OSECCR

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

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

AArch64 System register OSECCR_EL1 bits [31:0] are architecturally mapped to External register EDECCR[31:0].

If OSLSR_EL1.OSLK == 0, then OSECCR_EL1 returns an UNKNOWN value on reads and ignores writes.

Attributes

Field descriptions

When OSLSR_EL1.OSLK == 1:

Bits [63:32]

EDECCR, bits [31:0]

Accessing OSECCR_EL1

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

MRS <Xt>, OSECCR_EL1

op0	op1	CRn	CRm	op2
0b10	0b000	0b0000	0b0110	0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.OSECCR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif OSLSR_EL1.OSLK == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = OSECCR_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif OSLSR_EL1.OSLK == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = OSECCR_EL1; elsif PSTATE.EL == EL3 then if OSLSR_EL1.OSLK == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = OSECCR_EL1;

MSR OSECCR_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b10	0b000	0b0000	0b0110	0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.OSECCR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.<TDE,TDA> != '00' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif OSLSR_EL1.OSLK == '0' then return; else OSECCR_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TDA == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.TDA == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif OSLSR_EL1.OSLK == '0' then return; else OSECCR_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then if OSLSR_EL1.OSLK == '0' then return; else OSECCR_EL1 = X[t, 64];

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
EDECCR

OSECCR_EL1, OS Lock Exception Catch Control Register

Purpose