FIXMAP_START
#define KERNEL_MAP_END (FIXMAP_START)
#define __fix_to_virt(_x) (FIXMAP_START + ((_x) << PAGE_SHIFT))
(void *)FIXMAP_START, (void *)(FIXMAP_START + FIXMAP_SIZE),
unsigned long addr = FIXMAP_START;
unsigned long end = FIXMAP_START + FIXMAP_SIZE;