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97050a17aa
Memory Protection Unit (MPU) Enhancements
This commit introduces a new MPU wrapper that places additional
restrictions on unprivileged tasks. The following is the list of changes
introduced with the new MPU wrapper:
1. Opaque and indirectly verifiable integers for kernel object handles:
All the kernel object handles (for example, queue handles) are now
opaque integers. Previously object handles were raw pointers.
2. Saving the task context in Task Control Block (TCB): When a task is
swapped out by the scheduler, the task's context is now saved in its
TCB. Previously the task's context was saved on its stack.
3. Execute system calls on a separate privileged only stack: FreeRTOS
system calls, which execute with elevated privilege, now use a
separate privileged only stack. Previously system calls used the
calling task's stack. The application writer can control the size of
the system call stack using new configSYSTEM_CALL_STACK_SIZE config
macro.
4. Memory bounds checks: FreeRTOS system calls which accept a pointer
and de-reference it, now verify that the calling task has required
permissions to access the memory location referenced by the pointer.
5. System call restrictions: The following system calls are no longer
available to unprivileged tasks:
- vQueueDelete
- xQueueCreateMutex
- xQueueCreateMutexStatic
- xQueueCreateCountingSemaphore
- xQueueCreateCountingSemaphoreStatic
- xQueueGenericCreate
- xQueueGenericCreateStatic
- xQueueCreateSet
- xQueueRemoveFromSet
- xQueueGenericReset
- xTaskCreate
- xTaskCreateStatic
- vTaskDelete
- vTaskPrioritySet
- vTaskSuspendAll
- xTaskResumeAll
- xTaskGetHandle
- xTaskCallApplicationTaskHook
- vTaskList
- vTaskGetRunTimeStats
- xTaskCatchUpTicks
- xEventGroupCreate
- xEventGroupCreateStatic
- vEventGroupDelete
- xStreamBufferGenericCreate
- xStreamBufferGenericCreateStatic
- vStreamBufferDelete
- xStreamBufferReset
Also, an unprivileged task can no longer use vTaskSuspend to suspend
any task other than itself.
We thank the following people for their inputs in these enhancements:
- David Reiss of Meta Platforms, Inc.
- Lan Luo, Xinhui Shao, Yumeng Wei, Zixia Liu, Huaiyu Yan and Zhen Ling
of School of Computer Science and Engineering, Southeast University,
China.
- Xinwen Fu of Department of Computer Science, University of
Massachusetts Lowell, USA.
- Yuequi Chen, Zicheng Wang, Minghao Lin of University of Colorado
Boulder, USA.
|
2 years ago | |
|---|---|---|
| .. | ||
| ARMClang | 2 years ago | |
| ARMv8M | 2 years ago | |
| BCC/16BitDOS | 2 years ago | |
| CCS | 2 years ago | |
| CodeWarrior | 2 years ago | |
| Common | 2 years ago | |
| GCC | 2 years ago | |
| IAR | 2 years ago | |
| Keil | 2 years ago | |
| MPLAB | 2 years ago | |
| MSVC-MingW | 2 years ago | |
| MemMang | 2 years ago | |
| MikroC/ARM_CM4F | 2 years ago | |
| Paradigm/Tern_EE | 2 years ago | |
| RVDS | 2 years ago | |
| Renesas | 2 years ago | |
| Rowley | 2 years ago | |
| SDCC/Cygnal | 2 years ago | |
| Softune | 2 years ago | |
| Tasking/ARM_CM4F | 2 years ago | |
| ThirdParty | 2 years ago | |
| WizC/PIC18 | 2 years ago | |
| oWatcom/16BitDOS | 2 years ago | |
| CMakeLists.txt | 2 years ago | |
| readme.txt | 2 years ago | |
readme.txt
Each real time kernel port consists of three files that contain the core kernel components and are common to every port, and one or more files that are specific to a particular microcontroller and/or compiler. + The FreeRTOS/Source/Portable/MemMang directory contains the five sample memory allocators as described on the https://www.FreeRTOS.org WEB site. + The other directories each contain files specific to a particular microcontroller or compiler, where the directory name denotes the compiler specific files the directory contains. For example, if you are interested in the [compiler] port for the [architecture] microcontroller, then the port specific files are contained in FreeRTOS/Source/Portable/[compiler]/[architecture] directory. If this is the only port you are interested in then all the other directories can be ignored.