Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Each function has its own stack frame between %fp and %sp. Let Caller calls Callee. Then Caller's %sp becomes callee's %fp, and callee's %sp set to be a new value (a smaller one because stack grows from large address to small address). You can think that Callee's stack frame is on top of Caller's stack frame.
In Caller: put arguments in %o0 to %o5 registers or if number of arguments more than 6, prepare values in call linkage of the current stack frame. Then "call" address_of_callee; %o7 stored the returned address. (This %o7 will becomes %i7 in callee after the callee executes save instruction.)
In Callee: it executes "save" instruction:
So at this point in callee, %i6 (%fp was caller's %o6) is set, and %o6 (%sp is set to be a new value). Question: where is the old %fp? It is stored somewhere in the top portion of the previous stack frame (see step 0.) The return address of Callee is stored in %i7. Is it possible to write a program to overflow this %i7? What return address that you really can overflow? Question: how to access that return address.
The "restore" instruction is the inverse function of save. Then the "ret" instruction should branch to %i7+8. The normal address should be %i7+4 as the next instruction address after call. The extra 4 is because sparc has a "branch delay" instruction that is executed BEFORE the call is made even it is put just after CALL. Is it strange. Not really. This is because modern CPU is a pipeline machine. It loads instruction every clock cycle, and branch (or jump or call) somewhat cannot be really done until the later stage the pipeline. And then it is already too late because the one JUST after this branch has already been executed. If you want to know more, you should take a look at computer architecture textbook which I think every graduate should know.
You should be very clear what return address in server.c is overflowed? Is it the return address of main() or the return address of copy()?
Explain the class invariant. - It's a condition that ensures correct working of a class and defines all the valid states for an object. - When an object is created class inv
What is pointer?
write a program to calculate the cuboid
Working Ordered linked list: • Eachinteger in the queue is stored inside of a QueueItem. The QueueItem contains the integer, and a pointer to the next item in the queue. Fo
Define How Passing Arrays to a Function? A complete array can be passed to a function as an argument. The manner in which the array is passed be different from that of an ordin
Structure of C++ Program: Chronological order of C++ program. 1. Class declaration 2. Main function program 3. Member functions definitions 4. Include heade
c program to count the number of occurances of the string in padovan''s string
Define the Data File in C Programming? Many applications needs that information can written to or read from an auxiliary memory device. Such information is stock up on the memo
Hiding overloaded functions We cannot overload a base class function by redefining it in a derived class with a dissimilar argument list. Consider examples to see if similar fu
Constructors By definition, a constructor function of some class is a member function that automatically gets implemented whenever an instance of the class to which the constru
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd