ARM Virtual Address Validation with AT Instructions and MMU Considerations The process of validating whether a virtual address is mapped in an ARM architecture is a critical task, especially in systems where memory management is dynamic or where safety and reliability are paramount. The ARM architecture provides the Address Translation (AT) instruction, which is specifically…
ARM Cortex-A35 Cache Partitioning Challenges for Process Isolation The ARM Cortex-A35 processor, based on the ARMv8-A architecture, is widely used in embedded systems for its power efficiency and performance. However, one of the challenges faced by developers is ensuring process isolation in the shared L2 cache to prevent interference between processes. This is particularly critical…
ARM Cortex-M0 Hard Fault Recovery via Stacked PC Modification The ARM Cortex-M0 is a widely used processor in embedded systems due to its simplicity and efficiency. However, handling exceptions such as Hard Faults can be challenging, especially when the goal is to recover gracefully from such faults. A Hard Fault is typically triggered by severe…
Flash Memory Access Failures and Data Abort Exception Subtypes in ARMv8 The ARMv8 architecture introduces a sophisticated memory management system that relies on translation tables to map virtual addresses to physical addresses. When a memory access fails, the processor raises a Data Abort exception, which can be further categorized into subtypes based on the cause…
ARM Cortex-M33 Non-Secure Mode Execution Behavior and NOP-Like Symptoms When attempting to execute a test program on the ARM Cortex-M33 processor using the DS-5 MPS2 Fixed Virtual Platform (FVP) in non-secure mode, the program fails to execute instructions correctly. Instead, the processor appears to treat every instruction as a NOP (No Operation), with only the…
FMC Interface Initialization and SRAM Access Issues on STM32H743 The STM32H743 microcontroller features a Flexible Memory Controller (FMC) that enables interfacing with external memory devices such as SRAM, SDRAM, and NOR Flash. However, users often encounter issues when attempting to read from external SRAM using the FMC interface. A common symptom is that the FMC…
EL2 to EL1 Transition with Instruction Prefetch Abort on ERET The core issue revolves around the failure to transition from Exception Level 2 (EL2) to Exception Level 1 (EL1) in an ARMv8-A architecture. The transition is attempted by setting up the necessary system registers, including sctlr_el1, spsr_el2, elr_el2, and hcr_el2, followed by an eret instruction….
ARM Cortex-M0 Vector Table Remapping Limitations The ARM Cortex-M0 processor, being one of the most widely used 32-bit microcontrollers in embedded systems, has a fixed memory map that includes the vector table located at the beginning of the memory space. The vector table is a critical component of the Cortex-M0 architecture, as it contains the…
ARM Cortex-A Series Secondary Core Initialization and Wake-Up Mechanisms In ARM-based multiprocessor systems, the initialization and wake-up of secondary cores from the primary core is a critical process that involves setting the Program Counter (PC) and ensuring proper synchronization. The ARM architecture, particularly in the Cortex-A series, provides several mechanisms to achieve this, but the…
Accessing PSTATE.nRW to Determine CPU Run State The Cortex-A57 processor, part of the ARMv8-A architecture, supports both AArch64 and AArch32 execution states. The execution state determines whether the processor is operating in 64-bit or 32-bit mode. The PSTATE.nRW bit is a critical register that indicates the current execution state of the CPU. When PSTATE.nRW is…