Controlling update of content of a programmable read-only memory

1. A method of controlling update of content in a programmable read-only memory in a system, comprising:

determining a security status associated with the system, the security status being one of a secure mode and a non-secure mode, wherein determining the security status associated with the system comprises determining the security status by a security module that monitors a type of software executing in the system, wherein the security module sets the security status to the secure mode in response to the security module detecting that the type of software includes firmware instructions executing in the system, wherein the security module changes the security status to the non-secure mode in response to the security module detecting that the type of software includes operating system instructions executing in the system;

in response to detecting that the system is in the secure mode, enabling a write to the programmable read-only memory; and

in response to detecting that the security status is in the non-secure mode, disabling a write to the programmable read-only memory.

2. The method of claim 1 , wherein the security module executes on a tamper-protected portion of a device in the system.

3. The method of claim 1 , further comprising:

in response to detecting that a write to the programmable read-only memory is enabled, updating firmware instructions in the programmable read-only memory.

4. The method of claim 3 , wherein updating the firmware instructions in the programmable read-only memory comprises updating basic input/output system (BIOS) instructions.

5. The method of claim 3 , further comprising:

in response to detecting that a write to the programmable read-only memory is disabled, preventing an update of the firmware instructions in the programmable read-only memory.

6. The method of claim 1 , wherein controlling update of the content in the programmable read-only memory comprises controlling update of the content in one of an electrically erasable and programmable read-only memory and a flash memory.

7. The method of claim 1 , wherein controlling update of the content in the programmable read-only memory comprises controlling update of the content in the programmable read-only memory that is separate from mass storage and volatile memory in the system.

8. A system comprising:

a programmable read-only memory;

a security module comprising a central processing unit to detect a security status associated with the system and to provide security status information based on the detected security status, wherein detection of the security status is based on a type of software executing in the system, wherein the security module is configured to set the security status to a secure mode in response to the security module detecting that the type of software includes firmware instructions executing in the system, wherein the security module is configured to change the security status to a non-secure mode in response to the security module detecting that the type of software includes operating system instructions executing in the system; and

a control device to enable a write to the programmable read-only memory in response to the security status information indicating the secure mode, and

the control device to disable a write to the programmable read-only memory in response to the security status information indicating the non-secure mode.

9. The system of claim 8 , the programmable read-only memory to store firmware instructions, wherein the control device is configured to, in response to a request to update the firmware instructions:

write to the programmable read-only memory to update the firmware instructions in response to detecting that the security status information indicates the secure mode; and

block a write to the programmable read-only memory in response to detecting that the security status information indicates the non-secure mode.

10. The system of claim 8 , further comprising plural processing modules, the programmable read-only memory being part of one of the processing modules,

wherein the security status associated with the system comprises a security status of the one processing module.

11. The system of claim 8 , further comprising one or more mass storage devices and volatile memory devices, wherein the programmable read-only memory is separate from the one or more mass storage devices and volatile memory devices.

12. The system of claim 8 , further comprising one or more mass storage devices and volatile memory devices, wherein the programmable read-only memory is a different type of storage than the one or more mass storage devices and volatile memory devices.

13. An article comprising at least one non-transitory machine-readable storage medium containing instructions that when executed cause a system to:

determine a security status associated with the system, the security status being one of a secure mode and a non-secure mode, wherein determining the security status associated with the system comprises determining the security status by a security module that monitors a type of software executing in the system, wherein the security module sets the security status to the secure mode in response to the security module detecting that the type of software includes firmware instructions executing in the system, wherein the security module changes the security status to the non-secure mode in response to the security module detecting that the type of software includes operating system instructions executing in the system;

in response to determining that the security status is the secure mode, set security status information to indicate the secure mode for enabling an update of firmware instructions in a programmable read-only memory; and

in response to determining that the security status is the non-secure mode, set the security status information to indicate the non-secure mode for disabling the update of firmware instructions in the programmable read-only memory.

14. A system comprising:

a programmable read-only memory;

processor means for determining a security status associated with the system, the security status being one of a secure mode and a non-secure mode, wherein determining the security status associated with the system comprises determining the security status by a security module that monitors a type of software executing in the system, wherein the security module sets the security status to the secure mode in response to the security module detecting that the type of software includes firmware instructions executing in the system, wherein the security module changes the security status to the non-secure mode in response to the security module detecting that the type of software includes operating system instructions executing in the system;

means responsive to detecting that the system is in the secure mode for enabling an update of firmware instructions in the programmable read-only memory; and

means responsive to detecting that the security status is in the non-secure mode for disabling the update of the firmware instructions in the programmable read-only memory.