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Version 35 (modified by Joel Sherrill, on 12/12/19 at 17:27:29) (diff)


4.11 Release Notes

The 4.11 dot point release details are:

Tool Improvements

  • New ARM tool chain configuration: arm-rtems4.11?
  • This is the first release series to use the RTEMS Source Builder (RSB). With this, it is possible to provide target specific versions of the development tools on many hosts. This is important when GCC drops support for an old architecture or we are avoiding target specific bugs in a particular tool version. Nominally, most RTEMS targets will use the same tools and they have been upgraded to the following versions:
    • autoconf 2.69
    • automake 1.12.6
    • binutils 2.26
    • gcc 4.9.3 with newlib
    • gdb 7.9

The URL for the latest patch for each tool is captured in the RSB recipe to build that tool. All source and patches are fetched from the Internet as part of building your toolset.

RTEMS Improvements

In this section, we discuss public API level changes as well as improvements to the implementation of those API routines.

Public API changes usually fall into one of the following categories:

  • Addition of new methods
  • Modifications to prototypes
  • Deletion of obsoleted methods

Implementation improvements usually fall into one of the following categories:

  • Algorithm improvements in execution time or memory usage
  • Critical section reduction

API Changes

  • Score Chain API changed due to strict aliasing concerns. In case you have a compiler error related to RTEMS chains, you should use the appropriate API function and do not access chain control members directly.
  • The loopback interface of the network stack will be initialized now during the normal initialization via rtems_bsdnet_initialize_network(). The loop back interface configurations are now obsolete and must be removed. You will notices this if you encounter a linker error of undefined references to rtems_bsdnet_loopattach().
  • rtems_initialize_start_multitasking() no longer returns to the caller (usually boot_card()). All system termination paths should end up in _Terminate().
  • The clock driver API changed. The nanoseconds extension was removed. Clock drivers may provide a timecounter for high resolution timestamps. See
  • RTEMS_offsetof() was removed. This macro was not documented. Use the standard offsetof() instead. See
  • The file system API has changed considerably.
  • The work area initialization (RTEMS work space and C program heap) changed. Now a table based initialization is used.
  • The block device transfer request API changed.
  • The Termios interrupt write support invocation changed.
  • The Termios framework provides a new device model. The old device model is still supported for legacy drivers.
  • rtems_panic() / rtems_error(RTEMS_ERROR_PANIC ...) no longer cause a halt of the local system, but a reset (assuming no application or BSP-specific fatal error extension intervenes)
  • The Mongoose HTTP / web server has been updated to version 3.9, at the last point before the MIT -> GPL license change. Its API has changed considerably. In particular, please ensure you pass an initialised struct mg_callbacks as the first argument to mg_start(), with all members set to NULL if you don't use callbacks
  • POSIX keys and POSIX once are now available even if the POSIX API is not enabled.
  • The shell now relies on POSIX keys instead of task variables. This means that enough keys and key-value-pairs have to be configured.
  • C++ support now relies on POSIX keys instead of task variables. This means that enough keys and key-value-pairs have to be configured.
  • Private environments are now relying on POSIX keys instead of task variables.
    • There is one key automatically added to the configuration. The configuration hast to define one additional key-value-pairs for each thread that uses a private environment. If no private environment is used there is no need to change a existing configuration.
    • Please note that the chroot() function uses a private environment. If chroot() an appropriate number of key-value pair is necessary.
    • Please note that the ftp-server uses chroot() and therefore needs an appropriate number of key-value pairs.

API Additions

API Implementation Improvements

  • POSIX semaphores make now a copy of the name string (similar to POSIX message queues). This allows dynamic creation of POSIX semaphore names.
  • The fatal error handling changed considerable. The function _Internal_error_Occurred() can now be called in nearly every system state. The invocation of the fatal extension of an initial extension is guaranteed under the following conditions. The initial extensions reside in read-only memory. The following conditions must hold
    • the stack pointer is valid,
    • the code memory is valid,
    • the read-only data is valid, and
    • the read-write data is accessible.

API Deprecations

  • Notepads: rtems_task_set_note(), rtems_task_get_note(). Consider using POSIX keys instead.
  • Task Variables: rtems_task_variable_add(), rtems_task_variable_delete(). Consider using POSIX keys instead.
  • rtems_clock_get(). Use other clock methods instead.

API Removals

  • malloc_get_statistics(): Use malloc_info() instead. See also malloc shell command.

Configuration Changes

  • Possible to use new EDF scheduler (CONFIGURE_SCHEDULER_EDF) and new CBS scheduler (CONFIGURE_SCHEDULER_CBS).
  • More accurate workspace size estimate.
  • The stack space size estimate is now separate and not a part of the overall workspace size estimate.
  • The root file system mount parameters can be now configured via rtems_filesystem_root_configuration.
  • Add CONFIGURE_UNLIMITED_OBJECTS and CONFIGURE_UNLIMITED ALLOCATION_SIZE to auto-extend classic and posix objects whose resource limits are not otherwise defined.
  • The Configuration is now read-only and must be statically initialized via confdefs.h or similar.
  • BSPs can now register an initial extension via the BSP_INITIAL_EXTENSION define.

RTEMS Shell Improvements

The following improvements were made to the RTEMS Shell:

  • New command lsof to list all referenced file system locations.


  • Added support for the Moxie open source processor architecture.
  • Added support for the OpenRISC (or1k) open source processor architecture (target=or1k).
  • Added support for the Epiphany processor (eCore) architecture (target=epiphany).
  • Added support for the SPARC V9 CPU family, a 64-bit processor architecture (target=sparc64).
  • Added support for ARM Cortex-M (ARMv7-M).
  • Added support for Journalling Flash File System, Version 2 (JFFS2) imported from Linux 3.11 and eCos.
  • FTPFS will no longer use the BOOTP server address as default if no hostname was specified. The FTP path must specify the hostname. Applications can obtain the BOOTP server address and from the appropriate path.
  • Added new two configurable single processor schedulers: Earliest Deadline First (EDF) and Constant Bandwidht Server (CBS).
  • The exit(), _exit() and abort() functions lead to a fatal error. The fatal source is RTEMS_FATAL_SOURCE_EXIT and the fatal code is the exit status. The rtems_panic() and rtems_error() are also affected by this since they call one of these functions. Depending on the fatal error extensions this may lead to a bsp_reset(). A reset is the default provided by the BSP.
  • Thread-local storage (TLS): Supported on ARM, m68k, PowerPC and SPARC. Other architectures lack an implementation.
  • Scheduler Refactoring Improvements
  • TBD

BSPs and Device Drivers

  • General
    • TBD
  • New BSPs
    • BSPs for ARM
      • lm3s69xx - ARM Cortex-Mx based BSP supports Stellaris Microcontroller LM3S6965 (works only on Qemu), LM3S3749 and LM4F120
      • lpc24xx - NXP LPC1700, LPC4000
      • stm32f4xxxx - Discovery kit for STM32 F4 series - with STM32F407 MCU
      • stm32f10xxx - STM32F105RC MCU
      • Altera Cyclone V
      • Xilinx Zynq
      • RealView PBX (works only on Qemu)
      • raspberrypi - Raspberry Pi
      • Ti tms570 - TMS570LS3137 support, full header files, option to include hardware complete initialization to start directly from Flash
    • BSPs for bfin
    • BSPs for Epiphany
      • epiphany_sim - It runs on the Epiphany default simulator.
    • BSPs for moxie
      • moxiesim
    • BSPs for OpenRISC (or1k)
      • generic_or1k - This BSP can run on or1ksim (the main or1k simulator), QEMU, jor1k and a real or1k supported FPGA board (has been tested on Atlys board).
    • BSPs for sparc64 cpu model
    • BSPs for PowerPC
      • qemuprep? - run a variant of motorola_powerpc in qemu
      • QorIQ - P1020, T2080, T4240
      • t32mppc - Lauterbach Trace32 PowerPC simulator
  • Significant updates to existing BSPs
    • pc386 family (pc386 .. pc686) VESA BIOS Extension (VBE) based frame buffer configuration selected by default
      • the switch to graphic mode is controlled by multiboot option --video=auto|off|1024x768-32 etc.
      • application can override default none by exporting variable const char * const rtems_fb_default_mode="auto";
    • Full driver support for Milkymist SoC (video input, DMX, MIDI, USB input devices, ...)
  • Removal of obsoleted BSPs
    • i386ex - Removed 1 March 2011
    • ts_386ex - Removed 1 March 2011
  • Drivers: TBD

Test Suites

  • TBD


This section covers the API changes between the 4.10 and 4.11 release series which are expected to have an impact on application source code. This section does NOT cover additions to the API.

  • TBD