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SEV

Send Event is a hint instruction. It causes an event to be signaled to all PEs in the multiprocessor system. For more information, see Wait for Event mechanism and Send event.

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11010101000000110010000010011111
CRmop2

System

SEV

SystemHintOp op;

case CRm:op2 of
    when '0000 000' op = SystemHintOp_NOP;
    when '0000 001' op = SystemHintOp_YIELD;
    when '0000 010' op = SystemHintOp_WFE;
    when '0000 011' op = SystemHintOp_WFI;
    when '0000 100' op = SystemHintOp_SEV;
    when '0000 101' op = SystemHintOp_SEVL;
    when '0000 110'
        if !HaveDGHExt() then EndOfInstruction();                  // Instruction executes as NOP
        op = SystemHintOp_DGH;
    when '0000 111' SEE "XPACLRI";
    when '0001 xxx'
        case op2 of
            when '000' SEE "PACIA1716";
            when '010' SEE "PACIB1716";
            when '100' SEE "AUTIA1716";
            when '110' SEE "AUTIB1716";
            otherwise EndOfInstruction();                          // Instruction executes as NOP
    when '0010 000'
        if !HaveRASExt() then EndOfInstruction();                  // Instruction executes as NOP
        op = SystemHintOp_ESB;
    when '0010 001'
        if !HaveStatisticalProfiling() then EndOfInstruction();    // Instruction executes as NOP
        op = SystemHintOp_PSB;
    when '0010 010'
        if !HaveSelfHostedTrace() then EndOfInstruction();         // Instruction executes as NOP
        op = SystemHintOp_TSB;
    when '0010 100'
        op = SystemHintOp_CSDB;
    when '0011 xxx'
        case op2 of
            when '000' SEE "PACIAZ";
            when '001' SEE "PACIASP";
            when '010' SEE "PACIBZ";
            when '011' SEE "PACIBSP";
            when '100' SEE "AUTIAZ";
            when '101' SEE "AUTHASP";
            when '110' SEE "AUTIBZ";
            when '111' SEE "AUTIBSP";
    when '0100 xx0'
        op = SystemHintOp_BTI;
        // Check branch target compatibility between BTI instruction and PSTATE.BTYPE
        SetBTypeCompatible(BTypeCompatible_BTI(op2<2:1>));
    otherwise EndOfInstruction();                                 // Instruction executes as NOP

Operation

case op of
    when SystemHintOp_YIELD
        Hint_Yield();

    when SystemHintOp_DGH
        Hint_DGH();

    when SystemHintOp_WFE
        if IsEventRegisterSet() then
            ClearEventRegister();
        else
            trap = FALSE;
            if PSTATE.EL == EL0 then
                // Check for traps described by the OS which may be EL1 or EL2.
                if HaveTWEDExt() then
                    sctlr = SCTLR[];
                    trap  = sctlr.nTWE == '0';
                    target_el = EL1;
                else
                    AArch64.CheckForWFxTrap(EL1, TRUE);

            if !trap && PSTATE.EL IN {EL0, EL1} && EL2Enabled() && !IsInHost() then
                // Check for traps described by the Hypervisor.
                if HaveTWEDExt() then
                    trap = HCR_EL2.TWE == '1';
                    target_el = EL2;
                else
                    AArch64.CheckForWFxTrap(EL2, TRUE);

            if !trap && HaveEL(EL3) && PSTATE.EL != EL3 then
                // Check for traps described by the Secure Monitor.
                if HaveTWEDExt() then
                    trap = SCR_EL3.TWE == '1';
                    target_el = EL3;
                else
                    AArch64.CheckForWFxTrap(EL3, TRUE);

            if HaveTWEDExt() && trap && PSTATE.EL != EL3 then
                (delay_enabled, delay) = WFETrapDelay(target_el);    // (If trap delay is enabled, Delay amount)
                if !AArch64.WaitForEventUntilDelay(delay_enabled, delay) then
                    // Event did not arrive until delay expired
                    AArch64.WFxTrap(target_el, TRUE);                // Trap WFE
            else
                WaitForEvent();

    when SystemHintOp_WFI
        if !InterruptPending() then
            if PSTATE.EL == EL0 then
                // Check for traps described by the OS which may be EL1 or EL2.
                AArch64.CheckForWFxTrap(EL1, FALSE);
            if PSTATE.EL IN {EL0, EL1} && EL2Enabled() && !IsInHost() then
                // Check for traps described by the Hypervisor.
                AArch64.CheckForWFxTrap(EL2, FALSE);
            if HaveEL(EL3) && PSTATE.EL != EL3 then
                // Check for traps described by the Secure Monitor.
                AArch64.CheckForWFxTrap(EL3, FALSE);
            WaitForInterrupt();

    when SystemHintOp_SEV
        SendEvent();

    when SystemHintOp_SEVL
        SendEventLocal();

    when SystemHintOp_ESB
        if HaveTME() && TSTATE.depth > 0 then
            FailTransaction(TMFailure_ERR, FALSE);
        SynchronizeErrors();
        AArch64.ESBOperation();
        if PSTATE.EL IN {EL0, EL1} && EL2Enabled() then AArch64.vESBOperation();
        TakeUnmaskedSErrorInterrupts();

    when SystemHintOp_PSB
        ProfilingSynchronizationBarrier();

    when SystemHintOp_TSB
        TraceSynchronizationBarrier();

    when SystemHintOp_CSDB
        ConsumptionOfSpeculativeDataBarrier();

    when SystemHintOp_BTI
        SetBTypeNext('00');

    otherwise // do nothing
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