Frédéric Desbiens
3276b0efd5
A module reaches a kernel object's delete service through the Module Manager's dispatch layer, which asked one question about the pointer: does the object lie outside the module's own code and data. That is the policy for using an object, and using an object a module does not own is supported and intended -- txm_module_object_pointer_get_extended searches the system's created objects by name and hands back objects the application created and objects other modules created, so that a module can send to a shared queue, take a shared semaphore or get a shared mutex. Destroying one of those is not sharing it. A module could name any object it had a pointer to and have the privileged dispatcher delete it: a host service lost its queue, waiters were resumed with TX_DELETED, an owned mutex's priority inheritance was unwound, and an active timer stopped. Nothing in the manager intended that. The deallocation the delete path performs afterwards has always required the memory to belong to the calling module, so a delete of anything else could only ever end in TX_PTR_ERROR -- the ownership requirement was already there and was enforced one step too late, after the kernel object had been irreversibly destroyed and its waiters woken. An error returned at that point describes a cleanup failure and restores nothing. The eight delete dispatchers now ask the question before the delete rather than after it. A memory-protected module may delete an object only if the object is one it allocated from the manager's object pool, at the exact address the manager returned to it, for an allocation made for that type's control block size -- the same conditions the create dispatchers already apply, since deletion is the inverse of creation. Anything else returns TXM_MODULE_INVALID_MEMORY, which is what every other parameter rejection in the dispatch table returns, so no new value enters the module ABI and a module cannot use a delete request to tell "not yours" apart from "not a usable address". The object stays created, nothing waiting on it is resumed, and no created count moves, because the kernel was never asked. The ownership question is deliberately separate from whether an object is there at all and of the expected type. It establishes nothing about liveness or type, and it is composed with the checks that do rather than replacing them. _txm_module_manager_object_deallocate reached the manager's private header by subtracting from whatever address the caller supplied, and read it before deciding whether it was a header. All eight delete dispatchers call that function directly, so an object the module does not own arrived there as a matter of course rather than exceptionally: for an object the application allocated statically, or for any address outside the object pool, the words in front of it were unrelated memory read in privileged mode -- and acted on, since an address whose preceding words happened to name the calling module was unlinked from that module's allocation list and handed to the byte pool. It now finds the allocation by searching the module's own allocation list. The caller's address is compared and never dereferenced, so an address that names none of this module's allocations is refused without a privileged read of anything in front of it, and the search establishes what the header read could not: that the address is the exact start of an allocation rather than somewhere inside one. The search is bounded by the count the manager keeps beside the list and runs with interrupts disabled, so a damaged list cannot make it run on and it cannot observe the list being changed under it. The fix is in the deallocation itself rather than at a call site, so it covers all eight delete dispatchers, the deallocation request a module can make directly, protected and unprotected modules alike. txm_module_manager_stop needs no exemption and was not given one. It deletes the objects a module created by calling the internal _tx_*_delete services directly, and identifies them with _txm_module_manager_created_object_check rather than through a module request, so no caller-facing check stands in its way. The 209 expectations in the new test drive all eight object types through allocation, an ownership check by the owning module and by another, a check against a larger and a smaller expected size, and a deallocation that succeeds. They cover an object the application owns, deliberately preceded by a header naming the requesting module so that reading it can be seen to have happened; another module's object, checked and refused from both sides; every aligned interior offset of an allocation and the addresses of its header, its end, the pool's ends and one past the pool; a null pointer and an address with no room for a header in front of it; a request from no module at all; memory that has changed hands, where a stale pointer names an address that now belongs to another module; the bounds on the search, against a count smaller than the list and against a count larger than a list whose links are broken; releasing the head, the middle and the last of a list of three; and an object pool that was never created. Every call asserts that the interrupt lock came back balanced, and that the search ran with interrupts disabled exactly one deep. Restoring the previous deallocation fails four of them and then segmentation faults, on the null-pointer case, where the header in front of address zero is read; removing the ownership check fails 74. Line and branch coverage of the two new functions and of the changed _txm_module_manager_object_deallocate is 100%, with two branch outcomes excepted that are test scaffolding rather than product code: the host shim's stand-ins for TX_DISABLE and TX_RESTORE carry a maximum-depth test and an underflow guard, and the real ports' primitives are inline assembly with no branch at all. All 99 tests pass in each of the five configurations the tree builds with GCC 14. Nothing in the tree compiles the dispatch header, so the eight changed dispatchers were cross-compiled by hand: the two changed C files and a translation unit that includes the header build at -Werror with arm-none-eabi-gcc 13.2.1 for every GNU 32-bit module port -- Cortex-A7, M0+, M23, M3, M33, M4 and M7 -- and produce the same -Wall -Wextra warning counts as before the change, 117 on Cortex-A7 and 116 on each of the others. Cortex-R4 and RXv2 have no GNU module port, and the two AArch64 module ports have no toolchain available here; the new arithmetic is a comparison of two addresses of the same type, so a wider ALIGN_TYPE changes nothing about it. MISRA: all if bodies are braced, the address comparison goes through ALIGN_TYPE, no pointer the caller supplied is dereferenced, and no goto appears. No deviation is required. 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.