Function ring3_trampoline 

extern "C" fn ring3_trampoline() -> !

Trampoline that switches to user address space and does IRETQ to Ring 3.

This runs as a kernel task entry point. It:

1. Switches CR3 to the user address space
2. Pushes an IRET frame (SS, RSP, RFLAGS, CS, RIP)
3. Executes IRETQ to jump to Ring 3 code