Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
Find a file
Marco Casaroli 95c326704e arch/x86_64: Implement up_addrenv_fork() and provide POSIX fork().
Duplicate an address environment into freshly allocated pages mapped at the
same virtual addresses, which is what POSIX fork() is built on.

x86_64_fork_syscall() then lets the child run at the parent's stack addresses.
A pointer to a stack local taken before fork() must name the same object in
the child that it named in the parent, so the child adopts the parent's stack
geometry rather than being given a relocated copy; the parent's stack is
already in the duplicate, at the parent's address, with its contents.  That
shows up as a zero offset, which also means the copy would have the same
source and destination, so both the copy and the frame-pointer relocation are
skipped.

Build-verified on qemu-intel64:knsh_romfs.  NuttX on qemu-intel64 requires
tsc-deadline and pcid, which TCG does not implement, so it cannot be run on
this host.

Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-09-24 18:02:36 -03:00
.github build(deps): bump docker/setup-buildx-action from 4.3.0 to 4.4.1 2026-09-21 16:28:50 +08:00
arch arch/x86_64: Implement up_addrenv_fork() and provide POSIX fork(). 2026-09-24 18:02:36 -03:00
audio audio: limit the buffer count guard to shared ring requests 2026-08-05 07:58:53 +02:00
binfmt libs/libc/elf, binfmt: Describe the GOT by base and size, not by index. 2026-09-08 16:31:16 -03:00
boards arch/arm/rtl8730e: add UART character driver support 2026-09-24 21:24:35 +08:00
cmake cmake: fix undefined function name in parse args error messages 2026-09-11 21:15:22 +08:00
crypto crypto: fix chacha constants under GCC 15. 2026-09-20 08:22:11 -03:00
Documentation arch/x86_64: Implement up_addrenv_fork() and provide POSIX fork(). 2026-09-24 18:02:36 -03:00
drivers drivers/ioexpander/sx1509: include nuttx/arch.h for up_mdelay 2026-09-24 20:16:12 +08:00
dummy
fs docs: document chroot jail root 2026-09-20 22:27:38 +08:00
graphics graphics/nxterm: consume SGR escape sequences 2026-08-23 10:46:02 +08:00
include drivers/ioexpander: add an optional pin PWM operation 2026-09-24 20:16:12 +08:00
libs libc/stdio: allocate a buffer in getdelim() when *lineptr is NULL 2026-09-23 12:52:09 +08:00
mm mm/iob: fix CONFIG_NET_TIMESTAMPING typo in iob_alloc 2026-09-19 16:36:47 -03:00
net net/pkt: remove unused variable conn in append_timestamping 2026-09-19 18:32:45 -03:00
openamp cmake: Use NUTTX(_DIR/_BIN_DIR) instead CMAKE(_SRC_DIR/_BIN_DIR) 2026-08-09 11:13:08 -03:00
pass1 tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
sched sched/module: Increase /proc/modules line buffer. 2026-09-22 13:27:42 +08:00
syscall fs: add chroot() syscall 2026-09-20 22:27:38 +08:00
tools riscv/erbium: Add standalone Minion emulator support. 2026-09-24 15:38:14 +08:00
video video/videomode: Fix EDID parsing and formatting of video mode dumps 2026-08-29 11:09:11 -03:00
wireless wireless/bluetooth: Reject GATT operations on unconnected peers. 2026-09-24 09:51:44 +02:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines arch/arm: Reserve r10 via ARCHCFLAGS and hoist the PIC module flags. 2026-07-24 23:09:08 +08:00
.codespellrc zbus: Add linker support and documentation for the zbus port 2026-09-21 08:40:14 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore boards/risc-v/eic7700x: Adopt the common board layout. 2026-08-19 01:40:57 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml
.yamllint
AUTHORS AUTHORS: add Jorge Guzman 2026-08-25 08:43:13 -04:00
CMakeLists.txt cmake: reconfigure when .config changes 2026-09-14 18:40:45 -03:00
CONTRIBUTING.md contributing: Add requirement for 'Assisted-by' commit field 2026-07-12 09:42:28 +08:00
INVIOLABLES.md
Kconfig include/nuttx: Add link-time iterable sections infrastructure 2026-08-27 01:04:05 +08:00
LICENSE libs/libdsp: Add Matrix operations 2026-07-11 14:55:59 -03:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-09 22:41:11 +08:00
NOTICE
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes

POSIX Badge License Issues Tracking Badge Contributors GitHub Build Badge Documentation Badge MemBrowse

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.