ARM Cortex-M55 TrustZone Secure-to-Non-Secure Transition Overhead The ARM Cortex-M55 processor, with its TrustZone security extension, provides a robust mechanism for isolating secure and non-secure worlds. A common use case involves calling secure services from the non-secure world, which is facilitated by the cmse_ns_entry function and the BXNS instruction. However, when the same secure service is…
ARM Cortex-M33 FPU Configuration Errors and CMSIS DSP Library Function Redefinition When working with ARM Cortex-M33 microcontrollers, such as the Silicon Labs EFR32MG21, developers often leverage the CMSIS DSP library to implement digital signal processing (DSP) functionalities. However, integrating the CMSIS DSP library with the ARM Cortex-M33 core can lead to two common issues: function…
ARMv7 AArch32 EL3 Runtime Software Integration Challenges with ATF and OPTEED The integration of ARM Trusted Firmware (ATF) with OP-TEE (Open Portable Trusted Execution Environment) for ARMv7 AArch32 EL3 runtime software presents a unique set of challenges. Specifically, the issue revolves around the inability to build ATF with both PSCI (Power State Coordination Interface) services…
ARMv7M 24-Bit Data Storage and Mean Calculation Challenges The ARMv7M architecture, commonly found in microcontrollers like the Cortex-M series, is designed for efficient and deterministic real-time processing. However, handling 24-bit data in SRAM presents unique challenges, particularly when dealing with unaligned memory access and arithmetic operations. The task involves calculating the mean value of 16…
Secure World Access to Non-Secure Memory on ARMv8-M TrustZone The ARMv8-M architecture introduces TrustZone technology, which provides hardware-enforced isolation between Secure and Non-Secure worlds. This isolation is critical for security-sensitive applications, ensuring that Secure world code and data are protected from unauthorized access by Non-Secure world code. However, this isolation also introduces complexities when Secure…
ARM Cortex-M Memory Alignment Challenges with 24-Bit Data Structures When working with ARM Cortex-M processors, such as the STM32 series, one of the most common challenges developers face is handling data structures that do not align neatly with the processor’s native word sizes. The Cortex-M series, including the M0, M3, and M4, is designed to…
ARM Cortex-M CMSIS-DSP Fixed-Point Arithmetic and Saturation Behavior The ARM Cortex-M series microcontrollers are widely used in embedded systems due to their efficiency and performance. One of the key libraries provided by ARM for these processors is the CMSIS-DSP library, which offers a suite of digital signal processing (DSP) functions. Among these functions are those…
ARM-Based Multi-CPU Motherboard Architectures for High Memory and NUMA-Aware Systems The integration of multiple ARM CPUs on a single motherboard is a complex but increasingly viable solution for high-performance, low-power numerical applications. Unlike traditional x86 architectures, such as Intel Xeon, ARM-based systems require careful consideration of memory architecture, power efficiency, and NUMA (Non-Uniform Memory Access)…
SysTick Timer Behavior in Debug Mode and Its Implications The SysTick timer is a critical component in ARM Cortex-M and Cortex-A processors, providing a simple and efficient way to generate periodic interrupts for real-time operating systems (RTOS) or other time-sensitive applications. In ARMv7-A and ARMv8-A architectures, the SysTick timer is often used for task scheduling,…
Secure SVC Handler Failing to Return to Non-Secure Thread Mode The ARM Cortex-M33 processor, with its TrustZone security extension, allows for the separation of Secure and Non-Secure states, enabling secure execution environments. A critical aspect of this architecture is the ability to transition between Secure and Non-Secure states, particularly when returning from a Secure SVC…