* - flush_cache_page(mm, vmaddr, pfn) flushes a single page
* - flush_cache_range(vma, start, end) flushes a range of pages
* - flush_icache_range(start, end) flush a range of instructions
* - flush_cache_page(mm, vmaddr, pfn) flushes a single page
* - flush_cache_range(vma, start, end) flushes a range of pages
* - flush_icache_range(start, end) flush a range of instructions