KERN_VIRT_START
#define VMALLOC_START KERN_VIRT_START
#define KERN_IO_START (KERN_VIRT_START + (KERN_VIRT_SIZE >> 1))
pr_info("vmalloc start = 0x%lx\n", KERN_VIRT_START);
addr = KERN_VIRT_START + i * PGDIR_SIZE;
ptdump_range[0].start = KERN_VIRT_START;
{KERN_VIRT_START, ULONG_MAX},
kernel_ptd_info.base_addr = KERN_VIRT_START;