a3f8b55143
Some code paths in drivers/serial/serial.c load head and tail values of receive and transmit circular buffers with interrupts enabled, making it possible that the interrupt handler changes the value. As noted in the code, this is safe as long as the load itself is atomic. That is not true for 8bit architectures which fetch the 16-bit values using two load instructions. If interrupt handler runs between those two instructions and changes the value, the read returns corrupted data. This patch introduces CONFIG_ARCH_LDST_16BIT_NOT_ATOMIC configuration option which is automatically selected for AVR architecture. Based on this option, head and tail values are reduced to 8-bit length so the read remains atomic. Patch was tested by building on rv-virt:nsh - disassembly of functions from serial.c showed no difference which is correct as Risc-V does not need to protect reads of these values. There should be no impact for architectures that do not set the new configuration option. It was also tested by by custom echo application running on AVR128DA28. Signed-off-by: Kerogit <kr.git@kerogit.eu> |
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| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
Getting Started
First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.
Documentation
You can find the current NuttX documentation on the Documentation Page.
Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.
The old NuttX documentation is still available in the Apache wiki.
Supported Boards
NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.
Contributing
If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.
License
The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.