Memory remap

• ioremap

The function will map a range of I/O space to kernel space. That fix page table of some kernel memory to physical I/O memory. You can access the mapped kernel space as if you are accessing physical I/O memory.

• io_remap_pfn_range, remap_page_range

Remap address range in the kernel space to user space. User space process can access the mapped kernel address range by accessing user-space address.