cdd8032cb9
When compiling with O2 optimization, the compiler optimizes the code in a way that causes irq variable to be corrupted. The getipsr() function reads IPSR into r0, but the subsequent inline assembly that sets FPSCR also uses r0 without declaring it as clobbered. This causes the compiler to reuse r0 for the immediate value (0x40000), overwriting the IRQ number read from IPSR. The issue manifests as: - getipsr() correctly reads IPSR (e.g., 0xf for IRQ 15) - Compiler optimizes and reuses r0 for ARM_FPSCR_LTPSIZE_NONE (0x40000) - irq variable gets the wrong value 0x40000 instead of actual IRQ number - This leads to assertion failures in irq_dispatch due to invalid IRQ Root cause analysis from disassembly: mrs r0, IPSR ; Read IPSR to r0 mov.w r0, #262144 ; Compiler overwrites r0 with 0x40000! vmsr fpscr, r0 ; Set FPSCR str r0, [sp, #4] ; Store corrupted 0x40000 as irq ... ldr r0, [sp, #4] ; Load corrupted value bl irq_dispatch ; Call with wrong IRQ number 0x40000 Fix by adding r0 to the clobber list in the inline assembly, which forces the compiler to save irq value before using r0 for FPSCR setup. This issue only occurs at O2 optimization level and affects ARMv8-M architecture with FPU enabled. Signed-off-by: xuxingliang <xuxingliang@xiaomi.com> |
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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 | ||
| .editorconfig | ||
| .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.