实现三个功能

1：打印所有当前进程占用的内存的起始地址+结束地址

2：输入虚拟地址，打印物理地址

3：改变一个变量的值（通过虚拟地址及物理地址）-Write a module that is called mtest

•　When module loaded, module will create a proc fs entry /proc/mtest

•　/proc/mtest will accept 3 kind of input

􀂃　“listvma” will print all vma of current process in the format of

start-addr end-addr permission

e.g

0x10000 0x20000 rwx

0x30000 0x40000 r—

􀂃　“findpage addr” will find va->pa translation of address in current process’s

mm context and print it. If there is not va->pa translation, prink “tranlsation

not found”

􀂃　“writeval addr val” will change an unsigned long size content in current

process’s virtual address into val. Note module should write to identity

mapping address of addr and verify it from userspace address addr.

•　All the print can be done with printk and check result with dmesg.