xnu kernel

One pageThe kernel takes the physical page as the basic unit of memory management; the Memory Management Unit (MMU) transforms the virtual address into a physicalAddresses, which are typically processed in pages. The MMU manages the tables in the system in the page size unit.32-bit system: Page size 4KB64-bit system: Page size 8KBThe kernel represents each physical page in the system with the corresponding

Introduction to Linux Kernel Now let's look at the architecture of the Gnu/linux operating system from a relatively high altitude. You can consider the operating system from two levels, as shown in Figure 2. Figure 2. Basic architecture of Gnu/linux operating system The top is the user (or application) space. This is where the user application executes. Under User space is the kernel space, where the L

Because I do not have a real machine environment, so I need to simulate in the simulator, so I want to download the source code version of the support simulator, and the goldfish version is specifically provided for the simulator environment. The Goldfish project contains the kernel sources for the emulated platforms. One, first, to git clone https://android.googlesource.com/kernel/goldfish.git downloads

The module subsystem (ModuleSubsystem), the unified device model (uniieddevicemodel), and the PnP support module subsystem have undergone major changes. 2. stability is improved 1. module subsystemModule Subsystem, Unified Device Model, and PnP support Module Subsystem have undergone major changes. 2. improved stability To completely prevent the kernel from loading or exporting the kernel module in use, or

I have never thought of any good way to pass parameters to the kernel through registers until now the implementation of uboot reading. In uboot, the most common method to boot the kernel is the bootm command. The bootm command can boot the "uboot format" kernel. Let's take a moment to know what the kernel is in uboot

Transferred from: http://www.linuxidc.com/Linux/2013-12/93637.htmWhen migrating Linux to a new architecture, a number of issues that developers encounter are related to incorrect data types. Sticking with strict data types and compiling with-wall-wstrict-prototypes can avoid most bugs. -wall Show all warnings -wstrict-prototypes Rigorous detection of prototypes, if not consistent, warnings appear The data types used by the

Kernel synchronizationSynchronous introductionThe concept of synchronizationCritical section: Also known as a critical segment, is the code snippet that accesses and operates shared data.Competition conditions: 2 or more than 2 threads are executed simultaneously in the critical section, which constitutes a competitive condition.The so-called synchronization, in fact, prevent the formation of competitive conditions in the critical area.If the critical

This article provides a brief introduction to kernel-related basic concepts.Main content: Single Core and micro core Kernel version number 1. Single Core and micro-core principle Advantage disadvantage single core 1. Simple. 2. Efficient: All cores are in a large address space, so calls and call functions are s

executing at any time Soft interrupts and Tasklet: The kernel can wake up or dispatch soft interrupts and tasklet at any time, interrupting code that is currently executing Kernel preemption: The Linux kernel is preemptive, so the kernel's task may be preempted by another task Sleep and user space synchronization: Processes that execute in the

Basic synchronization mechanism of the kernel:Key features of the preemption kernel: a process running in the kernel state that may be replaced by another process during kernel functions execution.Kernel preemption: Linux 2.6 Allows users to configure the kernel to be very enabled when compilingProcess critical section

/proc/kallsyms records the names and addresses of all the exported symbols in the kernel We need to compile 2 kernel modules, and then one of the kernel modules to call functions in another kernel module The HELLO.C code is as follows #include From this we can see that we have called 2 functions Add_integar and Sub