xv6-riscv-kernel/user/usys.py

#!/usr/bin/env python3

template = """
.global {name}
{name}:
    li a7, SYS_{name}
    ecall
    ret
""".strip()


def genstub(syscall: str):
    if not 3 >= len(syscall) <= 15:
        raise ValueError("Syscall {} is too short/long!".format(syscall[:35]))

    return template.format(name=syscall)


syscalls = [
    "fork",
    "exit",
    "wait",
    "pipe",
    "read",
    "write",
    "close",
    "kill",
    "exec",
    "open",
    "mknod",
    "unlink",
    "fstat",
    "link",
    "mkdir",
    "chdir",
    "dup",
    "getpid",
    "sbrk",
    "sleep",
    "uptime",
    "trace",
    "halt",
]

assembly = "\n\n".join(map(genstub, syscalls))

# TODO: Perhaps do some more specific assertions on the code here
assert len(assembly) > 0, "No assembly code generated. Something is fishy"

with open("kernel/syscall.h", "r") as sfile:
    lines = list(filter(lambda x: x.startswith("#define"), sfile.readlines()))

    header_calls = set([line.split()[1] for line in lines])
    calls = set(["SYS_" + call for call in syscalls])

    if header_calls == calls:
        print("#All items match in both sets.")
    else:
        missing_in_calls = header_calls - calls
        missing_in_header_calls = calls - header_calls

        if missing_in_calls:
            print(
                "#These items are in header_calls but not in calls:", missing_in_calls
            )
        if missing_in_header_calls:
            print(
                "#These items are in calls but not in header_calls:",
                missing_in_header_calls,
            )

print("# generated by usys.py - do not edit\n")
print('#include "kernel/syscall.h"\n')
print(assembly)