IBM 10 SP1 EAL4 Manuale Utente
Each entry of the page map level-4 table, the page-directory pointer table, the page-directory table, and the
page table is represented by the same data structure. This data structure includes fields that interact in
implementing access control during paging. These fields are the Read/Write (R/W) flag, the User/Supervisor
(U/S) flag, and the No Execute (NX) flag.
The following diagram shows the bit positions in a page map level-4 entry. The flags hold the same bit
positions for page directory pointer, page directory, page table, and page entries for both 4 KB page and 2 MB
page sizes.
page table is represented by the same data structure. This data structure includes fields that interact in
implementing access control during paging. These fields are the Read/Write (R/W) flag, the User/Supervisor
(U/S) flag, and the No Execute (NX) flag.
The following diagram shows the bit positions in a page map level-4 entry. The flags hold the same bit
positions for page directory pointer, page directory, page table, and page entries for both 4 KB page and 2 MB
page sizes.
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Figure 5-62: 2 MB page translation, virtual to physical address translation
Figure 5-63: Page map level four entry