ARM GICv3 LPI Passthrough Behavior and State Machine The ARM Generic Interrupt Controller (GIC) version 3 introduces Locality-specific Peripheral Interrupts (LPIs), which are message-based interrupts designed for high-performance and scalable systems. Unlike traditional wired interrupts such as Peripheral Private Interrupts (PPIs) and Shared Peripheral Interrupts (SPIs), LPIs operate with a reduced state machine, which introduces…
TrustZone Architecture Compatibility in ARM Cortex-M3 The ARM Cortex-M3 is a widely used microcontroller core based on the ARMv7-M architecture. It is known for its efficiency, low power consumption, and robust performance in embedded systems. However, one of its limitations is the lack of support for ARM TrustZone technology, a hardware-based security feature introduced in…
ARM Cortex-M3/M4/M7 Lack Native TrustZone Support The ARM Cortex-M3, Cortex-M4, and Cortex-M7 processors are based on the ARMv7-M architecture, which does not include native support for ARM TrustZone technology. TrustZone, a hardware-based security feature, was introduced in the ARMv8-M architecture, specifically for Cortex-M23 and Cortex-M33 processors. TrustZone provides a hardware-enforced separation between secure and non-secure…
ARM Processor Identification Mechanisms in Multi-Core Architectures In multi-core ARM systems, identifying individual processors is a critical task for ensuring proper system initialization, task allocation, and runtime management. The ARM architecture provides several mechanisms for processor identification, each tailored to specific use cases and architectural variants. The primary registers involved in this process are the…
TCM Memory MPU Configuration and Execute-Never (XN) Permissions Conflict The Cortex-R5 processor, a member of ARM’s real-time processor family, is widely used in embedded systems for its deterministic performance and low-latency response. One of its key features is the Tightly Coupled Memory (TCM), which provides fast, predictable access to critical code and data. However, configuring…
ARM Cortex-A720 and DSU-120 Core Grouping for Virtualization and ASIL-B Compliance The ARM Cortex-A720, coupled with the DynamIQ Shared Unit (DSU-120), offers a highly configurable multi-core architecture that can be tailored for various use cases, including virtualization and safety-critical applications like ASIL-B compliance. A key question arises: can the cores be logically or physically partitioned…
ARM Cortex-A53 Cache Invalidation Blocking Issue During DC IVAC Operation The ARM Cortex-A53 processor, a widely used 64-bit ARMv8-A core, is known for its efficiency and performance in embedded systems. However, a specific issue has been observed when performing cache invalidation operations using the DC IVAC (Data Cache Invalidate by Virtual Address to PoC) instruction….
ARM Cortex-A53 Exception Level Transition Issues During BSP Development When developing a Board Support Package (BSP) for the NXP i.MX8M Mini, which utilizes the ARM Cortex-A53 processor, transitioning from Exception Level 3 (EL3) to Exception Level 1 (EL1) can be a complex task. The Cortex-A53 processor, being part of the ARMv8-A architecture, supports multiple exception…
ARM Cortex-R5 Link Register Offsets in Exception Modes The ARM Cortex-R5 processor, like other ARM cores, handles exceptions by saving the return address in the Link Register (LR) of the respective exception mode. However, the value stored in the LR can vary depending on the processor mode (ARM or Thumb) and the type of exception….
Cortex-R5 L1 Cache Write-Streaming Mode and Cache Miss Anomalies The ARM Cortex-R5 processor is widely used in real-time embedded systems due to its deterministic performance and robust feature set. One of the key features of the Cortex-R5 is its L1 cache subsystem, which includes separate instruction and data caches. However, there is some ambiguity regarding…