Identifies the current Process Identifier.
The value of the whole of this register is called the Context ID and is used by:
The significance of this register is for debug and trace use only.
AArch64 System register CONTEXTIDR_EL1 bits [31:0] are architecturally mapped to AArch32 System register CONTEXTIDR[31:0].
CONTEXTIDR_EL1 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 |
| RES0 | |||||||||||||||||||||||||||||||
| PROCID | |||||||||||||||||||||||||||||||
Reserved, RES0.
Process Identifier. This field must be programmed with a unique value that identifies the current process.
In AArch32 state, when TTBCR.EAE is set to 0, CONTEXTIDR.ASID holds the ASID.
In AArch64 state, CONTEXTIDR_EL1 is independent of the ASID, and for the EL1&0 translation regime either TTBR0_EL1 or TTBR1_EL1 holds the ASID.
The reset behavior of this field is:
When the Effective value of HCR_EL2.E2H is 1, without explicit synchronization, access from EL3 using the mnemonic CONTEXTIDR_EL1 or CONTEXTIDR_EL12 are not guaranteed to be ordered with respect to accesses using the other mnemonic.
Accesses to this register use the following encodings in the System register encoding space:
MRS <Xt>, CONTEXTIDR_EL1
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b000 | 0b1101 | 0b0000 | 0b001 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.TRVM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.CONTEXTIDR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() == '111' then X[t, 64] = NVMem[0x108]; else X[t, 64] = CONTEXTIDR_EL1; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then X[t, 64] = CONTEXTIDR_EL2; else X[t, 64] = CONTEXTIDR_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = CONTEXTIDR_EL1;
MSR CONTEXTIDR_EL1, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b000 | 0b1101 | 0b0000 | 0b001 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.TVM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.CONTEXTIDR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() == '111' then NVMem[0x108] = X[t, 64]; else CONTEXTIDR_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then CONTEXTIDR_EL2 = X[t, 64]; else CONTEXTIDR_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then CONTEXTIDR_EL1 = X[t, 64];
MRS <Xt>, CONTEXTIDR_EL12
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b101 | 0b1101 | 0b0000 | 0b001 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then X[t, 64] = NVMem[0x108]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then X[t, 64] = CONTEXTIDR_EL1; else UNDEFINED; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then X[t, 64] = CONTEXTIDR_EL1; else UNDEFINED;
MSR CONTEXTIDR_EL12, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b101 | 0b1101 | 0b0000 | 0b001 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then NVMem[0x108] = X[t, 64]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then CONTEXTIDR_EL1 = X[t, 64]; else UNDEFINED; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then CONTEXTIDR_EL1 = X[t, 64]; else UNDEFINED;