diff options
| -rw-r--r-- | nuttx/ChangeLog | 3 | ||||
| -rw-r--r-- | nuttx/Documentation/NuttX.html | 126 | ||||
| -rw-r--r-- | nuttx/Documentation/NuttXNxFlat.html | 549 | ||||
| -rw-r--r-- | nuttx/ReleaseNotes | 14 | ||||
| -rw-r--r-- | nuttx/TODO | 48 | ||||
| -rw-r--r-- | nuttx/examples/README.txt | 2 |
6 files changed, 666 insertions, 76 deletions
diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog index c0e2a2e9a..65fcd4ebd 100644 --- a/nuttx/ChangeLog +++ b/nuttx/ChangeLog @@ -773,7 +773,7 @@ * The NXP LPC2148 and STR711 targets can now also be built using the CodeSourcery or devkitARM Windows native toolchains. -0.4.8 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> +0.4.9 2009-06-26 Gregory Nutt <spudmonkey@racsa.co.cr> * Add strtoll() and strtoull(); Add macros for atol() and atoll(). * dup() and dup2() will now clone socket descriptors @@ -802,6 +802,7 @@ This file has been around for a long time, but I don't think it has every been used before (i.e., prior to the NXFLAT logic) +0.4.10 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html index 0dfc4d0e0..36eba419b 100644 --- a/nuttx/Documentation/NuttX.html +++ b/nuttx/Documentation/NuttX.html @@ -8,7 +8,7 @@ <tr align="center" bgcolor="#e4e4e4"> <td> <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1> - <p>Last Updated: June 25, 2009</p> + <p>Last Updated: June 26, 2009</p> </td> </tr> </table> @@ -411,6 +411,15 @@ <li>ROMFS filesystem support.</li> </p> </tr> +<tr> + <td><br></td> + <td> + <p> + <li><a href="NuttXNxFlat.html">NXFLAT</a>. + A new binary format call NXFLAT that can be used to + execute separately linked programs in place in a file system. + </p> +</tr> <tr> <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> @@ -687,8 +696,8 @@ </tr> </table> -<p><b>nuttx-0.4.8</b>. - This 40<sup>th</sup> release of NuttX (nuttx-0.4.8) was made on June 13, 2009 +<p><b>nuttx-0.4.9</b>. + This 41<sup>st</sup> release of NuttX (nuttx-0.4.9) was made on June 26, 2009 and is available for download from the <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a> website. @@ -698,21 +707,16 @@ </p> This release adds: <ul> - <li> - Support for the Olimex STRP711 board. That board is based on the STMicro - STR711 MCU (ARM7TDMI). Integration is complete on the basic port (boot logic, - system time, serial console). Two configurations have been verified: (1) The - board boots and passes the OS test with console output visible on UART0, and - the NuttShell (NSH) is fully functional with interrupt driven serial console. - An SPI driver is available but untested (because the Olimex card slot appears - to accept only MMC cards; I have only SD cards). Additional needed: USB and - driver, MMC integration. - </li> - <li> - Support for the CodeSourcery and devkitARM Windows-native GNU toolchains. - Makefiles have been modified for the LM3S6918, LPC2148, and STR711 to support - these toolchains under Cygwin. - </li> + <li> + Support for a new binary format call NXFLAT that can be used to + execute separately linked programs in place in a file system. + See <a href="NuttXNxFlat.html">NXFLAT Documentation</a> + for detailed information. + </li> + <li> + Several important bugs were files related to networking and ROMFS + (see the <a href="#currentrelease">ChangeLog</a> for a complete list). + </li> </ul> </p> @@ -1418,57 +1422,7 @@ Other memory: </table> <pre><ul> -nuttx-0.4.8 2009-06-13 Gregory Nutt <spudmonkey@racsa.co.cr> - - * lib/lib_*stream.c: Extend internal stream logic to support incoming streams. - * arch/arm/src/str71x: Serial output is now correct and timer interrupts are - working. The test at configs/olimex-strp711/ostest passes. This means that - the basic STR-P711 port is complete. - * configs/olimex-strp711/nsh: Add and verifed a NuttShell (NSH) configuration - for the STR-P711. - * arch/arm/str71x/str71x_serial.c: The STR711 interrupt driven serial driver - finally works after some extradinary measures to handle missed interrupts. - NSH is fully functional on the Olimex STR-P711 board. - * example/nsh: Moved architecture specific files from NSH directory to board- - specific directories. - * config/olimex-strp711/src/up_nsh.c: Add an NSH board specific directory for - for the Olimex STR7P11 board. - * Fixed build of LM3X6918 using the CodeSourcery Windows native toolchain. There - were lots of issues with Cygwin paths and Cygwin symbolic links. These changes - may work with the devarmKIT as well, but that remains untested. - * The NXP LPC2148 and STR711 targets can now also be built using the CodeSourcery - or devkitARM Windows native toolchains. - -pascal-0.1.2 2008-02-10 Gregory Nutt <spudmonkey@racsa.co.cr> - - * Add logic to build and link with the ZDS-II toolchain - use with the z16f. - * Make sure that POFF header structures are aligned - * Standardized POFF file format to big-endian - * Break up large switch statements to lower complexity - and eliminate a compiler bug - * Changes so that runtime compiles with SDCC. - -buildroot-0.1.6 2009-xx-xx <spudmonkey@racsa.co.cr> - - * Added config/arm7tdmi-defconfig-4.2.4 - * Added config/arm920t-defconfig-4.3.3 - * Correct error in arm-defconfig gcc-3.4.6 build. The gcc-3.4.6 configuration - does not not take --with-abi - * Correct error in gcc-3.4.6/gcc/collect.c. Calls open with O_CREAT but - does not specify mode. Newer host compilers can error out on this. -</pre></ul> - -<table width ="100%"> - <tr bgcolor="#e4e4e4"> - <td> - <a name="pendingchanges">Unreleased Changes</a> - </td> - </tr> -</table> - -<pre><ul> -nuttx-0.4.9 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> +nuttx-0.4.9 2009-06-26 Gregory Nutt <spudmonkey@racsa.co.cr> * Add strtoll() and strtoull(); Add macros for atol() and atoll(). * dup() and dup2() will now clone socket descriptors @@ -1494,9 +1448,17 @@ nuttx-0.4.9 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> This file has been around for a long time, but I don't think it has every been used before (i.e., prior to the NXFLAT logic) -pascal-0.1.3 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> +pascal-0.1.2 2008-02-10 Gregory Nutt <spudmonkey@racsa.co.cr> + + * Add logic to build and link with the ZDS-II toolchain + use with the z16f. + * Make sure that POFF header structures are aligned + * Standardized POFF file format to big-endian + * Break up large switch statements to lower complexity + and eliminate a compiler bug + * Changes so that runtime compiles with SDCC. -buildroot-0.1.7 2009-xx-xx <spudmonkey@racsa.co.cr> +buildroot-0.1.7 2009-06-26 <spudmonkey@racsa.co.cr> * configs/avr-defconfig-4.3.3: Added support for AVR to support a NuttX port of the ATmega128. @@ -1507,6 +1469,24 @@ buildroot-0.1.7 2009-xx-xx <spudmonkey@racsa.co.cr> <table width ="100%"> <tr bgcolor="#e4e4e4"> <td> + <a name="pendingchanges">Unreleased Changes</a> + </td> + </tr> +</table> + +<pre><ul> +nuttx-0.4.10 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> + +nuttx-0.4.10 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> + +pascal-0.1.3 2009-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr> + +buildroot-0.1.8 2009-xx-xx <spudmonkey@racsa.co.cr> +</pre></ul> + +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> <a name="TODO"><h1>Bugs, Issues, <i>Things-To-Do</i></h1></a> </td> </tr> @@ -1541,6 +1521,10 @@ buildroot-0.1.7 2009-xx-xx <spudmonkey@racsa.co.cr> </tr> <tr> <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> + <td><a href="NuttXNxFlat.html">NXFLAT</a> Binary Format</td> +</tr> +<tr> + <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> <td><a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a></td> </tr> <tr> diff --git a/nuttx/Documentation/NuttXNxFlat.html b/nuttx/Documentation/NuttXNxFlat.html new file mode 100644 index 000000000..289c8a35c --- /dev/null +++ b/nuttx/Documentation/NuttXNxFlat.html @@ -0,0 +1,549 @@ +<html> +<head> +<title>NXFLAT</title> +</head> +<body background="backgd.gif"> + +<hr><hr> +<table width ="100%"> + <tr align="center" bgcolor="#e4e4e4"> + <td> + <h1><big><font color="#3c34ec"><i>NXFLAT</i></font></big></h1> + <h2><font color="#dc143c">>>> Under Construction <<<</font></h2> + <p>Last Updated: June 26, 2009</p> + </td> + </tr> +</table> +<hr><hr> +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> + <h1>Table of Contents</h1> + </td> + </tr> +</table> + +<center><table width ="80%"> +<tr> +<td> +<table> +<tr> + <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> + <td> + <a href="#overview">1.0 Overview</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#functionality">1.1 Functionality</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#background">1.2 Background</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#limitations">1.3 Limitations</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#supported">1.4 Supported Processors</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#status">1.5 Development Status</a> + </td> +</tr> +<tr> + <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> + <td> + <a href="#toolchain">2.0 NXFLAT Toolchain</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#building">1.2 Building the NXFLAT Toolchain</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#mknxflat">1.2 mknxflat</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#ldnxflat">1.3 ldnxflat</a> + </td> +</tr> +<tr> + <td><br></td> + <td> + <a href="#making">1.4 Making an NXFLAT module</a> + </td> +</tr> +<tr> + <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> + <td> + <a href="#nogot">Appendix A. No GOT Operation</a> + </td> +</tr> +<tr> + <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td> + <td> + <a href="#pictext">Appendix B. PIC Text Workaround</a> + </td> +</tr> +</table> +</td> +</tr> +</table></center> + +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> + <a name="overview"><h1>1.0 Overview</h1></a> + </td> + </tr> +</table>f + +<a name="functionality"><h2>1.1 Functionality</h2></a> + +<p> + NXFLAT is a customized and simplified version of binary format implemented a few years ago called + <a HREF="http://xflat.sourceforge.net/">XFLAT</A> + With the NXFLAT binary format you will be able to do the following: +</p> +<ul> + <li>Place separately linked programs in a file system, and</li> + <li>Execute those programs by dynamically linking them to the base NuttX code.</li> +</ul> +<p> + This allows you to extend the NuttX base code after it has been written into FLASH. + One motivation for implementing NXFLAT is support clean CGI under an HTTPD server. +</p> +<p> + This feature is especially attractive when combined with the NuttX ROMFS support: + ROMFS allows you to execute programs in place (XIP) in flash without copying anything + other than the .data section to RAM. + In fact, the initial NXFLAT release will work only on ROMFS. +</p> +<p> + This NuttX feature includes: +</p> +<ul> + <li> + A dynamic loader that is built into the NuttX core + (See <a href="http://nuttx.cvs.sourceforge.net/viewvc/nuttx/nuttx/binfmt/">CVS</a>). + </li> + <li> + Minor changes to RTOS to support position independent code, and + </li> + <li> + A linker to bind ELF binaries to produce the NXFLAT binary format + (See <a href="http://nuttx.cvs.sourceforge.net/viewvc/nuttx/misc/buildroot/toolchain/nxflat">CVS). + </li> +</ul> + +<a name="background"><h2>1.2 Background</h2></a> + +<p> + NXFLAT is derived from <a href="http://xflat.sourceforge.net/">XFLAT</a>. + XFLAT is a toolchain add that provides full shared library and XIP executable + support for processors that have no Memory Management Unit (MMU). + NXFLAT is greatly simplified for the deeply embedded environment targeted by Nuttx: +</p> +<ul> + <li>NXFLAT does not support shared libraries, because</li> + <li>NXFLAT does not support <i>exportation</i> of symbol values from a module</li> +</ul> +<p> + Rather, the NXFLAT module only <i>imports</i> symbol values. + In the NXFLAT model, the (PIC<sup>1</sup>) NXFLAT module resides in a FLASH file system and + when it is loaded at run time, it is dynamically linked only to the (non-PIC) base NuttX + code: + The base NuttX <i>exports</i> a symbol table; the NXFLAT module <i>imports</i> those symbol value + to dynamically bind the module to the base code. +</p> +<p><sup>1</sup><small>"Position Independent Code"</small></p> + +<a name="limitations"><h2>1.3 Limitations</h2></a> + +<ul> + <li><b>ROMFS Only</b>. + The initial NXFLAT release will work only with executable modules residing on a ROMFS + file system. + That is because the loader depends on the capability to <code>mmap()</code> the code segment. + NUTTX does not provide any general kind of file mapping capability. + In fact, <i>true </i>file mapping is only possible with RTOSs and MCUs that provide an MMU<sup>1</sup> + and only ROMFS supports that kind of XIP execution from FLASH. + It is possible to simulate file mapping by allocating memory and copy the file into memory. + NXFLAT would work that kind of file mapping to and that feature could easily be added to NuttX. + </li> + <li><b>GCC/ARM/Cortex-M3 Only</b> + At present, the NXFLAT toolchain is only available for ARM and Cortex-M3 (thumb2) targets. + </li> + <li><b>Read-Only Data in RAM</b> + Read-only data must reside in RAM. + In code generated by GCC, all data references are indexed by the PIC<sup>2</sup> base register + (that is usually R10 or <i>sl</i> for the ARM processors). + The includes read-only data (<code>.rodata</code>). + Embedded firmware developers normally like to keep <code>.rodata</code> in FLASH with the code sections. + But because all data is referenced with the PIC base register, all of that data must lie in RAM. + A NXFLAT change to work around this is under investigation<sup>3</sup>. + </li> + <li><b>Globally Scoped Function Function Pointers</b> + If a function pointer is taken to a statically defined function, then (at least for ARM) GCC will + generate a relocation that NXFLAT cannot handle. + The workaround is make all such functions global in scope. + A fix would involve a change to the GCC compiler as described in <a href="#pictext">Appendix B</a>. + </li> + <li><b>No Callbacks</b> + Callbacks through function pointers must be avoided or, when then cannot be avoided, handled very specially. + The reason for this is that the PIC module requires setting of a special value in a PIC register. + If the callback does not set the PIC register, then the called back function will fail because + it will be unable to correct access data memory. + Special logic is in place to handle: Signal callbacks, watchdog timer callbacks. + But other callbacks (like those used with <code>qsort()</code> must be avoided in an NXFLAT module. + </li> +</ul> + +<ul><p> + <sup>1</sup><small>"Memory Management Unit"</small><br> + <sup>2</sup><small>"Position Independent Code"</small><br> + <sup>3</sup><small>A work around is under consideration: + At run time, the <code>.rodata</code> offsets will be indexed by a RAM address. + If the dynamic loader were to offset those <code>.rodata</code> offsets properly, it + still might be possible to reference <code>.rodata</code> in ROM. + That work around is still a top of investigation at this time.</small> +</p></ul> + +<a name="supported"><h2>1.4 Supported Processors</h2></a> + +<p> + As mentioned <a href="#limitations">above</a>, the NXFLAT toolchain is only available for ARM and + Cortex-M3 (thumb2) targets. + Furthermore, NXFLAT has only been tested on the Eagle-100 LMS6918 Cortex-M3 board. +</p> + +<a name="status"><h2>1.5 Development Status</h2></a> + +<p> + The initial release of NXFLAT was made in NuttX version 0.4.9. + Testing is limited to the tests found under <code>examples/nxflat</code> in the source tree. + Some known problems exist + (see the <a href="http://nuttx.cvs.sourceforge.net/*checkout*/nuttx/nuttx/TODO">TODO</a> list). + As such, NXFLAT is currently in an early alpha phase. +</p> + +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> + <a name="toolchain"><h1>2.0 NXFLAT Toolchain</h1></a> + </td> + </tr> +</table> + +<a name="building"><h2>1.2 Building the NXFLAT Toolchain</h2></a> + +<p> + In order to use NXFLAT, you must use special NXFLAT tools to create the binary module in FLASH. + To do this, you will need to download the buildroot package and build it on your Linux or Cygwin machine. + The buildroot can be downloaded from + <a https://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">Sourceforge</a>. + You will need version 0.1.7 or later. +</p> +<p> + Here are some general build instructions: +</p> +<ul> + + <li> + You must have already configured Nuttx in <code><some-dir>/nuttx</code> + <li> + <li> + Download the buildroot package <code>buildroot-0.x.y</code> into <code><some-dir></code> + <li> + <li> + Unpack <code><some-dir>/buildroot-0.x.y.tar.gz</code> using a command like <code>tar zxf buildroot-0.x.y</code>. + This will result in a new directory like <code><some-dir>/misc/buildroot-0.x.y</code> + </li> + <li> + Move this into position: <code>mv <some-dir>/misc/buildroot-0.x.y <code><some-dir>/buildroot</code> + </li> + <li> + <code>cd <code><some-dir>/buildroot</code> + </li> + <li> + Copy a configuration file into the top buildroot directory: <code>cp configs/abc-defconfig-x.y.z .config</code>. + </li> + <li> + Enable building of the NXFLAT tools by <code>make menuconfig</code>. + Select to build the NXFLAT toolchain with GCC (you can also select omit building GCC with and only build the + NXFLAT toolchain for use with your own GCC toolchain). + </li> + <li> + Make the toolchain: <code>make</code>. + When the make completes, the tool binaries will be available under + <code><some-dir>/buildroot/build_abc/staging_dir/bin</code> + </li> +</ul> + +<a name="mknxflat"><h2>1.2 mknxflat</h2></a> + +<p> + <code>mknxflat</code> is used to build a <i>thunk</i> file. + See <a href="#making">below</a> for usage. + +<ul><pre> +Usage: mknxflat [options] <bfd-filename> + +Where options are one or more of the following. Note +that a space is always required between the option and +any following arguments. + + -d Use dynamic symbol table. [symtab] + -f <cmd-filename> + Take next commands from <cmd-filename> [cmd-line] + -o <out-filename> + Output to <out-filename> [stdout] + -v Verbose output [no output] + -w Import weakly declared functions, i.e., weakly + declared functions are expected to be provided at + load-time [not imported] +</pre></ul> + +<a name="ldnxflat"><h2>1.3 ldnxflat</h2></a> + +<p> + <code>ldnxflat</code> is use to link your object files along with the <i>thunk</i> file + generated by <a href="#mknxflat"><code>mknxflat<code></a> to produce the NXFLAT binary module. + See <a href="#making">below</a> for usage. +</p> + +<ul><pre> +Usage: ldnxflat [options] <bfd-filename> + +Where options are one or more of the following. Note +that a space is always required between the option and +any following arguments. + + -d Use dynamic symbol table [Default: symtab] + -e <entry-point> + Entry point to module [Default: _start] + -o <out-filename> + Output to <out-filename> [Default: <bfd-filename>.nxf] + -s <stack-size> + Set stack size to <stack-size> [Default: 4096] + -v Verbose output. If -v is applied twice, additional + debug output is enabled [Default: no verbose output]. +</pre></ul> + +<a name="making"><h2>1.4 Making an NXFLAT module</h2></a> + +<p> + Below is a snippet from an NXFLAT make file (simplified from NuttX + <a href="http://nuttx.cvs.sourceforge.net/viewvc/*checkout*/nuttx/nuttx/examples/nxflat/tests/hello/Makefile?revision=1.6"> + Hello, World!</a> example. +<p> +<ul><table width="50%"> + +<ul><table> + <tr> + <th>Target 1</th> + <td><code>hello.r1:</code></td> + <td><code>hello.o</code></td> + </tr> + <tr> + <td><br></td> + <td><br></td> + <td><code>abc-elf-ld -r -d -warn-common -o $@ $^</code></td> + </tr> + <tr> + <th>Target 2</th> + <td><code>hello-thunk.S:</code></td> + <td><code>hello.r1</code></td> + </tr> + <tr> + <td><br></td> + <td><br></td> + <td><code>mknxflat -o $@ $^</code></td> + </tr> + <tr> + <th>Target 3</th> + <td><code>hello.r2:</code></td> + <td><code>hello-thunk.S</code></td> + </tr> + <tr> + <td><br></td> + <td><br></td> + <td> + <code>abc-elf-ld -r -d -warn-common -T binfmt/libnxflat/gnu-nxflat.ld -no-check-sections -o $@ hello.o hello-thunk.o</code> + </td> + </tr> + <tr> + <th>Target 4</th> + <td><code>hello:</code></td> + <td><code>hello.r2</code></td> + </tr> + <tr> + <td><br></td> + <td><br></td> + <td><code>ldnxflat -e main -s 2048 -o $@ $^</code></td> + </tr> + <tr> +</table></ul> + +<p><b>Target 1</b>. + This target links all of the object files together into one relocation object. + In this case, there is only a single object file, <code>hello.o</code>, and it is linked to produce <code>hello.r1</code>. +</p> + +<p><b>Target 2</b>. + Given <code>hello.r1</code>, this target will invoke <a href="#mknxflat"><code>mknxflat</code></a> + to make the <i>thunk</i> file, <code>hello-thunk.S</code>. + This <i>thunk</i> contains all of the information needed to create the imported function list. +</p> + +<p><b>Target 3</b> + This this target is similar to <b>Target 1</b>. + In this case, it will link together the object file, <code>hello.o</code> along with the assembled <i>thunk</i> file, + <code>hello-thunk.o</code> to create another, single relocatable object, <code>hello.r2</code>. + The linker script, <code>gnu-nxflat.ld</code> is required at this point to correctly position the sections. +</p> + +<p><b>Target 4</b>. + Finally, this target will use the <code>hello.r2</code> relocatable object to create the final, NXFLAT module + <code>hello</code> by calling <a href="#ldnxflat"><code>ldnxflat</code></a>. +</p> + +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> + <a name="nogot"><h1>Appendix A. No GOT Operation</h1></a> + </td> + </tr> +</table> + +<p> + When GCC generate position independent code, new code sections will appear in your programs. + One of these the the GOT (Global Offset Table) and, in ELF environments, the PLT (Procedure + Lookup Table. + For example, if your C code generated (ARM) assembly language like this without PIC: +<p> +<ul><pre> + ldr r1, .L0 <-- Fetch the offset to 'x' + ldr r0, [r10, r1] <-- Load the value of 'x' with PIC + offset + ... +.L0: .word x <-- Offset to 'x' +</pre></ul> + +<p> + Then when PIC is enabled (say with the -fpic compiler option), it will generate code like + this: +</p> + +<ul><pre> + ldr r1, .L0 <-- Fetch the offset to the GOT entry + ldr r1, [r10,r1] <-- Fetch the (relocated) address + of 'x' from the GOT + ldr r0, [r1, #0] <-- Fetch the value of 'x' + ... +.L1 .word x(GOT) <-- Offset to entry in the GOT +</pre></ul> + +<p>See <a href="http://xflat.sourceforge.net/NoMMUSharedLibs.html#shlibsgot">reference</a></p> + +<p> + Notice that the generates an extra level of indirection through the GOT. + This indirection is not needed by NXFLAT and only adds more RAM usage and + execution time. +</p> +<p> + NXFLAT (like <a href="http://xflat.sourceforge.net/">XFLAT</a>) can work even better with + the GOT. + Patches again older version of GCC exist to eliminate the GOT indirections. + Several are available <a href="http://xflat.cvs.sourceforge.net/viewvc/xflat/xflat/gcc/">here</a> + if you are inspired to port them to a new GCC version. +</p> + + +<table width ="100%"> + <tr bgcolor="#e4e4e4"> + <td> + <a name="pictext"><h1>Appendix B. PIC Text Workaround</h1></a> + </td> + </tr> +</table> + +<p> + There is a problem with the memory model in GCC that prevents it from + being used as you need to use it in the NXFLAT context. + The problem is that GCC PIC model assumes that the executable lies in a flat, contiguous (virtual) address space like: +<p> +<ul><table width="15%"> + <tr><th>Virtual</th></td> + <tr> + <td align="center" bgcolor="#e4e4e4"><code>.text</code></td> + </tr> + <tr> + <td align="center" bgcolor="#e4e4e4"><code>.got</code></td> + </tr> + <tr> + <td align="center" bgcolor="#e4e4e4"><code>.data</code></td> + </tr> + <tr> + <td align="center" bgcolor="#e4e4e4"><code>.bss</code></td> + </tr> +</table></ul> +<p> + It assumes that the PIC base register (usually r10 for ARM) points to the base of <code>.text</code> + so that any address in <code>.text</code>, <code>.got</code>, <code>.data</code>, <code>.bss</code> + can be found with an offset from the same base address. + But that is not the memory arrangement that we need in the XIP embedded environment. + We need two memory regions, one in FLASH containing shared code and on per task in RAM containing task-specific data: +</p> + +<ul><table width="30%"> + <tr><th>Flash</th><th>RAM</th></td> + <tr> + <td align="center" bgcolor="#e4e4e4"><code>.text</code></td> + <td align="center" bgcolor="#e4e4e4"><code>.got</code></td> + </tr> + <tr> + <td bgcolor="#e4e4e4"><br></td> + <td align="center" bgcolor="#e4e4e4"><code>.data</code></td> + </tr> + <tr> + <td bgcolor="#e4e4e4"><br></td> + <td align="center" bgcolor="#e4e4e4"><code>.bss</code></td> + </tr> +</table></ul> + +<p> + The PIC base register needs to point to the base of the <code>.got</code> and only + addresses in the <code>.got</code>, <code>.data</code>, and <code>.bss</code> + sections can be accessed as an offset from the PIC base register. + See also this + <a href="http://xflat.cvs.sourceforge.net/viewvc/*checkout*/xflat/xflat/gcc/README?revision=1.1.1.1">XFLAT discussion</a>. +</p> +<p> + Patches again older version of GCC exist to correct this GCC behavior. + Several are available <a href="http://xflat.cvs.sourceforge.net/viewvc/xflat/xflat/gcc/">here</a> + if you are inspired to port them to a new GCC version. +</p> + +</body> +</html> diff --git a/nuttx/ReleaseNotes b/nuttx/ReleaseNotes index f421c5365..d8c04ed2a 100644 --- a/nuttx/ReleaseNotes +++ b/nuttx/ReleaseNotes @@ -923,3 +923,17 @@ This is the 40th release of NuttX. This release adds: This tarball contains a complete CVS snapshot from June 13, 2009. +nuttx-0.4.9 +^^^^^^^^^^^ + +This is the 41st release of NuttX. This release adds: + + * Support for a new binary format call NXFLAT that can be used to + execute separately linked programs in place in a file system. + See http://www.nuttx.org/NuttXNxFlat.html. + + * Several important bugs were files related to networking and ROMFS + (see the ChangeLog for a complete list). + +This tarball contains a complete CVS snapshot from June 26, 2009. + diff --git a/nuttx/TODO b/nuttx/TODO index da9356e26..3370e58c0 100644 --- a/nuttx/TODO +++ b/nuttx/TODO @@ -1,4 +1,4 @@ -NuttX TODO List (Last updated June 19, 2009) +NuttX TODO List (Last updated June 26, 2009) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ (5) Task/Scheduler (sched/) @@ -6,15 +6,16 @@ NuttX TODO List (Last updated June 19, 2009) (1) Signals (sched/, arch/) (1) pthreads (sched/) (1) C++ Support + (5) Binary loaders (binfmt/) (12) Network (net/, netutils/) (1) USB (drivers/usbdev) (4) Libraries (lib/) (8) File system/Generic drivers (fs/, drivers/) (2) Graphics subystem (graphics/) (1) Pascal add-on (pcode/) - (0) Documentation (Documentation/) + (2) Documentation (Documentation/) (6) Build system / Toolchains - (2) NuttShell (NSH) (examples/nsh) + (3) NuttShell (NSH) (examples/nsh) (3) Other Applications & Tests (examples/) (2) Linux/Cywgin simulation (arch/sim) (3) ARM (arch/arm/) @@ -102,6 +103,39 @@ o C++ Support constructor logic will probably have to be performed by user logic in user_start(). +o Binary loaders (binfmt/) + ^^^^^^^^^^^^^^^^^^^^^^^^ + + Description: Not all of the NXFLAT test under examples/nxflat are working. + Most simply do not compile yet. tests/mutex runs okay but + outputs garbage on completion. + Status: Open + Priority: High + + Description: The ARM up_getpicbase() does not seem to work. This means + the some features like wdog's might not work in NXFLAT modules. + Status: Open + Priority: Medium-High + + Description: At present, all .rodata must be put into RAM. There is a + tentative design change that might allow .rodata to be placed + in FLASH (see Documentation/NuttXNxFlat.html). + Status: Open + Priority: Medium + + Description: If the function pointer to a statically defined function is + taken, then GCC generates a relocation that cannot be handled + by NXFLAT. There is a solution described in Documentataion/NuttXNxFlat.html, + by that would require a compiler change (which we want to avoid). + The simple workaround is to make such functions global in scope. + Status: Open + Priority: Low (probably will not fix) + + Description: In the NXFLAT symbol tables... Using a 32-bit hash value instead + of a string to identify a symbol should result in a smaller footprint. + Status: Open + Priority: Low + o Network (net/, netutils/) ^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -325,6 +359,10 @@ o Documentation (Documentation/) Status: Open Priority: Low + Description: Need to document binary loader APIs + Status: Open + Priority: Low + o Build system ^^^^^^^^^^^^ @@ -378,6 +416,10 @@ o NuttShell (NSH) (examples/nsh) Status: Open Priority: Med-High + Description: Add support to NSH to run NXFLAT programs from a ROMFS file system + Status: Open + Priority: Low + o Other Applications & Tests (examples/) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/nuttx/examples/README.txt b/nuttx/examples/README.txt index b31c37490..e228de207 100644 --- a/nuttx/examples/README.txt +++ b/nuttx/examples/README.txt @@ -143,7 +143,7 @@ examples/nxflat This example builds a small NXFLAT test case. This includes several test programs under examples/nxflat tests. These tests are build using the NXFLAT format and installed in a ROMFS file system. At run time, - each program int eh ROMFS file system is executed. + each program in the ROMFS file system is executed. Requires CONFIG_NXFLAT. examples/null ^^^^^^^^^^^^^ |