97dcbc010b
copy_kernel_mappings() copies exactly one PDPT entry, the 1GB linear window that maps physical 0-1GB at 4GB-5GB. The boot identity mapping of the low 4GB, which lives in PDPT entries 0-3 of g_pdpt_low (intel64_head.S:756, one page directory per 1GB) and is where every MMIO register is reached, is not carried over. A kernel thread never gets an address environment of its own and addrenv_switch() leaves the last one in place for it, so as soon as any process exists, kernel code touching MMIO faults. The HPET at 0xfed00000 finds it immediately -- CR2=fed000f0, in intel64_hpet_getreg() under clock_systime_ticks() on the lpwork thread -- and any MMIO driver would. Inherit the four boot PDPT entries. They point at the boot page directories rather than at copies, so anything intel64_map_region() adds later is inherited too, and they carry no X86_PAGE_USER, so user code still cannot reach them. Impact: runtime, CONFIG_ARCH_ADDRENV builds only. User-space access is unchanged; the entries added are supervisor-only. Assisted-by: Claude:claude-opus-5 Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> |
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| 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.