On Mon, Nov 16, 2015 at 08:04:00PM +0100, Ard Biesheuvel wrote: > OK. So you mean set TTBR to the zero page, perform the TLB flush and > only then switch to the new page tables? Not quite. If you have global mappings below TASK_SIZE, you would need this sequence when switching either to or from the UEFI page tables: - switch to another set of page tables which only map kernel space with nothing at all in userspace. - flush the TLB. - switch to your target page tables. As I say in response to one of your other patches, it's probably much easier to avoid any global mappings below TASK_SIZE. -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>