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Chapter 1: Physical and Virtual Memory

This chapter gives an overview of the management of physical and virtual memory in the MIPS® R4x00®, R8000(TM), and R10000(TM) processors. Access to physical devices is included in this topic, because device registers and bus attachments are accessed using physical memory addresses.

When you are designing a kernel-level driver, this information helps you understand the operation of the kernel functions that you call on, and the constraints on their operations. This information is only of academic interest if you intend to control a device from a user-level process.( See Chapter 3, "Device Control Software," for the difference between these two types of drivers.)

The following main topics are covered in this chapter.

"Physical Address Space" describes the range and meaning of address numbers on the hardware bus.
"Addresses of Memory and Devices" summarizes the hardware architecture by which the CPU accesses memory.
"The 32-Bit Address Space" describes the divisions of the 32-bit virtual address space and their uses.
"The 64-Bit Address Space" describes the divisions of the 64-bit virtual address space and their uses.
"Device Driver Use of Memory" describes the techniques and rules for how kernel-level device drivers allocate and use memory.

Note: This chapter tells only enough about memory access and cache management to explain the rules of the driver/kernel interface. For complete details on the MIPS hardware processors, see the hardware manuals listed under "Additional Reading" on page xxxix.

Physical Address Space
Addresses of Memory and Devices
The 32-Bit Address Space
The 64-Bit Address Space
Device Driver Use of Memory

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