US 5,850,559 AGranted

Method and apparatus for secure execution of software prior to a computer system being powered down or entering a low energy consumption mode

AssigneeCompaq Computer Corporation

InventorsMichael F. Angelo, Craig A. Miller

Life of this patent

Estimating the term…

Loading patent…

Abstract

A computer system that automatically and securely executes registered programs immediately prior to a transition to a reduced energy consumption state. A registrar table specifying registered programs and a secure modification detection value for each registered program are maintained in system management mode memory or other secure memory space in the computer system. A system management interrupt is generated following a request to remove power from the computer system or the occurrence of an event that triggers an energy saving mode. The system management interrupt handler routine then generates a current modification detection value for each registered program. The current modification detection values are compared with the secure modification detection values. Execution of a registered program is permitted if the values match. After all registered programs have been executed, the computer system automatically powers down or enters an energy saving mode. The computer system thereby allows secure and convenient execution of programs or commands that would typically interfere with normal computer use.

Claims23

Dependent claims

A method for secure execution of software prior to a computer system entering a reduced energy consumption state, the computer system having a processor incorporating system management capabilities, the computer system also having an application registrar maintained in protected system management memory and a stored table containing a modification detection value for programs contained in the application registrar, the computer system further including a power supply source, the method comprising the steps of:

registering a program with the application registrar;
generating a system management interrupt in response to a request to place the computer system in a reduced energy consumption state;
placing the computer system in system management mode as a result of said step of generating a system management mode interrupt;
and
executing a system management interrupt handler upon entry into system management mode, wherein said execution of the system management interrupt handler comprises the steps of:
generating a current modification detection value for the program registered with the application register;
determining if the stored table contains a secure modification detection value for the registered program or file;
retrieving the secure modification detection value if it exists in the stored table;
comparing the current modification detection value to the secure modification detection value if it exists in the stored table;
and
permitting execution of the registered program if the secure modification detection value exists in the stored table and the current modification detection value matches the secure modification detection value.

8 more elements

A computer system comprising:

a processor incorporating system management capabilities;
a protected system management memory, the protected system management memory containing:
a modification detection code for generating a modification detection value;
an application registrar containing a value that specifies a registered program,
a secure modification detection value for the registered program, wherein the secure modification detection value represents an authorized or unaltered condition for the program;
and
a system management mode interrupt handler routine for directing the processor to:
generate, via said modification detection code, a current modification detection value for the program registered with said application registrar;
determine if the current modification detection value is equal to the secure modification detection value;
permit execution of the registered program if the current modification detection value is equal to the secure modification detection value;
and
assert an activation signal to energy saving features of the computer system or otherwise cause the computer system to enter a low energy consumption mode without further intervention from the computer user;
and
an interrupt generator for generating a system management interrupt in response to a period of inactivity of predetermined length in a specified system component, wherein the system management mode interrupt causes the system management interrupt handler routine to be executed.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/693,458Filed 7 Aug 1996
Granted: 15 Dec 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G06F 1/26
Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00: power supply means, e.g. regulation thereof
G06F 1/30
Power supply means, e.g. regulation thereof: means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations
G06F 21/81
Protecting specific internal or peripheral components, in which the protection of a component leads to protection of the entire computer: by…
G06F
Computing and data processing