Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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Marco Casaroli 5f9edeb6e6 arch/x86_64: define the missing CONFIG_ARCH_HAVE_SYSCALL.
794c325947 ("arch/x64:Syscall support is enabled by default", 2025-05-27)
changed nine guards from CONFIG_LIB_SYSCALL to CONFIG_ARCH_HAVE_SYSCALL but
never added the Kconfig symbol.  Only ARCH_HAVE_SYSCALL_HOOKS exists in tree;
ARCH_HAVE_SYSCALL itself is defined nowhere, so it is always unset and since
that commit x86_64 has had no x86_64_syscall_entry(), no x86_64_syscall(), no
IA32_LSTAR/IA32_STAR programming and no syscall stub layer in any
configuration:

  arch/x86_64/src/common/Make.defs:37     x86_64_syscall.c not compiled
  arch/x86_64/src/common/CMakeLists.txt:41           likewise
  arch/x86_64/include/irq.h:86
  arch/x86_64/src/intel64/intel64_cpu.c:247, :386
  arch/x86_64/src/intel64/intel64_head.S:83, :351, :538
  arch/x86_64/src/intel64/intel64_saveusercontext.S:108

qemu-intel64:knsh_romfs and qemu-intel64:knsh_romfs_pci are the two
CONFIG_BUILD_KERNEL configurations in tree, and neither can have worked in
that time.  They still link -- nothing references the missing pieces, so
libstubs.a is simply never pulled in -- and then die the first time user code
executes SYSCALL.

Define the symbol with the condition the code had before that commit, which
is LIB_SYSCALL:  every protected and every kernel build needs the interface,
and a flat build is left exactly as it is today.

Impact: restores the system call interface for CONFIG_BUILD_KERNEL and
CONFIG_BUILD_PROTECTED on x86_64.  CONFIG_BUILD_FLAT is unaffected --
qemu-intel64:nsh still builds with ARCH_HAVE_SYSCALL unset.

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: define the missing CONFIG_ARCH_HAVE_SYSCALL. 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
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
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
README.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
ReleaseNotes

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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.