Change prototypes of up_create_stack and up_release_stack to include a task type parameter

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5765 42af7a65-404d-4744-a932-0658087f49c3

32 files changed, 694 insertions, 262 deletions

diff --git a/nuttx/arch/arm/src/common/up_createstack.c b/nuttx/arch/arm/src/common/up_createstack.c
index efa0e0a15..65eb91159 100644
--- a/nuttx/arch/arm/src/common/up_createstack.c
+++ b/nuttx/arch/arm/src/common/up_createstack.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/common/up_createstack.c
  *
- *   Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -111,24 +111,40 @@ static void *memset32(void *s, uint32_t  c, size_t n)
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/arm/src/common/up_releasestack.c b/nuttx/arch/arm/src/common/up_releasestack.c
index 94311b20c..711022f93 100644
--- a/nuttx/arch/arm/src/common/up_releasestack.c
+++ b/nuttx/arch/arm/src/common/up_releasestack.c
@@ -62,12 +62,34 @@
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
+ *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
  *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/arm/src/common/up_usestack.c b/nuttx/arch/arm/src/common/up_usestack.c
index 57eb1d36e..a141006bb 100644
--- a/nuttx/arch/arm/src/common/up_usestack.c
+++ b/nuttx/arch/arm/src/common/up_usestack.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/common/up_usestack.c
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -92,20 +92,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/arm/src/common/up_vfork.c b/nuttx/arch/arm/src/common/up_vfork.c
index 6340cb3b8..03fb09b2f 100644
--- a/nuttx/arch/arm/src/common/up_vfork.c
+++ b/nuttx/arch/arm/src/common/up_vfork.c
@@ -162,7 +162,8 @@ pid_t up_vfork(const struct vfork_s *context)
 
   /* Allocate the stack for the TCB */
 
-  ret = up_create_stack((FAR struct tcb_s *)child, stacksize);
+  ret = up_create_stack((FAR struct tcb_s *)child, stacksize,
+                        parent->flags & TCB_FLAG_TTYPE_MASK);
   if (ret != OK)
     {
       sdbg("up_create_stack failed: %d\n", ret);
diff --git a/nuttx/arch/avr/src/avr/up_createstack.c b/nuttx/arch/avr/src/avr/up_createstack.c
index 1eb56f918..60f6dceec 100644
--- a/nuttx/arch/avr/src/avr/up_createstack.c
+++ b/nuttx/arch/avr/src/avr/up_createstack.c
@@ -70,24 +70,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/avr/src/avr/up_usestack.c b/nuttx/arch/avr/src/avr/up_usestack.c
index 22bdcf84e..ebd911fb2 100644
--- a/nuttx/arch/avr/src/avr/up_usestack.c
+++ b/nuttx/arch/avr/src/avr/up_usestack.c
@@ -67,18 +67,26 @@
  *
  * Description:
  *   Setup up stack-related information in the TCB using pre-allocated stack
- *   memory
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
- *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
- *     the stack pointer.
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/avr/src/avr32/up_createstack.c b/nuttx/arch/avr/src/avr32/up_createstack.c
index 5d49f4977..da7e8788c 100644
--- a/nuttx/arch/avr/src/avr32/up_createstack.c
+++ b/nuttx/arch/avr/src/avr32/up_createstack.c
@@ -69,24 +69,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/avr/src/avr32/up_usestack.c b/nuttx/arch/avr/src/avr32/up_usestack.c
index 43dc6bfe9..86cdc2de4 100644
--- a/nuttx/arch/avr/src/avr32/up_usestack.c
+++ b/nuttx/arch/avr/src/avr32/up_usestack.c
@@ -65,20 +65,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/avr/src/common/up_releasestack.c b/nuttx/arch/avr/src/common/up_releasestack.c
index afce3261d..7d3e6f28c 100644
--- a/nuttx/arch/avr/src/common/up_releasestack.c
+++ b/nuttx/arch/avr/src/common/up_releasestack.c
@@ -62,12 +62,34 @@
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
+ *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
  *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/hc/src/common/up_createstack.c b/nuttx/arch/hc/src/common/up_createstack.c
index d5d5a853a..a8b192c4b 100644
--- a/nuttx/arch/hc/src/common/up_createstack.c
+++ b/nuttx/arch/hc/src/common/up_createstack.c
@@ -66,24 +66,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/hc/src/common/up_releasestack.c b/nuttx/arch/hc/src/common/up_releasestack.c
index f6eaec982..f8c2fa142 100644
--- a/nuttx/arch/hc/src/common/up_releasestack.c
+++ b/nuttx/arch/hc/src/common/up_releasestack.c
@@ -66,9 +66,31 @@
  *   A task has been stopped. Free all stack related resources retained in
  *   the defunct TCB.
  *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
+ *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/hc/src/common/up_usestack.c b/nuttx/arch/hc/src/common/up_usestack.c
index f23677be5..7f3c8fc66 100644
--- a/nuttx/arch/hc/src/common/up_usestack.c
+++ b/nuttx/arch/hc/src/common/up_usestack.c
@@ -64,19 +64,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB using pre-allocated
- *   stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor, etc.
- *     This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW. The initial value of the
- *     stack pointer.
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/mips/src/common/up_createstack.c b/nuttx/arch/mips/src/common/up_createstack.c
index e4689fc7c..b228e8061 100644
--- a/nuttx/arch/mips/src/common/up_createstack.c
+++ b/nuttx/arch/mips/src/common/up_createstack.c
@@ -87,24 +87,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/mips/src/common/up_releasestack.c b/nuttx/arch/mips/src/common/up_releasestack.c
index d507c3b7b..3ce46bebd 100644
--- a/nuttx/arch/mips/src/common/up_releasestack.c
+++ b/nuttx/arch/mips/src/common/up_releasestack.c
@@ -62,12 +62,34 @@
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
+ *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
  *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/mips/src/common/up_usestack.c b/nuttx/arch/mips/src/common/up_usestack.c
index 208c15bc0..fe1d27818 100644
--- a/nuttx/arch/mips/src/common/up_usestack.c
+++ b/nuttx/arch/mips/src/common/up_usestack.c
@@ -65,20 +65,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/mips/src/mips32/up_vfork.c b/nuttx/arch/mips/src/mips32/up_vfork.c
index 3714cfac7..15fd32812 100644
--- a/nuttx/arch/mips/src/mips32/up_vfork.c
+++ b/nuttx/arch/mips/src/mips32/up_vfork.c
@@ -167,7 +167,8 @@ pid_t up_vfork(const struct vfork_s *context)
 
   /* Allocate the stack for the TCB */
 
-  ret = up_create_stack((FAR struct tcb_s *)child, stacksize);
+  ret = up_create_stack((FAR struct tcb_s *)child, stacksize,
+                        parent->flags & TCB_FLAG_TTYPE_MASK);
   if (ret != OK)
     {
       sdbg("up_create_stack failed: %d\n", ret);
diff --git a/nuttx/arch/rgmp/src/nuttx.c b/nuttx/arch/rgmp/src/nuttx.c
index 0a13401c2..3dc531006 100644
--- a/nuttx/arch/rgmp/src/nuttx.c
+++ b/nuttx/arch/rgmp/src/nuttx.c
@@ -111,7 +111,7 @@ void up_allocate_heap(void **heap_start, size_t *heap_size)
     *heap_size = KERNBASE + kmem_size - (uint32_t)boot_freemem;
 }
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
     int ret = ERROR;
     size_t *adj_stack_ptr;
@@ -158,7 +158,7 @@ int up_use_stack(struct tcb_s *tcb, void *stack, size_t stack_size)
     return OK;
 }
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(struct tcb_s *dtcb, uint8_t ttype)
 {
     if (dtcb->stack_alloc_ptr) {
 		kufree(dtcb->stack_alloc_ptr);
diff --git a/nuttx/arch/sh/src/common/up_createstack.c b/nuttx/arch/sh/src/common/up_createstack.c
index 9abc05f76..3ffdc3050 100644
--- a/nuttx/arch/sh/src/common/up_createstack.c
+++ b/nuttx/arch/sh/src/common/up_createstack.c
@@ -66,24 +66,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/sh/src/common/up_releasestack.c b/nuttx/arch/sh/src/common/up_releasestack.c
index a8b9d7769..832578118 100644
--- a/nuttx/arch/sh/src/common/up_releasestack.c
+++ b/nuttx/arch/sh/src/common/up_releasestack.c
@@ -62,12 +62,34 @@
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
+ *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
  *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/sh/src/common/up_usestack.c b/nuttx/arch/sh/src/common/up_usestack.c
index 1cc383a91..7c2b9586e 100644
--- a/nuttx/arch/sh/src/common/up_usestack.c
+++ b/nuttx/arch/sh/src/common/up_usestack.c
@@ -65,20 +65,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/sim/src/up_createstack.c b/nuttx/arch/sim/src/up_createstack.c
index a6ebcc5fa..fe9986e65 100644
--- a/nuttx/arch/sim/src/up_createstack.c
+++ b/nuttx/arch/sim/src/up_createstack.c
@@ -67,25 +67,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup
- *   up stack-related information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
- *     processor, etc.  This value is retained only for debug
- *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
- *     initial value of the stack pointer.
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
+ *     etc.  This value is retained only for debug purposes.
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *     the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size: The requested stack size.  At least this much
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
  *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   int ret = ERROR;
 
diff --git a/nuttx/arch/sim/src/up_releasestack.c b/nuttx/arch/sim/src/up_releasestack.c
index c1e12ca00..56413f341 100644
--- a/nuttx/arch/sim/src/up_releasestack.c
+++ b/nuttx/arch/sim/src/up_releasestack.c
@@ -64,12 +64,34 @@
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
+ *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
  *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/sim/src/up_usestack.c b/nuttx/arch/sim/src/up_usestack.c
index afa419364..af2d8121d 100644
--- a/nuttx/arch/sim/src/up_usestack.c
+++ b/nuttx/arch/sim/src/up_usestack.c
@@ -64,20 +64,27 @@
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size: The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/x86/src/i486/up_createstack.c b/nuttx/arch/x86/src/i486/up_createstack.c
index 927abcf2e..bcce5fdcc 100644
--- a/nuttx/arch/x86/src/i486/up_createstack.c
+++ b/nuttx/arch/x86/src/i486/up_createstack.c
@@ -68,24 +68,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/x86/src/i486/up_releasestack.c b/nuttx/arch/x86/src/i486/up_releasestack.c
index 38a2dbfe8..0aa43ce58 100644
--- a/nuttx/arch/x86/src/i486/up_releasestack.c
+++ b/nuttx/arch/x86/src/i486/up_releasestack.c
@@ -65,9 +65,31 @@
  *   A task has been stopped. Free all stack related resources retained in
  *   the defunct TCB.
  *
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
+ *
  ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/x86/src/i486/up_usestack.c b/nuttx/arch/x86/src/i486/up_usestack.c
index 8865a9e3f..f972d8950 100644
--- a/nuttx/arch/x86/src/i486/up_usestack.c
+++ b/nuttx/arch/x86/src/i486/up_usestack.c
@@ -66,18 +66,26 @@
  *
  * Description:
  *   Setup up stack-related information in the TCB using pre-allocated stack
- *   memory
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
- *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
- *     the stack pointer.
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
  ****************************************************************************/
 
diff --git a/nuttx/arch/z16/src/common/up_createstack.c b/nuttx/arch/z16/src/common/up_createstack.c
index fcbf90bfe..d52318169 100644
--- a/nuttx/arch/z16/src/common/up_createstack.c
+++ b/nuttx/arch/z16/src/common/up_createstack.c
@@ -67,24 +67,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/z16/src/common/up_releasestack.c b/nuttx/arch/z16/src/common/up_releasestack.c
index f66186925..84cc4be7d 100644
--- a/nuttx/arch/z16/src/common/up_releasestack.c
+++ b/nuttx/arch/z16/src/common/up_releasestack.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * common/up_releasestack.c
  *
  *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <nuttx/config.h>
 
@@ -46,28 +46,50 @@
 #include "os_internal.h"
 #include "up_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Private Types
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Function Prototypes
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
  *
- ************************************************************/
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/z16/src/common/up_usestack.c b/nuttx/arch/z16/src/common/up_usestack.c
index 671930bbe..6396ce9c2 100644
--- a/nuttx/arch/z16/src/common/up_usestack.c
+++ b/nuttx/arch/z16/src/common/up_usestack.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * arch/z16/common/up_usestack.c
  *
  *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <nuttx/config.h>
 
@@ -49,38 +49,45 @@
 
 #include "up_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Private Types
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Function Prototypes
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
- ************************************************************/
+ ****************************************************************************/
 
 int up_use_stack(struct tcb_s *tcb, void *stack, size_t stack_size)
 {
diff --git a/nuttx/arch/z80/src/common/up_createstack.c b/nuttx/arch/z80/src/common/up_createstack.c
index c086839bf..1e47b09bd 100644
--- a/nuttx/arch/z80/src/common/up_createstack.c
+++ b/nuttx/arch/z80/src/common/up_createstack.c
@@ -66,24 +66,40 @@
  * Name: up_create_stack
  *
  * Description:
- *   Allocate a stack for a new thread and setup up stack-related
- *   information in the TCB.
+ *   Allocate a stack for a new thread and setup up stack-related information
+ *   in the TCB.
  *
- *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware, processor,
+ *   The following TCB fields must be initialized by this function:
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware, processor,
  *     etc.  This value is retained only for debug purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
  *     the stack pointer.
  *
- * Input Parameters:
- *   tcb: The TCB of new task
- *   stack_size:  The requested stack size.  At least this how much must be
- *     allocated.
+ * Inputs:
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The requested stack size.  At least this much
+ *     must be allocated.
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain contexts where the TCB may not be fully
+ *     initialized when up_create_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is allocated.  For example, kernel thread stacks should
+ *     be allocated from protected kernel memory.  Stacks for user tasks and
+ *     threads must come from memory that is accessible to user code.
  *
  ****************************************************************************/
 
-int up_create_stack(struct tcb_s *tcb, size_t stack_size)
+int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
 {
   /* Is there already a stack allocated of a different size? */
 
diff --git a/nuttx/arch/z80/src/common/up_releasestack.c b/nuttx/arch/z80/src/common/up_releasestack.c
index 346971610..beefc4744 100644
--- a/nuttx/arch/z80/src/common/up_releasestack.c
+++ b/nuttx/arch/z80/src/common/up_releasestack.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * common/up_releasestack.c
  *
  *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <nuttx/config.h>
 
@@ -46,28 +46,50 @@
 #include "os_internal.h"
 #include "up_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Private Types
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Function Prototypes
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Name: up_release_stack
  *
  * Description:
- *   A task has been stopped. Free all stack
- *   related resources retained int the defunct TCB.
+ *   A task has been stopped. Free all stack related resources retained in
+ *   the defunct TCB.
  *
- ************************************************************/
+ * Input Parmeters
+ *   - dtcb:  The TCB containing information about the stack to be released
+ *   - ttype:  The thread type.  This may be one of following (defined in
+ *     include/nuttx/sched.h):
+ *
+ *       TCB_FLAG_TTYPE_TASK     Normal user task
+ *       TCB_FLAG_TTYPE_PTHREAD  User pthread
+ *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
+ *
+ *     This thread type is normally available in the flags field of the TCB,
+ *     however, there are certain error recovery contexts where the TCB may
+ *     not be fully initialized when up_release_stack is called.
+ *
+ *     If CONFIG_NUTTX_KERNEL is defined, then this thread type may affect
+ *     how the stack is freed.  For example, kernel thread stacks may have
+ *     been allocated from protected kernel memory.  Stacks for user tasks
+ *     and threads must have come from memory that is accessible to user
+ *     code.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
 
-void up_release_stack(struct tcb_s *dtcb)
+void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
 {
   if (dtcb->stack_alloc_ptr)
     {
diff --git a/nuttx/arch/z80/src/common/up_usestack.c b/nuttx/arch/z80/src/common/up_usestack.c
index f6fdb5fd4..8d322e705 100644
--- a/nuttx/arch/z80/src/common/up_usestack.c
+++ b/nuttx/arch/z80/src/common/up_usestack.c
@@ -1,4 +1,4 @@
-/************************************************************
+/****************************************************************************
  * arch/z80/src/common/up_usestack.c
  *
  *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
@@ -31,11 +31,11 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Included Files
- ************************************************************/
+ ****************************************************************************/
 
 #include <nuttx/config.h>
 
@@ -48,38 +48,45 @@
 
 #include "up_internal.h"
 
-/************************************************************
+/****************************************************************************
  * Private Types
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Private Function Prototypes
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Global Functions
- ************************************************************/
+ ****************************************************************************/
 
-/************************************************************
+/****************************************************************************
  * Name: up_use_stack
  *
  * Description:
- *   Setup up stack-related information in the TCB
- *   using pre-allocated stack memory
+ *   Setup up stack-related information in the TCB using pre-allocated stack
+ *   memory.  This function is called only from task_init() when a task or
+ *   kernel thread is started (never for pthreads).
  *
  *   The following TCB fields must be initialized:
- *   adj_stack_size: Stack size after adjustment for hardware,
+ *
+ *   - adj_stack_size: Stack size after adjustment for hardware,
  *     processor, etc.  This value is retained only for debug
  *     purposes.
- *   stack_alloc_ptr: Pointer to allocated stack
- *   adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
+ *   - stack_alloc_ptr: Pointer to allocated stack
+ *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The
  *     initial value of the stack pointer.
  *
  * Inputs:
- *   tcb: The TCB of new task
- *   stack_size:  The allocated stack size.
+ *   - tcb: The TCB of new task
+ *   - stack_size:  The allocated stack size.
+ *
+ *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
+ *   does not require the task type (ttype) parameter.  The TCB flags will
+ *   always be set to provide the task type to up_use_stack() if it needs
+ *   that information.
  *
- ************************************************************/
+ ****************************************************************************/
 
 int up_use_stack(struct tcb_s *tcb, void *stack, size_t stack_size)
 {