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pigweed / third_party / github / FreeRTOS / FreeRTOS-Kernel / b6a43866da8fe030243c42b4e1a5fe2072cebe96
commitb6a43866da8fe030243c42b4e1a5fe2072cebe96[log] [tgz]
authorGaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>Tue Jul 14 16:22:14 2020 -0700
committerGitHub <noreply@github.com>Tue Jul 14 16:22:14 2020 -0700
tree1ae2155d79fe8b6381fe500c967897174b664713
parent587a83d647619bb0a508661c7bb4d6df89851582 [diff]
Add support for privileged heap to ARMV8-M ports (#85)

If xTaskCreate API is used to create a task, the task's stack is
allocated on heap using pvPortMalloc. This places the task's stack
in the privileged data section, if the heap is placed in the
privileged data section.

We use a separate MPU region to grant a task access to its stack.
If the task's stack is in the privileged data section, this results in
overlapping MPU regions as privileged data section is already protected
using a separate MPU region. ARMv8-M does not allow overlapping MPU
regions and this results in a fault. This commit ensures to not use a
separate MPU region for the task's stack if it lies within the
privileged data section.

Note that if the heap memory is placed in the privileged data section,
the xTaskCreate API cannot be used to create an unprivileged task as
the task's stack will be in the privileged data section and the task
won't have access to it. xTaskCreateRestricted and
xTaskCreateRestrictedStatic API should be used to create unprivileged
tasks.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
9 files changed
tree: 1ae2155d79fe8b6381fe500c967897174b664713
  1. .github/
  2. include/
  3. portable/
  4. CONTRIBUTING.md
  5. croutine.c
  6. event_groups.c
  7. GitHub-FreeRTOS-Kernel-Home.url
  8. History.txt
  9. LICENSE.md
  10. list.c
  11. queue.c
  12. Quick_Start_Guide.url
  13. README.md
  14. SECURITY.md
  15. stream_buffer.c
  16. tasks.c
  17. timers.c
README.md

Getting started

This repository contains FreeRTOS kernel source/header files and kernel ports only. This repository is referenced as a submodule in FreeRTOS/FreeRTOS repository, which contains pre-configured demo application projects under FreeRTOS/Demo directory.

The easiest way to use FreeRTOS is to start with one of the pre-configured demo application projects. That way you will have the correct FreeRTOS source files included, and the correct include paths configured. Once a demo application is building and executing you can remove the demo application files, and start to add in your own application source files. See the FreeRTOS Kernel Quick Start Guide for detailed instructions and other useful links.

Additionally, for FreeRTOS kernel feature information refer to the Developer Documentation, and API Reference.

Getting help

If you have any questions or need assistance troubleshooting your FreeRTOS project, we have an active community that can help on the FreeRTOS Community Support Forum.

Cloning this repository

To clone using HTTPS:

git clone https://github.com/FreeRTOS/FreeRTOS-Kernel.git

Using SSH:

git clone git@github.com:FreeRTOS/FreeRTOS-Kernel.git

Repository structure

  • The root of this repository contains the three files that are common to every port - list.c, queue.c and tasks.c. The kernel is contained within these three files. croutine.c implements the optional co-routine functionality - which is normally only used on very memory limited systems.

  • The ./portable directory contains the files that are specific to a particular microcontroller and/or compiler. See the readme file in the ./portable directory for more information.

  • The ./include directory contains the real time kernel header files.