ARM Cortex-M TrustZone Memory Access Vulnerabilities In ARM Cortex-M systems utilizing TrustZone technology, one of the most critical security challenges is ensuring that Non-Secure (NS) code cannot maliciously access Secure (S) memory regions. This issue arises due to the dual mapping of memory regions in both Secure and Non-Secure address spaces, which can lead to…
ARM Cortex-A9 ETB and Intel LBR: Functional Comparison and Use Cases The Intel Last Branch Recording (LBR) feature and ARM’s Embedded Trace Buffer (ETB) serve similar purposes in the context of instruction-level monitoring and debugging, but they differ significantly in implementation, capabilities, and overhead. Intel’s LBR is a hardware feature that records the most recent…
ARM Hardware Development for Hobbyists: Challenges and Opportunities Building ARM-based hardware as a serious hobbyist is a challenging yet rewarding endeavor. ARM processors, particularly Cortex-M series microcontrollers, are widely used in embedded systems due to their power efficiency, performance, and scalability. However, designing and implementing custom ARM-based hardware requires a combination of programming expertise, electronics…
ARM Cortex-M0 IT Instruction Misuse and Performance Impact The ARM Cortex-M0 processor, being a highly efficient and power-optimized microcontroller, relies heavily on the Thumb instruction set to achieve its design goals. One of the key features of the Thumb instruction set is the IT (If-Then) instruction, which allows for conditional execution of up to four…
ARM Cortex-M7 MPU Configuration and DDR Cache Attribute Challenges The ARM Cortex-M7 is a powerful microcontroller core designed for high-performance embedded applications. One of its key features is the Memory Protection Unit (MPU), which allows developers to define memory regions with specific attributes such as cacheability, shareability, and access permissions. However, configuring the MPU for…
ARM Cortex-A Series VMSAv8-64 Stage 2 Translation Regime: PA Size Implications The VMSAv8-64 architecture, used in ARM Cortex-A series processors, implements a two-stage address translation mechanism for virtualization. Stage 2 translation, managed by the hypervisor, maps Intermediate Physical Addresses (IPAs) to Physical Addresses (PAs). The Physical Address (PA) size supported by the system plays a…
ARM AArch64 AES Instructions and Incorrect Decryption Output The issue revolves around the incorrect implementation of the AES-128 ECB (Electronic Codebook) algorithm using ARM AArch64 cryptographic instructions, specifically the aese (AES single round encryption), aesd (AES single round decryption), aesmc (AES mix columns), and aesimc (AES inverse mix columns) instructions. The user reports that after…
ARM Cortex-A7 RTL Validation: Understanding the Scope and Requirements RTL (Register Transfer Level) validation is a critical phase in the development of any processor, including the ARM Cortex-A7. The Cortex-A7 is a highly efficient processor core designed for low-power applications, often used in embedded systems, mobile devices, and IoT applications. RTL validation ensures that the…
Cortex-R4 PMU Cycle Counter Behavior During Run-to-Readout vs Step-by-Step Execution The Cortex-R4 Performance Monitoring Unit (PMU) cycle counter is a critical tool for measuring the number of CPU cycles elapsed during code execution. However, discrepancies in cycle counter values between run-to-readout and step-by-step debugging scenarios can lead to confusion and misinterpretation of system performance. In…
ARM Cortex-M0/M0+ Debug State and Breakpoint Exception Challenges The ARM Cortex-M0 and Cortex-M0+ processors, based on the ARMv6-M architecture, present unique challenges when it comes to self-hosted debugging, particularly in handling breakpoint exceptions without an external Debug Access Port (DAP). Unlike their ARMv7-M counterparts (Cortex-M3, M4, M7), which support a "debug monitor" state for software-based…