How the MMU (memory management unit) in the processor protects memory segments

Having gone through one embedded processor architecture, I saw the MMU and mostly mentions memory protection features.

May i know

How does the MMU implement this protection and why is it needed? What does memory protection mean?

What are other ways to use MMU besides security (for example, virtual addressing)?

Pay attention to the embedded system without an OS.

__ Kanu

+5
source share
3 answers

, ( ), - , (, amba, axi, wishbone), . , , , . , , ( ) , , , , . , .., , , -, Sram ..

, , , , , 0 N-1 N . , , , 0 0x100 0x8000, , - , . : . , , ( ), , . 0x1100, - 0x8100, , 0x0100. . MMU ​​ , , mmu /. , , mmu 0x0100 , 0x0100, , , , 0x0100 0x1100. , 0x0100, , , , .

- , .. , mmu, , , , mmu. , , mmu, , mmu. , , , , , , , . ram, , , , . , , , , , mmu. ARM, , , , , , , - . , , , mmu , ( ). , . , , mmu , ram , 0x1000 virtual 0x1000 , . , . , ( , mmu, , ).

, , , , , .. . . , ​​ .. . , , mmu , , . , , mmu, / (), ​​/ . " " , , , Intel, , , , A bob, B ted, C alice, D . , , , , / .

mmus malloc. mmus , . malloc, " 4meg , 1kbyte alloc ?". , , 4kbyte . Malloc, , , mmu, , , mmu. 4096 * 10 , , , 10 mmu, 10 ( ) 10 .

, "" , , . mmu , , . , , , . , mmu / . , , / mmu, , , , mmu, : , , , .. , -os, mmu. , , , ( ), , () .

+14

MMU ( ) , . , ...

, , . , , , . , .

, - , , . , , , , .

, . , .

MMU - , , , . , . , ​​ , , A, B, A B .

, , 4 . . MMU, - . . - (, , ), .

, , . , , .

, . , DLL Windows .so Unix: , , .

MMU , , ​​ . , .

+7

, , , , . , , ; (, , , ).

There are many, many other functions provided by the MMU (virtual memory, dynamic movement, etc.).

What and why. To answer “how,” you must do more reading .

+3
source

All Articles