Linux 4.7 (pulled from github.com/torvalds/linux on Jul 20 2016), x86_64 Note: 64-bit x86 uses syscall instead of interrupt 0x80. The result value will be in %rax To find the implementation of a system call, grep the kernel tree for SYSCALL_DEFINE.\?(syscall, For example, to find the read system call: illusion:/usr/src/linux-source-3.19$ grep -rA3 'SYSCALL_DEFINE.\?(read,' * fs/read_write.c:SYSCAL