Modify executable bits of system management memory page table

• US 9,367,691 B2
• Filed: 07/31/2012
• Issued: 06/14/2016
• Est. Priority Date: 07/31/2012
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Piwonka, Mark A
• Primary Examiner(s): TSUI, DANIEL D
• Application Number:
  US14/391,209
• Publication Number:
  US 20150039812A1
• Time in Patent Office: 1,414 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0238 Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/14 Protection against unauthorised use of memory or access to memory
• CPC Class Codes: G06F 12/1425 the protection being physical, e.g. cell, word, block
• CPC Class Codes: G06F 21/572 Secure firmware programming, e.g. of basic input output system [BIOS]
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57

Abstract

A computing device to create a system management memory page table in response to the computing device powering on. The system management memory page table includes pages with executable bits. The computing device modifies the executable bits of the pages before launching an option read only memory of the computing device.

Claims

1. A computing device comprising:

a storage component to include option read only memory;

a controller to create a system management memory page table in response to the computing device powering on;

wherein pages of the system management memory page table include executable bits;

wherein the controller is to modify the executable bits of the pages before launching the option read only memory.

2. The computing device of claim 1 wherein a basic input output system of the computing device is launched to create the system management memory page table in response to the computing device powering on.

3. The computing device of claim 1 wherein the computing device powers on from a mechanical off state.

4. The computing device of claim 1 further comprising system management memory, wherein the system management memory page table is created inside of the system management memory.

5. The computing device of claim 1 wherein the option read only memory includes at least one of an operating system and a video option read only memory of the computing device.

6. A method for managing a computing device comprising:

creating a system management memory page table in response to a computing device powering on;

wherein the system management memory page table includes pages with executable bits; and

modifying the executable bits for the pages before option read only memory of the computing device is launched.

7. The method for managing a computing device of claim 6 wherein the executable bits for the pages are modified immediately after the system management memory page table is created.

8. The method for managing a computing device of claim 6 wherein the executable bits for the pages are modified immediately before the option read only memory of the computing device is launched.

9. The method for managing a computing device of claim 6 wherein modifying the executable bit includes disabling the executable bit such that it cannot be executed.

10. The method for managing a computing device of claim 6 wherein modifying the executable bit includes setting the executable bit to not execute.

11. The method for managing a computing device of claim 6 further comprising detecting for code residing outside system management memory attempting to execute code included in a page of the system management memory page table.

12. The method for managing a computing device of claim 11 further comprising generating a fault if the code included in the page is attempted to be executed.

13. A non-volatile computer readable medium comprising instructions that if executed by a controller cause the controller to:

create a system management memory page table with pages of executable bits in response to a computing device powering on; and

modify the executable bits for each page of the system management memory page table before an option read only memory of the computing device is launched;

wherein the controller restricts the code in the pages with the modified bit from being executed by system management memory code after the option read only memory has been launched.

14. The non-volatile computer readable medium of claim 13 wherein the system management memory page table resides inside a secured system memory of the computing device and the pages of the system management memory page table include code.

15. The non-volatile computer readable medium of claim 14 wherein system management memory code cannot execute code residing outside a secured system memory of the computing device.