On 04/05/2013 01:19 PM, Yinghai Lu wrote: > On Fri, Apr 5, 2013 at 1:05 PM, H. Peter Anvin <h...@zytor.com> wrote: > >> That makes zero difference, since the issue at hand is the *virtual* >> addresses the kernel are running at. Currently, the 64-bit kernel >> always runs at 0xffffffff81000000 virtual. We can't run out of >> arbitrary bits of the 64-bit address space because of the memory model. > > Not sure if I understand this. > > when bzImage64 is loaded high, the kernel high address 0xffffffff81000000 > is pointed to phys address above 4G without problem. >
That' s the problem. KASLR is about randomizing the *virtual* address space, not the *physical* address space. On 32 bits those are connected (which is a problem all on its own), on 64 bits not so much. >> >> Furthermore, dealing with the boot loaders means dealing with the boot >> loader maintainers, which can be insanely painful. Consider that Grub2, >> 10 years after this was implemented, still can't load more than one >> initramfs component. > > syslinux and pxelinux could do that? > Yes, they can. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
