Function allocate_kernel_stack_frames 

pub fn allocate_kernel_stack_frames(
    token: &IrqDisabledToken,
    order: u8,
) -> Result<PhysFrame, AllocError>

Allocate physically contiguous pages for a kernel stack.

Kernel stacks need a contiguous physical backing in the current design because they are carved as a single block and directly accessed through the HHDM. This is distinct from DMA intent, so keep a dedicated API.