MMU learning summary

When a few app At the same time
1 They are stored in sdram On
2 Their addresses are different

Link address ：
Program runtime , Address

Generally, compile a app when , You need to specify its link address separately

linux On app The starting address of the program is the same .
When cpu function app When reading instructions , Read from the same address above .

The reason for introducing virtual addresses
1 Give Way app With the same link address , Compile . （ Good portability ）

How to achieve 1g Of app, Can be in 64M Run on memory
1 First app When stored in emmc Upper
2 When running app when ,linux Devices generally move data to ddr On
3 app Of va0 Mapped to the actual address pa0
va1 To Mapped to the actual address pa 1 On .
function va2 when , No, the actual physical address is available , Then it's possible to put pa0 Data replacement , In the va2 The data of .