Load-Time Relocation ∞ Operating System Process 3 Process 6 Process 1

Load-Time Relocation Operating System Process 3 Process 6 Process 1 0 CS 111 Lecture Notes: Virtual Memory Slide 1

Base & Bounds Example 2000 1420 Process Virtual Address Space SP 140 RETURN 66 62 CALL 140 0 CS 111 Lecture Notes: Virtual Memory Slide 2

x86-64 Address Translation 64-bit Virtual Address 16 9 9 9 9 12 PML1 (Page Table) PML2 (Page Directory) PML4 PML3 (Page Directory Pointer Table) PML4 Base CS 111 Lecture Notes: Virtual Memory 40 12 Page Frame Offset 52-bit Physical Address Slide 3

Accessing User Memory write(fd, buffer, length) Pages User Address Space (Virtual) OS Address Space (Physical) CS 111 Lecture Notes: Virtual Memory Slide 4

OS and User in Same Address Space Operating System Stack Data Code 0 CS 111 Lecture Notes: Virtual Memory Slide 5