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Memory Management 7-15
The ZSEL values 0−15 select ZPR fields Z0−Z15, respectively.
The fields are defined within the ZPR as follows:
While it is common for TLB_entry[EX, WR] to be identical for all member pages in a group, this is not
required. The ZPR field alters the protection defined by TLB_entry[EX] and TLB_entry[WR], on a
page-by-page basis, as shown in the ZPR illustration. An application program (presumed to be
running in the problem state) can have execute and write permissions as defined by TLB_entry[EX]
and TLB_entry[WR] for the individual pages, or no access (denies loads, as well as stores and
execution), or complete access.
Figure 7-5. Zone Protection Register (ZPR)
0:1 Z0 TLB page access control for all pages in this zone.
In the problem state (MSR[PR] = 1):
00 No access
01 Access controlled by applicable
TLB_entry[EX, WR]
10 Access controlled by applicable
TLB_entry[EX, WR]
11 Accessed as if execute and write
permissions (TLB_entry[EX, WR]) are
granted
In the supervisor state (MSR[PR] = 0):
00 Access controlled by applicable
TLB_entry[EX, WR]
01 Access controlled by applicable
TLB_entry[EX, WR]
10 Accessed as if execute and write
permissions (TLB_entry[EX, WR]) are
granted
11 Accessed as if execute and write
permissions (TLB_entry[EX, WR]) are
granted
2:3 Z1 See the description of Z0.
4:5 Z2 See the description of Z0.
6:7 Z3 See the description of Z0.
8:9 Z4 See the description of Z0.
10:11 Z5 See the description of Z0.
12:13 Z6 See the description of Z0.
14:15 Z7 See the description of Z0.
16:17 Z8 See the description of Z0.
18:19 Z9 See the description of Z0.
20:21 Z10 See the description of Z0.
22:23 Z11 See the description of Z0.
24:25 Z12 See the description of Z0.
26:27 Z13 See the description of Z0.
28:29 Z14 See the description of Z0.
30:31 Z15 See the description of Z0.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Z0
Z1
Z2
Z3
Z6Z4
Z5
Z8 Z10 Z12 Z14
Z7 Z9 Z11 Z13 Z15