An address environment is the property of a task group, not of a thread

13 files changed, 271 insertions, 299 deletions

diff --git a/nuttx/Documentation/NuttXBinfmt.html b/nuttx/Documentation/NuttXBinfmt.html
index 2f4f6e425..0df3b6475 100644
--- a/nuttx/Documentation/NuttXBinfmt.html
+++ b/nuttx/Documentation/NuttXBinfmt.html
@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX Binary Loader</i></font></big></h1>
-      <p>Last Updated: January 16, 2013</p>
+      <p>Last Updated: August 22, 2014</p>
     </td>
   </tr>
 </table>
@@ -170,7 +170,7 @@ struct binary_s
    */
 
 #ifdef CONFIG_ADDRENV
-  task_addrenv_t addrenv;              /* Task address environment */
+  group_addrenv_t addrenv;             /* Task group address environment */
 #endif
 
   size_t mapsize;                      /* Size of the mapped address region (needed for munmap) */
diff --git a/nuttx/Documentation/NuttxPortingGuide.html b/nuttx/Documentation/NuttxPortingGuide.html
index 011048d2a..88c7bb2e1 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 21, 2014</p>
+      <p>Last Updated: August 22, 2014</p>
     </td>
   </tr>
 </table>
@@ -107,13 +107,13 @@
     <a href="#addrenv">4.4 Address Environments</a>
     <ul>
       <a href="#up_addrenv_create">4.4.1 <code>up_addrenv_create()</code></a></br>
-      <a href="#up_addrenv_vaddr">4.4.2 <code>up_addrenv_vaddr()</code></a></br>
-      <a href="#up_addrenv_select">4.4.3 <code>up_addrenv_select()</code></a></br>
-      <a href="#up_addrenv_restore">4.4.4 <code>up_addrenv_restore()</code></a></br>
-      <a href="#up_addrenv_destroy">4.4.5 <code>up_addrenv_destroy()</code></a></br>
+      <a href="#up_addrenv_destroy">4.4.2 <code>up_addrenv_destroy()</code></a></br>
+      <a href="#up_addrenv_vaddr">4.4.3 <code>up_addrenv_vaddr()</code></a></br>
+      <a href="#up_addrenv_select">4.4.4 <code>up_addrenv_select()</code></a></br>
+      <a href="#up_addrenv_restore">4.4.5 <code>up_addrenv_restore()</code></a></br>
       <a href="#up_addrenv_assign">4.4.6 <code>up_addrenv_assign()</code></a></br>
-      <a href="#up_addrenv_share">4.4.7 <code>up_addrenv_share()</code></a></br>
-      <a href="#up_addrenv_release">4.4.8 <code>up_addrenv_release()</code></a>
+      <a href="#up_addrenv_attach">4.4.7 <code>up_addrenv_attach()</code></a></br>
+      <a href="#up_addrenv_detach">4.4.8 <code>up_addrenv_detach()</code></a>
     </ul>
     <a href="#exports">4.5 APIs Exported by NuttX to Architecture-Specific Logic</a>
     <ul>
@@ -2625,7 +2625,7 @@ int up_alarm_cancel(FAR struct timespec *ts);
   May be called from interrupt level handling or from the normal tasking level. iterrupts may need to be disabled internally to assure non-reentrancy.
 </ul>
 
-<h5><a name="upalarmstart">4.3.4.4.5 <code>up_alarm_start()</code></a></h5>
+<h5><a name="upalarmstart">4.3.4.4.4 <code>up_alarm_start()</code></a></h5>
 <p><b>Function Prototype</b>:<p>
 <ul><pre>
 #include &lt;nuttx/arch.h&gt;
@@ -2930,8 +2930,7 @@ VxWorks provides the following comparable interface:
     <p>
       <b>Binary Loader Support</b>.
       These are low-level interfaces used in <code>binfmt/</code> to instantiate tasks with address environments.
-      These interfaces all operate on type <code>task_addrenv_t</code> which is an abstract representation of a asks's address environment and must be defined in arch/arch.h if <code>CONFIG_ADDRENV</code> is defined.
-      These low-level interfaces include:
+      These interfaces all operate on type <code>group_addrenv_t</code> which is an abstract representation of a task group's address environment and the type must be defined in<code>arch/arch.h</code> if <code>CONFIG_ADDRENV</code> is defined. These low-level interfaces include:
     </p>
     <ul>
       <li>
@@ -2939,24 +2938,24 @@ VxWorks provides the following comparable interface:
         Create an address environment.
       </li>
       <li>
-        <a href="#up_addrenv_vaddr">4.4.2 <code>up_addrenv_vaddr()</code></a>:
+        <a href="#up_addrenv_destroy">4.4.2 <code>up_addrenv_destroy()</code></a>:
+        Destroy an address environment.
+      </li>
+      <li>
+        <a href="#up_addrenv_vaddr">4.4.3 <code>up_addrenv_vaddr()</code></a>:
         Returns the virtual base address of the address environment.
       </li>
       <li>
-        <a href="#up_addrenv_select">4.4.3 <code>up_addrenv_select()</code></a>:
+        <a href="#up_addrenv_select">4.4.4 <code>up_addrenv_select()</code></a>:
         Instantiate an address environment.
       </li>
       <li>
-        <a href="#up_addrenv_restore">4.4.4 <code>up_addrenv_restore()</code></a>:
+        <a href="#up_addrenv_restore">4.4.5 <code>up_addrenv_restore()</code></a>:
         Restore an address environment.
       </li>
       <li>
-        <a href="#up_addrenv_destroy">4.4.5 <code>up_addrenv_destroy()</code></a>:
-        Destroy an address environment.
-      </li>
-      <li>
         <a href="#up_addrenv_assign">4.4.6 <code>up_addrenv_assign()</code></a>:
-        Assign an address environment to a TCB.
+        Assign an address environment to a thread.
       </li>
     </ul>
   </li>
@@ -2964,31 +2963,30 @@ VxWorks provides the following comparable interface:
     <p>
       <b>Tasking Support</b>.
       Other interfaces must be provided to support higher-level interfaces used by the NuttX tasking logic.
-      These interfaces are* used by the functions in <code>sched/</code> and all operate on the TCB which as been assigned an address environment by <code>up_addrenv_assign()</code>.
+      These interfaces are* used by the functions in <code>sched/</code> and all operate on the task group which as been assigned an address environment by <code>up_addrenv_assign()</code>.
     </p>
     <ul>
       <li>
-        <a href="#up_addrenv_share">4.4.7 <code>up_addrenv_share()</code></a>:
-        Clone the address environment assigned to one TCB to another.
+        <a href="#up_addrenv_attach">4.4.7 <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_release">4.4.8 <code>up_addrenv_release()</code></a>:
-        Release the TCB's reference to an address environment when a task/thread exits.
+        <a href="#up_addrenv_detach">4.4.8 <code>up_addrenv_detach()</code></a>:
+        Release the thread's reference to a group address environment when a task/thread exits.
       </li>
     </ul>
   </li>
 </ol>
 
-
 <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 envsize, FAR task_addrenv_t *addrenv);</code>
+  <code>int up_addrenv_create(size_t envsize, FAR group_addrenv_t *addrenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  This function is called from the binary loader logic when a new task is created in order to instantiate an address environment for the task.
+  This function is called when a new task is created in order to instantiate an address environment for the new task group.
   <code>up_addrenv_create()</code> is essentially the allocator of the physical memory for the new task.
 </ul>
 <p><b>Input Parameters</b>:</p>
@@ -3001,81 +2999,81 @@ 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_vaddr">4.4.2 <code>up_addrenv_vaddr()</code></a></h3>
+<h3><a name="up_addrenv_destroy">4.4.2 <code>up_addrenv_destroy()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr);</code>
+  <code>int up_addrenv_destroy(group_addrenv_t addrenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  Return the virtual address associated with the newly create address environment.
-  This function is used by the binary loaders in order get an address that can be used to initialize the new task.
+  This function is called when a final thread leaves the task group and the task group is destroyed.  This function then destroys the defunct address environment, releasing the underlying physical memory allocated by <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 up_addrenv_create.</li>
-  <li><code>vaddr</code>: The location to return the virtual address.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_select">4.4.3 <code>up_addrenv_select()</code></a></h3>
+<h3><a name="up_addrenv_vaddr">4.4.3 <code>up_addrenv_vaddr()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_select(task_addrenv_t addrenv, hw_addrenv_t *oldenv);</code>
+  <code>int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  After an address environment has been established for a task (via <code>up_addrenv_create())</code>, this function may be called to to instantiate that address environment in the virtual address space.
-  This might be necessary, for example, to load the code for the task from a file or to access address environment private data.
+  Return the virtual address associated with the newly create address environment.
+  This function is used by the binary loaders in order get an address that can be used to initialize the new task.
 </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>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.
-    Note that this may be a task agnostic, hardware representation that is different from <code>task_addrenv_t</code>.
-  </li>
+  <li><code>vaddr</code>: The location to return the virtual address.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_restore">4.4.4 <code>up_addrenv_restore()</code></a></h3>
+<h3><a name="up_addrenv_select">4.4.4 <code>up_addrenv_select()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_restore(hw_addrenv_t oldenv);</code>
+  <code>int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  After an address environment has been temporarily instantiated by <code>up_addrenv_select</code>,
-  this function may be called to to restore the original address environment.
+  After an address environment has been established for a task (via <code>up_addrenv_create())</code>, this function may be called to to instantiate that address environment in the virtual address space.
+  This might be necessary, for example, to load the code for the task from a file or to access address environment private data.
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>oldenv</code>: The hardware representation of the address environment previously returned by <code>up_addrenv_select()</code>.</li>
+  <li><code>addrenv</code>: The representation of the task address environment previously returned by up_addrenv_create.</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.
+    Note that this may be a task agnostic, hardware representation that is different from <code>group_addrenv_t</code>.
+  </li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_destroy">4.4.5 <code>up_addrenv_destroy()</code></a></h3>
+<h3><a name="up_addrenv_restore">4.4.5 <code>up_addrenv_restore()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_destroy(task_addrenv_t addrenv);</code>
+  <code>int up_addrenv_restore(hw_addrenv_t oldenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  Called from the binary loader loader during error handling to destroy the address environment previously created by <code>up_addrenv_create()</code>.
+  After an address environment has been temporarily instantiated by <code>up_addrenv_select</code>,
+  this function may be called to to restore the original address environment.
 </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>oldenv</code>: The hardware representation of the address environment previously returned by <code>up_addrenv_select()</code>.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
@@ -3085,55 +3083,60 @@ VxWorks provides the following comparable interface:
 <h3><a name="up_addrenv_assign">4.4.6 <code>up_addrenv_assign()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_assign(task_addrenv_t addrenv, FAR struct tcb_s *tcb);</code>
+  <code>int up_addrenv_assign(group_addrenv_t addrenv, FAR struct task_group_s *group);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  Assign an address environment to a TCB.
+  Assign an address environment to a new task group.
 </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>tcb</code>: The TCB of the task to receive the address environment.</li>
+  <li><code>addrenv</code>: The representation of the group address environment previously returned by <code>up_addrenv_create</code>.</li>
+  <li><code>group</code>: The new task group to receive the address environment.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_share">4.4.7 <code>up_addrenv_share()</code></a></h3>
+<h3><a name="up_addrenv_attach">4.4.7 <code>up_addrenv_attach()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_share(FAR const struct tcb_s *ptcb, FAR struct tcb_s *ctcb);</code>
+  <code>int up_addrenv_attach(FAR struct task_group_s *group, FAR struct tcb_s *tcb);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  This function is called from the core scheduler logic when a thread is created that needs to share the address environment of its parent task.
-  In this case, the parent's address environment needs to be &quot;cloned&quot; for the child thread.
+  <p>
+  This function is called from the core scheduler logic when a thread is created that needs to share the address environment of its task group.
+  In this case, the group's address environment may need to be &quot;cloned&quot; for the child thread.
+  </p>
+  <p>
+  NOTE: In most platforms, nothing will need to be done in this case.
+  Simply being a member of the group that has the address environment may be sufficient.
+  </p>
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
-  <li><code>ptcb</code>: The TCB of the parent task that has the address environment.</li>
-  <li><code>ctcb</code>: The TCB of the child thread needing the address environment.</li>
+  <li><code>group</code>: The task group to which the new thread belongs.</li>
+  <li><code>ctcb</code>: The TCB of the thread needing the address environment.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
   Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure.
 </ul>
 
-<h3><a name="up_addrenv_release">4.4.8 <code>up_addrenv_release()</code></a></h3>
+<h3><a name="up_addrenv_detach">4.4.8 <code>up_addrenv_detach()</code></a></h3>
 <p><b>Function Prototype</b>:<p>
 <ul>
-  <code>int up_addrenv_release(FAR struct tcb_s *tcb);</code>
+  <code>int up_addrenv_detach(FAR struct task_group_s *group, FAR struct task_group_s *tcb);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
-  This function is called when a task or thread exits in order to release its reference to an address environment.
-  When there are no further references to an address environment, that address environment should
-  be destroyed.
+  This function is called when a task or thread exits in order to release its reference to an address environment.  The address environment, however, should persist until up_addrenv_destroy() is called when the task group is itself destroyed.  Any resources unique to this thread  may be destroyed now.
 </ul>
 <p><b>Input Parameters</b>:</p>
 <ul>
+  <li><code>group</code>: The group to which the thread belonged.</li>
   <li><code>tcb</code>: The TCB of the task or thread whose the address environment will be released.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
diff --git a/nuttx/arch/z80/include/z180/arch.h b/nuttx/arch/z80/include/z180/arch.h
index d7cf82a26..72306b930 100644
--- a/nuttx/arch/z80/include/z180/arch.h
+++ b/nuttx/arch/z80/include/z180/arch.h
@@ -1,6 +1,5 @@
 /****************************************************************************
  * arch/z80/arch.h
- * arch/chip/arch.h
  *
  *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
@@ -73,7 +72,7 @@ typedef uint8_t hw_addrenv_t;
  */
 
 struct z180_cbr_s;
-typedef FAR struct z180_cbr_s *task_addrenv_t;
+typedef FAR struct z180_cbr_s *group_addrenv_t;
 #endif
 
 /****************************************************************************
diff --git a/nuttx/arch/z80/include/z180/irq.h b/nuttx/arch/z80/include/z180/irq.h
index 1d0c27cb4..ba809bad8 100644
--- a/nuttx/arch/z80/include/z180/irq.h
+++ b/nuttx/arch/z80/include/z180/irq.h
@@ -173,7 +173,7 @@ typedef uint16_t chipreg_t;
 struct z180_cbr_s
 {
   uint8_t cbr;   /* The CBR value used by the thread */
-  uint8_t crefs; /* The number of threads sharing this CBR value */
+  uint8_t crefs; /* The number of task groups using this CBR value (0 or 1) */
   uint8_t pages; /* The number of 4KB pages of physical memory in the allocation */
 };
 
@@ -183,10 +183,6 @@ struct z180_cbr_s
 
 struct xcptcontext
 {
-  /* CBR allocation */
-
-  FAR struct z180_cbr_s *cbr;
-
   /* Register save area */
 
   chipreg_t regs[XCPTCONTEXT_REGS];
diff --git a/nuttx/arch/z80/src/z180/z180_mmu.c b/nuttx/arch/z80/src/z180/z180_mmu.c
index 4306eaf5f..c54fda148 100644
--- a/nuttx/arch/z80/src/z180/z180_mmu.c
+++ b/nuttx/arch/z80/src/z180/z180_mmu.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/z80/src/z180/z180_mmu.c
  *
- *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012, 2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -180,36 +180,37 @@ return g_physhandle ? OK : -ENOMEM;
  * Address Environment Interfaces
  *
  * Low-level interfaces used in binfmt/ to instantiate tasks with address
- * environments.  These interfaces all operate on task_addrenv_t which is an
- * abstract representation of the address environment and must be provided
- * by arch/arch.h is CONFIG_ADDRENV is defined.
+ * environments.  These interfaces all operate on type group_addrenv_t which
+ * is an abstract representation of a task group's address environment and
+ * must be defined in arch/arch.h if CONFIG_ADDRENV is defined.
  *
  *   up_addrenv_create  - Create an address environment
+ *   up_addrenv_destroy - Destroy an address environment.
  *   up_addrenv_vaddr   - Returns the virtual base address of the address
  *                        environment
  *   up_addrenv_select  - Instantiate an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_assign  - Assign an address environment to a TCB
+ *   up_addrenv_restore - Restore an address environment
+ *   up_addrenv_assign  - Assign an address environment to a group
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
- * used by the functions in sched/ and all operate on the TCB which as been
- * assigned an address environment by up_addrenv_assign().
+ * used by the functions in sched/ and all operate on the thread which whose
+ * group been assigned an address environment by up_addrenv_assign().
  *
- *   up_addrenv_share   - Clone the address environment assigned to one TCB
+ *   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_release - Release the TCBs reference to an address
- *                        environment when a task/thread exists.
+ *   up_addrenv_detach - Release the threads reference to an address
+ *                        environment when a task/thread exits.
  *
  ****************************************************************************/
 /****************************************************************************
  * Name: up_addrenv_create
  *
  * Description:
- *   This function is called from the binary loader logic when a new
- *   task is created in order to instantiate an address environment for the
- *   task.  up_addrenv_create is essentially the allocator of the physical
+ *   This function is called when a new task is created in order to
+ *   instantiate an address environment for the new task group.
+ *   up_addrenv_create() is essentially the allocator of the physical
  *   memory for the new task.
  *
  * Input Parameters:
@@ -223,7 +224,7 @@ return g_physhandle ? OK : -ENOMEM;
  *
  ****************************************************************************/
 
-int up_addrenv_create(size_t envsize, FAR task_addrenv_t *addrenv)
+int up_addrenv_create(size_t envsize, FAR group_addrenv_t *addrenv)
 {
   FAR struct z180_cbr_s *cbr;
   irqstate_t flags;
@@ -280,7 +281,7 @@ int up_addrenv_create(size_t envsize, FAR task_addrenv_t *addrenv)
 
   cbr->cbr     = (uint8_t)alloc;
   cbr->pages   = (uint8_t)npages;
-  *addrenv     = (task_addrenv_t)cbr;
+  *addrenv     = (group_addrenv_t)cbr;
 
   irqrestore(flags);
   return OK;
@@ -294,6 +295,42 @@ errout_with_irq:
 }
 
 /****************************************************************************
+ * Name: up_addrenv_destroy
+ *
+ * Description:
+ *   This function is called when a final thread leaves the task group and
+ *   the task group is destroyed.  This function then destroys the defunct
+ *   address environment, releasing the underlying physical memory.
+ *
+ * Input Parameters:
+ *   addrenv - The address environment to be destroyed.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int up_addrenv_destroy(group_addrenv_t addrenv)
+{
+  FAR struct z180_cbr_s *cbr = (FAR struct z180_cbr_s *)addrenv;
+
+  DEBUGASSERT(cbr);
+
+  /* Free the physical address space backing up the mapping */
+
+#ifdef CONFIG_GRAN_SINGLE
+  gran_free((FAR void *)cbr->cbr, cbr->pages);
+#else
+  gran_free(g_physhandle, (FAR void *)cbr->cbr, cbr->pages);
+#endif
+
+  /* And make the CBR structure available for re-use */
+
+  z180_mmu_freecbr(cbr);
+  return OK;
+}
+
+/****************************************************************************
  * Name: up_addrenv_vaddr
  *
  * Description:
@@ -311,7 +348,7 @@ errout_with_irq:
  *
  ****************************************************************************/
 
-int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr)
+int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr)
 {
   return CONFIG_Z180_COMMON1AREA_VIRTBASE;
 }
@@ -334,14 +371,14 @@ int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr)
  *     This may be used with up_addrenv_restore() to restore the original
  *     address environment that was in place before up_addrenv_select() was
  *     called.  Note that this may be a task agnostic, hardware
- *     representation that is different from task_addrenv_t.
+ *     representation that is different from group_addrenv_t.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
  *
  ****************************************************************************/
 
-int up_addrenv_select(task_addrenv_t addrenv, hw_addrenv_t *oldenv)
+int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
 {
   FAR struct z180_cbr_s *cbr = (FAR struct z180_cbr_s *)addrenv;
   irqstate_t flags;
@@ -384,126 +421,75 @@ int up_addrenv_restore(hw_addrenv_t oldenv)
 }
 
 /****************************************************************************
- * Name: up_addrenv_destroy
- *
- * Description:
- *   Called from the binary loader loader during error handling to destroy
- *   the address environment previously created by up_addrenv_create().
- *
- * Input Parameters:
- *   addrenv - The representation of the task address environment previously
- *     returned by up_addrenv_create.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-int up_addrenv_destroy(task_addrenv_t addrenv)
-{
-  FAR struct z180_cbr_s *cbr = (FAR struct z180_cbr_s *)addrenv;
-
-  DEBUGASSERT(cbr);
-
-  /* Free the physical address space backing up the mapping */
-
-#ifdef CONFIG_GRAN_SINGLE
-  gran_free((FAR void *)cbr->cbr, cbr->pages);
-#else
-  gran_free(g_physhandle, (FAR void *)cbr->cbr, cbr->pages);
-#endif
-
-  /* And make the CBR structure available for re-use */
-
-  z180_mmu_freecbr(cbr);
-  return OK;
-}
-
-/****************************************************************************
  * Name: up_addrenv_assign
  *
  * Description:
- *   Assign an address environment to a TCB.
+ *   Assign an address environment to a task group.
  *
  * Input Parameters:
  *   addrenv - The representation of the task address environment previously
- *     returned by up_addrenv_create.
- *   tcb - The TCB of the task to receive the address environment.
+ *     returned by up_addrenv_create().
+ *   group - The task group to receive the address environment.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
  *
  ****************************************************************************/
 
-int up_addrenv_assign(task_addrenv_t addrenv, FAR struct tcb_s *tcb)
+int up_addrenv_assign(group_addrenv_t addrenv, FAR struct task_group_s *group)
 {
-  FAR struct z180_cbr_s *cbr = (FAR struct z180_cbr_s *)addrenv;
-
   /* Make sure that there is no address environment in place on this TCB */
 
-  DEBUGASSERT(cbr && tcb->xcp.cbr == NULL);
+  DEBUGASSERT(addrenv && group->addrenv == NULL);
 
-  /* Save the CBR strucure in the TCB.  This is an atomic operation so no
+  /* Save the CBR structure in the group.  This is an atomic operation so no
    * special precautions should be needed.
    */
 
-  tcb->xcp.cbr = cbr;
+  group->addrenv = addrenv;
   return OK;
 }
 
 /****************************************************************************
- * Name: up_addrenv_share
+ * Name: up_addrenv_attach
  *
  * Description:
  *   This function is called from the core scheduler logic when a thread
- *   is created that needs to share the address ennvironment of its parent
- *   task.  In this case, the parent's address environment needs to be
- *   "cloned" for the child.
+ *   is created that needs to share the address environment of its task
+ *   group.
  *
  * Input Parameters:
- *   ptcb - The TCB of the parent task that has the address environment.
- *   ctcb - The TCB of the child thread needing the address environment.
+ *   group - The task group to which the new thread belongs.
+ *   tcb   - The tcb of the thread needing the address environment.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
  *
  ****************************************************************************/
 
-int up_addrenv_share(FAR const struct tcb_s *ptcb, FAR struct tcb_s *ctcb)
+int up_addrenv_attach(FAR struct task_group_s *group, FAR struct tcb_s *tcb)
 {
-  irqstate_t flags;
-
-  /* Make sure that the child has no address environment.  It is okay if
-   * if the parent does not have one.
-   */
+  /* There is nothing that needs to be done */
 
-  DEBUGASSERT(ctcb->xcp.cbr == NULL);
-
-  flags = irqsave();
-  if (ptcb->xcp.cbr)
-    {
-      /* Clone the CBR by incrementing the reference counting and saving a
-       * copy in the child thread's TCB.
-       */
-
-      ptcb->xcp.cbr->crefs++;
-      ctcb->xcp.cbr = ptcb->xcp.cbr;
-    }
-
-  irqrestore(flags);
   return OK;
 }
 
 /****************************************************************************
- * Name: up_addrenv_release
+ * Name: up_addrenv_detach
  *
  * Description:
  *   This function is called when a task or thread exits in order to release
- *   its reference to an address environment.  When there are no further
- *   references to an address environment, that address environment should
- *   be destroyed.
+ *   its reference to an address environment.  The address environment,
+ *   however, should persist until up_addrenv_destroy() is called when the
+ *   task group is itself destroyed.  Any resources unique to this thread
+ *   may be destroyed now.
+ *
+ *   NOTE: In some platforms, nothing will need to be done in this case.
+ *   Simply being a member of the group that has the address environment
+ *   may be sufficient.
  *
  * Input Parameters:
+ *   group - The group to which the thread belonged.
  *   tcb - The TCB of the task or thread whose the address environment will
  *     be released.
  *
@@ -512,39 +498,10 @@ int up_addrenv_share(FAR const struct tcb_s *ptcb, FAR struct tcb_s *ctcb)
  *
  ****************************************************************************/
 
-int up_addrenv_release(FAR struct tcb_s *tcb)
+int up_addrenv_detach(FAR struct task_group_s *group,
+                      FAR struct task_group_s *tcb);
 {
-  FAR struct z180_cbr_s *cbr;
-  irqstate_t flags;
-
-  /* Check if the task has an address environment. */
-
-  flags = irqsave();
-  cbr   = tcb->xcp.cbr;
-  if (cbr)
-    {
-      /* Nullify the reference to the CBR structure and decrement the number
-       * of references on the CBR.
-       */
-
-      tcb->xcp.cbr = NULL;
-
-      /* If the reference count would decrement to zero, then free the CBR
-       * structure.
-       */
-
-      if (cbr->crefs <= 1)
-        {
-          up_addrenv_destroy(cbr);
-        }
-      else
-        {
-          /* Otherwise, just decrement the reference count */
-
-          cbr->crefs--;
-        }
-    }
+  /* There is nothing that needs to be done */
 
-  irqrestore(flags);
   return OK;
 }
diff --git a/nuttx/binfmt/binfmt_execmodule.c b/nuttx/binfmt/binfmt_execmodule.c
index 13c692018..c765724bd 100644
--- a/nuttx/binfmt/binfmt_execmodule.c
+++ b/nuttx/binfmt/binfmt_execmodule.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * binfmt/binfmt_execmodule.c
  *
- *   Copyright (C) 2009, 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2013-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -205,10 +205,10 @@ int exec_module(FAR const struct binary_s *binp)
   up_initial_state(&tcb->cmn);
 #endif
 
-  /* Assign the address environment to the task */
+  /* Assign the address environment to the new task group */
 
 #ifdef CONFIG_ADDRENV
-  ret = up_addrenv_assign(binp->addrenv, &tcb->cmn);
+  ret = up_addrenv_assign(binp->addrenv, tcb->group);
   if (ret < 0)
     {
       err = -ret;
diff --git a/nuttx/include/nuttx/arch.h b/nuttx/include/nuttx/arch.h
index 4fb3a193a..b1e972be5 100644
--- a/nuttx/include/nuttx/arch.h
+++ b/nuttx/include/nuttx/arch.h
@@ -669,27 +669,27 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size);
  * Address Environment Interfaces
  *
  * Low-level interfaces used in binfmt/ to instantiate tasks with address
- * environments.  These interfaces all operate on type task_addrenv_t which
- * is an abstract representation of a task's address environment and must be
- * defined in arch/arch.h if CONFIG_ADDRENV is defined.
+ * environments.  These interfaces all operate on type group_addrenv_t which
+ * is an abstract representation of a task group's address environment and
+ * must be defined in arch/arch.h if CONFIG_ADDRENV is defined.
  *
  *   up_addrenv_create  - Create an address environment
+ *   up_addrenv_destroy - Destroy an address environment.
  *   up_addrenv_vaddr   - Returns the virtual base address of the address
  *                        environment
  *   up_addrenv_select  - Instantiate an address environment
  *   up_addrenv_restore - Restore an address environment
- *   up_addrenv_destroy - Destroy an address environment.
- *   up_addrenv_assign  - Assign an address environment to a TCB
+ *   up_addrenv_assign  - Assign an address environment to a group
  *
  * Higher-level interfaces used by the tasking logic.  These interfaces are
- * used by the functions in sched/ and all operate on the TCB which as been
- * assigned an address environment by up_addrenv_assign().
+ * used by the functions in sched/ and all operate on the thread which whose
+ * group been assigned an address environment by up_addrenv_assign().
  *
- *   up_addrenv_share   - Clone the address environment assigned to one TCB
+ *   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_release - Release the TCBs reference to an address
+ *   up_addrenv_detach  - Release the threads reference to an address
  *                        environment when a task/thread exits.
  *
  ****************************************************************************/
@@ -697,9 +697,9 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size);
  * Name: up_addrenv_create
  *
  * Description:
- *   This function is called from the binary loader logic when a new
- *   task is created in order to instantiate an address environment for the
- *   task.  up_addrenv_create is essentially the allocator of the physical
+ *   This function is called when a new task is created in order to
+ *   instantiate an address environment for the new task group. 
+ *   up_addrenv_create() is essentially the allocator of the physical
  *   memory for the new task.
  *
  * Input Parameters:
@@ -714,7 +714,27 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_create(size_t envsize, FAR task_addrenv_t *addrenv);
+int up_addrenv_create(size_t envsize, FAR group_addrenv_t *addrenv);
+#endif
+
+/****************************************************************************
+ * Name: up_addrenv_destroy
+ *
+ * Description:
+ *   This function is called when a final thread leaves the task group and
+ *   the task group is destroyed.  This function then destroys the defunct
+ *   address environment, releasing the underlying physical memory.
+ *
+ * Input Parameters:
+ *   addrenv - The address environment to be destroyed.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ADDRENV
+int up_addrenv_destroy(group_addrenv_t addrenv);
 #endif
 
 /****************************************************************************
@@ -736,17 +756,17 @@ int up_addrenv_create(size_t envsize, FAR task_addrenv_t *addrenv);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr);
+int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr);
 #endif
 
 /****************************************************************************
  * Name: up_addrenv_select
  *
  * Description:
- *   After an address environment has been established for a task (via
+ *   After an address environment has been established for a task group (via
  *   up_addrenv_create().  This function may be called to to instantiate
  *   that address environment in the virtual address space.  this might be
- *   necessary, for example, to load the code for the task from a file or
+ *   necessary, for example, to load the code for the task group from a file or
  *   to access address environment private data.
  *
  * Input Parameters:
@@ -757,7 +777,7 @@ int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr);
  *     This may be used with up_addrenv_restore() to restore the original
  *     address environment that was in place before up_addrenv_select() was
  *     called.  Note that this may be a task agnostic, hardware
- *     representation that is different from task_addrenv_t.
+ *     representation that is different from group_addrenv_t.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -765,15 +785,15 @@ int up_addrenv_vaddr(FAR task_addrenv_t addrenv, FAR void **vaddr);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_select(task_addrenv_t addrenv, hw_addrenv_t *oldenv);
+int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);
 #endif
 
 /****************************************************************************
  * Name: up_addrenv_restore
  *
  * Description:
- *   After an address environment has been temporarilty instantiated by
- *   up_addrenv_select, this function may be called to to restore the
+ *   After an address environment has been temporarily instantiated by
+ *   up_addrenv_select(), this function may be called to to restore the
  *   original address environment.
  *
  * Input Parameters:
@@ -790,35 +810,15 @@ int up_addrenv_restore(hw_addrenv_t oldenv);
 #endif
 
 /****************************************************************************
- * Name: up_addrenv_destroy
- *
- * Description:
- *   Called from the binary loader loader during error handling to destroy
- *   the address environment previously created by up_addrenv_create().
- *
- * Input Parameters:
- *   addrenv - The representation of the task address environment previously
- *     returned by up_addrenv_create.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_ADDRENV
-int up_addrenv_destroy(task_addrenv_t addrenv);
-#endif
-
-/****************************************************************************
  * Name: up_addrenv_assign
  *
  * Description:
- *   Assign an address environment to a TCB.
+ *   Assign an address environment to a new task group.
  *
  * Input Parameters:
  *   addrenv - The representation of the task address environment previously
- *     returned by up_addrenv_create.
- *   tcb - The TCB of the task to receive the address environment.
+ *     returned by up_addrenv_create().
+ *   group - The new task group to receive the address environment.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -826,21 +826,24 @@ int up_addrenv_destroy(task_addrenv_t addrenv);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_assign(task_addrenv_t addrenv, FAR struct tcb_s *tcb);
+int up_addrenv_assign(group_addrenv_t addrenv, FAR struct task_group_s *group);
 #endif
 
 /****************************************************************************
- * Name: up_addrenv_share
+ * Name: up_addrenv_attach
  *
  * Description:
  *   This function is called from the core scheduler logic when a thread
- *   is created that needs to share the address ennvironment of its parent
- *   task.  In this case, the parent's address environment needs to be
- *   "cloned" for the child.
+ *   is created that needs to share the address environment of its task
+ *   group.
+ *
+ *   NOTE: In some platforms, nothing will need to be done in this case.
+ *   Simply being a member of the group that has the address environment
+ *   may be sufficient.
  *
  * Input Parameters:
- *   ptcb - The TCB of the parent task that has the address environment.
- *   ctcb - The TCB of the child thread needing the address environment.
+ *   group - The task group to which the new thread belongs.
+ *   tcb   - The TCB of the thread needing the address environment.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -848,19 +851,25 @@ int up_addrenv_assign(task_addrenv_t addrenv, FAR struct tcb_s *tcb);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_share(FAR const struct tcb_s *ptcb, FAR struct tcb_s *ctcb);
+int up_addrenv_attach(FAR struct task_group_s *group, FAR struct tcb_s *tcb);
 #endif
 
 /****************************************************************************
- * Name: up_addrenv_release
+ * Name: up_addrenv_detach
  *
  * Description:
  *   This function is called when a task or thread exits in order to release
- *   its reference to an address environment.  When there are no further
- *   references to an address environment, that address environment should
- *   be destroyed.
+ *   its reference to an address environment.  The address environment,
+ *   however, should persist until up_addrenv_destroy() is called when the
+ *   task group is itself destroyed.  Any resources unique to this thread
+ *   may be destroyed now.
+ *
+ *   NOTE: In some platforms, nothing will need to be done in this case.
+ *   Simply being a member of the group that has the address environment
+ *   may be sufficient.
  *
  * Input Parameters:
+ *   group - The group to which the thread belonged.
  *   tcb - The TCB of the task or thread whose the address environment will
  *     be released.
  *
@@ -870,7 +879,8 @@ int up_addrenv_share(FAR const struct tcb_s *ptcb, FAR struct tcb_s *ctcb);
  ****************************************************************************/
 
 #ifdef CONFIG_ADDRENV
-int up_addrenv_release(FAR struct tcb_s *tcb);
+int up_addrenv_detach(FAR struct task_group_s *group,
+                      FAR struct task_group_s *tcb);
 #endif
 
 /****************************************************************************
diff --git a/nuttx/include/nuttx/binfmt/binfmt.h b/nuttx/include/nuttx/binfmt/binfmt.h
index 4e5052a7f..e9bc03a78 100644
--- a/nuttx/include/nuttx/binfmt/binfmt.h
+++ b/nuttx/include/nuttx/binfmt/binfmt.h
@@ -125,7 +125,7 @@ struct binary_s
    */
 
 #ifdef CONFIG_ADDRENV
-  task_addrenv_t addrenv;              /* Task address environment */
+  group_addrenv_t addrenv;             /* Task group address environment */
 #endif
 
   size_t mapsize;                      /* Size of the mapped address region (needed for munmap) */
diff --git a/nuttx/include/nuttx/binfmt/elf.h b/nuttx/include/nuttx/binfmt/elf.h
index 7bfe0d9a3..9f058d6e1 100644
--- a/nuttx/include/nuttx/binfmt/elf.h
+++ b/nuttx/include/nuttx/binfmt/elf.h
@@ -131,8 +131,8 @@ struct elf_loadinfo_s
    */
 
 #ifdef CONFIG_ADDRENV
-  task_addrenv_t addrenv;  /* Task address environment */
-  hw_addrenv_t   oldenv;   /* Saved hardware address environment */
+  group_addrenv_t    addrenv;    /* Task group address environment */
+  hw_addrenv_t       oldenv;     /* Saved hardware address environment */
 #endif
 
   uint16_t           symtabidx;  /* Symbol table section index */
diff --git a/nuttx/include/nuttx/binfmt/nxflat.h b/nuttx/include/nuttx/binfmt/nxflat.h
index c87235c68..c3a7ce29d 100644
--- a/nuttx/include/nuttx/binfmt/nxflat.h
+++ b/nuttx/include/nuttx/binfmt/nxflat.h
@@ -103,13 +103,13 @@ struct nxflat_loadinfo_s
    */
 
 #ifdef CONFIG_ADDRENV
-  task_addrenv_t addrenv;  /* Task address environment */
-  hw_addrenv_t   oldenv;   /* Saved hardware address environment */
+  group_addrenv_t addrenv; /* Task group address environment */
+  hw_addrenv_t oldenv;     /* Saved hardware address environment */
 #endif
 
   /* File descriptors */
 
-  int    filfd;            /* Descriptor for the file being loaded */
+  int filfd;               /* Descriptor for the file being loaded */
 
   /* This is a copy of the NXFLAT header (still in network order) */
 
diff --git a/nuttx/include/nuttx/sched.h b/nuttx/include/nuttx/sched.h
index f0e52de3f..5ef5337fc 100644
--- a/nuttx/include/nuttx/sched.h
+++ b/nuttx/include/nuttx/sched.h
@@ -1,7 +1,7 @@
 /********************************************************************************
  * include/nuttx/sched.h
  *
- *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -99,6 +99,8 @@
 #    define HAVE_TASK_GROUP   1          /* Sockets */
 #  elif !defined(CONFIG_DISABLE_MQUEUE)
 #    define HAVE_TASK_GROUP   1          /* Message queues */
+#  elif defined(CONFIG_ADDRENV)
+#    define HAVE_TASK_GROUP   1          /* Address environment */
 #  endif
 #endif
 
@@ -264,25 +266,24 @@ struct dspace_s
 
 /* struct task_group_s ***********************************************************/
 /* All threads created by pthread_create belong in the same task group (along with
- * the thread of the original task).  struct task_group_s is a shared, "breakaway"
- * structure referenced by each TCB.
+ * the thread of the original task).  struct task_group_s is a shared structure
+ * referenced by the TCB of each thread that is a member of the task group.
  *
  * This structure should contain *all* resources shared by tasks and threads that
  * belong to the same task group:
  *
  *   Child exit status
- *   Environment varibles
+ *   Environment variables
  *   PIC data space and address environments
  *   File descriptors
  *   FILE streams
  *   Sockets
- *
- * Currenty, however, this implementation only applies to child exit status.
+ *   Address environments.
  *
  * Each instance of struct task_group_s is reference counted. Each instance is
- * created with a reference count of one.  The reference incremeneted when each
+ * created with a reference count of one.  The reference incremented when each
  * thread joins the group and decremented when each thread exits, leaving the
- * group.  When the refernce count decrements to zero, the struc task_group_s
+ * group.  When the reference count decrements to zero, the struct task_group_s
  * is free.
  */
 
@@ -313,9 +314,9 @@ struct task_group_s
   FAR pid_t *tg_members;            /* Members of the group                     */
 #endif
 
-  /* atexit/on_exit support ****************************************************/
-
 #if defined(CONFIG_SCHED_ATEXIT) && !defined(CONFIG_SCHED_ONEXIT)
+  /* atexit support ************************************************************/
+
 # if defined(CONFIG_SCHED_ATEXIT_MAX) && CONFIG_SCHED_ATEXIT_MAX > 1
   atexitfunc_t tg_atexitfunc[CONFIG_SCHED_ATEXIT_MAX];
 # else
@@ -324,6 +325,8 @@ struct task_group_s
 #endif
 
 #ifdef CONFIG_SCHED_ONEXIT
+  /* on_exit support ***********************************************************/
+
 # if defined(CONFIG_SCHED_ONEXIT_MAX) && CONFIG_SCHED_ONEXIT_MAX > 1
   onexitfunc_t tg_onexitfunc[CONFIG_SCHED_ONEXIT_MAX];
   FAR void *tg_onexitarg[CONFIG_SCHED_ONEXIT_MAX];
@@ -333,23 +336,22 @@ struct task_group_s
 # endif
 #endif
 
+#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
   /* Child exit status **********************************************************/
 
-#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
   FAR struct child_status_s *tg_children; /* Head of a list of child status     */
 #endif
 
+#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
   /* waitpid support ************************************************************/
   /* Simple mechanism used only when there is no support for SIGCHLD            */
 
-#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
   sem_t tg_exitsem;                 /* Support for waitpid                      */
   int *tg_statloc;                  /* Location to return exit status           */
 #endif
 
-  /* Pthreads *******************************************************************/
-
 #ifndef CONFIG_DISABLE_PTHREAD
+  /* Pthreads *******************************************************************/
                                     /* Pthread join Info:                       */
   sem_t tg_joinsem;                 /*   Mutually exclusive access to join data */
   FAR struct join_s *tg_joinhead;   /*   Head of a list of join data            */
@@ -357,15 +359,15 @@ struct task_group_s
   uint8_t tg_nkeys;                 /* Number pthread keys allocated            */
 #endif
 
+#ifndef CONFIG_DISABLE_SIGNALS
   /* POSIX Signal Control Fields ************************************************/
 
-#ifndef CONFIG_DISABLE_SIGNALS
   sq_queue_t sigpendingq;           /* List of pending signals                  */
 #endif
 
+#ifndef CONFIG_DISABLE_ENVIRON
   /* Environment variables ******************************************************/
 
-#ifndef CONFIG_DISABLE_ENVIRON
   size_t     tg_envsize;            /* Size of environment string allocation    */
   FAR char  *tg_envp;               /* Allocated environment strings            */
 #endif
@@ -376,19 +378,19 @@ struct task_group_s
    * life of the PIC data is managed.
    */
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
   /* File descriptors ***********************************************************/
 
-#if CONFIG_NFILE_DESCRIPTORS > 0
   struct filelist tg_filelist;      /* Maps file descriptor to file             */
 #endif
 
+#if CONFIG_NFILE_STREAMS > 0
   /* FILE streams ***************************************************************/
   /* In a flat, single-heap build.  The stream list is allocated with this
    * structure.  But kernel mode with a kernel allocator, it must be separately
    * allocated using a user-space allocator.
    */
 
-#if CONFIG_NFILE_STREAMS > 0
 #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
   FAR struct streamlist *tg_streamlist;
 #else
@@ -396,16 +398,24 @@ struct task_group_s
 #endif
 #endif
 
+#if CONFIG_NSOCKET_DESCRIPTORS > 0
   /* Sockets ********************************************************************/
 
-#if CONFIG_NSOCKET_DESCRIPTORS > 0
   struct socketlist tg_socketlist;  /* Maps socket descriptor to socket         */
 #endif
-  /* POSIX Named Message Queue Fields *******************************************/
 
 #ifndef CONFIG_DISABLE_MQUEUE
+  /* POSIX Named Message Queue Fields *******************************************/
+
   sq_queue_t tg_msgdesq;            /* List of opened message queues           */
 #endif
+
+#ifdef CONFIG_ADDRENV
+  /* POSIX Named Message Queue Fields *******************************************/
+  /* POSIX Named Message Queue Fields *******************************************/
+
+  group_addrenv_t addrenv;          /* Task group address environment           */
+#endif
 };
 #endif
 
@@ -508,7 +518,7 @@ struct tcb_s
   int pterrno;                           /* Current per-thread errno            */
 
   /* State save areas ***********************************************************/
-  /* The form and content of these fields are processor-specific.               */
+  /* The form and content of these fields are platform-specific.                */
 
   struct xcptcontext xcp;                /* Interrupt register save area        */
 
diff --git a/nuttx/sched/pthread/pthread_create.c b/nuttx/sched/pthread/pthread_create.c
index 9ee5cc5d9..85ec3c5d8 100644
--- a/nuttx/sched/pthread/pthread_create.c
+++ b/nuttx/sched/pthread/pthread_create.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * sched/pthread/pthread_create.c
  *
- *   Copyright (C) 2007-2009, 2011, 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011, 2013-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -254,11 +254,11 @@ int pthread_create(FAR pthread_t *thread, FAR pthread_attr_t *attr,
       return ENOMEM;
     }
 
+#ifdef HAVE_TASK_GROUP
   /* Bind the parent's group to the new TCB (we have not yet joined the
    * group).
    */
 
-#ifdef HAVE_TASK_GROUP
   ret = group_bind(ptcb);
   if (ret < 0)
     {
@@ -267,14 +267,11 @@ int pthread_create(FAR pthread_t *thread, FAR pthread_attr_t *attr,
     }
 #endif
 
-  /* Share the address environment of the parent task.  NOTE:  Only tasks
-   * created throught the nuttx/binfmt loaders may have an address
-   * environment.
-   */
-
 #ifdef CONFIG_ADDRENV
-  ret = up_addrenv_share((FAR const struct tcb_s *)g_readytorun.head,
-                         (FAR struct tcb_s *)ptcb);
+  /* Share the address environment of the parent task group. */
+
+  ret = up_addrenv_attach(ptcb->group,
+                          (FAR const struct tcb_s *)g_readytorun.head);
   if (ret < 0)
     {
       errcode = -ret;
@@ -323,9 +320,9 @@ int pthread_create(FAR pthread_t *thread, FAR pthread_attr_t *attr,
           priority = SCHED_FIFO;
         }
 
+#if CONFIG_RR_INTERVAL > 0
       /* Get the scheduler policy for this thread */
 
-#if CONFIG_RR_INTERVAL > 0
       policy = sched_getscheduler(0);
       if (policy == ERROR)
         {
@@ -358,9 +355,9 @@ int pthread_create(FAR pthread_t *thread, FAR pthread_attr_t *attr,
 
   pthread_argsetup(ptcb, arg);
 
+#ifdef HAVE_TASK_GROUP
   /* Join the parent's task group */
 
-#ifdef HAVE_TASK_GROUP
   ret = group_join(ptcb);
   if (ret < 0)
     {
@@ -373,11 +370,11 @@ int pthread_create(FAR pthread_t *thread, FAR pthread_attr_t *attr,
 
   ptcb->joininfo = (FAR void *)pjoin;
 
+#if CONFIG_RR_INTERVAL > 0
   /* If round robin scheduling is selected, set the appropriate flag
    * in the TCB.
    */
 
-#if CONFIG_RR_INTERVAL > 0
   if (policy == SCHED_RR)
     {
       ptcb->cmn.flags    |= TCB_FLAG_ROUND_ROBIN;
diff --git a/nuttx/sched/sched/sched_releasetcb.c b/nuttx/sched/sched/sched_releasetcb.c
index 7c7eeae3a..3899911f3 100644
--- a/nuttx/sched/sched/sched_releasetcb.c
+++ b/nuttx/sched/sched/sched_releasetcb.c
@@ -193,10 +193,10 @@ int sched_releasetcb(FAR struct tcb_s *tcb, uint8_t ttype)
       /* Release this thread's reference to the address environment */
 
 #ifdef CONFIG_ADDRENV
-      ret = up_addrenv_release(tcb);
+      ret = up_addrenv_detach(tcp->group, tcb);
 #endif
 
-      /* Leave the group (if we did not already leady in task_exithook.c) */
+      /* Leave the group (if we did not already leave in task_exithook.c) */
 
 #ifdef HAVE_TASK_GROUP
       group_leave(tcb);