US 11,907,411 B2
Secure operating modes for computing devices
Mason Andrew Gunyuzlu, Spring, TX (US); Robert Stephen Craig, Spring, TX (US); and Tevin Richards, Spring, TX (US)
Assigned to HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P., Spring, TX (US)
Appl. No. 17/777,843
Filed by HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P., Spring, TX (US)
PCT Filed Dec. 9, 2019, PCT No. PCT/US2019/065156
§ 371(c)(1), (2) Date May 18, 2022,
PCT Pub. No. WO2021/118520, PCT Pub. Date Jun. 17, 2021.
Prior Publication US 2022/0414271 A1, Dec. 29, 2022
Int. Cl. G06F 21/83 (2013.01); G06F 21/31 (2013.01); G06F 21/74 (2013.01)
CPC G06F 21/83 (2013.01) [G06F 21/31 (2013.01); G06F 21/74 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A computing device comprising:
a main processor to run an operating system enabled to establish communication from an external device to the main processor via a hardware interrupt handler when the external device is connected to the computing device; and
a keyboard controller to:
detect a lock keystroke sequence at a keyboard;
transmit scan codes corresponding to the lock keystroke sequence to the main processor; and
in response to detecting the lock keystroke sequence, cause the main processor to:
lock a user account running on the operating system by presenting a lock screen that prompts a user for a password before allowing access to the computing device;
halt the operating system, and
enter a secure operating mode in which communication from the external device to the main processor via the hardware interrupt handler is blocked, wherein the secure operating mode is enabled to reference an alternative interrupt descriptor table, wherein the alternative interrupt descriptor table references alternative instructions for execution and wherein the alternative instructions referenced by the alternative interrupt descriptor table include instructions for the main processor to log indications of attempts by external devices to connect to the computing device.