/src/common/up_internal.h
index 6e874b2cab..1a7c1e304c 100644
--- a/arch/arm/src/common/up_internal.h
+++ b/arch/arm/src/common/up_internal.h
@@ -166,7 +166,7 @@ extern volatile uint32_t *current_regs;
  * CONFIG_DRAM_END
  */
 
-extern const uint32_t g_heapbase;
+extern const uint32_t g_idle_topstack;
 
 /* Address of the saved user stack pointer */
 
diff --git a/arch/arm/src/dm320/dm320_allocateheap.c b/arch/arm/src/dm320/dm320_allocateheap.c
index 1383b93dae..27a7e7a90d 100644
--- a/arch/arm/src/dm320/dm320_allocateheap.c
+++ b/arch/arm/src/dm320/dm320_allocateheap.c
@@ -85,6 +85,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = (DM320_SDRAM_VADDR + CONFIG_DRAM_SIZE) - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = (DM320_SDRAM_VADDR + CONFIG_DRAM_SIZE) - g_idle_topstack;
 }
diff --git a/arch/arm/src/imx/imx_allocateheap.c b/arch/arm/src/imx/imx_allocateheap.c
index 37b05eb7f5..f94a7fe444 100644
--- a/arch/arm/src/imx/imx_allocateheap.c
+++ b/arch/arm/src/imx/imx_allocateheap.c
@@ -86,8 +86,8 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = (IMX_SDRAM_VSECTION + CONFIG_DRAM_SIZE) - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = (IMX_SDRAM_VSECTION + CONFIG_DRAM_SIZE) - g_idle_topstack;
 }
 
 /****************************************************************************
diff --git a/arch/arm/src/kinetis/kinetis_vectors.S b/arch/arm/src/kinetis/kinetis_vectors.S
index 7fa223615b..11ac46221b 100644
--- a/arch/arm/src/kinetis/kinetis_vectors.S
+++ b/arch/arm/src/kinetis/kinetis_vectors.S
@@ -738,13 +738,13 @@ g_intstackbase:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.  The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.word	HEAP_BASE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
diff --git a/arch/arm/src/lm/lm_vectors.S b/arch/arm/src/lm/lm_vectors.S
index 1d3553b4e1..0f4300065c 100644
--- a/arch/arm/src/lm/lm_vectors.S
+++ b/arch/arm/src/lm/lm_vectors.S
@@ -336,13 +336,13 @@ g_intstackbase:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.  The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
diff --git a/arch/arm/src/lpc17xx/lpc17_allocateheap.c b/arch/arm/src/lpc17xx/lpc17_allocateheap.c
index f316570f55..047edf5e31 100644
--- a/arch/arm/src/lpc17xx/lpc17_allocateheap.c
+++ b/arch/arm/src/lpc17xx/lpc17_allocateheap.c
@@ -198,9 +198,12 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
 #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
-  /* Get the unaligned size of the user-space heap */
+  /* Get the unaligned size and position of the user-space heap.
+   * This heap begins after the user-space .bss section at an offset
+   * of CONFIG_MM_KERNEL_HEAPSIZE (subject to alignment).
+   */
 
-  uintptr_t ubase = (uintptr_t)g_heapbase + CONFIG_MM_KERNEL_HEAPSIZE;
+  uintptr_t ubase = (uintptr_t)USERSPACE->us_bssend + CONFIG_MM_KERNEL_HEAPSIZE;
   size_t    usize = CONFIG_DRAM_END - ubase;
   int       log2;
 
@@ -231,8 +234,8 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
   /* Return the heap settings */
 
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = CONFIG_DRAM_END - g_idle_topstack;
 #endif
 }
 
@@ -249,9 +252,12 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
 void up_allocate_kheap(FAR void **heap_start, size_t *heap_size)
 {
-  /* Get the unaligned size of the user-space heap */
+  /* Get the unaligned size and position of the user-space heap.
+   * This heap begins after the user-space .bss section at an offset
+   * of CONFIG_MM_KERNEL_HEAPSIZE (subject to alignment).
+   */
 
-  uintptr_t ubase = (uintptr_t)g_heapbase + CONFIG_MM_KERNEL_HEAPSIZE;
+  uintptr_t ubase = (uintptr_t)USERSPACE->us_bssend + CONFIG_MM_KERNEL_HEAPSIZE;
   size_t    usize = CONFIG_DRAM_END - ubase;
   int       log2;
 
@@ -268,10 +274,12 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size)
   usize = (1 << log2);
   ubase = CONFIG_DRAM_END - usize;
 
-  /* Return the kernel heap settings */
+  /* Return the kernel heap settings (i.e., the part of the heap region
+   * that was not dedicated to the user heap).
+   */
 
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = ubase - (uintptr_t)g_heapbase;
+  *heap_start = (FAR void*)USERSPACE->us_bssend;
+  *heap_size  = ubase - (uintptr_t)USERSPACE->us_bssend;
 }
 #endif
 
diff --git a/arch/arm/src/lpc17xx/lpc17_vectors.S b/arch/arm/src/lpc17xx/lpc17_vectors.S
index 25d2e7f193..eca382b1b1 100644
--- a/arch/arm/src/lpc17xx/lpc17_vectors.S
+++ b/arch/arm/src/lpc17xx/lpc17_vectors.S
@@ -417,13 +417,13 @@ g_intstackbase:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.  The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.word	HEAP_BASE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
diff --git a/arch/arm/src/lpc214x/lpc214x_head.S b/arch/arm/src/lpc214x/lpc214x_head.S
index 6784811545..ea2ea12207 100644
--- a/arch/arm/src/lpc214x/lpc214x_head.S
+++ b/arch/arm/src/lpc214x/lpc214x_head.S
@@ -604,7 +604,7 @@ __start:
 	 * _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_IDLETHREAD_STACKSIZE.  The heap continues
-	 * from there until the end of memory.  See g_heapbase
+	 * from there until the end of memory.  See g_idle_topstack
 	 * below.
 	 */
 
@@ -617,18 +617,18 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.long	_edata
 	.size	__start, .-__start
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to LCO
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
 
diff --git a/arch/arm/src/lpc2378/lpc23xx_head.S b/arch/arm/src/lpc2378/lpc23xx_head.S
index a4cab8f05d..578b777534 100755
--- a/arch/arm/src/lpc2378/lpc23xx_head.S
+++ b/arch/arm/src/lpc2378/lpc23xx_head.S
@@ -204,7 +204,7 @@ __start:
 	 * _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_IDLETHREAD_STACKSIZE.  The heap continues
-	 * from there until the end of memory.  See g_heapbase
+	 * from there until the end of memory.  See g_idle_topstack
 	 * below.
 	 */
 
@@ -217,18 +217,18 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.long	_edata
 	.size	__start, .-__start
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to LCO
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	
 	.end
 
diff --git a/arch/arm/src/lpc31xx/lpc31_allocateheap.c b/arch/arm/src/lpc31xx/lpc31_allocateheap.c
index f57c343ef9..7c2c8696ab 100644
--- a/arch/arm/src/lpc31xx/lpc31_allocateheap.c
+++ b/arch/arm/src/lpc31xx/lpc31_allocateheap.c
@@ -180,8 +180,8 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = LPC31_HEAP_VEND - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = LPC31_HEAP_VEND - g_idle_topstack;
 }
 
 /************************************************************************
diff --git a/arch/arm/src/lpc43xx/lpc43_allocateheap.c b/arch/arm/src/lpc43xx/lpc43_allocateheap.c
index c33f9f1ede..4d9d7b21c8 100644
--- a/arch/arm/src/lpc43xx/lpc43_allocateheap.c
+++ b/arch/arm/src/lpc43xx/lpc43_allocateheap.c
@@ -211,10 +211,10 @@
  * thread is the thread that the system boots on and, eventually, becomes the
  * idle, do nothing task that runs only when there is nothing else to run.
  * The heap continues from there until the configured end of memory.
- * g_heapbase is the beginning of this heap region (not necessarily aligned).
+ * g_idle_topstack is the beginning of this heap region (not necessarily aligned).
  */
 
-const uint32_t g_heapbase = (uint32_t)&_ebss + CONFIG_IDLETHREAD_STACKSIZE;
+const uint32_t g_idle_topstack = (uint32_t)&_ebss + CONFIG_IDLETHREAD_STACKSIZE;
 
 /****************************************************************************
  * Private Functions
@@ -244,8 +244,8 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
   /* Start with the first SRAM region */
 
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
 
 /************************************************************************
diff --git a/arch/arm/src/nuc1xx/nuc_start.c b/arch/arm/src/nuc1xx/nuc_start.c
index 67c06c7a5f..fa5f249a3f 100644
--- a/arch/arm/src/nuc1xx/nuc_start.c
+++ b/arch/arm/src/nuc1xx/nuc_start.c
@@ -77,7 +77,7 @@
  * Public Data
  ****************************************************************************/
 
-const uint32_t g_heapbase = HEAP_BASE;
+const uint32_t g_idle_topstack = HEAP_BASE;
 
 /****************************************************************************
  * Private Functions
diff --git a/arch/arm/src/sam3u/sam3u_allocateheap.c b/arch/arm/src/sam3u/sam3u_allocateheap.c
index 86d5fbf368..576fae8023 100644
--- a/arch/arm/src/sam3u/sam3u_allocateheap.c
+++ b/arch/arm/src/sam3u/sam3u_allocateheap.c
@@ -109,9 +109,12 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
 #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
-  /* Get the unaligned size of the user-space heap */
+  /* Get the unaligned size and position of the user-space heap.
+   * This heap begins after the user-space .bss section at an offset
+   * of CONFIG_MM_KERNEL_HEAPSIZE (subject to alignment).
+   */
 
-  uintptr_t ubase = (uintptr_t)g_heapbase + CONFIG_MM_KERNEL_HEAPSIZE;
+  uintptr_t ubase = (uintptr_t)USERSPACE->us_bssend + CONFIG_MM_KERNEL_HEAPSIZE;
   size_t    usize = CONFIG_DRAM_END - ubase;
   int       log2;
 
@@ -142,8 +145,8 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
   /* Return the heap settings */
 
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = CONFIG_DRAM_END - g_idle_topstack;
 #endif
 }
 
@@ -160,9 +163,12 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
 void up_allocate_kheap(FAR void **heap_start, size_t *heap_size)
 {
-  /* Get the unaligned size of the user-space heap */
+  /* Get the unaligned size and position of the user-space heap.
+   * This heap begins after the user-space .bss section at an offset
+   * of CONFIG_MM_KERNEL_HEAPSIZE (subject to alignment).
+   */
 
-  uintptr_t ubase = (uintptr_t)g_heapbase + CONFIG_MM_KERNEL_HEAPSIZE;
+  uintptr_t ubase = (uintptr_t)USERSPACE->us_bssend + CONFIG_MM_KERNEL_HEAPSIZE;
   size_t    usize = CONFIG_DRAM_END - ubase;
   int       log2;
 
@@ -179,10 +185,12 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size)
   usize = (1 << log2);
   ubase = CONFIG_DRAM_END - usize;
 
-  /* Return the kernel heap settings */
+  /* Return the kernel heap settings (i.e., the part of the heap region
+   * that was not dedicated to the user heap).
+   */
 
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = ubase - (uintptr_t)g_heapbase;
+  *heap_start = (FAR void*)USERSPACE->us_bssend;
+  *heap_size  = ubase - (uintptr_t)USERSPACE->us_bssend;
 }
 #endif
 
diff --git a/arch/arm/src/sam3u/sam3u_vectors.S b/arch/arm/src/sam3u/sam3u_vectors.S
index ec0287e343..eba6edd3ae 100644
--- a/arch/arm/src/sam3u/sam3u_vectors.S
+++ b/arch/arm/src/sam3u/sam3u_vectors.S
@@ -443,13 +443,13 @@ g_intstackbase:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.  The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.word	HEAP_BASE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
diff --git a/arch/arm/src/stm32/stm32_allocateheap.c b/arch/arm/src/stm32/stm32_allocateheap.c
index 149de86489..6a29fb16c7 100644
--- a/arch/arm/src/stm32/stm32_allocateheap.c
+++ b/arch/arm/src/stm32/stm32_allocateheap.c
@@ -88,7 +88,7 @@
 #endif
 
 /* For the STM312F10xxx family, all internal SRAM is in one contiguous block
- * starting at g_heapbase and extending through CONFIG_DRAM_END (my apologies for
+ * starting at g_idle_topstack and extending through CONFIG_DRAM_END (my apologies for
  * the bad naming).  In addition, external FSMC SRAM may be available.
  */
 
@@ -198,7 +198,7 @@
  *
  * 3)  64Kb of CCM SRAM beginning at address 0x1000:0000
  *
- * As determined by ld.script, g_heapbase lies in the 112Kb memory
+ * As determined by ld.script, g_idle_topstack lies in the 112Kb memory
  * region and that extends to 0x2001:0000.  But the  first and second memory
  * regions are contiguous and treated as one in this logic that extends to
  * 0x2002:0000.
@@ -370,8 +370,8 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size  = SRAM1_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size  = SRAM1_END - g_idle_topstack;
 }
 
 /****************************************************************************
diff --git a/arch/arm/src/stm32/stm32_vectors.S b/arch/arm/src/stm32/stm32_vectors.S
index ab29c2e144..6b9c0affe9 100644
--- a/arch/arm/src/stm32/stm32_vectors.S
+++ b/arch/arm/src/stm32/stm32_vectors.S
@@ -426,14 +426,14 @@ g_intstackbase:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.  The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
 
diff --git a/arch/arm/src/str71x/str71x_head.S b/arch/arm/src/str71x/str71x_head.S
index e83affa374..710fd57a58 100644
--- a/arch/arm/src/str71x/str71x_head.S
+++ b/arch/arm/src/str71x/str71x_head.S
@@ -599,7 +599,7 @@ dtor_end:
 	 * _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_IDLETHREAD_STACKSIZE.  The heap continues
-	 * from there until the end of memory.  See g_heapbase
+	 * from there until the end of memory.  See g_idle_topstack
 	 * below.
 	 */
 
@@ -612,18 +612,18 @@ LC2:	.long	_eronly	/* Where .data defaults are stored in FLASH */
 	.long	_edata
 	.size	__start, .-__start
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to LCO
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
 	.end
 
diff --git a/arch/avr/src/at90usb/at90usb_head.S b/arch/avr/src/at90usb/at90usb_head.S
index be747632b7..1e705ba713 100755
--- a/arch/avr/src/at90usb/at90usb_head.S
+++ b/arch/avr/src/at90usb/at90usb_head.S
@@ -266,14 +266,14 @@ __do_clear_bss:
  * Heap Base
  ****************************************************************************/
 
-	/* This global variable is unsigned long g_heapbase and is exported from
+	/* This global variable is unsigned long g_idle_topstack and is exported from
 	 * here only because of its coupling to other uses of _enoinit in this file
 	 */
 
 	.data
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.word	_enoinit+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	.end
diff --git a/arch/avr/src/atmega/atmega_head.S b/arch/avr/src/atmega/atmega_head.S
index 95de2f100c..89c3cd1f9c 100755
--- a/arch/avr/src/atmega/atmega_head.S
+++ b/arch/avr/src/atmega/atmega_head.S
@@ -260,14 +260,14 @@ __do_clear_bss:
  * Heap Base
  ****************************************************************************/
 
-	/* This global variable is unsigned long g_heapbase and is exported from
+	/* This global variable is unsigned long g_idle_topstack and is exported from
 	 * here only because of its coupling to other uses of _enoinit in this file
 	 */
 
 	.data
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.word	_enoinit+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	.end
diff --git a/arch/avr/src/avr/avr_internal.h b/arch/avr/src/avr/avr_internal.h
index 031000cd19..2c78791e40 100644
--- a/arch/avr/src/avr/avr_internal.h
+++ b/arch/avr/src/avr/avr_internal.h
@@ -81,7 +81,7 @@ extern volatile uint8_t *current_regs;
  * heap is CONFIG_DRAM_END
  */
 
-extern uint16_t g_heapbase;
+extern uint16_t g_idle_topstack;
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/avr/src/avr/up_dumpstate.c b/arch/avr/src/avr/up_dumpstate.c
index 62e80255fc..6ba50d2381 100644
--- a/arch/avr/src/avr/up_dumpstate.c
+++ b/arch/avr/src/avr/up_dumpstate.c
@@ -181,7 +181,7 @@ void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 1;
+      ustackbase = g_idle_topstack - 1;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/avr/src/avr32/avr32_internal.h b/arch/avr/src/avr32/avr32_internal.h
index 3d45f6c54d..bcac8074ab 100644
--- a/arch/avr/src/avr32/avr32_internal.h
+++ b/arch/avr/src/avr32/avr32_internal.h
@@ -79,7 +79,7 @@ extern volatile uint32_t *current_regs;
  * heap is CONFIG_DRAM_END
  */
 
-extern uint32_t g_heapbase;
+extern uint32_t g_idle_topstack;
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/avr/src/avr32/up_dumpstate.c b/arch/avr/src/avr32/up_dumpstate.c
index 32db56f0d4..90cb228377 100644
--- a/arch/avr/src/avr32/up_dumpstate.c
+++ b/arch/avr/src/avr32/up_dumpstate.c
@@ -158,7 +158,7 @@ void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/avr/src/avr32/up_nommuhead.S b/arch/avr/src/avr32/up_nommuhead.S
index 316e68aaff..149b1f26fd 100644
--- a/arch/avr/src/avr32/up_nommuhead.S
+++ b/arch/avr/src/avr32/up_nommuhead.S
@@ -141,17 +141,17 @@ __start:
 	.word	up_lowinit
 	.size	__start, .-__start
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to other
 	 * uses of _ebss in this file
 	 */
 
 	.data
 	.align	4
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	.end
 
diff --git a/arch/avr/src/common/up_allocateheap.c b/arch/avr/src/common/up_allocateheap.c
index 3a67ff6a74..3893e3a2d9 100644
--- a/arch/avr/src/common/up_allocateheap.c
+++ b/arch/avr/src/common/up_allocateheap.c
@@ -82,6 +82,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/hc/src/common/up_allocateheap.c b/arch/hc/src/common/up_allocateheap.c
index b107baaa53..f0c8f58a42 100644
--- a/arch/hc/src/common/up_allocateheap.c
+++ b/arch/hc/src/common/up_allocateheap.c
@@ -81,6 +81,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/hc/src/common/up_internal.h b/arch/hc/src/common/up_internal.h
index 0de737fb62..87503c56fb 100644
--- a/arch/hc/src/common/up_internal.h
+++ b/arch/hc/src/common/up_internal.h
@@ -141,7 +141,7 @@ extern volatile uint8_t *current_regs;
  * The end of the heap is CONFIG_DRAM_END
  */
 
-extern uint16_t g_heapbase;
+extern uint16_t g_idle_topstack;
 
 /* Address of the saved user stack pointer */
 
diff --git a/arch/hc/src/m9s12/m9s12_assert.c b/arch/hc/src/m9s12/m9s12_assert.c
index 62ad33d2d1..9f97ec4dbf 100644
--- a/arch/hc/src/m9s12/m9s12_assert.c
+++ b/arch/hc/src/m9s12/m9s12_assert.c
@@ -169,7 +169,7 @@ static void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/hc/src/m9s12/m9s12_start.S b/arch/hc/src/m9s12/m9s12_start.S
index 66c1b80f9a..c79388030c 100755
--- a/arch/hc/src/m9s12/m9s12_start.S
+++ b/arch/hc/src/m9s12/m9s12_start.S
@@ -233,7 +233,7 @@ __start:
 	 * _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_IDLETHREAD_STACKSIZE.  The heap continues
-	 * from there until the end of memory.	See g_heapbase
+	 * from there until the end of memory.	See g_idle_topstack
 	 * below.
 	 */
 
@@ -262,12 +262,12 @@ __start:
  * and is of size CONFIG_IDLETHREAD_STACKSIZE.	The IDLE thread is the thread that
  * the system boots on and, eventually, becomes the idle, do nothing task that runs
  * only when there is nothing else to run.	The heap continues from there until the
- * end of memory.  See g_heapbase below.
+ * end of memory.  See g_idle_topstack below.
  */
 
-	.globl	g_heapbase
-	.type	g_heapbase, object
-g_heapbase:
+	.globl	g_idle_topstack
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.hword	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 	.end
diff --git a/arch/mips/src/common/up_allocateheap.c b/arch/mips/src/common/up_allocateheap.c
index b8c449ff12..f6dc515111 100644
--- a/arch/mips/src/common/up_allocateheap.c
+++ b/arch/mips/src/common/up_allocateheap.c
@@ -82,6 +82,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/mips/src/common/up_internal.h b/arch/mips/src/common/up_internal.h
index 927538dea2..1950a74e6b 100644
--- a/arch/mips/src/common/up_internal.h
+++ b/arch/mips/src/common/up_internal.h
@@ -138,7 +138,7 @@ extern volatile uint32_t *current_regs;
  * of the heap is CONFIG_DRAM_END
  */
 
-extern uint32_t g_heapbase;
+extern uint32_t g_idle_topstack;
 
 /* Address of the saved user stack pointer */
 
diff --git a/arch/mips/src/mips32/up_dumpstate.c b/arch/mips/src/mips32/up_dumpstate.c
index 064aa0681f..bdd21726b9 100644
--- a/arch/mips/src/mips32/up_dumpstate.c
+++ b/arch/mips/src/mips32/up_dumpstate.c
@@ -167,7 +167,7 @@ void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/mips/src/pic32mx/pic32mx-head.S b/arch/mips/src/pic32mx/pic32mx-head.S
index 2e1a340805..471effc3f2 100644
--- a/arch/mips/src/pic32mx/pic32mx-head.S
+++ b/arch/mips/src/pic32mx/pic32mx-head.S
@@ -122,7 +122,7 @@
 	.global	g_nestlevel
 #endif
 #endif
-	.global	g_heapbase
+	.global	g_idle_topstack
 
 	/* Imported symbols */
 
@@ -698,13 +698,13 @@ g_nestlevel:
 #endif
 #endif
 
-/* This global variable is unsigned int g_heapbase and is exported here only
+/* This global variable is unsigned int g_idle_topstack and is exported here only
  * because of its coupling to idle thread stack.
  */
 
 	.sdata
-	.type	g_heapbase, object
-g_heapbase:
+	.type	g_idle_topstack, object
+g_idle_topstack:
 	.long	PIC32MX_HEAP_BASE
-	.size	g_heapbase, .-g_heapbase
+	.size	g_idle_topstack, .-g_idle_topstack
 
diff --git a/arch/sh/src/common/up_allocateheap.c b/arch/sh/src/common/up_allocateheap.c
index ad1935d9a5..734a504837 100644
--- a/arch/sh/src/common/up_allocateheap.c
+++ b/arch/sh/src/common/up_allocateheap.c
@@ -81,6 +81,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/sh/src/common/up_internal.h b/arch/sh/src/common/up_internal.h
index f56e97c976..99c273ca6a 100644
--- a/arch/sh/src/common/up_internal.h
+++ b/arch/sh/src/common/up_internal.h
@@ -140,7 +140,7 @@ extern volatile uint32_t *current_regs;
  * CONFIG_DRAM_END
  */
 
-extern uint32_t g_heapbase;
+extern uint32_t g_idle_topstack;
 #endif
 
 /****************************************************************************
diff --git a/arch/sh/src/m16c/chip.h b/arch/sh/src/m16c/chip.h
index 0a91d6041e..02140df790 100644
--- a/arch/sh/src/m16c/chip.h
+++ b/arch/sh/src/m16c/chip.h
@@ -253,20 +253,20 @@
 
 #ifndef __ASSEMBLY__
 
-extern uint16_t g_snbss;		/* Start of near .bss */
-extern uint16_t g_enbss;		/* End+1 of near .bss */
-extern uint16_t g_sndata;		/* Start of near .data */
-extern uint16_t g_endata;		/* End+1 of near .data */
-extern uint32_t g_enronly;		/* Start of relocated read-only data in FLASH */
+extern uint16_t g_snbss;         /* Start of near .bss */
+extern uint16_t g_enbss;         /* End+1 of near .bss */
+extern uint16_t g_sndata;        /* Start of near .data */
+extern uint16_t g_endata;        /* End+1 of near .data */
+extern uint32_t g_enronly;       /* Start of relocated read-only data in FLASH */
 #ifdef CONFIG_M16C_HAVEFARRAM
-  extern uint32_t g_sfbss;		/* Start of far .bss */
-  extern uint32_t g_efbss;		/* End+1 of far .bss */
-  extern uint32_t g_sfdata;		/* Start of far .data */
-  extern uint32_t g_efdata;		/* End_1 of far .data */
-  extern uint32_t g_efronly;	/* Start of relocated read-only data in FLASH */
+  extern uint32_t g_sfbss;       /* Start of far .bss */
+  extern uint32_t g_efbss;       /* End+1 of far .bss */
+  extern uint32_t g_sfdata;      /* Start of far .data */
+  extern uint32_t g_efdata;      /* End_1 of far .data */
+  extern uint32_t g_efronly;     /* Start of relocated read-only data in FLASH */
 #endif
-extern uint32_t g_svarvect;		/* Start of variable vectors */
-extern uint32_t g_heapbase;		/* Start of the heap */
+extern uint32_t g_svarvect;      /* Start of variable vectors */
+extern uint32_t g_idle_topstack; /* Start of the heap */
 
 /* Address of the saved user stack pointer */
 
diff --git a/arch/sh/src/m16c/m16c_dumpstate.c b/arch/sh/src/m16c/m16c_dumpstate.c
index 3570a9ebe8..8083f62bd1 100644
--- a/arch/sh/src/m16c/m16c_dumpstate.c
+++ b/arch/sh/src/m16c/m16c_dumpstate.c
@@ -171,7 +171,7 @@ void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 1;
+      ustackbase = g_idle_topstack - 1;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/sh/src/m16c/m16c_head.S b/arch/sh/src/m16c/m16c_head.S
index 4e6b0e2c83..4709463139 100644
--- a/arch/sh/src/m16c/m16c_head.S
+++ b/arch/sh/src/m16c/m16c_head.S
@@ -147,11 +147,11 @@ _g_svarvect:
 	.long	_svarvect
 	.size	_g_svarvect, .-_g_svarvect
 
-	.globl	_g_heapbase
-	.type	_g_heapbase, object
-_g_heapbase:
+	.globl	_g_idle_topstack
+	.type	_g_idle_topstack, object
+_g_idle_topstack:
 	.long	_enbss+CONFIG_ARCH_INTERRUPTSTACK+CONFIG_IDLETHREAD_STACKSIZE
-	.size	_g_heapbase, .-_g_heapbase
+	.size	_g_idle_topstack, .-_g_idle_topstack
 
 /************************************************************************************
  * Code
diff --git a/arch/sh/src/sh1/sh1_dumpstate.c b/arch/sh/src/sh1/sh1_dumpstate.c
index 3d101c92dd..8990f66158 100644
--- a/arch/sh/src/sh1/sh1_dumpstate.c
+++ b/arch/sh/src/sh1/sh1_dumpstate.c
@@ -160,7 +160,7 @@ void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/sh/src/sh1/sh1_head.S b/arch/sh/src/sh1/sh1_head.S
index 9a52b9bb39..774d227843 100644
--- a/arch/sh/src/sh1/sh1_head.S
+++ b/arch/sh/src/sh1/sh1_head.S
@@ -507,18 +507,18 @@ __start0:
 
 	.section	.data
 
-	/* This global variable is unsigned long g_heapbase and is
+	/* This global variable is unsigned long g_idle_topstack and is
 	 * exported from here only because of its coupling to the stack
 	 * above.
 	 */
 
 	.data
 	.align	4
-	.globl	_g_heapbase
-	.type	_g_heapbase, object
-_g_heapbase:
+	.globl	_g_idle_topstack
+	.type	_g_idle_topstack, object
+_g_idle_topstack:
 	.long	_ebss+CONFIG_IDLETHREAD_STACKSIZE
-	.size	_g_heapbase, .-_g_heapbase
+	.size	_g_idle_topstack, .-_g_idle_topstack
 
 	.end
 
diff --git a/arch/x86/src/common/up_allocateheap.c b/arch/x86/src/common/up_allocateheap.c
index b56f9b59a0..55f60f0566 100644
--- a/arch/x86/src/common/up_allocateheap.c
+++ b/arch/x86/src/common/up_allocateheap.c
@@ -82,6 +82,6 @@
 void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 {
   up_ledon(LED_HEAPALLOCATE);
-  *heap_start = (FAR void*)g_heapbase;
-  *heap_size = CONFIG_DRAM_END - g_heapbase;
+  *heap_start = (FAR void*)g_idle_topstack;
+  *heap_size = CONFIG_DRAM_END - g_idle_topstack;
 }
diff --git a/arch/x86/src/common/up_assert.c b/arch/x86/src/common/up_assert.c
index 173ca6623c..ed83eb6ce5 100644
--- a/arch/x86/src/common/up_assert.c
+++ b/arch/x86/src/common/up_assert.c
@@ -128,7 +128,7 @@ static void up_dumpstate(void)
 
   if (rtcb->pid == 0)
     {
-      ustackbase = g_heapbase - 4;
+      ustackbase = g_idle_topstack - 4;
       ustacksize = CONFIG_IDLETHREAD_STACKSIZE;
     }
   else
diff --git a/arch/x86/src/common/up_internal.h b/arch/x86/src/common/up_internal.h
index c27717c387..3351e24c4f 100644
--- a/arch/x86/src/common/up_internal.h
+++ b/arch/x86/src/common/up_internal.h
@@ -140,7 +140,7 @@ extern volatile uint32_t *current_regs;
  * heap is CONFIG_DRAM_END
  */
 
-extern uint32_t g_heapbase;
+extern uint32_t g_idle_topstack;
 
 /* Address of the saved user stack pointer */
 
diff --git a/arch/x86/src/qemu/qemu_head.S b/arch/x86/src/qemu/qemu_head.S
index 2b86c18354..22c4904695 100755
--- a/arch/x86/src/qemu/qemu_head.S
+++ b/arch/x86/src/qemu/qemu_head.S
@@ -50,7 +50,7 @@
  * the end of BSS and is of size CONFIG_IDLETHREAD_STACKSIZE.  The IDLE thread
  * is the thread that the system boots on and, eventually, becomes the idle,
  * do nothing task that runs only when there is nothing else to run.  The
- * heap continues from there until the end of memory.  See g_heapbase below.
+ * heap continues from there until the end of memory.  See g_idle_topstack below.
  */
 
 #define STACKBASE	((_ebss + 0x1f) & 0xffffffe0)
@@ -78,7 +78,7 @@
 	.global	__start						/* Making entry point visible to linker */
 	.global	os_start					/* os_start is defined elsewhere */
 	.global	up_lowsetup					/* up_lowsetup is defined elsewhere */
-	.global	g_heapbase					/* The start of the heap */
+	.global	g_idle_topstack				/* The start of the heap */
 
 /****************************************************************************
  * .text
@@ -154,8 +154,8 @@ hang:
  * until the end of memory.
  */
 
-	.type	g_heapbase, @object
-g_heapbase:
+	.type	g_idle_topstack, @object
+g_idle_topstack:
 	.long	_ebss
-	.size	g_heapbase, . - g_heapbase
+	.size	g_idle_topstack, . - g_idle_topstack
 	.end