Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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Marco Casaroli 3c8cfa307d arch/x86_64: give the page allocator the physical page pool base.
mm_pginitialize() documents heap_start as "the physical address of the start
of memory region", and every x86_64 consumer of mm_pgalloc() agrees:
create_spgtables(), x86_64_get_pgtable() and up_addrenv_create() all put the
result through x86_64_pgvaddr() before touching it.  x86_64_pgvaddr() in turn
range-checks against CONFIG_ARCH_PGPOOL_PBASE (arch/x86_64/src/common/
pgalloc.h:67).  arm64's equivalent passes CONFIG_ARCH_PGPOOL_PBASE.

up_allocate_pgheap() passed CONFIG_ARCH_PGPOOL_VBASE instead, and in the
other branch X86_64_PGPOOL_BASE + X86_64_LOAD_OFFSET, which is the same
mistake spelled out.  Every page handed out was therefore a virtual address
that fell outside the pool's physical window, x86_64_pgvaddr() returned 0,
and the first x86_64_pgwipe() memset NULL.

It presents as a page fault in memset() under create_spgtables() the first
time a process address environment is created, which is loading the init
program.  qemu-intel64:knsh_romfs sets PGPOOL_PBASE=0x00c000000 and
PGPOOL_VBASE=0x10c000000, so the value passed was off by the 4GB load
offset.

Impact: runtime, CONFIG_ARCH_ADDRENV builds only (CONFIG_MM_PGALLOC).

Assisted-by: Claude:claude-opus-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-08-04 01:43:41 +08:00
.github !arch/stm32: move stm32l1 and finalize the directory split 2026-07-03 10:27:27 +08:00
arch arch/x86_64: give the page allocator the physical page pool base. 2026-08-04 01:43:41 +08:00
audio tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
binfmt tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
boards tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
cmake cmake: Sanitize NAME for _main symbol generation 2026-08-03 20:59:22 +08:00
crypto tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
Documentation docs/raspberrypi-4b: Documentation about the SD card updated 2026-08-03 20:57:47 +08:00
drivers drivers/ioexpander/iso1i813t.c: fix error startup condition 2026-08-04 00:36:38 +08:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
graphics tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
include lib/math32: Avoid __uint128_t casts for LDC ImportC 2026-08-03 22:20:43 +08:00
libs tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
mm tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
net tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
openamp tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
pass1 tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
sched tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
syscall tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
tools tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
video tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
wireless tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-08-04 00:36:32 +08:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
.codespellrc arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake: Do not link an executable to detect the compiler. 2026-08-03 22:21:10 +08:00
CONTRIBUTING.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
INVIOLABLES.md
Kconfig sched/misc/assert: Add CONFIG_SCHED_DUMP_TASKS and CONFIG_SCHED_DUMP_STACK 2026-07-04 13:29:32 -04:00
LICENSE !arch/stm32: move stm32l1 and finalize the directory split 2026-07-03 10:27:27 +08:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-06 12:04:07 -03:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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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.