Vehicle Memory Violation Notification via Privileged Authority Levels
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Solution Overview
Problem
Existing vehicle-mounted devices lack an efficient mechanism to notify memory access violations to the outside without requiring a hypervisor and without necessitating processor restart.
Innovation Solution
Implementing a processor with three or more authority levels, including a higher authority level for an abnormality notification function, to detect and notify memory access violations, thereby preventing hijacking and eliminating the need for a hypervisor and processor restart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hypervisor is used to detect and notify memory access violations, then the notification reliability is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the hypervisor layer from the system architecture and replaces it with a direct authority level mechanism. The abnormality notification function is given a higher authority level than the OS and applications, allowing it to detect and notify memory access violations without requiring a hypervisor. This extraction simplifies the device complexity while maintaining notification reliability.
Solution Approach 2:
The patent segments the authority levels into distinct hierarchical tiers: applications have the lowest authority level, the OS has a middle authority level, and the abnormality notification function has the highest authority level. This segmentation allows each component to operate with appropriate permissions and enables the notification function to access memory regions regardless of which authority level caused the violation, eliminating the need for a hypervisor.
2Reliability
If the microcomputer is restarted to notify memory access violations, then the notification completeness is improved, but the loss of time increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring the abnormality notification function with the highest authority level before any memory access violations occur. This allows the system to immediately detect and notify violations without requiring processor restart. The notification function is already in place and empowered to access any memory region, eliminating the need for restart-based notification mechanisms.
3Ease of operation
If the abnormality notification function has the same authority level as the OS, then the ease of operation is improved, but the reliability of notification decreases due to potential hijacking
Solution Approach 1:
The patent applies preliminary anti-action by giving the abnormality notification function a higher authority level than the OS, preventing the OS or applications from hijacking the notification function. This hierarchical authority structure ensures that even if the OS is compromised, it cannot prevent the notification function from detecting and reporting memory access violations, as the notification function operates at a higher authority level that cannot be overridden by lower-level components.
Data Source
AI summary
A vehicle-mounted device includes a processor capable of setting three or more authority levels related to memory access, wherein a higher authority level than authority levels of an OS and an application is set for an abnormality notification function of notifying a memory access violation to an outside of the vehicle-mounted device.