Author: System on Chips

ARM64 NEON SIMD as a Replacement for SSE4.2 in CNDP The Cloud Native Data Plane (CNDP) project is a high-performance, user-space library designed to accelerate packet processing for cloud-native applications. Originally developed for x86_64 architectures, CNDP relies heavily on Intel’s SSE4.2 instruction set for SIMD (Single Instruction, Multiple Data) operations, which are critical for achieving…

ARM Cortex-M23 TrustZone Initialization and SAU Configuration Problems The ARM Cortex-M23 processor, designed for embedded systems requiring robust security, incorporates ARM TrustZone technology to create a secure and non-secure (NS) execution environment. TrustZone enables the partitioning of memory and peripherals into secure and non-secure regions, managed by the Security Attribution Unit (SAU) and System Control…

ARMv7-M HardFault Triggered by Instruction Access Violation During Signal Handler Execution The core issue revolves around a HardFault occurring when returning from a memory fault (MemFault) handler and attempting to execute a signal handler in an ARMv7-M architecture. The fault manifests as an instruction access violation (CFAULT = 0x1) with a "FORCED" HardFault (HFAULT =…

Cortex-M33 Unprivileged Mode Stack Corruption and Register Zeroing in Secure State When running an unprivileged application in the secure state on the Cortex-M33 processor (specifically on the STM32U5 microcontroller with TrustZone enabled), a critical issue arises. The system exhibits unexpected behavior during context switching and exception handling. Specifically, when the Link Register (LR) is set…

DSU CHI Interface Coherency and Link Deactivation Overview The DynamIQ Shared Unit (DSU) is a critical component in ARM-based systems, particularly when connected to an interconnect via the Coherent Hub Interface (CHI). The DSU acts as a master interface, managing coherency and communication between multiple cores, caches, and the interconnect. A key aspect of the…

ARM Cortex Cache Line Faults and Their Impact on System Reliability Cache memory in ARM processors is a critical component that significantly impacts system performance and reliability. However, like any other hardware component, cache memory is susceptible to manufacturing defects, aging, or environmental factors that can introduce faulty bits. These faulty bits, often referred to…

Cache Contents Mismatch with Main TLB After Enabling MMU and Configuring Memory Attributes The core issue revolves around a mismatch between the contents of the L1 data cache and the main TLB after enabling the MMU and configuring memory attributes for a specific SRAM region (0x30000000-0x30200000). The user observed that the L1 data cache only…

ARM Cortex-M3 Event Register Behavior During WFE and SEV Operations The ARM Cortex-M3 processor includes a 1-bit Event Register (ER) that plays a critical role in managing low-power modes and synchronization between threads or interrupts. The Event Register is closely tied to the Wait For Event (WFE) and Send Event (SEV) instructions, which are used…

ARM Cortex-A72 Branch Prediction Mechanism and Disabling Implications The ARM Cortex-A72 is a high-performance out-of-order execution core designed for advanced applications requiring both power efficiency and computational throughput. One of its key features is the branch predictor, which speculatively executes instructions based on predicted branch outcomes to minimize pipeline stalls. Disabling the branch predictor on…

ARM Cortex-A65 MPIDR Core ID Issue: PE1 Not Responding The ARM Cortex-A65 is a high-performance processor designed for multi-core implementations, often used in scenarios requiring high throughput and scalability. One of the key features of multi-core ARM processors is the ability to identify each Processing Element (PE) using the Multiprocessor Affinity Register (MPIDR). The MPIDR…