LORSA_EL1, LORegion Start Address (EL1)
The LORSA_EL1 characteristics are:
Purpose
Indicates whether the current LORegion descriptor selected by LORC_EL1.DS is enabled, and holds the physical address of the start of the LORegion.
Configuration
This register is present only when ARMv8.1-LOR is implemented. Otherwise, direct accesses to LORSA_EL1 are UNDEFINED.
This register is RES0 if any of the following apply:
- No LORegion descriptors are supported by the PE.
- LORC_EL1.DS points to a LORegion that is not supported by the PE.
Attributes
LORSA_EL1 is a 64-bit register.
Field descriptions
The LORSA_EL1 bit assignments are:
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 |
RES0 | SA[51:48] | SA[47:16] | |||||||||||||||||||||||||||||
SA[47:16] | RES0 | Valid | |||||||||||||||||||||||||||||
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 |
Any of the fields in this register are permitted to be cached in a TLB.
Bits [63:52]
Reserved, RES0.
SA[51:48], bits [51:48]
When ARMv8.2-LPA is implemented:
When ARMv8.2-LPA is implemented:
Extension to SA[47:16]. See SA[47:16] for more details.
This field resets to an architecturally UNKNOWN value.
Otherwise:
Otherwise:
Reserved, RES0.
SA[47:16], bits [47:16]
Bits [47:16] of the start physical address of the LORegion described in the current LORegion descriptor selected by LORC_EL1.DS. Bits[15:0] of this address are defined to be 0x0000. For implementations with fewer than 48 bits, the upper bits of this field are RES0.
When ARMv8.2-LPA is implemented, and 52-bit addresses and a 64KB translation granule are in use, SA[51:48] form the upper part of the address value. Otherwise, for implementations with fewer than 52 physical address bits, SA[51:48] are RES0.
This field resets to an architecturally UNKNOWN value.
Bits [15:1]
Reserved, RES0.
Valid, bit [0]
Indicates whether the current LORegion Descriptor is enabled.
Valid | Meaning |
---|---|
0b0 |
Disabled |
0b1 |
Enabled |
This field resets to 0.
Accessing the LORSA_EL1
Accesses to this register use the following encodings:
MRS <Xt>, LORSA_EL1
op0 | op1 | CRn | CRm | op2 |
---|---|---|---|---|
0b11 | 0b000 | 0b1010 | 0b0100 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then UNDEFINED; elsif SCR_EL3.NS == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TLOR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.LORSA_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else return LORSA_EL1; elsif PSTATE.EL == EL2 then if SCR_EL3.NS == '0' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else return LORSA_EL1; elsif PSTATE.EL == EL3 then if SCR_EL3.NS == '0' then UNDEFINED; else return LORSA_EL1;
MSR LORSA_EL1, <Xt>
op0 | op1 | CRn | CRm | op2 |
---|---|---|---|---|
0b11 | 0b000 | 0b1010 | 0b0100 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then UNDEFINED; elsif SCR_EL3.NS == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TLOR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.LORSA_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else LORSA_EL1 = X[t]; elsif PSTATE.EL == EL2 then if SCR_EL3.NS == '0' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.TLOR == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else LORSA_EL1 = X[t]; elsif PSTATE.EL == EL3 then if SCR_EL3.NS == '0' then UNDEFINED; else LORSA_EL1 = X[t];