Userspace from syscalls

The kernel provides some functions to access the user-space from the kernel space during syscalls. Some of these are :

• get_user()

• put_user()

• copy_from_user()

• copy_to_user()

These functions also check if the pointer is in user-space and also handle faults if the pointer is invalid. For invalid pointers, they return non-zero value.

Remember syscalls run in process context so current is valid.