DBGOSECCR

Provides a mechanism for an operating system to access the contents of EDECCR that are otherwise invisible to software, so it can save/restore the contents of EDECCR over powerdown on behalf of the external debugger.

Configuration

AArch32 System register DBGOSECCR bits [31:0] are architecturally mapped to AArch64 System register OSECCR_EL1[31:0].

AArch32 System register DBGOSECCR bits [31:0] are architecturally mapped to External register EDECCR[31:0].

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

If DBGOSLSR.OSLK == 0 then DBGOSECCR returns an UNKNOWN value on reads and ignores writes.

Attributes

Field descriptions

When DBGOSLSR.OSLK == 1:

EDECCR, bits [31:0]

Accessing DBGOSECCR

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	0b0000	0b0110	0b010

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.TDA == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDA> != '00' then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); elsif DBGOSLSR.OSLK == '0' then R[t] = bits(32) UNKNOWN; else R[t] = DBGOSECCR; 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.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); elsif DBGOSLSR.OSLK == '0' then R[t] = bits(32) UNKNOWN; else R[t] = DBGOSECCR; elsif PSTATE.EL == EL3 then if DBGOSLSR.OSLK == '0' then R[t] = bits(32) UNKNOWN; else R[t] = DBGOSECCR;

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

coproc	opc1	CRn	CRm	opc2
0b1110	0b000	0b0000	0b0110	0b010

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.TDA == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.<TDE,TDA> != '00' then AArch64.AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.<TDE,TDA> != '00' then AArch32.TakeHypTrapException(0x05); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); elsif DBGOSLSR.OSLK == '0' then return; else DBGOSECCR = R[t]; 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.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); elsif DBGOSLSR.OSLK == '0' then return; else DBGOSECCR = R[t]; elsif PSTATE.EL == EL3 then if DBGOSLSR.OSLK == '0' then return; else DBGOSECCR = R[t];

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
EDECCR

DBGOSECCR, Debug OS Lock Exception Catch Control Register

Purpose