8d32b668ec
The commit 84d0689 "Nano-malloc: Fix for unwanted external heap fragmentation" from newlib 4.1.0 introduced several optimizations, one of which is as follows: When the last chunk in the free list is smaller than requested, nano_malloc() calls sbrk(0) to see if the heap's current head is adjacent to this chunk, and if so it asks sbrk() to allocate the difference in bytes only and expands the current chunk. This doesn't work if the heap consists of non-contiguous regions. sbrk(0) returns the the current region's head if the region has any remaining capacity. But if this capacity is not enough for the second (non-trivial) call to sbrk() described above, allocation will happen from the next region if available. Expanding the current chunk won't work and will result in a segmentation fault. So this optimization needs to be reverted in order to bring back compatibility with non-contiguous heaps. Before the next version of newlib becomes available and gets updated in the GCC Arm Embedded Toolchain, we work around this issue by including the fix in Mbed OS. The linker prioritizes malloc() from the project to the one from the toolchain. |
||
|---|---|---|
| .github | ||
| TESTS | ||
| UNITTESTS | ||
| cmsis | ||
| connectivity | ||
| docker_images/mbed-os-env | ||
| docs | ||
| drivers | ||
| events | ||
| extern | ||
| features | ||
| hal | ||
| platform | ||
| rtos | ||
| storage | ||
| targets | ||
| tools | ||
| .astylerc | ||
| .codecheckignore | ||
| .coveragerc | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .lgtm.yml | ||
| .mergify.yml | ||
| .pylintrc | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| DOXYGEN_FRONTPAGE.md | ||
| Jenkinsfile | ||
| LICENSE-apache-2.0.txt | ||
| LICENSE.md | ||
| README.md | ||
| doxyfile_options | ||
| doxygen_options.json | ||
| logo.png | ||
| mbed.h | ||
| requirements.txt | ||
README.md
Arm Mbed OS is an open source embedded operating system designed specifically for the "things" in the Internet of Things. It includes all the features you need to develop a connected product based on an Arm Cortex-M microcontroller, including security, connectivity, an RTOS and drivers for sensors and I/O devices.
Mbed OS provides a platform that includes:
- Security foundations.
- Cloud management services.
- Drivers for sensors, I/O devices and connectivity.
Release notes
The release notes detail the current release. You can also find information about previous versions.
License and contributions
The software is provided under the Apache-2.0 license. Contributions to this project are accepted under the same license. Please see contributing.md for more information.
This project contains code from other projects. The original license text is included in those source files. They must comply with our license guide.
Folders containing files under different permissive license than Apache 2.0 are listed in the LICENSE file.
Getting started for developers
We have a developer website for asking questions, engaging with others, finding information on boards and components, using an online IDE and compiler, reading the documentation and learning about what's new and what's coming next in Mbed OS.
Getting started for contributors
We also have a contributing and publishing guide that covers licensing, contributor agreements and style guidelines.
Documentation
For more information about Mbed OS, please see our published documentation. It includes Doxygen for our APIs, step-by-step tutorials, porting information and background reference materials about our architecture and tools.
To contribute to this documentation, please see the mbed-os-5-docs repository.