* Made the example builds work with LLVM, and fixed four that were broken on Linux The gnu example builds are the natural LLVM path: Arm Toolchain for Embedded is LLVM based, consumes GNU ld linker scripts, and needs none of the scatter files or Arm DS projects the ac6 examples carry. So rather than port the ac6 examples, teach the gnu scripts to drive either toolchain. Each script now selects the toolchain from a TOOLCHAIN variable that defaults to gnu, so every existing invocation behaves exactly as before. TOOLCHAIN=atfe switches the compiler, adds the target triple, passes the entry symbol through to the linker rather than to the driver, and links the toolchain's own semihosting library in place of --specs=nosys.specs, which is a GCC spec file mechanism with no LLVM equivalent. That last choice avoids adding a syscall stub source to every example. The scripts are parameterised rather than duplicated. Copies of build scripts would drift the first time one side was edited, which is the failure this repository has just spent several changes recovering from. Four sample scripts could not run on a case-sensitive filesystem at all. They compiled MP_PrivateTimer.s and V7.s while the files on disk are MP_PrivateTimer.S and v7.s, and the Cortex-A5 and A9 scripts named MP_GIC.s where the file is MP_GIC.S. The link lines named V7.o accordingly. Corrected to match the files, which is why the Cortex-A5, A7, A8 and A9 examples now build on Linux where before they could not. Extend scripts/check_clang.sh to link the example builds as well as compile the sources, since compiling proves the sources parse while only linking exercises entry symbols, linker scripts and the C library together. Eight examples are listed as not expected to link, each with its reason, so the gaps stay visible rather than being silently skipped. Five of them fail with the GNU toolchain too and are therefore not LLVM problems: the Cortex-M0 example's crt0 references __text_load_start__, __text_start__ and __text_end__, which its linker script never defines, while the Cortex-M4 script defines the equivalents; the arm9, arm11, Cortex-R4 and Cortex-R5 examples need newlib multilib variants that are not present in every GNU toolchain packaging. The Cortex-A12, A15 and A17 examples fail only with LLVM, because their link line omits -nostartfiles so the toolchain's own crt0 is linked and wants picolibc's __data_start, __data_source, __data_size and __bss_size, which their linker script does not define. Verified by building every example with both toolchains. Seven link with both: Cortex-A5, A7, A8, A9, M3, M4 and M7. The GNU results are unchanged where they worked before, and now also succeed for the four scripts with the case bug. Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com> * Resolved the compiler path before running the example builds The example stage runs each build script from inside its own directory, so a relative path passed with --clang stopped resolving there and every example build failed instantly. Local runs passed an absolute path and did not show it; the CI job passes a path relative to the workspace root, which did. Resolve the compiler to an absolute path once, before any directory change, and print it so the toolchain in use is visible in the log. Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com> * Parameterised the archiver as well, and stopped the check hiding failures The toolchain selection covered the compiler but not arm-none-eabi-ar, which the scripts invoke 628 times to assemble the library archive. A machine with an LLVM toolchain and no GNU one therefore could not build any example, which is exactly the situation in CI: the runner has no Arm GNU toolchain installed. Local runs had one, so this only appeared once the job ran. Select the archiver alongside the compiler, taking llvm-ar from beside clang in the toolchain. The four scripts that call arm-none-eabi-ld directly are left alone: they are arm9, arm11, Cortex-R4 and Cortex-R5, all already listed as not expected to link, and their invocations are specific to GNU ld in ways that parameterising would not resolve. The check reported "example build produced no image" and then filtered the log for lines containing "error", which hid the actual cause, since a missing tool reports "command not found" or "No such file or directory". It now prints the tail of the log. That filtering cost two CI round trips to diagnose something the first run already knew. Verified by shadowing arm-none-eabi-gcc, arm-none-eabi-ar, arm-none-eabi-ld and the aarch64 equivalents with stubs that fail loudly, then running the whole check: all 711 sources assemble, all eight profiles compile and all seven example builds link without any GNU tool being invoked. The GNU default path still produces an identical image. The diagnostics were confirmed by pointing the archiver at a name that does not exist and checking that the reason appears. Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
Eclipse ThreadX RTOS
This advanced real-time operating system (RTOS) is designed specifically for deeply embedded applications. Among the multiple benefits it provides are advanced scheduling facilities, message passing, interrupt management, and messaging services. Eclipse ThreadX RTOS has many advanced features, including picokernel architecture, preemption threshold, event chaining, and a rich set of system services.
Here are the key features and modules of ThreadX:
Getting Started
Eclipse ThreadX has been integrated to the semiconductor's SDKs and development environment. You can develop using the tools of choice from STMicroelectronics, NXP, Renesas and Microchip.
We also provide getting started guide and samples using development boards from semiconductors you can build and test with.
See Overview of Eclipse ThreadX RTOS for the high-level overview.
Repository Structure and Usage
Directory layout
.
├── cmake # CMakelist files for building the project
├── common # Core ThreadX files
├── common_modules # Core ThreadX module files
├── common_smp # Core ThreadX SMP files
├── docs # Documentation supplements
├── ports # Architecture and compiler specific files. See below for directory breakdown
│ ├── cortex_m7
│ │ ├── iar # Example IAR compiler sample project
│ │ │ ├── example build # IAR workspace and sample project files
│ │ │ ├── inc # tx_port.h for this architecture
│ │ │ └── src # Source files for this architecture
│ │ ├── ac6 # Example ac6/Keil sample project
│ │ ├── gnu # Example gnu sample project
│ │ └── ...
│ └── ...
├── ports_modules # Architecture and compiler specific files for threadX modules
├── ports_smp # Architecture and compiler specific files for threadX SMP
├── samples # demo_threadx.c
└── utility # Test cases and utilities
Branches & Releases
The master branch has the most recent code with all new features and bug fixes. It does not represent the latest General Availability (GA) release of the library. Each official release (preview or GA) will be tagged to mark the commit and push it into the Github releases tab, e.g. v6.2-rel.
When you see xx-xx-xxxx, 6.x or x.x in function header, this means the file is not officially released yet. They will be updated in the next release. See example below.
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_initialize_low_level Cortex-M23/GNU */
/* 6.x */
/* AUTHOR */
/* */
/* Scott Larson, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function is responsible for any low-level processor */
/* initialization, including setting up interrupt vectors, setting */
/* up a periodic timer interrupt source, saving the system stack */
/* pointer for use in ISR processing later, and finding the first */
/* available RAM memory address for tx_application_define. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _tx_initialize_kernel_enter ThreadX entry function */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 09-30-2020 Scott Larson Initial Version 6.1 */
/* xx-xx-xxxx Scott Larson Include tx_user.h, */
/* resulting in version 6.x */
/* */
/**************************************************************************/
Supported Architecture Ports
ThreadX
arc_em cortex_a12 cortex_m0 cortex_r4
arc_hs cortex_a15 cortex_m23 cortex_r5
arm11 cortex_a17 cortex_m3 cortex_r7
arm9 cortex_a34 cortex_m33
c667x cortex_a35 cortex_m4
linux cortex_a5 cortex_m55
risc-v32 cortex_a53 cortex_m7
rxv1 cortex_a55 cortex_m85
rxv2 cortex_a57
rxv3 cortex_a5x
win32 cortex_a65
xtensa cortex_a65ae
cortex_a7
cortex_a72
cortex_a73
cortex_a75
cortex_a76
cortex_a76ae
cortex_a77
cortex_a8
cortex_a9
ThreadX Modules
Eclipse ThreadX Modules component provides an infrastructure for applications to dynamically load modules that are built separately from the resident portion of the application.
cortex_a35
cortex_a35_smp
cortex_a7
cortex_m0+
cortex_m23
cortex_m3
cortex_m33
cortex_m4
cortex_m7
cortex_r4
rxv2
ThreadX SMP
Eclipse ThreadX SMP is a high-performance real-time SMP kernel designed specifically for embedded applications.
arc_hs_smp
cortex_a34_smp
cortex_a35_smp
cortex_a53_smp
cortex_a55_smp
cortex_a57_smp
cortex_a5x_smp
cortex_a5_smp
cortex_a65ae_smp
cortex_a65_smp
cortex_a72_smp
cortex_a73_smp
cortex_a75_smp
cortex_a76ae_smp
cortex_a76_smp
cortex_a77_smp
cortex_a78_smp
cortex_a7_smp
cortex_a9_smp
linux
Adaptation layer for ThreadX
ThreadX is an advanced real-time operating system (RTOS) designed specifically for deeply embedded applications. To help ease application migration to ThreadX RTOS, Eclipse ThreadX provides adaption layers for various legacy RTOS APIs (FreeRTOS, POSIX, OSEK, etc.).
Component dependencies
The main components of ThreadX RTOS are each provided in their own repository, but there are dependencies between them, as shown in the following graph. This is important to understand when setting up your builds.
You will have to take the dependency graph above into account when building anything other than ThreadX itself.
Building and using the library
Instruction for building the ThreadX as static library using Arm GNU Toolchain and CMake. If you are using toolchain and IDE from semiconductor, you might follow its own instructions to use ThreadX RTOS components as explained in the Getting Started section.
-
Install the following tools:
- CMake version 3.0 or later
- Arm GNU Toolchain for arm-none-eabi
- Ninja
-
Cloning the repo
$ git clone https://github.com/eclipse-threadx/threadx.git -
Define the features and addons you need in
tx_user.hand build together with the component source code. You can refer totx_user_sample.has an example. -
Building as a static library
Each component of ThreadX RTOS comes with a composable CMake-based build system that supports many different MCUs and host systems. Integrating any of these components into your device app code is as simple as adding a git submodule and then including it in your build using the CMake
add_subdirectory().While the typical usage pattern is to include ThreadX into your device code source tree to be built & linked with your code, you can compile this project as a standalone static library to confirm your build is set up correctly.
An example of building the library for Cortex-M4:
$ cmake -Bbuild -GNinja -DCMAKE_TOOLCHAIN_FILE=cmake/cortex_m4.cmake . $ cmake --build ./build
Licensing
License terms for using Eclipse ThreadX are defined in the LICENSE.txt file of this repo. Please refer to this file for all definitive licensing information for all content, incl. the history of this repo.
Resources
The following are references to additional ThreadX RTOS resources:
- Product introduction: https://github.com/eclipse-threadx/rtos-docs
- Product issues and bugs, or feature requests: https://github.com/eclipse-threadx/threadx/issues
- TraceX Installer: https://aka.ms/azrtos-tracex-installer
You can also check previous questions or ask new ones on StackOverflow using the threadx-rtos and threadx tags.
Security
Eclipse ThreadX provides OEMs with components to secure communication and to create code and data isolation using underlying MCU/MPU hardware protection mechanisms. It is ultimately the responsibility of the device builder to ensure the device fully meets the evolving security requirements associated with its specific use case.
Contribution
Please follow the instructions provided in the CONTRIBUTING.md for the corresponding repository.

