PAGE TABLE MANAGEMENT

摘要

Page table data for each page within a memory address space includes a write permission flag and a dirty-bit-modifier flag. The write permission flag is initialised to a value indicating that write access is not permitted. When a write access occurs, then the dirty-bit-modifier flag indicates whether or not the action of the write permission flag may be overridden. If the action of the write permission flag may be overridden, then the write access is permitted and the write permission flag is changed to indicate that write access is thereafter permitted. A page for which the write permission flag indicates that writes are permitted is a dirty page.

主权项

1. Apparatus for processing data comprising:
processing circuitry configured to manage page table data, said page table data specifying access management parameters associated with pages of memory within a memory address space; wherein for each page of memory, said access management parameters include: a write permission flag indicating whether or not write access is permitted to said page; and a dirty-bit-modifier flag indicating whether or not, if said write permission flag indicates write access is not permitted to said page, then action of said write permission flag is permitted to be overridden to permit a write access to said page and changing of said write permission flag to indicate write access is permitted to said page.