OS Lock Access Register
Used to lock or unlock the OS Lock.
AArch64 System register OSLAR_EL1 bits [31:0] are architecturally mapped to External register OSLAR_EL1[31:0].
This register is present only when FEAT_AA64 is implemented. Otherwise, direct accesses to OSLAR_EL1 are UNDEFINED.
The OS Lock can also be locked or unlocked using DBGOSLAR.
OSLAR_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 | |||||||||||||||||||||||||||||||
| RES0 | OSLK | ||||||||||||||||||||||||||||||
Reserved, RES0.
On writes to OSLAR_EL1, bit[0] is copied to the OS Lock.
Use OSLSR_EL1.OSLK to check the current status of the lock.
Accesses to this register use the following encodings in the System register encoding space:
MSR OSLAR_EL1, <Xt>
(op0 = 0b10, op1 = 0b000, CRn = 0b0001, CRm = 0b0000, op2 = 0b100)
if !IsFeatureImplemented(FEAT_AA64) then Undefined(); elsif HaveEL(EL3) && !(EffectivelyAtEL0InHost() || EffectivelyAtEL0NotInHost() || PSTATE.EL == EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDOSA == '1' then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGWTR_EL2().OSLAR_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDOSA] != '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSLAR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSLAR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then OSLAR_EL1() = X{64}(t); end;
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