On Linux, this syscall doesn't take any arguments; instead,
it assumes the context was put on the stack.
The change is trivial, but I'd like to make sure I got this right; I have a patch that implements signal delivery on arm64, but it's still somewhat buggy. I'm not sure where the argument got here in the first place.
The Linux implementation can be found here: https://elixir.bootlin.com/linux/latest/source/arch/arm64/kernel/signal.c
That’s precisely what I’ve done, except that I stole the trampoline from Linux. It’s three instructions, and I’d rather not diverge here, to avoid complicating matters for native Linux debuggers or unwinders.