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DBGOSECCR: Debug OS Lock Exception Catch Control Register

Purpose

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

DBGOSECCR is a 32-bit register.

Field descriptions

When DBGOSLSR.OSLK == 1:

313029282726252423222120191817161514131211109876543210
EDECCR

EDECCR, bits [31:0]

Used for save/restore to EDECCR over powerdown.

Reads or writes to this field are indirect accesses to EDECCR.

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>}

coprocopc1CRnCRmopc2
0b11100b0000b00000b01100b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !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 EL3SDDUndef() 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 HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() 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>}

coprocopc1CRnCRmopc2
0b11100b0000b00000b01100b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !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 EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x05); elsif DBGOSLSR.OSLK == '0' then return; else DBGOSECCR = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() 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];