Architectures and Processors

FIQ Latency Measurement Challenges in ARM Cortex-A7 with TrustZone When working with ARM Cortex-A7 processors that have TrustZone security extensions enabled, measuring Fast Interrupt Request (FIQ) latency can be particularly challenging. The primary issue revolves around determining whether an FIQ occurred while the General Purpose Operating System (GPOS) was executing or while the Real-Time Operating…

ARMv8-M Memory Aliasing and Secure-Non-Secure Address Space Partitioning The ARMv8-M architecture introduces a robust security model that partitions memory into Secure and Non-Secure address spaces. This partitioning is critical for implementing TrustZone technology, which isolates sensitive code and data from less trusted software. In the context of the FVP_MPS2_AEMv8M model, this partitioning is achieved through…

ARMv8 Cache Partitioning and ThunderX Implementation Details Cache partitioning in ARMv8 architectures, particularly in the context of Cavium ThunderX processors, involves the division of shared cache resources among multiple cores to optimize performance for specific workloads. The ThunderX processor, designed for server and datacenter markets, supports up to 16 partitions in its shared L2 cache….

ARM Cortex-M and Cortex-R Programming Efficiency Challenges Efficient C programming on ARM Cortex-M and Cortex-R platforms requires a deep understanding of the underlying architecture, instruction sets, and optimization techniques. While the ARM architecture has evolved significantly over the years, the fundamental programming model for Cortex-M and Cortex-R processors remains consistent with earlier ARM architectures. However,…

ARM Cortex-A53 Spinlock Failure in Multi-Core Environment The issue at hand involves the failure of a spinlock implementation on an ARM Cortex-A53 multi-core system, specifically on a Xilinx ZCU102 board. The spinlock is designed to synchronize the execution of all Cortex-A53 cores, but only CPU 0 is able to acquire the lock. The other cores…

GIC-400 Virtual Interrupt Handling Flow and Priority Management The ARM Generic Interrupt Controller (GIC-400) is a critical component in managing interrupts for ARM Cortex-A57 processors, especially in virtualized environments. The GIC-400 supports virtualization extensions, enabling hypervisors to manage physical interrupts and inject virtual interrupts into Virtual Machines (VMs). Understanding the flow of interrupt handling, priority…

ARM Cortex-M0 Periodic Resets During Continuous Operation The issue at hand involves an ARM Cortex-M0 based microcontroller, specifically the Nuvoton M058LBN, experiencing periodic resets during continuous operation. The user reports that the microcontroller executes a while(1) loop with several functions that should run indefinitely. However, after printing a debug statement approximately ten times, the microcontroller…

Understanding LDREX/STREX Exclusivity Range and Its Implications on Mutex Handling The ARM Cortex-M series of processors, including the M3, M4, and M7, implement a mechanism for atomic read-modify-write operations through the use of the LDREX (Load Exclusive) and STREX (Store Exclusive) instructions. These instructions are fundamental for implementing synchronization primitives such as mutexes and semaphores…

ARM Cortex-A11 PL011 UART Virtual Address Mapping Challenges When porting the Linux kernel to a custom ARM1176JZFS-based SoC, one of the critical tasks is configuring the PL011 UART for low-level debugging. The PL011 UART, a PrimeCell peripheral, is physically mapped to a specific address in the SoC’s memory space. In this case, the UART is…

ARM Cortex-A vs. Cortex-M: Choosing the Right Processor for FPGA Design When transitioning from VLSI/ASIC logic design to FPGA design with embedded ARM processors, the first critical decision is selecting the appropriate ARM processor family. The two primary options are ARM Cortex-A and ARM Cortex-M processors, each catering to different application domains and design complexities….