https://bugs.winehq.org/show_bug.cgi?id=53682
--- Comment #16 from Kevin Puetz PuetzKevinA@JohnDeere.com ---
I wonder where I'm missing an initialization of it
I think you're missing it in _wine_syscall_dispatcher itself, when entered in the "normal" case (i.e. output_syscalls in tools/winebuild/import.c, when calling a function which the .spec file declared as `-syscall`). In that case the id is in x8, and the syscall_frame is built up on the stack (via all the code prior to the 3: label that __wine_syscall_dispatcher_return is jumping back to).
Or to put it another way, there should be an `str sp, [x10, #0x120]` somewhere in the vicinity of https://gitlab.winehq.org/wine/wine/-/blob/master/dlls/ntdll/unix/signal_arm... to initialize your new syscall_stack (no longer just alignment padding) along with everything else as it builds up a new syscall_frame. Or something like that (haven't actually tested this)...