4.3.61 Reset Management Register, EL3

The RMR_EL3 characteristics are:
Controls the Execution state that the processor boots into and allows request of a Warm reset.
Usage constraints
The accessibility to the RMR_EL3 by Exception level is:
EL0 EL1(NS) EL1(S) EL2 EL3(SCR.NS = 1) EL3(SCR.NS = 0)
- - - - RW RW
The RMR_EL3 is
  • Common to the Secure and Non-secure states.
  • Architecturally mapped to the AArch32 RMR register.
Write access to RMR_EL3 is disabled when the CP15SDISABLE signal is HIGH and EL3 is using AArch32.
See the register summary in Table 4-11 AArch64 reset registers.
The following figure shows the RMR_EL3 bit assignments.
Figure 4-53 RMR_EL3 bit assignments
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The following table shows the RMR_EL3 bit assignments.

Table 4-72 RMR_EL3 bit assignments

Bits Name Function
[31:2] - Reserved, RES0.
[1] RR
Reset Request. The values are:
This is the reset value. It is set to zero by either a Cold or Warm reset.
Requests a Warm reset.
[0] AA64a
Determines the Execution state at processor boot time. The values are:
AArch32 state.
AArch64 state.
If software requests a Warm reset by setting RR=1 then it can use the AA64 bit to change Execution state.
To access the RMR_EL3 in AArch64 state, read or write the register with:
MRS <Xt>, RMR_EL3; Read EL3 Reset Management Register
MSR RMR_EL3, <Xt>; Write EL3 Reset Management Register
To access the RMR, in AArch32 state, read or write the CP15 register with:
MRC p15, 0, <Rt>, c12, c0, 2; Read Reset Management Register
MCR p15, 0, <Rt>, c12, c0, 2; Write Reset Management Register
a For a Cold reset, the value of this bit is set by the AA64nAA32 signal.
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