Doc: add migration warning to updating release system and elf programs

Add a migration warning to the update release system and the elf
programs documentation pages. This is just to add a papertrail from
where the documentation originate in case of error during the migration
process. Also fix a bit of formatting in the pages

Author: lvanasse

Documentation/guides/fully_linked_elf.rst

@@ -1,6 +1,11 @@
+===============================
 ELF Programs – No Symbol Tables
 ===============================
 
+.. warning:: 
+    Migrated from: 
+    https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=139629542
+
 You can easily extend the firmware in your released, embedded system using ELF  
 programs provided via a file system (for example, an SD card or downloaded into  
 on-board SPI FLASH). In order to support such post-release updates, your  
@@ -13,7 +18,7 @@ Alan Carvalho de Assis has also made a video based on this example in the
 YouTube `NuttX Channel <https://www.youtube.com/watch?v=oL6KAgkTb8M>`_.
 
 Creating the Export Package
----------------------------
+===========================
 
 At the time that you release the firmware, you should create and save an  
 export package. The export package is all that you need to create  
@@ -104,7 +109,7 @@ content of this ZIP file is the following directory structure:
     `- .config
 
 The Add-On Build Directory
---------------------------
+==========================
 
 In order to create the add-on ELF program, you will need (1) the export  
 package, (2) the program build ``Makefile``, (3) a linker script used by the  
@@ -121,7 +126,7 @@ package, (2) the program build ``Makefile``, (3) a linker script used by the
    script (``mkdefines.sh``).
 
 Hello Example
--------------
+=============
 
 To keep things manageable, let's use a concrete example. Suppose the ELF  
 program that we wish to add to the release code is the single source file  
@@ -142,7 +147,7 @@ Let's say that we have a directory called ``addon`` and it contains the
 Bash script called ``mkdefines.sh`` that will create a linker script.
 
 Building the ELF Program
-------------------------
+========================
 
 The first step in creating the ELF program is to unzip the Export Package. We  
 start with our ``addon`` directory containing the following:
@@ -173,7 +178,7 @@ the content from the released NuttX code that we need to build the ELF
 program.
 
 The Makefile
-------------
+============
 
 The ELF program is created simply as:
 
@@ -261,7 +266,7 @@ Below is the ``Makefile`` used to create the ELF program:
    rm -f *.o
 
 The Linker Script
------------------
+=================
 
 Two linker scripts are used. One is a normal file (we'll call it the main  
 linker script), and the other, ``defines.ld``, is created on-the-fly as  
@@ -335,7 +340,7 @@ The main linker script, ``gnu-elf.ld``, contains the following:
    }
 
 Creating the ``defines.ld`` Linker Script
------------------------------------------
+=========================================
 
 The additional linker script ``defines.ld`` is created through a three-step  
 process:
@@ -444,7 +449,7 @@ Here is an example ``defines.ld`` created by ``mkdefines.sh``:
    printf = 0x0800aefc | 0x00000001 ;
 
 Replacing an NSH Built-In Function
-----------------------------------
+==================================
 
 Files can be executed by ``NSH`` from the command line by simply typing the  
 name of the ELF program. This requires:
@@ -486,7 +491,7 @@ replaced with the version in the file system:
    nsh>
 
 Version Dependency
-------------------
+==================
 
 .. note::
 
@@ -501,7 +506,7 @@ The alternative approach using :doc:`Symbol Tables <fully_linked_elf>` is more
 or less version independent.
 
 Tightly Coupled Memories
-------------------------
+========================
 
 Most MCUs based on ARMv7-M family processors support some kind of Tightly  
 Coupled Memory (TCM). These TCMs have somewhat different properties for  

Documentation/guides/partially_linked_elf.rst

@@ -1,8 +1,13 @@
+=================================
 ELF Programs – With Symbol Tables
 =================================
 
+.. warning:: 
+    Migrated from: 
+    https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=139629543
+
 Updating a Release System with ELF Programs – With Symbol Tables
------------------------------------------------------------------
+================================================================
 
 You can easily extend the firmware in your released, embedded system using
 ELF programs provided via a file system. For example, an SD card or, perhaps,
@@ -16,7 +21,7 @@ The files shown in this Wiki page can be downloaded
 `here <https://cwiki.apache.org/confluence/download/attachments/139629402/elfprog-wsymtab.tar.gz?version=1&modificationDate=1576735523000&api=v2>`_
 
 Creating a Symbol Table
------------------------
+=======================
 
 There are several ways to create an application symbol table. Only two are
 compatible with the example provided here:
@@ -75,7 +80,7 @@ compatible with the example provided here:
    - Include application logic to provide the symbol table. If ``CONFIG_EXAMPLES_NSH_SYMTAB=y`` is set, NSH can handle this automatically.
 
 Export Package
---------------
+==============
 
 At the time of firmware release, you should create and save an export package.
 This export package contains all the necessary files required to create
@@ -142,7 +147,7 @@ of this ZIP file are organized as follows:
    `- .config
 
 Add-On Build Directory
------------------------
+======================
 
 In order to create the add-on ELF program, you will need:
 
@@ -155,7 +160,7 @@ that non-GNU toolchains would likely require a significantly different
 Makefile and linker script.
 
 Hello Example
--------------
+=============
 
 To keep things manageable, let's use a concrete example. Suppose the ELF 
 program that we wish to add to the release code is the simple 
@@ -180,7 +185,7 @@ Let's say that we have a directory called ``addon`` that contains the following:
 
 
 Building the ELF Program
-------------------------
+========================
 
 The first step in creating the ELF program is to unzip the export 
 package. Starting in the ``addon`` directory:
@@ -209,7 +214,7 @@ the ELF program.
 
 
 The Makefile
-------------
+============
 
 To build the ELF program, simply run:
 
@@ -278,7 +283,7 @@ The Makefile used to create the ELF program is as follows:
     rm -f *.o
 
 The Linker Script
------------------
+=================
 
 The linker script that I am using in this example, gnu-elf.ld, 
 contains the following:
@@ -349,7 +354,7 @@ contains the following:
     }
 
 Replacing NSH Built-In Functions
---------------------------------
+================================
 
 Files can be executed by NSH from the command line by simply typing the name 
 of the ELF program. This requires (1) that the feature be enabled with 
@@ -397,7 +402,7 @@ successfully. The built-in version will be ignored. It has been replaced with
 the version in the file system.
 
 Tightly Coupled Memories
-------------------------
+========================
 
 Most MCUs based on ARMv7-M family processors support some kind of Tightly 
 Coupled Memory (TCM). These TCMs have somewhat different properties for 

Documentation/guides/updating_release_system_elf.rst

@@ -1,5 +1,10 @@
+===========================================
 Updating a Release System with ELF Programs
-============================================
+===========================================
+
+.. warning:: 
+    Migrated from: 
+    https://cwiki.apache.org/confluence/display/NUTTX/Updating+a+Release+System+with+ELF+Programs
 
 You can enhance the functionality of your released embedded system by adding
 ELF programs, which can be loaded from a file system. These programs can be
@@ -9,15 +14,15 @@ easy updates or extensions to the system's firmware.
 There are two ways you can accomplish this:
 
 Partially linked
-----------------
+================
 This describes building the partially linked, relocatable ELF program that 
 depends on a symbol table provided by the base firmware in FLASH.
 
 Reference:
 - See :doc:`Partially Linked ELF Programs <partially_linked_elf>`
 
 Fully linked
-------------
+============
 This describes building a fully linked, relocatable ELF program that does 
 not depend on any symbol table information.