dcps3

Debug Change PE State to EL3 (A32)

DCPS3

Switches execution to EL3 (Debug).

Pseudocode Operation

CurrentEL ← EL3; PSTATE.EL ← '11'; PSTATE.SS ← '0';

Encoding

Binary Layout

111101111000

31:20

1111

19:16

1000

15:12

0000000000

11:2

11

1:0

 

Format System

Opcode 0xF78F8003

Extension A32 (System)

Operands

Related

Other forms of dcps3

• dcps3 Debug Change PE State to EL3

More in A32 (System)

Reference

View in Arm A64 ISA Reference ↗ Arm AArch32 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xF78F8003	DCPS3		T32		111101111000 | 1111 | 1000 | 0000000000 | 11

Description

Debug Change PE State to EL3 allows the debugger to move the PE into EL3 from a lower Exception level or to a specific mode at the current Exception level. DCPS3 is undefined if any of: When the PE executes DCPS3: For more information on the operation of the DCPS<n> instructions, see DCPS.

Operation

if !Halted() || EDSCR.SDD == '1' then UNDEFINED;

if ELUsingAArch32(EL3) then
    from_secure = CurrentSecurityState() == SS_Secure;
    if PSTATE.M == M32_Monitor then SCR.NS = '0';
    AArch32.WriteMode(M32_Monitor);
    if HavePANExt() then
        if !from_secure then
            PSTATE.PAN = '0';
        elsif SCTLR.SPAN == '0' then
            PSTATE.PAN = '1';
    PSTATE.E = SCTLR.EE;

    LR_mon = bits(32) UNKNOWN;
    SPSR_mon = bits(32) UNKNOWN;

    DLR = bits(32) UNKNOWN;
    DSPSR = bits(32) UNKNOWN;
else                                        // Targeting EL3 using AArch64
    AArch64.MaybeZeroRegisterUppers();
    MaybeZeroSVEUppers(EL3);
    PSTATE.nRW = '0';
    PSTATE.SP = '1';
    PSTATE.EL = EL3;
    if HaveUAOExt() then PSTATE.UAO = '0';

    ELR_EL3 = bits(64) UNKNOWN;
    ESR_EL3 = bits(64) UNKNOWN;
    SPSR_EL3 = bits(64) UNKNOWN;

    DLR_EL0 = bits(64) UNKNOWN;
    DSPSR_EL0 = bits(64) UNKNOWN;

    sync_errors = HaveIESB() && SCTLR_EL3.IESB == '1';
    if HaveDoubleFaultExt() && EffectiveEA() == '1' && SCR_EL3.NMEA == '1' then
        sync_errors = TRUE;
    // SCTLR_EL3.IESB might be ignored in Debug state.
    if !ConstrainUnpredictableBool(Unpredictable_IESBinDebug) then
        sync_errors = FALSE;
    if sync_errors then SynchronizeErrors();

UpdateEDSCRFields();                        // Update EDSCR PE state flags