ARM Cortex-M33 Secure to Non-Secure Transition Failure During Reset Handler Execution The ARM Cortex-M33 processor, with its TrustZone security extension, allows for the partitioning of code and data into secure and non-secure worlds. This partitioning is crucial for applications requiring robust security, such as IoT devices, where sensitive operations must be isolated from less trusted…
SAU Region Configuration Mismatch and Hard Fault During Disabling The Secure Attribution Unit (SAU) is a critical component in ARM Cortex-M processors with TrustZone support, enabling the partitioning of memory into secure and non-secure regions. The SAU configuration process involves setting up the number of regions, their base addresses, limits, and security attributes. However, improper…
ETMCCER Register Indicates Return Stack Buffer (RSB) Implementation Status The Zynq-7000 SoC, which integrates a dual-core ARM Cortex-A9 processor, has been a popular choice for embedded systems due to its balance of performance and power efficiency. One of the key features of modern processors, including the Cortex-A9, is the implementation of program flow speculation techniques…
ARM Cortex-M4 LOCKUP State and BusFault Errors on ATSAME54P20A The issue at hand involves an ATSAME54P20A microcontroller based on the ARM Cortex-M4 architecture, which has entered a LOCKUP state, preventing further code downloads and causing BusFault and HardFault handler errors. The LOCKUP state is a severe fault condition in ARM Cortex-M processors, where the processor…
ARM Cortex-A72 Atomic Write Failure with LDAXR/STLXR Instructions The issue at hand involves an infinite loop occurring during the execution of atomic write operations using the LDAXR (Load-Acquire Exclusive Register) and STLXR (Store-Release Exclusive Register) instructions on an ARM Cortex-A72 processor. The code in question attempts to perform an atomic modification of a memory location…
ARM Cortex-M Privilege Mode Challenges in Driver Implementation Running driver code in privileged mode on ARM Cortex-M processors is a common requirement for ensuring secure and reliable access to hardware peripherals. However, the transition between user mode and privileged mode introduces complexities, particularly when developers aim to abstract this process for ease of use. The…
Cortex-M MPU Privileged Code Access Violation Behavior When working with the Cortex-M Memory Protection Unit (MPU), one of the critical scenarios to understand is how the processor handles user-mode attempts to access privileged code regions. In this case, the privileged code is stored in a memory region configured as privileged-read-only, user-denied, and executable. When a…
ARMv8-A Architecture and SVE Instruction Set Compatibility in Qualcomm Centriq 2400 The Qualcomm Centriq 2400 is a server-grade processor based on the ARMv8-A architecture, which is widely used in high-performance computing and embedded systems. The Scalable Vector Extension (SVE) is an optional feature within the ARMv8-A architecture, designed to enhance vector processing capabilities for workloads…
Cortex-A53 MIPS Calculation and Its Limitations The Cortex-A53 is a highly efficient ARMv8-A processor core designed for low-power applications, often found in mobile devices and embedded systems. One of the key metrics used to evaluate processor performance is MIPS (Millions of Instructions Per Second), which provides a theoretical upper bound on the number of instructions…
ARMv8 PMU Cycle Counter Instability During Secure-EL1 Code Execution The Performance Monitoring Unit (PMU) in ARMv8 architectures is a critical tool for measuring the performance of code execution, particularly in low-level environments such as Secure-EL1. However, when attempting to measure the cycle count of a simple loop in Secure-EL1 on an ARMv8 big.LITTLE system, unstable…