mmap_min_addr

I notice that on x86_64 we set CONFIG_DEFAULT_MMAP_MIN_ADDR=4096 CONFIG_LSM_MMAP_MIN_ADDR=65536 I think we should be defaulting the DAC based protection to 64k as well (or dropping the LSM value to 4k). I guess the Kconfig default is 4k but testing when we wrote this feature said ia64, ppc64 and x86 could safely be 64k arm and maybe others should only be 32k If it is safe to run with SELinux enforcing 64k it should be safe to run with root/non-root enforcing 64k...