Peripheral Bitmask Access Control for Task-Specific SoC Isolation
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Solution Overview
Problem
Existing SoCs allow firmware complete access to all peripherals, leading to potential faults or malicious access, which can corrupt other peripherals, necessitating improved access control.
Innovation Solution
Implement programmable access control identifiers and access controllers to manage access to peripherals based on operating modes and task-specific permissions, using bitmasks to set access settings dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If firmware is given complete access to all peripherals, then ease of operation is improved, but reliability deteriorates due to potential faults or malicious access corrupting peripherals
Solution Approach 1:
The patent divides peripheral access control into separate segments by implementing individual access control identifiers for different peripherals. Each peripheral has its own access control identifier that can be independently programmed, allowing the transaction host to grant or deny access to specific peripherals on a per-peripheral basis rather than having uniform access to all peripherals.
Solution Approach 2:
The patent introduces access control identifiers as intermediary elements between the transaction host and peripherals. These identifiers act as mediators that the transaction host can program to control access, preventing direct uncontrolled access to peripherals while still allowing legitimate access when needed.
2Reliability
If access control identifiers are programmed for each peripheral, then reliability is improved by preventing unauthorized access, but device complexity increases
Solution Approach 1:
The patent uses parameter changes by programming access control identifiers with different values to control access states. The transaction host can change the parameters (access control identifier values) of peripherals dynamically based on operating modes and task requirements, providing flexible control without complex hardware structures.
Solution Approach 2:
The access control identifiers serve multiple functions: they act as access control mechanisms, operating mode indicators, and task permission managers. This multi-functionality reduces the need for separate complex control structures for each function, simplifying the overall device complexity while maintaining reliable access control.
3Reliability
If complex software is used for access control, then reliability is improved, but the processor size and cost increase
Solution Approach 1:
The patent replaces complex software-based access control mechanisms with a simpler hardware-level identifier system. Instead of requiring complex operating system kernels or security software to manage peripheral access, the system uses programmable access control identifiers that can be managed with minimal software overhead, reducing processor complexity and cost.
Data Source
AI summary
An electronic device includes a transaction host, first and second peripherals, memory, an access control register, and first and second access controllers. The memory stores access control identifier management instructions, a first task related to the first peripheral, and a first bitmask indicating respective access settings for the first and second peripherals for performing the first task. The access control register includes a first access control identifier for the first peripheral and a second access control identifier for the second peripheral. The transaction host executes the access control identifier management instructions to program the first and second access control identifiers based on the first bitmask, and subsequently executes the first task. The first and second access controllers control access to the first and second peripherals, respectively, based on the respective first and second access control identifiers programmed based on the first bitmask.