Function k_is_user_context 

pub unsafe extern "C" fn k_is_user_context() -> bool

Indicate whether the CPU is currently in user mode

@return true if the CPU is currently running with user permissions

CAUTION! If you branch on k_is_user_context() and then perform a kernel-only operation, you must insert a memory barrier before the privileged operation. Both the compiler and the CPU may reorder memory operations around the branch. Without a barrier, memory accesses related to the privileged path may move before the context check or be speculated.