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S2POR_EL1: Stage 2 Permission Overlay Register (EL1)

Purpose

Stage 2 Permission Overlay Register for EL1&0 translation regime.

Configuration

This register is present only when FEAT_S2POE is implemented. Otherwise, direct accesses to S2POR_EL1 are UNDEFINED.

Attributes

S2POR_EL1 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
Perm15Perm14Perm13Perm12Perm11Perm10Perm9Perm8
Perm7Perm6Perm5Perm4Perm3Perm2Perm1Perm0

Perm<m>, bits [4m+3:4m], for m = 15 to 0

Configures stage 2 Overlay Permissions.

Perm<m>Meaning
0b0000

No Access.

0b0001

Reserved - treated as No Access.

0b0010

MRO.

0b0011

MRO-TL1.

0b0100

WO.

0b0101

Reserved - treated as No Access.

0b0110

MRO-TL0.

0b0111

MRO-TL01.

0b1000

RO.

0b1001

RO+uX.

0b1010

RO+pX.

0b1011

RO+puX.

0b1100

RW.

0b1101

RW+uX.

0b1110

RW+pX.

0b1111

RW+puX.

This field is not permitted to be cached in a TLB.

When stage 2 Permission Overlay mechanism is disabled, this register is ignored.

The reset behavior of this field is:

Accessing S2POR_EL1

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, S2POR_EL1

op0op1CRnCRmop2
0b110b0000b10100b00100b101

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.PIEn == '0' then UNDEFINED; elsif EL2Enabled() && HCR_EL2.TRVM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.nS2POR_EL1 == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.PIEn == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif EffectiveHCR_EL2_NVx() == '1x1' then X[t, 64] = NVMem[0x2B8]; else X[t, 64] = S2POR_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.PIEn == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.PIEn == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = S2POR_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = S2POR_EL1;

MSR S2POR_EL1, <Xt>

op0op1CRnCRmop2
0b110b0000b10100b00100b101

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.PIEn == '0' then UNDEFINED; elsif EL2Enabled() && HCR_EL2.TVM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.nS2POR_EL1 == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.PIEn == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif EffectiveHCR_EL2_NVx() == '1x1' then NVMem[0x2B8] = X[t, 64]; else S2POR_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.PIEn == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.PIEn == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else S2POR_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then S2POR_EL1 = X[t, 64];