Series : Bridging Software Craftsmanship and Bare-Metal Firmware (Trusted Firmware – A)

Part 1: The Foundations of Firmware Construction Introduction: What is Software Construction? In this inaugural part of our series on Trusted Firmware-A (TF-A), we begin by examining Software Construction, the central, hands-on activity of creating software. While "coding" is often used as a shorthand, true construction involves substantial professional judgment. It is not merely the mechanical…

Firmware Security and the Importance of Constant-Time Programming (Part – 2)

Understanding Constant-Time String Comparison: A Deep Dive Constant-time comparison of strings is an important security measure that helps maintain the consistent execution time for a string comparison operation, no matter what strings are being input. This supposedly minor detail goes a long way in avoiding timing attacks, which are a side-channel attack group that takes…

Firmware Security and the Importance of Constant-Time Programming (Part – 1)

Introduction Low-level software that communicates with hardware directly in the form of firmware is a critical element of modern computing platforms. Firmware initializes hardware, handles system resources, and delivers a secure environment for operating systems and applications. Firmware is the attack point of first contact, however, as it sits on a privileged plane within system…

[Micro Learning] Interrupt Stack in Zephyr RISC V

Introduction The _interrupt_stack is a critical component in managing interrupt handling within the Zephyr RTOS for the RISCV32 architecture. Its primary purpose is to provide a dedicated and isolated stack for Interrupt Service Routines (ISRs), ensuring that they operate independently of thread-specific stacks. This separation is vital for preventing data corruption, improving real-time performance, and…