The creator of syscall.sh has released a major update to their Linux system call reference website and API, originally launched in 2020. The site now covers 27 architectures — from x86_64 and ARM64 to RISC-V, LoongArch, and s390x — with syscall numbers, arguments, registers, and calling conventions for every mainline kernel release from Linux 3.3 to 7.3.
Each architecture page includes a kernel version selector that shows when each syscall was added or removed, and a downloadable JSON file (e.g., `/x64/syscalls.json`) containing the full history. The data is generated directly from the kernel source by parsing syscall tables and `SYSCALL_DEFINE` macros, ensuring the numbers match what the kernel actually dispatches.
The REST API at https://api.syscall.sh/v2 supports queries like `curl https://api.syscall.sh/v2/syscalls/x64/read` and provides diffs between kernel releases. A comprehensive calling convention table documents register layouts for every supported architecture, from `syscall`/`int 0x80` on x86 to `svc`, `ecall`, `trap`, and `brki` instructions elsewhere.
The project remains a solo effort; mobile layout improvements are noted as a work in progress. The Hacker News post has 12 points and 2 comments as of writing.
Source: Hacker News · Summarized by HeadlinesBriefing