DBGOSLSR

AArch32 System register DBGOSLSR bits [31:0] are architecturally mapped to AArch64 System register OSLSR_EL1[31:0].

This register is present only when EL1 is capable of using AArch32. Otherwise, direct accesses to DBGOSLSR are UNDEFINED.

The OS Lock status is also visible in the external debug interface through EDPRSR.

Attributes

Field descriptions

Bits [31:4]

OSLM, bits [3, 0]

OS Lock model implemented. Identifies the form of OS save and restore mechanism implemented.

OSLM	Meaning
0b00	OS Lock not implemented.
0b10	OS Lock implemented.

All other values are reserved. In an Armv8 implementation the value 0b00 is not permitted.

The OSLM field is split as follows:

OSLM[1] is DBGOSLSR[3].
OSLM[0] is DBGOSLSR[0].

nTT, bit [2]

OSLK, bit [1]

OS Lock Status.

OSLK	Meaning
0b0	OS Lock unlocked.
0b1	OS Lock locked.

The OS Lock is locked and unlocked by writing to the OS Lock Access Register.

The reset behavior of this field is:

On a Cold reset, this field resets to 1.

Accessing DBGOSLSR

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

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc	opc1	CRn	CRm	opc2
0b1110	0b000	0b0001	0b0001	0b100

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) && MDCR_EL3.TDOSA == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDOSA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDOSA> != '00' then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDOSA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); else R[t] = DBGOSLSR; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && MDCR_EL3.TDOSA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDOSA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); else R[t] = DBGOSLSR; elsif PSTATE.EL == EL3 then R[t] = DBGOSLSR;

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																												OSLM[1]	nTT	OSLK	OSLM[0]

DBGOSLSR, Debug OS Lock Status Register

Purpose

Configuration