Hey Andy, On Fri, Jan 19, 2018 at 08:30:33AM -0800, Andy Lutomirski wrote: > I meant that we could have sp0 have a genuinely constant value per > cpu. That means that the entry trampoline ends up with RIP, etc in a > different place depending on whether VM was in use, but the entry > trampoline code should be able to handle that. sp1 would have a value > that varies by task, but it could just point to the top of the stack > instead of being changed depending on whether VM is in use. Instead, > the entry trampoline would offset the registers as needed to keep > pt_regs in the right place. > > I think you already figured all of that out, though :) Yes, and after looking a while into it, it would make a nice cleanup for the entry code. On the other side, it would change the layout for the in-kernel 'struct pt_regs', so that the user-visible pt_regs ends up with a different layout than the one we use in the the kernel. This can certainly be all worked out, but it makes this nice entry-code cleanup not so nice and clean anymore. At least the work required to make it work without breaking user-space is not in the scope of this patch-set. Regards, Joerg -- 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>
