Frédéric Desbiens 68eb205768 Made the Arm ports build with LLVM, and added a check that keeps them that way (#593)
The gnu ports are only ever built with GNU tooling, and GNU as accepts several
non-canonical forms that LLVM's assembler rejects. Nothing noticed, because
nothing built them with anything else. This matters beyond clang itself: Arm
Toolchain for Embedded is LLVM based and is the successor to Arm Compiler 6, so
these are the code paths ac6 users move onto.

Seven files needed changing, none of which alters the emitted code:

LDREX and STREX take no offset in A32 state; the #imm form is Thumb-2 only. GNU
as drops the redundant zero, LLVM rejects it. Removed from the Cortex-A5, A7 and
A9 SMP protect routines.

ARMv8-M Baseline has no flag-preserving MOV immediate, so GNU as already emits
MOVS. Writing MOVS in the two Cortex-M23 sources says what the assembler was
doing anyway. One of them sits in a branch only compiled for the single mode
secure configurations, which is why it had never surfaced.

The Cortex-M0 schedule routine wrote LDR r0, =#0x10000000 with a stray hash,
which its own sibling file already wrote correctly.

The Cortex-M0 system return routine selected the numbered subsection .text 32,
which makes LLVM place the constant pool beyond the range a Thumb-1 PC relative
load can reach. Plain .text fixes it and GNU accepts either form. The reason is
recorded in the file, since 32 files pair a numbered subsection with a literal
pool load and the rest only escape because Thumb-2 and A32 have far more range.

Add scripts/check_clang.sh, which assembles every Arm gnu port source and
compiles the common C sources for one core per architecture profile, and a
clang_check workflow that installs Arm Toolchain for Embedded and runs it. The
toolchain version is pinned and checksum verified, for the same reason the
runner image is pinned.

The port directory to target mapping in that script is explicit rather than
prefix matched. Prefix matching is what makes cortex_a5 also match cortex_a53
and cortex_a55, which are AArch64, and assembling those as ARM32 produces
hundreds of misleading errors; that mistake cost real time while measuring this,
so the reason is recorded next to the table.

Verified with Arm Toolchain for Embedded 22.1.0: 711 of 711 assembly sources
assemble and 185 of 185 C sources compile for all eight profiles, against 6
assembly failures before the change. arm-none-eabi-gcc still assembles all 315
ARM32 sources, so nothing regressed for GNU. The check was confirmed to fail
when any one of the fixes is reverted.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-08-10 11:40:54 -04:00
…
…
…

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:

ThreadX Key Features

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.

dependency graph

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.

  1. Install the following tools:

  2. Cloning the repo

    $ git clone https://github.com/eclipse-threadx/threadx.git
    
  3. Define the features and addons you need in tx_user.h and build together with the component source code. You can refer to tx_user_sample.h as an example.

  4. 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:

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.

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