Add logic to initialize the per-process user heap when each user process is started

15 files changed, 326 insertions, 132 deletions

diff --git a/nuttx/Documentation/NuttxPortingGuide.html b/nuttx/Documentation/NuttxPortingGuide.html
index a2d1d0884..eb5a67cc1 100644
--- a/nuttx/Documentation/NuttxPortingGuide.html
+++ b/nuttx/Documentation/NuttxPortingGuide.html
@@ -12,7 +12,7 @@
       <h1><big><font color="#3c34ec">
         <i>NuttX RTOS Porting Guide</i>
       </font></big></h1>
-      <p>Last Updated: August 29, 2014</p>
+      <p>Last Updated: September 10, 2014</p>
     </td>
   </tr>
 </table>
@@ -110,11 +110,12 @@
       <a href="#up_addrenv_destroy">4.4.2 <code>up_addrenv_destroy()</code></a></br>
       <a href="#up_addrenv_vtext">4.4.3 <code>up_addrenv_vtext()</code></a></br>
       <a href="#up_addrenv_vdata">4.4.4 <code>up_addrenv_vdata()</code></a></br>
-      <a href="#up_addrenv_select">4.4.5 <code>up_addrenv_select()</code></a></br>
-      <a href="#up_addrenv_restore">4.4.6 <code>up_addrenv_restore()</code></a></br>
-      <a href="#up_addrenv_clone">4.4.7 <code>up_addrenv_clone()</code></a></br>
-      <a href="#up_addrenv_attach">4.4.8 <code>up_addrenv_attach()</code></a></br>
-      <a href="#up_addrenv_detach">4.4.9 <code>up_addrenv_detach()</code></a>
+      <a href="#up_addrenv_heapsize">4.4.5 <code>up_addrenv_heapsize()</code></a></br>
+      <a href="#up_addrenv_select">4.4.6 <code>up_addrenv_select()</code></a></br>
+      <a href="#up_addrenv_restore">4.4.7 <code>up_addrenv_restore()</code></a></br>
+      <a href="#up_addrenv_clone">4.4.8 <code>up_addrenv_clone()</code></a></br>
+      <a href="#up_addrenv_attach">4.4.9 <code>up_addrenv_attach()</code></a></br>
+      <a href="#up_addrenv_detach">4.4.10 <code>up_addrenv_detach()</code></a>
     </ul>
     <a href="#exports">4.5 APIs Exported by NuttX to Architecture-Specific Logic</a>
     <ul>
@@ -2927,15 +2928,19 @@ VxWorks provides the following comparable interface:
         Returns the virtual base address of the <code>.bss</code>/<code>.data</code> address environment.
       </li>
       <li>
-        <a href="#up_addrenv_select">4.4.5 <code>up_addrenv_select()</code></a>:
+        <a href="#up_addrenv_heapsize">4.4.5 <code>up_addrenv_heapsize()</code></a>:
+       Return the initial heap size.
+      </li>
+      <li>
+        <a href="#up_addrenv_select">4.4.6 <code>up_addrenv_select()</code></a>:
         Instantiate an address environment.
       </li>
       <li>
-        <a href="#up_addrenv_restore">4.4.6 <code>up_addrenv_restore()</code></a>:
+        <a href="#up_addrenv_restore">4.4.7 <code>up_addrenv_restore()</code></a>:
         Restore an address environment.
       </li>
       <li>
-        <a href="#up_addrenv_clone">4.4.7 <code>up_addrenv_clone()</code></a>:
+        <a href="#up_addrenv_clone">4.4.8 <code>up_addrenv_clone()</code></a>:
         Copy an address environment from one location to another.
       </li>
     </ul>
@@ -2948,12 +2953,12 @@ VxWorks provides the following comparable interface:
     </p>
     <ul>
       <li>
-        <a href="#up_addrenv_attach">4.4.8 <code>up_addrenv_attach()</code></a>:
+        <a href="#up_addrenv_attach">4.4.9 <code>up_addrenv_attach()</code></a>:
         Clone the group address environment assigned to a new thread.
         This operation is done when a pthread is created that share's the same address environment.
       </li>
       <li>
-        <a href="#up_addrenv_detach">4.4.9 <code>up_addrenv_detach()</code></a>:
+        <a href="#up_addrenv_detach">4.4.10 <code>up_addrenv_detach()</code></a>:
         Release the thread's reference to a group address environment when a task/thread exits.
       </li>
     </ul>
@@ -2963,7 +2968,7 @@ VxWorks provides the following comparable interface:
 <h3><a name="up_addrenv_create">4.4.1 <code>up_addrenv_create()</code></a></h3>
 <p><b>Function Prototype</b>:</p>
 <ul>
-  <code>int up_addrenv_create(size_t textsize, size_t datasize, FAR group_addrenv_t *addrenv);</code>
+  <code>int up_addrenv_create(size_t textsize, size_t datasize, size_t heapsize, FAR group_addrenv_t *addrenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
@@ -2974,6 +2979,7 @@ VxWorks provides the following comparable interface:
 <ul>
   <li><code>textsize</code>: The size (in bytes) of the <code>.text</code> address environment needed by the task.  This region may be read/execute only.</li>
   <li><code>datasize</code>: The size (in bytes) of the <code>.bss/.data</code> address environment needed by the task.   This region may be read/write only.</li>
+  <li><code>heapsize</code>: The initial size (in bytes) of the heap address environment needed by the task.  This region may be read/write only.</li>
   <li><code>addrenv</code>: The location to return the representation of the task address environment.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
@@ -2992,7 +2998,7 @@ VxWorks provides the following comparable interface:
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>addrenv</code>: The representation of the task address environment previously returned by up_addrenv_create.</li>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by <code>up_addrenv_create()</code>.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
@@ -3011,7 +3017,7 @@ VxWorks provides the following comparable interface:
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>addrenv</code>: The representation of the task address environment previously returned by up_addrenv_create.</li>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by <code>up_addrenv_create()</code>.</li>
   <li><code>vtext</code>: The location to return the virtual address.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
@@ -3031,7 +3037,7 @@ VxWorks provides the following comparable interface:
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>addrenv</code>: The representation of the task address environment previously returned by up_addrenv_create.</li>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by <code>up_addrenv_create()</code>.</li>
   <li><code>textsize</code>: For some implementations, the text and data will be saved in the same memory region (read/write/execute) and, in this case, the virtual address of the data just lies at this offset into the common region.</li>
   <li><code>vdata</code>: The location to return the virtual address.</li>
 </ul>
@@ -3040,7 +3046,27 @@ VxWorks provides the following comparable interface:
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_select">4.4.5 <code>up_addrenv_select()</code></a></h3>
+<h3><a name="up_addrenv_heapsize">4.4.5 <code>up_addrenv_heapsize()</code></a></h3>
+<p><b>Function Prototype</b>:<p>
+<ul>
+  <code>ssize_t up_addrenv_heapsize(FAR const group_addrenv_t *addrenv);</code>
+</ul>
+<p><b>Description</b>:</p>
+<ul>
+  Return the initial heap allocation size.
+  That is the amount of memory allocated by <code>up_addrenv_create()</code> when the heap memory region was first created.
+  This may or may not differ from the <code>heapsize</code> parameter that was passed to <code>up_addrenv_create()</code>.
+</ul>
+<p><b>Input Parameters</b>:</p>
+<ul>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by <code>up_addrenv_create()</code>.</li>
+</ul>
+<p><b>Returned Value</b>:</p>
+<ul>
+  The initial heap size allocated is returned on success; a negated <code>errno</code> value on failure.
+</ul>
+
+<h3><a name="up_addrenv_select">4.4.6 <code>up_addrenv_select()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
   <code>int up_addrenv_select(group_addrenv_t *addrenv, save_addrenv_t *oldenv);</code>
@@ -3052,7 +3078,7 @@ VxWorks provides the following comparable interface:
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>addrenv</code>: The representation of the task address environment previously returned by up_addrenv_create.</li>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by <code>up_addrenv_create()</code>.</li>
   <li><code>oldenv</code>:
     The address environment that was in place before <code>up_addrenv_select()</code> was called.
     This may be used with <code>up_addrenv_restore()</code> to restore the original  address environment that was in place before <code>up_addrenv_select()</code> was called.
@@ -3064,7 +3090,7 @@ VxWorks provides the following comparable interface:
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_restore">4.4.6 <code>up_addrenv_restore()</code></a></h3>
+<h3><a name="up_addrenv_restore">4.4.7 <code>up_addrenv_restore()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
   <code>int up_addrenv_restore(save_addrenv_t oldenv);</code>
@@ -3083,7 +3109,7 @@ VxWorks provides the following comparable interface:
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_clone">4.4.7 <code>up_addrenv_clone()</code></a></h3>
+<h3><a name="up_addrenv_clone">4.4.8 <code>up_addrenv_clone()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
   <code>int up_addrenv_clone(FAR const task_group_s *src, FAR struct task_group_s *dest);</code>
@@ -3102,7 +3128,7 @@ VxWorks provides the following comparable interface:
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_attach">4.4.8 <code>up_addrenv_attach()</code></a></h3>
+<h3><a name="up_addrenv_attach">4.4.9 <code>up_addrenv_attach()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
   <code>int up_addrenv_attach(FAR struct task_group_s *group, FAR struct tcb_s *tcb);</code>
@@ -3128,7 +3154,7 @@ VxWorks provides the following comparable interface:
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_detach">4.4.9 <code>up_addrenv_detach()</code></a></h3>
+<h3><a name="up_addrenv_detach">4.4.10 <code>up_addrenv_detach()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
   <code>int up_addrenv_detach(FAR struct task_group_s *group, FAR struct task_group_s *tcb);</code>
diff --git a/nuttx/arch/arm/include/arch.h b/nuttx/arch/arm/include/arch.h
index 2f1991622..02e66aaf4 100644
--- a/nuttx/arch/arm/include/arch.h
+++ b/nuttx/arch/arm/include/arch.h
@@ -133,9 +133,19 @@ do { \
 
 struct group_addrenv_s
 {
+  /* Level 1 page table entries for each group section */
+
   FAR uintptr_t *text[ARCH_TEXT_NSECTS];
   FAR uintptr_t *data[ARCH_DATA_NSECTS];
   FAR uintptr_t *heap[ARCH_HEAP_NSECTS];
+
+  /* Initial heap allocation (in bytes).  This exists only provide an
+   * indirect path for passing the size of the initial heap to the heap
+   * initialization logic.  These operations are separated in time and
+   * architecture.  REVISIT:  I would like a better way to do this.
+   */
+
+  size_t heapsize;
 };
 
 typedef struct group_addrenv_s group_addrenv_t;
@@ -153,9 +163,7 @@ struct save_addrenv_s
 {
   FAR uint32_t text[ARCH_TEXT_NSECTS];
   FAR uint32_t data[ARCH_DATA_NSECTS];
-#if 0 /* Not yet implemented */
   FAR uint32_t heap[ARCH_HEAP_NSECTS];
-#endif
 };
 
 typedef struct save_addrenv_s save_addrenv_t;
diff --git a/nuttx/arch/arm/include/armv7-a/irq.h b/nuttx/arch/arm/include/armv7-a/irq.h
index 00e7244ae..f9d5225b3 100755
--- a/nuttx/arch/arm/include/armv7-a/irq.h
+++ b/nuttx/arch/arm/include/armv7-a/irq.h
@@ -274,17 +274,15 @@ struct xcptcontext
   struct xcpt_syscall_s syscall[CONFIG_SYS_NNEST];
 #endif
 
-#ifdef CONFIG_ARCH_ADDRENV
+#if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_ARCH_STACK_DYNAMIC)
   /* This table holds the physical address of the level 2 page table used
    * to map the thread's stack memory.  This array will be initially of
    * zeroed and would be back-up up with pages during page fault exception
    * handling to support dynamically sized stacks for each thread.
    */
 
-#if 0 /* Not yet implemented */
   FAR uintptr_t *stack[ARCH_STACK_NSECTS];
 #endif
-#endif
 };
 #endif
 
diff --git a/nuttx/arch/arm/src/armv7-a/arm_addrenv.c b/nuttx/arch/arm/src/armv7-a/arm_addrenv.c
index 4d68fd655..aa28efbdb 100644
--- a/nuttx/arch/arm/src/armv7-a/arm_addrenv.c
+++ b/nuttx/arch/arm/src/armv7-a/arm_addrenv.c
@@ -40,27 +40,28 @@
  * is an abstract representation of a task group's address environment and
  * must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
  *
- *   up_addrenv_create  - Create an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_vtext   - Returns the virtual base address of the .text
- *                        address environment
- *   up_addrenv_vdata   - Returns the virtual base address of the .bss/.data
- *                        address environment
- *   up_addrenv_select  - Instantiate an address environment
- *   up_addrenv_restore - Restore an address environment
- *   up_addrenv_clone   - Copy an address environment from one location to
- *                        another.
+ *   up_addrenv_create   - Create an address environment
+ *   up_addrenv_destroy  - Destroy an address environment.
+ *   up_addrenv_vtext    - Returns the virtual base address of the .text
+ *                         address environment
+ *   up_addrenv_vdata    - Returns the virtual base address of the .bss/.data
+ *                         address environment
+ *   up_addrenv_heapsize - Returns the size of the initial heap allocation.
+ *   up_addrenv_select   - Instantiate an address environment
+ *   up_addrenv_restore  - Restore an address environment
+ *   up_addrenv_clone    - Copy an address environment from one location to
+ *                         another.
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
  * used by the functions in sched/ and all operate on the thread which whose
  * group been assigned an address environment by up_addrenv_clone().
  *
- *   up_addrenv_attach  - Clone the address environment assigned to one TCB
- *                        to another.  This operation is done when a pthread
- *                        is created that share's the same address
- *                        environment.
- *   up_addrenv_detach  - Release the threads reference to an address
- *                        environment when a task/thread exits.
+ *   up_addrenv_attach   - Clone the address environment assigned to one TCB
+ *                         to another.  This operation is done when a pthread
+ *                         is created that share's the same address
+ *                         environment.
+ *   up_addrenv_detach   - Release the threads reference to an address
+ *                         environment when a task/thread exits.
  *
  ****************************************************************************/
 
@@ -153,6 +154,10 @@ static void set_l2_entry(FAR uint32_t *l2table, uintptr_t paddr,
  * Description:
  *   Create one memory region.
  *
+ * Returned Value:
+ *   On success, the number of pages allocated is returned.  Otherwise, a
+ *   negated errno value is returned.
+ *
  ****************************************************************************/
 
 static int up_addrenv_create_region(FAR uintptr_t **list,
@@ -264,7 +269,7 @@ static int up_addrenv_create_region(FAR uintptr_t **list,
       irqrestore(flags);
     }
 
-  return OK;
+  return npages;
 }
 
 /****************************************************************************
@@ -437,6 +442,8 @@ static void up_addrenv_destroy_region(FAR uintptr_t **list,
  *     actual size of the data region that is allocated will include a
  *     OS private reserved region at the beginning.  The size of the
  *     private, reserved region is give by ARCH_DATA_RESERVE_SIZE.
+ *   heapsize - The initial size (in bytes) of the heap address environment
+ *     needed by the task.  This region may be read/write only.
  *   addrenv - The location to return the representation of the task address
  *     environment.
  *
@@ -445,7 +452,7 @@ static void up_addrenv_destroy_region(FAR uintptr_t **list,
  *
  ****************************************************************************/
 
-int up_addrenv_create(size_t textsize, size_t datasize,
+int up_addrenv_create(size_t textsize, size_t datasize, size_t heapsize,
                       FAR group_addrenv_t *addrenv)
 {
   int ret;
@@ -503,8 +510,22 @@ int up_addrenv_create(size_t textsize, size_t datasize,
     }
 #endif
 
-  /* Notice that no pages are yet allocated for the heap */
+  /* Allocate heap space pages */
+
+  ret = up_addrenv_create_region(addrenv->heap, ARCH_HEAP_NSECTS,
+                                 CONFIG_ARCH_HEAP_VBASE, heapsize,
+                                 MMU_L2_UDATAFLAGS);
+  if (ret < 0)
+    {
+      bdbg("ERROR: Failed to create heap region: %d\n", ret);
+      goto errout;
+    }
 
+  /* Save the initial heap size allocated.  This will be needed when
+   * the heap data structures are initialized.
+   */
+
+  addrenv->heapsize = (size_t)ret << MM_PGSHIFT;
   return OK;
 
 errout:
@@ -543,12 +564,10 @@ int up_addrenv_destroy(FAR group_addrenv_t *addrenv)
   up_addrenv_destroy_region(addrenv->data, ARCH_DATA_NSECTS,
                             CONFIG_ARCH_DATA_VBASE);
 
-#if 0 /* Not yet implemented */
   /* Destroy the heap region */
 
   up_addrenv_destroy_region(addrenv->heap, ARCH_HEAP_NSECTS,
                             CONFIG_ARCH_HEAP_VBASE);
-#endif
 
   memset(addrenv, 0, sizeof(group_addrenv_t));
   return OK;
@@ -617,6 +636,31 @@ int up_addrenv_vdata(FAR group_addrenv_t *addrenv, uintptr_t textsize,
 }
 
 /****************************************************************************
+ * Name: up_addrenv_heapsize
+ *
+ * Description:
+ *   Return the initial heap allocation size.  That is the amount of memory
+ *   allocated by up_addrenv_create() when the heap memory region was first
+ *   created.  This may or may not differ from the heapsize parameter that
+ *   was passed to up_addrenv_create()
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *     returned by up_addrenv_create.
+ *
+ * Returned Value:
+ *   The initial heap size allocated is returned on success; a negated
+ *   errno value on failure.
+ *
+ ****************************************************************************/
+
+ssize_t up_addrenv_heapsize(FAR const group_addrenv_t *addrenv)
+{
+  DEBUGASSERT(addrenv);
+  return (ssize_t)addrenv->heapsize;
+}
+
+/****************************************************************************
  * Name: up_addrenv_select
  *
  * Description:
@@ -698,7 +742,6 @@ int up_addrenv_select(FAR const group_addrenv_t *addrenv,
         }
     }
 
-#if 0 /* Not yet implemented */
   for (vaddr = CONFIG_ARCH_HEAP_VBASE, i = 0;
        i < ARCH_HEAP_NSECTS;
        vaddr += SECTION_SIZE, i++)
@@ -722,7 +765,6 @@ int up_addrenv_select(FAR const group_addrenv_t *addrenv,
           mmu_l1_clrentry(vaddr);
         }
     }
-#endif
 
   return OK;
 }
@@ -770,7 +812,6 @@ int up_addrenv_restore(FAR const save_addrenv_t *oldenv)
       mmu_l1_restore(vaddr, oldenv->data[i]);
     }
 
-#if 0 /* Not yet implemented */
   for (vaddr = CONFIG_ARCH_HEAP_VBASE, i = 0;
        i < ARCH_HEAP_NSECTS;
        vaddr += SECTION_SIZE, i++)
@@ -779,7 +820,6 @@ int up_addrenv_restore(FAR const save_addrenv_t *oldenv)
 
       mmu_l1_restore(vaddr, oldenv->heap[i]);
     }
-#endif
 
   return OK;
 }
diff --git a/nuttx/arch/z80/src/z180/z180_mmu.c b/nuttx/arch/z80/src/z180/z180_mmu.c
index e1373851d..e63e18403 100644
--- a/nuttx/arch/z80/src/z180/z180_mmu.c
+++ b/nuttx/arch/z80/src/z180/z180_mmu.c
@@ -184,15 +184,16 @@ return g_physhandle ? OK : -ENOMEM;
  * is an abstract representation of a task group's address environment and
  * must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
  *
- *   up_addrenv_create  - Create an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_vtext   - Returns the virtual base address of the .text
- *                        address environment
- *   up_addrenv_vdata   - Returns the virtual base address of the .bss/.data
- *                        address environment
- *   up_addrenv_select  - Instantiate an address environment
- *   up_addrenv_restore - Restore an address environment
- *   up_addrenv_clone   - Copy an address environment from one location to
+ *   up_addrenv_create   - Create an address environment
+ *   up_addrenv_destroy  - Destroy an address environment.
+ *   up_addrenv_vtext    - Returns the virtual base address of the .text
+ *                         address environment
+ *   up_addrenv_vdata    - Returns the virtual base address of the .bss/.data
+ *                         address environment
+ *   up_addrenv_heapsize - Returns the size of the initial heap allocation.
+ *   up_addrenv_select   - Instantiate an address environment
+ *   up_addrenv_restore  - Restore an address environment
+ *   up_addrenv_clone    - Copy an address environment from one location to
  *                        another.
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
@@ -200,11 +201,11 @@ return g_physhandle ? OK : -ENOMEM;
  * group been assigned an address environment by up_addrenv_clone().
  *
  *   up_addrenv_attach   - Clone the address environment assigned to one TCB
- *                        to another.  This operation is done when a pthread
- *                        is created that share's the same address
- *                        environment.
- *   up_addrenv_detach - Release the threads reference to an address
- *                        environment when a task/thread exits.
+ *                         to another.  This operation is done when a pthread
+ *                         is created that share's the same address
+ *                         environment.
+ *   up_addrenv_detach   - Release the threads reference to an address
+ *                         environment when a task/thread exits.
  *
  ****************************************************************************/
 /****************************************************************************
@@ -220,6 +221,11 @@ return g_physhandle ? OK : -ENOMEM;
  *   textsize - The size (in bytes) of the .text address environment needed
  *     by the task.  This region may be read/execute only.
  *   datasize - The size (in bytes) of the .data/.bss address environment
+ *     needed by the task.  This region may be read/write only.  NOTE: The
+ *     actual size of the data region that is allocated will include a
+ *     OS private reserved region at the beginning.  The size of the
+ *     private, reserved region is give by ARCH_DATA_RESERVE_SIZE.
+ *   heapsize - The initial size (in bytes) of the heap address environment
  *     needed by the task.  This region may be read/write only.
  *   addrenv - The location to return the representation of the task address
  *     environment.
@@ -229,7 +235,7 @@ return g_physhandle ? OK : -ENOMEM;
  *
  ****************************************************************************/
 
-int up_addrenv_create(size_t textsize, size_t datasize,
+int up_addrenv_create(size_t textsize, size_t datasize, size_t heapsize,
                       FAR group_addrenv_t *addrenv)
 {
   FAR struct z180_cbr_s *cbr;
@@ -241,7 +247,7 @@ int up_addrenv_create(size_t textsize, size_t datasize,
 
   /* Convert the size from bytes to numbers of pages */
 
-  envsize = textsize + datasize;
+  envsize = textsize + datasize + heapsize;
   npages  = PHYS_ALIGNUP(envsize);
   if (npages < 1)
     {
@@ -390,6 +396,32 @@ int up_addrenv_vdata(FAR group_addrenv_t *addrenv, uintptr_t textsize,
 }
 
 /****************************************************************************
+ * Name: up_addrenv_heapsize
+ *
+ * Description:
+ *   Return the initial heap allocation size.  That is the amount of memory
+ *   allocated by up_addrenv_create() when the heap memory region was first
+ *   created.  This may or may not differ from the heapsize parameter that
+ *   was passed to up_addrenv_create()
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *     returned by up_addrenv_create.
+ *
+ * Returned Value:
+ *   The initial heap size allocated is returned on success; a negated
+ *   errno value on failure.
+ *
+ ****************************************************************************/
+
+ssize_t up_addrenv_heapsize(FAR const group_addrenv_t *addrenv)
+{
+  /* Not implemented */
+
+  return (ssize_t)-ENOSYS;
+}
+
+/****************************************************************************
  * Name: up_addrenv_select
  *
  * Description:
diff --git a/nuttx/binfmt/binfmt_execmodule.c b/nuttx/binfmt/binfmt_execmodule.c
index 1afb4e8b3..b9a1dde79 100644
--- a/nuttx/binfmt/binfmt_execmodule.c
+++ b/nuttx/binfmt/binfmt_execmodule.c
@@ -48,6 +48,7 @@
 
 #include <nuttx/arch.h>
 #include <nuttx/kmalloc.h>
+#include <nuttx/mm.h>
 #include <nuttx/binfmt/binfmt.h>
 
 #include "sched/sched.h"
@@ -164,9 +165,9 @@ int exec_module(FAR const struct binary_s *binp)
       goto errout;
     }
 
-  /* Instantiate the address environment containing the destructors */
-
 #ifdef CONFIG_ARCH_ADDRENV
+  /* Instantiate the address environment containing the user heap */
+
   ret = up_addrenv_select(&binp->addrenv, &oldenv);
   if (ret < 0)
     {
@@ -174,9 +175,18 @@ int exec_module(FAR const struct binary_s *binp)
       err = -ret;
       goto errout_with_tcb;
     }
+
+  /* Initialize the user heap */
+
+  umm_initialize((FAR void *)CONFIG_ARCH_HEAP_VBASE,
+                 up_addrenv_heapsize(&binp->addrenv));
 #endif
 
-  /* Allocate the stack for the new task (always from the user heap) */
+  /* Allocate the stack for the new task.
+   *
+   * REVISIT:  This allocation is currently always from the user heap.  That
+   * will need to change if/when we want to support dynamic stack allocation.
+   */
 
   stack = (FAR uint32_t*)kumm_malloc(binp->stacksize);
   if (!stack)
@@ -185,18 +195,6 @@ int exec_module(FAR const struct binary_s *binp)
       goto errout_with_addrenv;
     }
 
-  /* Restore the address environment */
-
-#ifdef CONFIG_ARCH_ADDRENV
-  ret = up_addrenv_restore(&oldenv);
-  if (ret < 0)
-    {
-      bdbg("ERROR: up_addrenv_select() failed: %d\n", ret);
-      err = -ret;
-      goto errout_with_stack;
-    }
-#endif
-
   /* Initialize the task */
 
   ret = task_init((FAR struct tcb_s *)tcb, binp->filename, binp->priority,
@@ -262,6 +260,18 @@ int exec_module(FAR const struct binary_s *binp)
       goto errout_with_stack;
     }
 
+#ifdef CONFIG_ARCH_ADDRENV
+  /* Restore the address environment of the caller */
+
+  ret = up_addrenv_restore(&oldenv);
+  if (ret < 0)
+    {
+      bdbg("ERROR: up_addrenv_select() failed: %d\n", ret);
+      err = -ret;
+      goto errout_with_stack;
+    }
+#endif
+
   return (int)pid;
 
 errout_with_stack:
diff --git a/nuttx/binfmt/libelf/libelf.h b/nuttx/binfmt/libelf/libelf.h
index 4304e64f2..58ec757b8 100644
--- a/nuttx/binfmt/libelf/libelf.h
+++ b/nuttx/binfmt/libelf/libelf.h
@@ -283,6 +283,8 @@ int elf_loaddtors(FAR struct elf_loadinfo_s *loadinfo);
  *     for the ELF image (read/execute).
  *   datasize - The size (in bytes) of the .bss/.data address environment
  *     needed for the ELF image (read/write).
+ *   heapsize - The initial size (in bytes) of the heap address environment
+ *     needed by the task.  This region may be read/write only.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -290,13 +292,13 @@ int elf_loaddtors(FAR struct elf_loadinfo_s *loadinfo);
  ****************************************************************************/
 
 int elf_addrenv_alloc(FAR struct elf_loadinfo_s *loadinfo, size_t textsize,
-                      size_t datasize);
+                      size_t datasize, size_t heapsize);
 
 /****************************************************************************
  * Name: elf_addrenv_select
  *
  * Description:
- *   Temporarity select the task's address environemnt.
+ *   Temporarily select the task's address environemnt.
  *
  * Input Parameters:
  *   loadinfo - Load state information
diff --git a/nuttx/binfmt/libelf/libelf_addrenv.c b/nuttx/binfmt/libelf/libelf_addrenv.c
index 08beed008..6b3be4306 100644
--- a/nuttx/binfmt/libelf/libelf_addrenv.c
+++ b/nuttx/binfmt/libelf/libelf_addrenv.c
@@ -80,6 +80,8 @@
  *     for the ELF image (read/execute).
  *   datasize - The size (in bytes) of the .bss/.data address environment
  *     needed for the ELF image (read/write).
+ *   heapsize - The initial size (in bytes) of the heap address environment
+ *     needed by the task.  This region may be read/write only.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -87,7 +89,7 @@
  ****************************************************************************/
 
 int elf_addrenv_alloc(FAR struct elf_loadinfo_s *loadinfo, size_t textsize,
-                      size_t datasize)
+                      size_t datasize, size_t heapsize)
 {
 #ifdef CONFIG_ARCH_ADDRENV
   FAR void *vtext;
@@ -96,7 +98,7 @@ int elf_addrenv_alloc(FAR struct elf_loadinfo_s *loadinfo, size_t textsize,
 
   /* Create an address environment for the new ELF task */
 
-  ret = up_addrenv_create(textsize, datasize, &loadinfo->addrenv);
+  ret = up_addrenv_create(textsize, datasize, heapsize, &loadinfo->addrenv);
   if (ret < 0)
     {
       bdbg("ERROR: up_addrenv_create failed: %d\n", ret);
@@ -145,7 +147,7 @@ int elf_addrenv_alloc(FAR struct elf_loadinfo_s *loadinfo, size_t textsize,
  *
  * Description:
  *   Release the address environment previously created by
- *   elf_addrenv_create().  This function  is called only under certain error
+ *   elf_addrenv_alloc().  This function  is called only under certain error
  *   conditions after the module has been loaded but not yet started.
  *   After the module has been started, the address environment will
  *   automatically be freed when the module exits.
diff --git a/nuttx/binfmt/libelf/libelf_load.c b/nuttx/binfmt/libelf/libelf_load.c
index 5fd4ce570..75ecb30fc 100644
--- a/nuttx/binfmt/libelf/libelf_load.c
+++ b/nuttx/binfmt/libelf/libelf_load.c
@@ -49,6 +49,7 @@
 #include <errno.h>
 #include <debug.h>
 
+#include <nuttx/addrenv.h>
 #include <nuttx/binfmt/elf.h>
 
 #include "libelf.h"
@@ -62,7 +63,11 @@
 #define ELF_ALIGNDOWN(a) ((unsigned long)(a) & ~ELF_ALIGN_MASK)
 
 #ifndef MAX
-#define MAX(x,y) ((x) > (y) ? (x) : (y))
+#  define MAX(x,y) ((x) > (y) ? (x) : (y))
+#endif
+
+#ifndef MIN
+#  define MIN(x,y) ((x) < (y) ? (x) : (y))
 #endif
 
 /****************************************************************************
@@ -229,6 +234,7 @@ static inline int elf_loadfile(FAR struct elf_loadinfo_s *loadinfo)
 
 int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 {
+  size_t heapsize;
   int ret;
 
   bvdbg("loadinfo: %p\n", loadinfo);
@@ -247,9 +253,17 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 
   elf_elfsize(loadinfo);
 
+  /* Determine the heapsize to allocate */
+
+#ifdef CONFIG_ARCH_STACK_DYNAMIC
+  heapsize = ARCH_HEAP_SIZE;
+#else
+  heapsize = MIN(ARCH_HEAP_SIZE, CONFIG_ELF_STACKSIZE);
+#endif
+
   /* Allocate (and zero) memory for the ELF file. */
 
-  ret = elf_addrenv_alloc(loadinfo, loadinfo->textsize, loadinfo->datasize);
+  ret = elf_addrenv_alloc(loadinfo, loadinfo->textsize, loadinfo->datasize, heapsize);
   if (ret < 0)
     {
       bdbg("ERROR: elf_addrenv_alloc() failed: %d\n", ret);
diff --git a/nuttx/binfmt/libnxflat/libnxflat.h b/nuttx/binfmt/libnxflat/libnxflat.h
index fc3826295..32d82df74 100644
--- a/nuttx/binfmt/libnxflat/libnxflat.h
+++ b/nuttx/binfmt/libnxflat/libnxflat.h
@@ -116,7 +116,7 @@ int nxflat_addrenv_alloc(FAR struct nxflat_loadinfo_s *loadinfo, size_t envsize)
  *
  * Description:
  *   Release the address environment previously created by
- *   nxflat_addrenv_create().  This function  is called only under certain
+ *   nxflat_addrenv_alloc().  This function  is called only under certain
  *   error conditions after the module has been loaded but not yet
  *   started. After the module has been started, the address environment
  *   will automatically be freed when the module exits.
diff --git a/nuttx/binfmt/libnxflat/libnxflat_addrenv.c b/nuttx/binfmt/libnxflat/libnxflat_addrenv.c
index fb3dbe09a..c7e82f537 100644
--- a/nuttx/binfmt/libnxflat/libnxflat_addrenv.c
+++ b/nuttx/binfmt/libnxflat/libnxflat_addrenv.c
@@ -52,6 +52,10 @@
  * Pre-Processor Definitions
  ****************************************************************************/
 
+#ifndef MIN
+#  define MIN(x,y) ((x) < (y) ? (x) : (y))
+#endif
+
 /****************************************************************************
  * Private Constant Data
  ****************************************************************************/
@@ -88,6 +92,7 @@ int nxflat_addrenv_alloc(FAR struct nxflat_loadinfo_s *loadinfo, size_t envsize)
 #ifdef CONFIG_ARCH_ADDRENV
   FAR void *vdata;
   save_addrenv_t oldenv;
+  size_t heapsize;
   int ret;
 #endif
 
@@ -103,9 +108,17 @@ int nxflat_addrenv_alloc(FAR struct nxflat_loadinfo_s *loadinfo, size_t envsize)
     }
 
 #ifdef CONFIG_ARCH_ADDRENV
+  /* Determine the heapsize to allocate */
+
+#ifdef CONFIG_ARCH_STACK_DYNAMIC
+  heapsize = ARCH_HEAP_SIZE;
+#else
+  heapsize = MIN(loadinfo->stacksize, ARCH_HEAP_SIZE);
+#endif
+
   /* Create a D-Space address environment for the new NXFLAT task */
 
-  ret = up_addrenv_create(envsize, &loadinfo->addrenv);
+  ret = up_addrenv_create(0, envsize, heapsize, &loadinfo->addrenv);
   if (ret < 0)
     {
       bdbg("ERROR: up_addrenv_create failed: %d\n", ret);
diff --git a/nuttx/include/nuttx/addrenv.h b/nuttx/include/nuttx/addrenv.h
index 6b1fc2809..385bce32e 100644
--- a/nuttx/include/nuttx/addrenv.h
+++ b/nuttx/include/nuttx/addrenv.h
@@ -245,27 +245,28 @@ struct addrenv_reserve_s
  * is an abstract representation of a task group's address environment and
  * must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
  *
- *   up_addrenv_create  - Create an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_vtext   - Returns the virtual base address of the .text
- *                        address environment
- *   up_addrenv_vdata   - Returns the virtual base address of the .bss/.data
- *                        address environment
- *   up_addrenv_select  - Instantiate an address environment
- *   up_addrenv_restore - Restore an address environment
- *   up_addrenv_clone   - Copy an address environment from one location to
- *                        another.
+ *   up_addrenv_create   - Create an address environment
+ *   up_addrenv_destroy  - Destroy an address environment.
+ *   up_addrenv_vtext    - Returns the virtual base address of the .text
+ *                         address environment
+ *   up_addrenv_vdata    - Returns the virtual base address of the .bss/.data
+ *                         address environment
+ *   up_addrenv_heapsize - Returns the size of the initial heap allocation.
+ *   up_addrenv_select   - Instantiate an address environment
+ *   up_addrenv_restore  - Restore an address environment
+ *   up_addrenv_clone    - Copy an address environment from one location to
+ *                         another.
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
  * used by the functions in sched/ and all operate on the thread which whose
  * group been assigned an address environment by up_addrenv_clone().
  *
- *   up_addrenv_attach  - Clone the address environment assigned to one TCB
- *                        to another.  This operation is done when a pthread
- *                        is created that share's the same address
- *                        environment.
- *   up_addrenv_detach  - Release the threads reference to an address
- *                        environment when a task/thread exits.
+ *   up_addrenv_attach   - Clone the address environment assigned to one TCB
+ *                         to another.  This operation is done when a pthread
+ *                         is created that share's the same address
+ *                         environment.
+ *   up_addrenv_detach   - Release the threads reference to an address
+ *                         environment when a task/thread exits.
  *
  ****************************************************************************/
 
diff --git a/nuttx/include/nuttx/arch.h b/nuttx/include/nuttx/arch.h
index 9344383a8..92deaacca 100644
--- a/nuttx/include/nuttx/arch.h
+++ b/nuttx/include/nuttx/arch.h
@@ -724,27 +724,28 @@ uintptr_t pgalloc(uintptr_t brkaddr, unsigned int npages);
  * is an abstract representation of a task group's address environment and
  * must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
  *
- *   up_addrenv_create  - Create an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_vtext   - Returns the virtual base address of the .text
- *                        address environment
- *   up_addrenv_vdata   - Returns the virtual base address of the .bss/.data
- *                        address environment
- *   up_addrenv_select  - Instantiate an address environment
- *   up_addrenv_restore - Restore an address environment
- *   up_addrenv_clone   - Copy an address environment from one location to
- *                        another.
+ *   up_addrenv_create   - Create an address environment
+ *   up_addrenv_destroy  - Destroy an address environment.
+ *   up_addrenv_vtext    - Returns the virtual base address of the .text
+ *                         address environment
+ *   up_addrenv_vdata    - Returns the virtual base address of the .bss/.data
+ *                         address environment
+ *   up_addrenv_heapsize - Returns the size of the initial heap allocation.
+ *   up_addrenv_select   - Instantiate an address environment
+ *   up_addrenv_restore  - Restore an address environment
+ *   up_addrenv_clone    - Copy an address environment from one location to
+ *                         another.
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
  * used by the functions in sched/ and all operate on the thread which whose
  * group been assigned an address environment by up_addrenv_clone().
  *
- *   up_addrenv_attach  - Clone the address environment assigned to one TCB
- *                        to another.  This operation is done when a pthread
- *                        is created that share's the same address
- *                        environment.
- *   up_addrenv_detach  - Release the threads reference to an address
- *                        environment when a task/thread exits.
+ *   up_addrenv_attach   - Clone the address environment assigned to one TCB
+ *                         to another.  This operation is done when a pthread
+ *                         is created that share's the same address
+ *                         environment.
+ *   up_addrenv_detach   - Release the threads reference to an address
+ *                         environment when a task/thread exits.
  *
  ****************************************************************************/
 /****************************************************************************
@@ -764,6 +765,8 @@ uintptr_t pgalloc(uintptr_t brkaddr, unsigned int npages);
  *     actual size of the data region that is allocated will include a
  *     OS private reserved region at the beginning.  The size of the
  *     private, reserved region is give by ARCH_DATA_RESERVE_SIZE.
+ *   heapsize - The initial size (in bytes) of the heap address environment
+ *     needed by the task.  This region may be read/write only.
  *   addrenv - The location to return the representation of the task address
  *     environment.
  *
@@ -773,7 +776,7 @@ uintptr_t pgalloc(uintptr_t brkaddr, unsigned int npages);
  ****************************************************************************/
 
 #ifdef CONFIG_ARCH_ADDRENV
-int up_addrenv_create(size_t textsize, size_t datasize,
+int up_addrenv_create(size_t textsize, size_t datasize, size_t heapsize,
                       FAR group_addrenv_t *addrenv);
 #endif
 
@@ -851,6 +854,29 @@ int up_addrenv_vdata(FAR group_addrenv_t *addrenv, uintptr_t textsize,
 #endif
 
 /****************************************************************************
+ * Name: up_addrenv_heapsize
+ *
+ * Description:
+ *   Return the initial heap allocation size.  That is the amount of memory
+ *   allocated by up_addrenv_create() when the heap memory region was first
+ *   created.  This may or may not differ from the heapsize parameter that
+ *   was passed to up_addrenv_create()
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *     returned by up_addrenv_create.
+ *
+ * Returned Value:
+ *   The initial heap size allocated is returned on success; a negated
+ *   errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ARCH_ADDRENV
+ssize_t up_addrenv_heapsize(FAR const group_addrenv_t *addrenv);
+#endif
+
+/****************************************************************************
  * Name: up_addrenv_select
  *
  * Description:
diff --git a/nuttx/include/nuttx/mm.h b/nuttx/include/nuttx/mm.h
index 3330b2bfc..b748c16b4 100644
--- a/nuttx/include/nuttx/mm.h
+++ b/nuttx/include/nuttx/mm.h
@@ -297,9 +297,7 @@ void mm_addregion(FAR struct mm_heap_s *heap, FAR void *heapstart,
 
 /* Functions contained in umm_initialize.c **********************************/
 
-#if !defined(CONFIG_BUILD_PROTECTED) || !defined(__KERNEL__)
 void umm_initialize(FAR void *heap_start, size_t heap_size);
-#endif
 
 /* Functions contained in kmm_initialize.c **********************************/
 
diff --git a/nuttx/mm/umm_initialize.c b/nuttx/mm/umm_initialize.c
index d7288e474..fb812d5c5 100644
--- a/nuttx/mm/umm_initialize.c
+++ b/nuttx/mm/umm_initialize.c
@@ -88,8 +88,36 @@ struct mm_heap_s g_mmheap;
  *
  * Description:
  *   This is a simple wrapper for the mm_initialize() function.  This
- *   function is exported from the user-space blob so that the kernel
- *   can initialize the user-mode allocator.
+ *   function will initialize the user heap.
+ *
+ *   CONFIG_BUILD_FLAT:
+ *     There is only kernel mode "blob" containing both containing both
+ *     kernel and application code.  There is only one heap that use is
+ *     used by both the kernel and application logic.
+ *
+ *     In this configuration, this function is called early in os_start()
+ *     to initialize the common heap.
+ *
+ *   CONFIG_BUILD_PROTECTED
+ *     In this configuration, there are two "blobs", one containing
+ *     protected kernel logic and one containing unprotected application
+ *     logic.  Depending upon the setting of CONFIG_MM_KERNEL_HEAP there
+ *     may be only a signal shared heap, much as with CONFIG_BUILD_FLAT.
+ *     Or there may be separate protected/kernel and unprotected/user
+ *     heaps.
+ *
+ *     In either case, this function is still called early in os_start()
+ *     to initialize the user heap.
+ *
+ *   CONFIG_BUILD_KERNEL
+ *     In this configuration there are multiple user heaps, one for each
+ *     user process.  Furthermore, each heap is initially empty; memory
+ *     is added to each heap dynamically via sbrk().  The heap data
+ *     structure was set to zero when the address environment was created.
+ *     Otherwise, the heap is uninitialized.
+ *
+ *     This function is not called at all.  Rather, this function is called
+ *     when each user process is created before the first allocation is made.
  *
  * Parameters:
  *   heap_start - Address of the beginning of the (initial) memory region
@@ -102,10 +130,6 @@ struct mm_heap_s g_mmheap;
 
 void umm_initialize(FAR void *heap_start, size_t heap_size)
 {
-#if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_BUILD_KERNEL)
-  DEBUGASSERT(ARCH_DATA_RESERVE_SIZE >= sizeof(struct addrenv_reserve_s));
-#endif
-
   mm_initialize(USR_HEAP, heap_start, heap_size);
 }