Author: System on Chips

Cortex-A76 MMU Translation Table Initialization and EL2 to EL1 Transition Issues The core issue revolves around the failure to initialize the Memory Management Unit (MMU) translation tables correctly on an ARM Cortex-A76 processor during the boot process of a bare metal kernel. The problem manifests when the kernel attempts to transition from Exception Level 2…

ARM Cortex-A7 TrustZone Architecture and Documentation Gaps The ARM Cortex-A7 processor, part of the ARMv7-A architecture, incorporates ARM TrustZone technology to provide a secure execution environment. TrustZone divides the system into Secure and Non-Secure worlds, allowing sensitive operations to be isolated from the rest of the system. However, implementing TrustZone on the Cortex-A7 can be…

ARM Cortex-A GPT Information Caching in TLB: Architectural Implications The ARM Cortex-A architecture introduces a mechanism where Granule Protection Table (GPT) information can be cached within the Translation Lookaside Buffer (TLB). This architectural feature is designed to optimize performance and reduce area overhead in systems implementing Stage 1, Stage 2, and Granule Protection Check (GPC)…

ARM Cortex-A53 Cache Behavior in Uncacheable Memory Regions The ARM Cortex-A53 processor is a widely used 64-bit CPU core that implements the ARMv8-A architecture. One of its key features is the L1 data cache, which is designed to improve performance by reducing memory access latency. However, the behavior of the L1 data cache when interacting…

ARM Cortex-M55 AXI 64-bit Peripheral Write Access Issue: Splitting into Two 32-bit Transactions The ARM Cortex-M55 processor, while capable of generating 64-bit AXI transactions for normal memory, splits 64-bit write accesses to peripheral (device) memory into two separate 32-bit AXI transactions. This behavior is observed when using the STRD (Store Register Dual) instruction to write…

ARM Cortex-M33 HardFault_Handler Implementation Challenges The ARM Cortex-M33 processor, part of the ARMv8-M architecture, introduces several advanced features such as TrustZone security, enhanced DSP capabilities, and improved fault handling mechanisms. However, implementing a robust HardFault_Handler for the Cortex-M33 can be challenging, especially when the goal is to capture and dump core register contents during a…

ARM Cortex-X3, A715, A510 Throughput Discrepancy in Int8 vs FP32 Multiplication The discrepancy in throughput between Int8 and FP32 multiplication on ARM Cortex-X3, A715, and A510 processors is a nuanced issue that requires a deep understanding of the underlying microarchitectures, instruction latencies, and resource availability. The expectation of a 4x increase in throughput when switching…

ARM Cortex-M7 Intrinsics and SIMD Instructions in MATLAB Simulations The core issue revolves around the challenge of emulating ARM Cortex-M7 intrinsics and SIMD (Single Instruction, Multiple Data) instructions on an x86 architecture to maintain bit-exactness in MATLAB simulations. The original algorithms were developed and qualified in MATLAB using "pure" C code, which was then encapsulated…

Understanding CDBGDCD_EL3 Register Encoding and L1 Data Cache Extraction The ARM Cortex-A55 processor provides a mechanism for direct access to internal memory, including the L1 Data (L1D) cache, through the use of debug registers. Specifically, the CDBGDCD_EL3 register is used to select a particular cache line by encoding the index, set, and way information. Once…

ARM Cortex-R Cache Architecture and Default Configuration The ARM Cortex-R series processors, such as the one used in the TI-AWR294x, are designed for real-time applications where deterministic performance is critical. These processors typically feature a hierarchical cache architecture, including Level 1 (L1) instruction and data caches, and sometimes Level 2 (L2) unified caches. The L1…