From 2cb9d5c7b0540bfa95eff98b5c5afe74f6b4858a Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sun, 24 Aug 2014 09:57:53 -0600
Subject: [PATCH] Add addrenv.h; First cut at Cortex-A address environment
 structures; Add configuration options to setup address enviornment

---
 Documentation/NuttxPortingGuide.html |  10 +-
 arch/Kconfig                         |  58 ++++++++-
 arch/arm/include/arch.h              |  32 ++++-
 arch/arm/include/armv7-a/irq.h       |  10 ++
 arch/arm/src/armv7-a/arm_addrenv.c   |   8 +-
 arch/z80/include/z180/arch.h         |   2 +-
 arch/z80/src/z180/z180_mmu.c         |   6 +-
 binfmt/binfmt_unloadmodule.c         |   2 +-
 binfmt/libnxflat/libnxflat_addrenv.c |   2 +-
 include/nuttx/addrenv.h              | 177 +++++++++++++++++++++++++++
 include/nuttx/arch.h                 |  12 +-
 include/nuttx/binfmt/elf.h           |   2 +-
 include/nuttx/binfmt/nxflat.h        |   2 +-
 include/nuttx/pgalloc.h              |   2 +-
 14 files changed, 300 insertions(+), 25 deletions(-)
 create mode 100644 include/nuttx/addrenv.h

diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index eb5a9509d3..e76b2ce0a5 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -2541,7 +2541,7 @@ config ARCH_SIM
 </p>
 <p>
   Since timers are a limited resource, the use of two timers could be an issue on some systems.
-  The job could be done with a single timer if, for example, the single timer were kept in a free-running at all times. Some timer/counters have the capability to generate a compare interrupt when the timer matches a comparison value but also to continue counting without stopping. If your hardware supports such counters, one might used the <code>CONFIG_SCHED_TICKLESS_ALARM</code> option and be able to simply set the comparison count at the value of the free running timer <i>PLUS</i> the desired delay. Then you could have both with a single timer: An alarm and a free-running counter with the same timer! 
+  The job could be done with a single timer if, for example, the single timer were kept in a free-running at all times. Some timer/counters have the capability to generate a compare interrupt when the timer matches a comparison value but also to continue counting without stopping. If your hardware supports such counters, one might used the <code>CONFIG_SCHED_TICKLESS_ALARM</code> option and be able to simply set the comparison count at the value of the free running timer <i>PLUS</i> the desired delay. Then you could have both with a single timer: An alarm and a free-running counter with the same timer!
 </p>
 <p>
   In addition to these imported interfaces, the RTOS will export the following interfaces for use by the platform-specific interval timer implementation:
@@ -3041,7 +3041,7 @@ VxWorks provides the following comparable interface:
 <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_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);</code>
+  <code>int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
@@ -3054,7 +3054,7 @@ VxWorks provides the following comparable interface:
   <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>.
+    Note that this may be a task agnostic, platform-specific representation that may or may not be different from <code>group_addrenv_t</code>.
   </li>
 </ul>
 <p><b>Returned Value</b>:</p>
@@ -3065,7 +3065,7 @@ VxWorks provides the following comparable interface:
 <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_restore(hw_addrenv_t oldenv);</code>
+  <code>int up_addrenv_restore(save_addrenv_t oldenv);</code>
 </ul>
 <p><b>Description</b>:</p>
 <ul>
@@ -3074,7 +3074,7 @@ VxWorks provides the following comparable interface:
 </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>oldenv</code>: The platform-specific representation of the address environment previously returned by <code>up_addrenv_select()</code>.</li>
 </ul>
 <p><b>Returned Value</b>:</p>
 <ul>
diff --git a/arch/Kconfig b/arch/Kconfig
index 92bdb83429..4db654dd01 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -154,7 +154,7 @@ config ARCH_HAVE_EXTCLK
 	bool
 	default n
 
-config ARCH_ADDRENV
+menuconfig ARCH_ADDRENV
 	bool "Address environments"
 	default n
 	depends on ARCH_HAVE_ADDRENV
@@ -162,6 +162,62 @@ config ARCH_ADDRENV
 		Support per-task address environments using the MMU... i.e., support
 		"processes"
 
+if ARCH_ADDRENV && ARCH_HAVE_MMU
+
+config ARCH_TEXT_VBASE
+	hex "Virtual .text base"
+	---help---
+		The virtual address of the beginning the .text region
+
+config ARCH_DATA_VBASE
+	hex "Virtual .bss/.data base"
+	---help---
+		The virtual address of the beginning of the .bss/.data region.
+
+config ARCH_HEAP_VBASE
+	hex "Virtual heap base"
+	---help---
+		The virtual address of the beginning of the heap region.
+
+config ARCH_STACK_VBASE
+	hex "Virtual stack base"
+	---help---
+		The virtual address of the beginning the stack region
+
+config ARCH_TEXT_NPAGES
+	int "Max .text pages"
+	default 1
+	---help---
+		The maximum number of pages that can allocated for the .text region.
+		This, along with knowledge of the page size, determines the size of
+		the .text virtual address space. Default is 1.
+
+config ARCH_DATA_NPAGES
+	int "Max .bss/.data pages"
+	default 1
+	---help---
+		The maximum number of pages that can allocated for the .bss/.data
+		region. This, along with knowledge of the page size, determines the
+		size of the .bss/.data virtual address space. Default is 1.
+
+config ARCH_HEAP_NPAGES
+	int "Max heap pages"
+	default 1
+	---help---
+		The maximum number of pages that can allocated for the heap region.
+		This, along with knowledge of the page size, determines the size of
+		the heap virtual address space. Default is 1.
+
+config ARCH_STACK_NPAGES
+	int "Max. stack pages"
+	default 1
+	---help---
+		The maximum number of pages that can allocated for the stack region.
+		This, along with knowledge of the page size, determines the size of
+		the stack virtual address space. Default is 1.
+
+endif # ARCH_ADDRENV && ARCH_HAVE_MMU
+
 menuconfig PAGING
 	bool "On-demand paging"
 	default n
diff --git a/arch/arm/include/arch.h b/arch/arm/include/arch.h
index d0b2602eba..6495c52304 100644
--- a/arch/arm/include/arch.h
+++ b/arch/arm/include/arch.h
@@ -50,7 +50,7 @@
 #endif
 
 /****************************************************************************
- * Definitions
+ * Pre-processor Definitions
  ****************************************************************************/
 
 #ifdef CONFIG_PIC
@@ -99,6 +99,36 @@ do { \
  * Public Types
  ****************************************************************************/
 
+#ifdef CONFIG_ARCH_ADDRENV
+/* The task group resources are retained in a single structure, task_group_s
+ * that is defined in the header file nuttx/include/nuttx/sched.h. The type
+ * group_addrenv_t must be defined by platform specific logic in
+ * nuttx/arch/<architecture>/include/arch.h.
+ *
+ * These tables would hold the physical address of the level 2 page tables.
+ * All would be initially NULL and would not be backed up with physical memory
+ * until mappings in the level 2 page table are required.
+ */
+
+struct group_addrenv_s
+{
+  FAR uint32_t *text[CONFIG_ARCH_TEXT_NPAGES];
+  FAR uint32_t *data[CONFIG_ARCH_DATA_NPAGES];
+  FAR uint32_t *heap[CONFIG_ARCH_HEAP_NPAGES];
+};
+
+typedef struct group_addrenv_s group_addrenv_t;
+
+/* This type is used when the OS needs to temporarily instantiate a
+ * different address environment.  Used in the implementation of
+ *
+ *   int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv);
+ *   int up_addrenv_restore(save_addrenv_t oldenv);
+ */
+
+typedef group_addrenv_t *save_addrenv_t;
+#endif
+
 /****************************************************************************
  * Public Variables
  ****************************************************************************/
diff --git a/arch/arm/include/armv7-a/irq.h b/arch/arm/include/armv7-a/irq.h
index 0b7b0589ed..98fd8b154d 100755
--- a/arch/arm/include/armv7-a/irq.h
+++ b/arch/arm/include/armv7-a/irq.h
@@ -240,6 +240,16 @@ struct xcptcontext
 #ifdef CONFIG_PAGING
   uintptr_t far;
 #endif
+
+#ifdef CONFIG_ARCH_ADDRENV
+  /* This table holds the physical address of the level 2 page table used
+   * to map the thread's stack memory.  This array will be initially of
+   * zeroed and would be back-up up with pages during page fault exception
+   * handling to support dynamically sized stacks for each thread.
+   */
+
+  FAR uint32_t *stack[CONFIG_ARCH_STACK_NPAGES];
+#endif
 };
 #endif
 
diff --git a/arch/arm/src/armv7-a/arm_addrenv.c b/arch/arm/src/armv7-a/arm_addrenv.c
index 335ab205a0..5aa21aa6c5 100644
--- a/arch/arm/src/armv7-a/arm_addrenv.c
+++ b/arch/arm/src/armv7-a/arm_addrenv.c
@@ -70,6 +70,7 @@
 #include <errno.h>
 
 #include <nuttx/arch.h>
+#include <nuttx/addrenv.h>
 #include <arch/arch.h>
 
 #ifdef CONFIG_ARCH_ADDRENV
@@ -77,6 +78,7 @@
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
+/* Configuration ************************************************************/
 
 /****************************************************************************
  * Private Data
@@ -95,7 +97,7 @@
  *
  * Description:
  *   This function is called when a new task is created in order to
- *   instantiate an address environment for the new task group. 
+ *   instantiate an address environment for the new task group.
  *   up_addrenv_create() is essentially the allocator of the physical
  *   memory for the new task.
  *
@@ -187,7 +189,7 @@ int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr)
  *
  ****************************************************************************/
 
-int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
+int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv)
 {
 #warning Missing logic
   return -ENOSYS;
@@ -210,7 +212,7 @@ int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
  *
  ****************************************************************************/
 
-int up_addrenv_restore(hw_addrenv_t oldenv)
+int up_addrenv_restore(save_addrenv_t oldenv)
 {
 #warning Missing logic
   return -ENOSYS;
diff --git a/arch/z80/include/z180/arch.h b/arch/z80/include/z180/arch.h
index 85422fdca2..64e1112f52 100644
--- a/arch/z80/include/z180/arch.h
+++ b/arch/z80/include/z180/arch.h
@@ -65,7 +65,7 @@
  */
 
 #ifdef CONFIG_ARCH_ADDRENV
-typedef uint8_t hw_addrenv_t;
+typedef uint8_t save_addrenv_t;
 
 /* At the task-level, the z180 address environment is represented as struct
  * z180_cbr_s which is defined in irq.h.
diff --git a/arch/z80/src/z180/z180_mmu.c b/arch/z80/src/z180/z180_mmu.c
index 3289026f96..5f788859f1 100644
--- a/arch/z80/src/z180/z180_mmu.c
+++ b/arch/z80/src/z180/z180_mmu.c
@@ -378,7 +378,7 @@ int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr)
  *
  ****************************************************************************/
 
-int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
+int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv)
 {
   FAR struct z180_cbr_s *cbr = (FAR struct z180_cbr_s *)addrenv;
   irqstate_t flags;
@@ -388,7 +388,7 @@ int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
   /* Return the current CBR value from the CBR register */
 
   flags = irqsave();
-  *oldenv = (hw_addrenv_t)inp(Z180_MMU_CBR);
+  *oldenv = (save_addrenv_t)inp(Z180_MMU_CBR);
 
   /* Write the new CBR value into CBR register */
 
@@ -414,7 +414,7 @@ int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv)
  *
  ****************************************************************************/
 
-int up_addrenv_restore(hw_addrenv_t oldenv)
+int up_addrenv_restore(save_addrenv_t oldenv)
 {
   outp(Z180_MMU_CBR, (uint8_t)oldenv);
   return OK;
diff --git a/binfmt/binfmt_unloadmodule.c b/binfmt/binfmt_unloadmodule.c
index 1387e79ac5..20de9d50a7 100644
--- a/binfmt/binfmt_unloadmodule.c
+++ b/binfmt/binfmt_unloadmodule.c
@@ -88,7 +88,7 @@ static inline int exec_dtors(FAR struct binary_s *binp)
 {
   binfmt_dtor_t *dtor = binp->dtors;
 #ifdef CONFIG_ARCH_ADDRENV
-  hw_addrenv_t oldenv;
+  save_addrenv_t oldenv;
   int ret;
 #endif
   int i;
diff --git a/binfmt/libnxflat/libnxflat_addrenv.c b/binfmt/libnxflat/libnxflat_addrenv.c
index 049c033827..7f3e351766 100644
--- a/binfmt/libnxflat/libnxflat_addrenv.c
+++ b/binfmt/libnxflat/libnxflat_addrenv.c
@@ -89,7 +89,7 @@ int nxflat_addrenv_alloc(FAR struct nxflat_loadinfo_s *loadinfo, size_t envsize)
   FAR struct dspace_s *dspace;
 #ifdef CONFIG_ARCH_ADDRENV
   FAR void *vaddr;
-  hw_addrenv_t oldenv;
+  save_addrenv_t oldenv;
   int ret;
 #endif
 
diff --git a/include/nuttx/addrenv.h b/include/nuttx/addrenv.h
new file mode 100644
index 0000000000..6460e22138
--- /dev/null
+++ b/include/nuttx/addrenv.h
@@ -0,0 +1,177 @@
+/****************************************************************************
+ * include/nuttx/addrenv.h
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_ADDRENV_H
+#define __INCLUDE_NUTTX_ADDRENV_H 1
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#ifdef CONFIG_ARCH_ADDRENV
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************/
+/* Pre-requisites */
+
+#ifndef CONFIG_MM_PGALLOC
+#  error CONFIG_MM_PGALLOC not defined
+#endif
+
+#ifndef CONFIG_MM_PGSIZE
+#  error CONFIG_MM_PGSIZE not defined
+#endif
+
+/* .text region */
+
+#ifndef CONFIG_ARCH_TEXT_VBASE
+#  error CONFIG_ARCH_TEXT_VBASE not defined
+#  define CONFIG_ARCH_TEXT_VBASE 0
+#endif
+
+#if (CONFIG_ARCH_TEXT_VBASE & CONFIG_MM_MASK) != 0
+#  error CONFIG_ARCH_TEXT_VBASE not aligned to page boundary
+#endif
+
+#ifndef CONFIG_ARCH_TEXT_NPAGES
+#  warning CONFIG_ARCH_TEXT_NPAGES not defined
+#  define CONFIG_ARCH_TEXT_NPAGES 1
+#endif
+
+#define CONFIG_ARCH_TEXT_SIZE  (CONFIG_ARCH_TEXT_NPAGES * CONFIG_MM_PGSIZE)
+
+/* .bss/.data region */
+
+#ifndef CONFIG_ARCH_DATA_VBASE
+#  error CONFIG_ARCH_DATA_VBASE not defined
+#  define CONFIG_ARCH_DATA_VBASE (CONFIG_ARCH_TEXT_VBASE + CONFIG_ARCH_TEXT_SIZE)
+#endif
+
+#if (CONFIG_ARCH_DATA_VBASE & CONFIG_MM_MASK) != 0
+#  error CONFIG_ARCH_DATA_VBASE not aligned to page boundary
+#endif
+
+#ifndef CONFIG_ARCH_DATA_NPAGES
+#  warning CONFIG_ARCH_DATA_NPAGES not defined
+#  define CONFIG_ARCH_DATA_NPAGES 1
+#endif
+
+#define CONFIG_ARCH_DATA_SIZE  (CONFIG_ARCH_DATA_NPAGES * CONFIG_MM_PGSIZE)
+
+/* Heap region */
+
+#ifndef CONFIG_ARCH_HEAP_VBASE
+#  error CONFIG_ARCH_HEAP_VBASE not defined
+#  define CONFIG_ARCH_HEAP_VBASE (CONFIG_ARCH_DATA_VBASE + CONFIG_ARCH_DATA_SIZE)
+#endif
+
+#if (CONFIG_ARCH_HEAP_VBASE & CONFIG_MM_MASK) != 0
+#  error CONFIG_ARCH_HEAP_VBASE not aligned to page boundary
+#endif
+
+#ifndef CONFIG_ARCH_HEAP_NPAGES
+#  warning CONFIG_ARCH_HEAP_NPAGES not defined
+#  define CONFIG_ARCH_HEAP_NPAGES 1
+#endif
+
+#define CONFIG_ARCH_HEAP_SIZE  (CONFIG_ARCH_HEAP_NPAGES * CONFIG_MM_PGSIZE)
+
+/* Stack region */
+
+#ifndef CONFIG_ARCH_STACK_VBASE
+#  error CONFIG_ARCH_STACK_VBASE not defined
+#  define CONFIG_ARCH_STACK_VBASE (CONFIG_ARCH_HEAP_VBASE + CONFIG_ARCH_HEAP_SIZE)
+#endif
+
+#if (CONFIG_ARCH_STACK_VBASE & CONFIG_MM_MASK) != 0
+#  error CONFIG_ARCH_STACK_VBASE not aligned to page boundary
+#endif
+
+#ifndef CONFIG_ARCH_STACK_NPAGES
+#  warning CONFIG_ARCH_STACK_NPAGES not defined
+#  define CONFIG_ARCH_STACK_NPAGES 1
+#endif
+
+#define CONFIG_ARCH_STACK_SIZE (CONFIG_ARCH_STACK_NPAGES * CONFIG_MM_PGSIZE)
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Address Environment Interfaces
+ *
+ * Low-level interfaces used in binfmt/ to instantiate tasks with address
+ * 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_ARCH_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_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 thread which whose
+ * group been assigned an address environment by up_addrenv_assign().
+ *
+ *   up_addrenv_attach  - Clone the address environment assigned to one TCB
+ *                        to another.  This operation is done when a pthread
+ *                        is created that share's the same address
+ *                        environment.
+ *   up_addrenv_detach  - Release the threads reference to an address
+ *                        environment when a task/thread exits.
+ *
+ ****************************************************************************/
+
+/* Prototyped in include/nuttx/arch.h as part of the OS/platform interface */
+
+#endif /* CONFIG_ARCH_ADDRENV */
+#endif /* __INCLUDE_NUTTX_ADDRENV_H */
diff --git a/include/nuttx/arch.h b/include/nuttx/arch.h
index 5ff80a5eae..951d959fe1 100644
--- a/include/nuttx/arch.h
+++ b/include/nuttx/arch.h
@@ -698,7 +698,7 @@ void up_allocate_kheap(FAR void **heap_start, size_t *heap_size);
  *
  * Description:
  *   This function is called when a new task is created in order to
- *   instantiate an address environment for the new task group. 
+ *   instantiate an address environment for the new task group.
  *   up_addrenv_create() is essentially the allocator of the physical
  *   memory for the new task.
  *
@@ -776,8 +776,8 @@ int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr);
  *     The address environment that was in place before up_addrenv_select().
  *     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 group_addrenv_t.
+ *     called.  Note that this may be a task agnostic, platform-specific
+ *     representation that may or may not be different from group_addrenv_t.
  *
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
@@ -785,7 +785,7 @@ int up_addrenv_vaddr(FAR group_addrenv_t addrenv, FAR void **vaddr);
  ****************************************************************************/
 
 #ifdef CONFIG_ARCH_ADDRENV
-int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);
+int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv);
 #endif
 
 /****************************************************************************
@@ -797,7 +797,7 @@ int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);
  *   original address environment.
  *
  * Input Parameters:
- *   oldenv - The hardware representation of the address environment
+ *   oldenv - The platform-specific representation of the address environment
  *     previously returned by up_addrenv_select.
  *
  * Returned Value:
@@ -806,7 +806,7 @@ int up_addrenv_select(group_addrenv_t addrenv, hw_addrenv_t *oldenv);
  ****************************************************************************/
 
 #ifdef CONFIG_ARCH_ADDRENV
-int up_addrenv_restore(hw_addrenv_t oldenv);
+int up_addrenv_restore(save_addrenv_t oldenv);
 #endif
 
 /****************************************************************************
diff --git a/include/nuttx/binfmt/elf.h b/include/nuttx/binfmt/elf.h
index 1b944eeafa..ec79ffb48f 100644
--- a/include/nuttx/binfmt/elf.h
+++ b/include/nuttx/binfmt/elf.h
@@ -132,7 +132,7 @@ struct elf_loadinfo_s
 
 #ifdef CONFIG_ARCH_ADDRENV
   group_addrenv_t    addrenv;    /* Task group address environment */
-  hw_addrenv_t       oldenv;     /* Saved hardware address environment */
+  save_addrenv_t     oldenv;     /* Saved hardware address environment */
 #endif
 
   uint16_t           symtabidx;  /* Symbol table section index */
diff --git a/include/nuttx/binfmt/nxflat.h b/include/nuttx/binfmt/nxflat.h
index 52fd0a4166..f44f4c77bd 100644
--- a/include/nuttx/binfmt/nxflat.h
+++ b/include/nuttx/binfmt/nxflat.h
@@ -104,7 +104,7 @@ struct nxflat_loadinfo_s
 
 #ifdef CONFIG_ARCH_ADDRENV
   group_addrenv_t addrenv; /* Task group address environment */
-  hw_addrenv_t oldenv;     /* Saved hardware address environment */
+  save_addrenv_t oldenv;   /* Saved hardware address environment */
 #endif
 
   /* File descriptors */
diff --git a/include/nuttx/pgalloc.h b/include/nuttx/pgalloc.h
index ebaa06d12e..1db59dee57 100644
--- a/include/nuttx/pgalloc.h
+++ b/include/nuttx/pgalloc.h
@@ -66,7 +66,7 @@
  *
  * Dependencies:  CONFIG_ARCH_HAVE_MMU and CONFIG_GRAN
  */
- 
+
 #ifndef CONFIG_MM_PGALLOC_PGSIZE
 #  define CONFIG_MM_PGALLOC_PGSIZE 4096
 #endif