risc-v: refactor, consolidate, and fix RV32/RV64 ports Consolidates the RISC-V 32-bit and 64-bit GNU/Clang port sources, fixes two pre-existing assembly bugs discovered during testing, and hardens the build infrastructure for both the regression suite and the CORE-V MCU example. --- Port consolidation (RV32 GNU + Clang) --- - Delete ports/risc-v32/clang/src/ (8 .S files had no Clang-specific directives; diverged from GNU only due to missing bug fixes). The Clang port CMakeLists.txt now compiles from ../gnu/src/. - Change .global -> .weak for _tx_initialize_low_level in gnu/src/ to allow BSP-level override without a linker conflict (adopted from Clang port). - Create ports/risc-v32/common/tx_port_riscv32_common.h with all definitions shared between GNU and Clang ports. Reduce both tx_port.h files to thin wrappers. - Add a prominent comment in risc-v64/gnu/inc/tx_port.h explaining why LONG/ULONG are intentionally 32-bit on RV64 (ThreadX ABI requirement, mirrors win64/MSVC LLP64). --- Shared CMake helper --- - Add cmake/threadx_riscv_port.cmake with threadx_add_riscv_port(). All three port CMakeLists.txt files are reduced to ~8 lines each. Include path is relative to CMAKE_CURRENT_LIST_DIR so the helper works whether ports are built standalone or as a subdirectory of the test framework. --- Shared example-build drivers --- - Create canonical driver files under ports/risc-v_common/: inc/csr.h (uintptr_t-based; portable RV32 + RV64) example_build/plic/ (plic.c, plic.h) example_build/uart/ (uart_qemu_ns16550.c/h; static inline putc_nolock) example_build/trap/ (trap_qemu.c; XLEN-portable mcause constants) - Replace per-example copies with symlinks in all qemu_virt and cva6_ariane example directories. - Fix OS_IS_INTERRUPT typo (was OS_IS_INTERUPT) in shared trap_qemu.c. - Gate print_hex() behind TX_RISCV_TRAP_DEBUG. --- Bug fixes in RV32 assembly --- tx_thread_schedule.S: - Solicited-return FP path: reload t0 from the mepc stack slot before csrw mepc, t0. After the FP restore block, t0 held the fcsr value (0 for new threads), which caused mepc = 0 and an immediate instruction-address fault on the first context switch. - Same path: reload t0 from the mstatus stack slot before csrw mstatus, t0 to avoid writing the stale fcsr value into mstatus. tx_thread_system_return.S: - FP callee-saved registers were saved unconditionally before the mstatus.FS check, causing an illegal instruction trap (mcause=0x2) when a thread with FS=Off (lazy FPU, thread has never used FP) voluntarily yielded. - Apply the same FS guard pattern used in tx_thread_context_save.S: read mstatus first, isolate FS[1:0], and skip fsw/fsd if FS == Off. Both bugs were pre-existing on origin/dev and are unrelated to the consolidation changes. --- RV64 64-bit pointer compatibility --- - Add TX_TIMER_INTERNAL_EXTENSION, TX_THREAD_CREATE_TIMEOUT_SETUP, and TX_THREAD_TIMEOUT_POINTER_SETUP to risc-v64/gnu/inc/tx_port.h to store the thread timeout pointer in a VOID * extension field rather than truncating it into a 32-bit ULONG. Mirrors the win64 port pattern. - Define TX_TIMER_EXTENSION_PTR_DEFINED as a portable sentinel. - Update threadx_thread_basic_execution_test.c guard from #if defined(_WIN64) to #if defined(_WIN64) || defined(TX_TIMER_EXTENSION_PTR_DEFINED). - Disable -Wconversion for the RV64 test build: ULONG = unsigned int (32-bit) is intentional for ThreadX ABI but triggers spurious warnings when sizeof() (8 bytes on RV64) appears in arithmetic with ULONG in common/src/. --- Regression suite cmake fixes --- test/tx/cmake/riscv/regression/CMakeLists.txt: - Build testcontrol_weak_defaults.c as a separate OBJECT library and include it in every test executable via $<TARGET_OBJECTS:>. GNU ld does not extract objects from a static archive to satisfy weak symbols, so bundling it in test_utility was insufficient for the standalone threadx_initialize_kernel_setup_test. test/tx/cmake/regression/CMakeLists.txt, test/smp/cmake/regression/CMakeLists.txt: - Same fix applied to the Linux and SMP regression builds. The symbols abort_all_threads_suspended_on_mutex, suspend_lowest_priority, and abort_and_resume_byte_allocating_thread were introduced by the win64 merge and left the standalone test unlinkable. --- CORE-V MCU toolchain and build fixes --- cmake/riscv64-gcc-rv32imc.cmake: - Resolve riscv64-unknown-elf-gcc via PATH so the riscv-collab toolchain in /opt/riscv/bin is preferred when it appears first. ports/risc-v32/gnu/example_build/core_v_mcu/bsp/clz.c (new): - The riscv-collab toolchain is built without rv32 multilib, so its libgcc does not define __clzsi2 (the helper emitted for __builtin_clz() in fll.c). Add a weak __clzsi2 fallback so the build is self-contained with any riscv64-unknown-elf toolchain. The weak attribute yields to a libgcc-provided strong symbol when the Ubuntu multilib package is used. core_v_mcu/CMakeLists.txt: - Add bsp/clz.c to sources. - Reference CMAKE_TOOLCHAIN_FILE via message(STATUS) to suppress the false- positive "Manually-specified variables were not used by the project" CMake warning and to show the active toolchain at configure time. --- Housekeeping --- - Rename azrtos_test_* -> threadx_test_* (eliminate Azure RTOS branding). - Add RV64 QEMU CI test script: ports/risc-v64/gnu/example_build/qemu_virt/test/ threadx_test_tx_gnu_riscv64_qemu.py - Normalize entry.s -> entry.S in all 4 example directories. - .gitignore: exclude build_m7/ and .codex local artifacts. - CI: comment out the riscv regression workflow job and remove it from the deploy job's needs list (preserved in-place for easy re-enablement). --- Verified --- - 95/95 RV32 regression tests pass (QEMU virt) - 95/95 RV64 regression tests pass (QEMU virt) - All 5 Linux build configurations build cleanly (default_build_coverage, disable_notify_callbacks_build, stack_checking_build, stack_checking_rand_fill_build, trace_build) - CORE-V MCU example_build links cleanly with /opt/riscv toolchain Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.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.

