Secure Access Unit Memory Mapping for Peripheral Protection
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Solution Overview
Problem
Modern computer systems face challenges in preventing erroneous access to critical peripherals, such as PWM modules, which can lead to motor control issues due to software errors or electrical noise, causing potential damage.
Innovation Solution
Implementing a Secure Access Unit (SAU) that maps processor requests to protected memory locations, using unlocking keys and memory protection devices like Memory Protection Units (MPUs) to ensure secure access to fine-grained memory regions, allowing only valid accesses to critical peripherals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory protection is implemented to prevent erroneous access to critical peripherals, then reliability is improved, but device complexity increases
Solution Approach 1:
A Secure Access Unit (SAU) is introduced as an intermediary component between the processor and protected memory regions. The SAU receives memory access requests from the processor, validates them against security policies, and only permits access to protected regions if the request is valid. This mediator approach resolves the contradiction by providing reliable protection without requiring the processor itself to become more complex.
Solution Approach 2:
The memory space is segmented into protected regions and unprotected regions, with the SAU controlling access to the protected segments. This segmentation allows the system to maintain simplicity in the overall architecture while providing targeted protection to critical peripheral registers, thereby improving reliability without proportionally increasing device complexity.
2Reliability
If fine-grained memory protection is implemented to protect specific peripheral registers, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The SAU operates autonomously to enforce memory protection policies without requiring intervention from the processor or operating system. It automatically validates access requests, manages security contexts, and controls permission to protected regions. This self-service capability maintains ease of operation for software developers while ensuring reliable protection of fine-grained memory regions.
Solution Approach 2:
The SAU acts as an intermediary that transparently handles the complexity of fine-grained protection. Software developers continue to access peripheral registers using standard memory access instructions, but the SAU intercepts and validates these requests automatically. This mediator approach preserves ease of operation while implementing reliable fine-grained protection.
3Adaptability or versatility
If multiple unlocking mechanisms are provided for different applications, then adaptability is improved, but device complexity increases
Solution Approach 1:
The SAU implements a universal security context mechanism that can be configured to support multiple applications and access control policies. Rather than requiring separate unlocking mechanisms for each application, the SAU provides a single unified interface that can be programmed with different security policies and access control rules. This multi-functional approach improves adaptability while avoiding the complexity of multiple specialized mechanisms.
Data Source
AI summary
The present disclosure includes, among other things, methods, systems, program products, and devices for providing access to memory in a system with memory protection. A request is received from a processor for a memory access at a first memory location. A second memory location is determined. The second memory location is associated with the first memory location and is protected from access by the processor. The requested memory access is performed at the second memory location.