On 1/18/19 1:14 PM, Sebastian Andrzej Siewior wrote: > The kernel saves task's FPU registers on user's signal stack before > entering the signal handler. Can we avoid that and have in-kernel memory > for that? Does someone rely on the FPU registers from the task in the > signal handler?
This is part of our ABI for *sure*. Inspecting that state is how userspace makes sense of MPX or protection keys faults. We even use this in selftests/.
