Secure operating system switching

• US 7,950,020 B2
• Filed: 03/13/2007
• Issued: 05/24/2011
• Est. Priority Date: 03/16/2006
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Sun, Jun, Zhou, Dong
• Primary Examiner(s): Nguyen; Van H
• Application Number:
  US11/724,016
• Publication Number:
  US 20080092145A1
• Time in Patent Office: 1,533 Days
• Field of Search: 719/310, 719/312, 719/319, 713/100
• US Class Current: 719/319
• CPC Class Codes: G06F 12/1441 for a range
• CPC Class Codes: G06F 12/145 the protection being virtual, e.g. for virtual blocks or segments before a translation mechanism
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

A method and apparatus is disclosed herein for secure operating system switching. In one embodiment, the method comprises identifying a second operating system of a plurality of operating systems that is to be active next; causing a memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active; and causing the second operating system to become active.

Claims

1. A method for enabling a plurality of operating systems to run concurrently on a computer, wherein a first operating system in the plurality of operating systems is currently active, the method comprising:

identifying a second operating system from the plurality of operating systems that is to be active next, the second operating system having the same privileges to system resources as the first operating system for operation system switching;

causing a memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active;

causing the second operating system to become active;

determining that a forcible switching event occurred, wherein identifying the second operating system that is to be active next occurs in response to determining that the forcible switching event has occurred, wherein a forcible switch can occur between any two operating systems in the plurality of operating systems;

performing a forced control transfer; and

initiating operating system switching in response to an operating system switching event,

wherein the forcible switching event occurs after a currently active operating system fails to become inactive and fails to allow the second operating system to become active, and

wherein the operating system switching event is generated in response to a switching button being depressed.

2. The method defined in claim 1 wherein causing the second operation system to become active comprises performing a resume operation for the second operating system to cause the second operating system to resume operation.

3. The method defined in claim 1 wherein the operating system switching event is a user event.

4. The method defined in claim 1 wherein the switching button is mapped as a secure device with state that the plurality of operating systems cannot alter and one or more interrupts that the plurality of operating systems cannot block.

5. The method defined in claim 1 wherein the operating system switching event is generated after a timer reaches a predetermined time, where the timer is trigger to run in response to the switching button being depressed.

6. The method defined in claim 1 wherein causing the memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active comprises statically partitioning memory into non-secure memory that is accessible by the second operating system and secure memory that is not accessible to the second operating system.

7. The method defined in claim 6 wherein the secure memory and non-secure memory include portions of memory on a chip.

8. The method defined in claim 1 further comprising monitoring for memory access violation by one or more operating systems in the plurality of operating systems other than the second operating system.

9. The method defined in claim 1 further comprising:

the second operating system performing a resume operation.

10. The method defined in claim 9 wherein the second operating system performing a resume operation comprises:

one or more drivers of the second operating system restoring hardware device states;

a kernel in the second operating system restoring and resuming operation of one or more subsystems; and

resuming normal operation by the second operating system.

11. The method defined in claim 9 further comprising:

receiving an indication to switch from a currently active operating system to the second operating system; and

the currently active operating system saving state associated with the currently active operating system.

12. The method defined in claim 11 wherein receiving the indication is in response to a user action or an operating system event.

13. The method defined in claim 1 further comprising:

the first operating system performing a suspend operation.

14. The method defined in claim 13 wherein the first operating system performing a suspend operation comprises:

saving state associated with one or more sub-systems and one or more hardware devices.

15. An article of manufacture having one or more non-transitory computer readable storage media storing instructions thereon which, when executed by a system, cause the system to perform a method for enabling a plurality of operating systems to run concurrently on a computer, wherein a first operating system in the plurality of operating systems is currently active, the method comprising:

identifying a second operating system of a plurality of operating systems that is to be active next, the second operating system having the same privileges to system resources as the first operating system for operation system switching;

causing a memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active;

causing the second operating system to become active;

determining that a forcible switching event occurred, wherein identifying the second operating system that is to be active next occurs in response to determining that the forcible switching event has occurred, wherein a forcible switch can occur between any two operating systems in the plurality of operating systems;

performing a forced control transfer; and

initiating operating system switching in response to an operating system switching event,

wherein the forcible switching event occurs after a currently active operating system fails to become inactive and fails to allow the second operating system to become active, and

wherein the operating system switching event is generated in response to a switching button being depressed.

16. The article of manufacture defined in claim 15 wherein causing the second operation system to become active comprises performing a resume operation for the second operating system to cause the second operating system to resume operation.

17. The article of manufacture defined in claim 15 wherein the switching button is mapped as a secure device with state that the plurality of operating systems cannot alter and one or more interrupts that the plurality of operating systems cannot block.

18. The article of manufacture defined in claim 15 wherein causing the memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active comprises statically partitioning memory into non-secure memory that is accessible by the second operating system and secure memory that is not accessible to the second operating system.

19. The article of manufacture defined in claim 15 further comprising:

the second operating system performing a resume operation.

20. The article of manufacture defined in claim 19 further comprising:

receiving an indication to switch from a currently active operating system to the second operating system; and

the current operating saving state associated with the currently active operating system.

21. The article of manufacture defined in claim 20 wherein receiving the indication is in response to a user action or an operating system event.

22. A system for enabling a plurality of operating systems to run concurrently on a computer, wherein a first operating system in the plurality of operating systems is currently active, said system comprising:

a memory;

a processor, in communications with the memory and configured to perform;

identifying a second operating system of a plurality of operating systems that is to be active next, the second operating system having the same privileges to system resources as the first operating system for operation system switching;

causing a memory access controller to enable exclusive access to a portion of memory for the second operating system once the second operating system becomes active;

causing the second operating system to become active;

determining that a forcible switching event occurred, wherein identifying the second operating system that is to be active next occurs in response to determining that the forcible switching event has occurred, wherein a forcible switch can occur between any two operating systems in the plurality of operating systems;

performing a forced control transfer; and

initiating operating system switching in response to an operating system switching event,

wherein the forcible switching event occurs after a currently active operating system fails to become inactive and fails to allow the second operating system to become active, and

wherein the operating system switching event is generated in response to a switching button being depressed.