3.2.51. c9, User Enable Register

The purpose of the USER ENable (USEREN) Register is to enable User mode to have access to the Performance Monitor Registers.

Note

USEREN Register does not provide access to the registers that control interrupt generation.

The USEREN Register is:

Figure 3.45 shows the bit arrangement of the USEREN Register.

Figure 3.45. User Enable Register format


Table 3.100 shows how the bit values correspond with the USEREN Register functions.

Table 3.100. User Enable Register bit functions

BitsFieldFunction
[31:1]-Reserved. RAZ, SBZP
[0]ENUser mode enable

Table 3.101 shows the results of attempted access for each mode.

Table 3.101. Results of access to the User Enable Register

 

Secure privileged

Nonsecure privileged

Secure User

Nonsecure User

ENReadWriteReadWriteReadWriteReadWrite
0DataDataDataDataData

Undefined

exception

Data

Undefined

exception

1DataDataDataDataData

Undefined

exception

Data

Undefined

exception


To access the USEREN Register, read or write CP15 with:

MRC p15, 0, <Rd>, c9, c14, 0 ; Read USEREN Register
MCR p15, 0, <Rd>, c9, c14, 0 ; Write USEREN Register
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