memcpy_*fs()

inline void memcpy_tofs(void * to, const void * from, unsigned long n)

inline void memcpy_fromfs(void * to, const void * from, unsigned long n)

It is not clear which way the copy occurs. Does "from" mean user space, or kernel space. Contrarily, does "to" mean kernel space or user space?

Assuming the "tofs" and "fromfs" refer to the Frame Segment register, can one assume it always points to user space? How does this carry over to other architectures? Do they have Frame Segment registers?