On Tue, Nov 11, 2014 at 12:05 PM, Andy Lutomirski <l...@amacapital.net> wrote: > On 11/10/2014 03:55 PM, Andi Kleen wrote: >> To prevent recursive interrupts clobbering this >> state in the task_struct this is only done for interrupts >> coming directly from ring 3. > > Since this just came up in a different context today, I'd like to > propose a different solution to this piece of the problem. > > Can we change the paranoid entry to check if the entry came from ring 3 > and to just switch stacks immediately to the standard kernel stack and > run the non-paranoid entry code? This eliminates paranoid_userspace > entirely, and there are no special gsbase machinations any more for the > entry-from-userspace path. > > In fact, I think that this will result in the MSR KERNEL_GS_BASE value > *always* matching the userspace gs value from any C code in the kernel, > since we'll always swapgs exactly once on entry from userspace.
I'll send patches in a couple hours. I have it mostly working. --Andy -- 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/
