4 ms·

There's no such thing as bare metal any more. https://en.wikipedia.org/wiki/System_Management_Mode https://en.wikipedia.org/wiki/System_Management_Mode - the CP

There's no such thing as bare metal any more. https://en.wikipedia.org/wiki/System_Management_Mode https://en.wikipedia.org/wiki/System_Management_Mode - the CPU itself may at times spend some time doing "other things" such as changing the spin speed of the cooling fans, or interpreting the signals from the USB keyboard. The OS (running in ring 0) has no control over this - the CPU effectively just pauses for a little bit every now and again.

pjc50 11y ago
I'm not aware of any ARM systems that have this yet.
- jevinskie 11y ago
  TrustZone. It is "one level deeper" just like any other hypervisor or monitor. As far as I know, it is quite common in Android phones for HSM and DRM purposes. Yay? =\ http://www.arm.com/products/processors/technologies/trustzone/ http://www.arm.com/products/processors/technologies/trustzon... Edit: And, of course, it is probably exploitable in some way. See http://bits-please.blogspot.com/2015/08/exploring-qualcomms-trustzone.html http://bits-please.blogspot.com/2015/08/exploring-qualcomms-...