2 Commits (2cdd0e5e55b8fae5c80943ec09dc960457aef34a)

Author	SHA1	Message	Date
kar-rahul-aws	50b2d8fb66	Update mpu_wrappers_v2.c (#709) ... * Update mpu_wrappers_v2.c * Initialize Internal QueueSet Handle to NULL --------- Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>	2 years ago
kar-rahul-aws	97050a17aa	Memory Protection Unit (MPU) Enhancements (#705) ... 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