dcps2

Debug Change PE State to EL2 (A32)

DCPS2

Switches execution to EL2 (Debug).

Pseudocode Operation

DebugChangeEL(EL2); // Changes exception level and branches to debug handler

Encoding

Binary Layout

111101111000

31:20

1111

19:16

1000

15:12

0000000000

11:2

10

1:0

 

Format System

Opcode 0xF78F8002

Extension A32 (System)

Operands

Related

Other forms of dcps2

• dcps2 Debug Change PE State to EL2

More in A32 (System)

Reference

View in Arm A64 ISA Reference ↗ Arm AArch32 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xF78F8002	DCPS2		T32		111101111000 | 1111 | 1000 | 0000000000 | 10

Description

Debug Change PE State to EL2 allows the debugger to move the PE into EL2 from a lower Exception level. DCPS2 is undefined if any of: When the PE executes DCPS2: For more information on the operation of the DCPS<n> instructions, see DCPS.

Operation

if !Halted() || !EL2Enabled() then UNDEFINED;

if ELUsingAArch32(EL2) then
    AArch32.WriteMode(M32_Hyp);
    PSTATE.E = HSCTLR.EE;

    ELR_hyp = bits(32) UNKNOWN;
    HSR = bits(32) UNKNOWN;
    SPSR_hyp = bits(32) UNKNOWN;

    DLR = bits(32) UNKNOWN;
    DSPSR = bits(32) UNKNOWN;
else                                        // Targeting EL2 using AArch64
    AArch64.MaybeZeroRegisterUppers();
    MaybeZeroSVEUppers(EL2);
    PSTATE.nRW = '0';
    PSTATE.SP = '1';
    PSTATE.EL = EL2;
    if HavePANExt() && SCTLR_EL2.SPAN == '0' && HCR_EL2.E2H == '1' && HCR_EL2.TGE == '1' then
        PSTATE.PAN = '1';
    if HaveUAOExt() then PSTATE.UAO = '0';

    ELR_EL2 = bits(64) UNKNOWN;
    ESR_EL2 = bits(64) UNKNOWN;
    SPSR_EL2 = bits(64) UNKNOWN;

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

    // SCTLR_EL2.IESB might be ignored in Debug state.
    if (HaveIESB() && SCTLR_EL2.IESB == '1' &&
          !ConstrainUnpredictableBool(Unpredictable_IESBinDebug)) then
        SynchronizeErrors();

UpdateEDSCRFields();                        // Update EDSCR PE state flags