System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-88
ID021414
Non-Confidential
To access the TCR_EL1:
MRS <Xt>, TCR_EL1 ; Read TCR_EL1 into Xt
MSR TCR_EL1, <Xt> ; Write Xt to TCR_EL1
[25:24]
IRGN1
Inner cacheability attribute for memory associated with translation table walks using TTBR1_EL1. The possible
values are:
0b00
Normal memory, Inner Non-cacheable.
0b01
Normal memory, Inner Write-Back Write-Allocate Cacheable.
0b10
Normal memory, Inner Write-Through Cacheable.
0b11
Normal memory, Inner Write-Back no Write-Allocate Cacheable.
[23]
EPD1
Translation table walk disable for translations using TTBR1_EL1. Controls whether a translation table walk is
performed on a TLB miss for an address that is translated using TTBR1_EL1. The possible values are:
0
Perform translation table walk using TTBR1_EL1.
1
A TLB miss on an address translated from TTBR1_EL1 generates a Translation fault. No
translation table walk is performed.
[22]
A1
Selects whether TTBR0_EL1 or TTBR1_EL1 defines the ASID. The possible values are:
0
TTBR0_EL1.ASID defines the ASID.
1
TTBR1_EL1.ASID defines the ASID.
[21:16]
T1SZ
Size offset of the memory region addressed by TTBR1_EL1. The region size is 2
(64-T1SZ)
bytes.
[15:14]
TG0
TTBR0_EL1 granule size. The possible values are:
0b00
4 KB.
0b10
64 KB.
[13:12]
SH0
Shareability attribute for memory associated with translation table walks using TTBR0_EL1. The possible
values are:
0b00
Non-shareable.
0b01
Reserved.
0b10
Outer shareable.
0b11
Inner shareable.
[11:10]
ORGN0
Outer cacheability attribute for memory associated with translation table walks using TTBR0_EL1. The possible
values are:
0b00
Normal memory, Outer Non-cacheable.
0b01
Normal memory, Outer Write-Back Write-Allocate Cacheable.
0b10
Normal memory, Outer Write-Through Cacheable.
0b11
Normal memory, Outer Write-Back no Write-Allocate Cacheable.
[9:8]
IRGN0
Inner cacheability attribute for memory associated with translation table walks using TTBR0_EL1. The possible
values are:
0b00
Normal memory, Inner Non-cacheable.
0b01
Normal memory, Inner Write-Back Write-Allocate Cacheable.
0b10
Normal memory, Inner Write-Through Cacheable.
0b11
Normal memory, Inner Write-Back no Write-Allocate Cacheable.
[7:6]
-
Reserved,
RES
0.
[5:0]
T0SZ
Size offset of the memory region addressed by TTBR0_EL1. The region size is 2
(64-T0SZ)
bytes.
Table 4-83 TCR_EL1 bit assignments (continued)
Bits
Name
Function