Linux System Call Tables by Architecture · syscall.sh

Every Linux syscall table in one place, grouped by architecture: system calls for 27 architectures with their numbers, arguments and registers, from Linux 3.3 to 7.3.

Architectures

Every architecture’s table, with the full history of when each syscall appeared and when it was dropped, is also a plain JSON file at //syscalls.json, for example /x64/syscalls.json.

Calling conventions

Number in NR, arguments in ARG0 to ARG5, then the instruction. The result comes back in RETURN.

API

curl https://api.syscall.sh/v2/syscalls/x64/read

Any kernel release, diffs between releases and more in the API docs.

Syscall tables across kernel versions

Entries get added and, rarely, removed between releases. Each architecture page has a kernel selector, and its JSON download records when each entry first appeared (since) and when it was dropped (removed_in).

Removed entries stay visible: pick “all, with removed” in the kernel selector and each dropped syscall is marked with the release that dropped it.

Where the data comes from

Everything on this site is read from the kernel source itself. For each architecture, the generator walks the syscall table and the SYSCALL_DEFINE macros of every mainline release it scans, so these are the numbers the kernel actually dispatches on.

It also records each architecture’s calling convention, the instruction that enters the kernel, so every syscall table shows exactly where the number and the arguments go.

A syscall whose since equals the first release scanned for its architecture was already there back then, and may be much older.

Descriptions and full history

The short descriptions come from the Linux man pages project, and the io_uring ones from liburing. Whenever the data changes, the site is rebuilt from the syscall API.