online mmu

ARM MMU page table frame First on the arm MMU of the page table structure of the general block diagram (the following discussion is gradually expanded by the diagram): The above is arm's page diagram of the typical structure: that is, the two-level page table structure: where the First Level page table (L1) is made up of 12bit (Bits[31:20]) of the virtual address, the first Level page table has 4,096 item,

Analysis of S3C2440 storage controller and MMU K-style Reprinted please indicate from Hengyang Normal College 08 electric 2 k-style http://blog.csdn.net/ayangke,QQ:843308498 mailbox: yangkeemail@qq.com 1. S3C2440 storage controller If you have written an arm bare metal program of S3C2440, you should know that the starting address of the SDRAM is usually 0x30000000, but have you ever wondered why? I will give you a brief introduction below. According t

Configuration and use of 3.MMUThe basic knowledge of the previous use of the physical address to light the LED lights, now, learning the relevant knowledge of the MMU, the following is the use of MMU knowledge, with virtual address to light LED lights. And the MMU is closed, so the MMU will have to open the

(1), MMU introductionA, Rights managementPrograms in different address spaces cannot access each other, or an error occurs.B, Address mappingThe teacher in the video on the MMU explanation is not a lot, ask also just understand the concept of the MMU, can be reference books or the following article about the MMUHttp://www.cnblogs.com/bigbear1385/p/5325344.html1,

The MMU insinuate analysis of ARM v7-a series CPUSummary : The ARM v7-a series CPUs include many extensions, such as multicore processor extensions, large physical address extensions, Trustzone extensions, and virtualization extensions. If large physical addresses are supported, multi-core processors must be supported, and if virtualization is supported, large physical addresses, multicore processors, and TrustZone must be supported. After adding thes

Close the MMU and cache1.Cache is a small, but very fast-access memory that holds a copy of the data in the most recently used memory. By function divided into icache (instruction cache) and Dcache (data cache)2. The virtual address is the address used in the program, and the physical address is the actual address used in the physical storage unit. Virtual addresses allow the process to use a larger amount of space. The role of the

First, we need to distinguish between three addresses on the ARM CPU: virtual address, transformed virtual address (mva,modified va,virtual), Physical address (pa,physical addresses) After starting the MMU, the CPU core sends out the virtual address Va,va is converted to MVA for the MMU use, where MVA is converted to PA, and finally the actual device is read and written by Pa.The role of the

Author: wogoyixikexie @ gliet -------------------------------------------- Next, let's take a look at this figure and look at it with instructions. However, I always think this figure is very different from the settings described in the program. ------------------------------------------------ Here we will add the role of MMU and the consequences of not using MMU. -----------------------------------------

Storage (virtualMemory ).Virtual MemoryBasic IdeasYesThe total size of programs, data, and stacks can exceed the size of physical storage. The operating system keeps the currently used parts in the memory, and saves other unused parts on the disk.. For example, for a 16 MB program and a machine with a memory of only 4 MB, the operating system can choose which 4 MB of content is stored in the memory at each time, swap program segments between memory and disk as needed, so that the 16 M program c

1. Does the kernel have a virtual address before opening the MMU? Where's the virtual address without the MMU?A: Yes, due to the loading of the address and the execution of the different address caused by not opening the MMU before there will be a virtual address problem.2. What is the difference between the on-load address and the execution address. Why is there

Category: Embeddedhttp://blog.chinaunix.net/uid-26435987-id-3082166.html (EXT)/************************************************Name:mmu. CDESC:revision:2002.2.28 ver 0.0************************************************/#include "def.h"#include "Option.h"#include "2440addr.h"#include "2440lib.h"#include "2440slib.h"#include "Mmu.h"//Segment (section) is a storage block of size 1MB1) Only the sections table is used. Only segment storage blocks are used2) The Cachable/non-cachable area can is change

This article will introduce the process of the MMU section conversion in detail, and attach a more detailed article about the MMU at the end of the paper. Specifically what is the MMU, what time period is the conversion is not in this article, directly poke at the end of the link.First, the conditions for the segment conversion. We want to have a virtual address,

), temporarily for a while, and then return when you're done. This allows others to use the address space to access other physical memory, allowing access to all physical memory using a limited address space.For the mapping of s3c2440 's user-space address, a page table is used, and it is important to note that the page table is a dynamic concept, which means that the page table is likely to be modified as the program runs. The MMU provides two basic

Linux Space Division MMU, linux DivisionLinux Kernel Address Space DivisionGenerally, 32-bit Linux kernel address space is divided into 0 ~ 3G is the user space, 3 ~ 4G is the kernel space. Note that the 32-bit kernel address space is divided, and the 64-bit kernel address space is divided differently. In a 32-bit Linux system, the entire 4 GB virtual storage space is from 0x00000000 to 0xFFFFFFFF.Kernel space: the kernel space indicates the code or

Arm mmu source code analysis, armmmu source code The mmu module is provided in the arm7 and later versions. This module can remap addresses in units. This is a module that extends the address space and increases code flexibility. The following is a source code Void rt_hw_mmu_init (struct mem_desc * mdesc, rt_uint32_t size){ unsigned int i; unsigned int reg; unsigned int low,high,ram; low = (0xa100

Transferred from: http://blog.chinaunix.net/uid-23193900-id-3187782.html1.MMU Introduction The MMU Management Unit, Memory Management Unit, primary responsibility: mapping virtual addresses to physical addresses, providing hardware-mechanism memory access checks. 2. Basic concept virtual address (Vsan Address,va), modified virtual address (Modified VA), Physical address (phisical addresses)VA is the address

Today, debugging has encountered a particularly strange problem. It is difficult to use serial port sending,CodeIt is like this: If (flag in memory mapped REG ){ Write Char to transmit Reg } Something sent from the serial port is always wrong. JTAG debugging found that the single step is correct, but an error occurs as long as it runs at full speed. After thinking about it, it seems that it is wrong to read the flag back, but how is it possible ?? After careful consideration, I fou

/*************************************** *********Name: MMU. cDesc:Revision: 1.0**************************************** ********/ # Include "def. H"# Include "option. H"# Include "2440addr. H"# Include "2440lib. H"# Include "2440slib. H"# Include "MMU. H" // 1) only the section table is used.// 2) The cachable/non-cachable area can be changed by mmt_default value.// The section size is 1 MB. Extern char _

The role of the MMU in Linux:1. Conversion of virtual reality2. Control memory Access allowed--The physical address is not continuous, it is converted into a continuous virtual address, and the programming is more convenient.--can map memory to 0 address to debug Interrupt service Program--some of the system's address segments are not allowed to be accessed, otherwise it will have unpredictable consequences, in order to avoid such errors, you can use

/************************************************************************************************************** ****Reference:Description: Re-encounter these words when learning a bare-metal interrupt, this time to figure it out. *************************************************************************************************************** ***/ This three words for a long time did not understand, today a little bit clear to write down. Physical address is the main line, others are foil. The CP