This article explains how system calls differ from regular function calls, demonstrates a simple x86_64 hello‑world program that uses the syscall instruction, and details how Linux maps syscall numbers to kernel functions via the MSR LSTAR register.
This article explains how the x86‑64 paging mechanism maps virtual addresses to physical memory, detailing the required protection‑mode conditions, page‑table structures, control‑register settings, various paging modes (32‑bit, PAE, 4‑level, 5‑level), and provides concrete kernel code examples and address‑translation demonstrations.
This article explains the role, operation, and different modes of x86‑64 memory paging, describes how page directories and tables are set up in assembly, shows the relevant control‑register bits, and provides practical code examples for enabling and managing paging in a protected‑mode kernel.
This article provides a comprehensive overview of how Linux kernel system calls are implemented on the x86-64 architecture, covering the conceptual differences from regular function calls, register conventions, initialization processes, syscall tables, and practical assembly examples such as write and getpid.
Memory paging, a core memory‑management technique used in modern operating systems and x86‑64 processors, divides physical memory into fixed‑size pages, enabling virtual memory, isolation, sharing, lazy loading, and protection, while the article explains page tables, hierarchical paging modes, and provides assembly code for enabling paging.
The article analyzes a crash that occurs on Windows 10 when a 64‑bit program mixes RSP and ESP instructions, explains how writing to the 32‑bit ESP register zero‑extends the upper 32 bits of RSP, and shows how this stack‑pointer mismatch leads to an access‑violation error that does not appear on Windows 7.
This article thoroughly explains low‑level function call implementation, covering Intel and AT&T assembly syntax, the evolution of CPU registers from 16‑bit to 64‑bit x86, caller‑ and callee‑saved conventions, stack‑based to register‑based parameter passing, stack frame setup, and assembly representations of control structures.
