Holds the stack pointer associated with EL2. When executing at EL2, the value of SPSel. SP determines the current stack pointer:
| SPSel.SP | Current stack pointer |
|---|---|
| 0b0 | SP_EL0 |
| 0b1 | SP_EL2 |
This register has no effect if EL2 is not enabled in the current Security state.
SP_EL2 is a 64-bit register.
| 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Stack pointer | |||||||||||||||||||||||||||||||
| Stack pointer | |||||||||||||||||||||||||||||||
Stack pointer.
The reset behavior of this field is:
This accessibility information only applies to accesses using the MRS or MSR instructions.
When the value of SPSel.SP is 1, this register is also accessible at EL2 as the current stack pointer.
When the value of SPSel.SP is 0, SP_EL0 is used as the current stack pointer at all Exception levels.
Accesses to this register use the following encodings in the System register encoding space:
MRS <Xt>, SP_EL2
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b110 | 0b0100 | 0b0001 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then X[t, 64] = SP_EL2;
MSR SP_EL2, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b110 | 0b0100 | 0b0001 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then SP_EL2 = X[t, 64];