SMC

Secure monitor call

This instruction causes an exception to EL3.

SMC is available only for software executing at EL1 or higher. It is UNDEFINED in EL0.

If the values of HCR_EL2.TSC and SCR_EL3.SMD are both 0, execution of an SMC instruction at EL1 or higher generates a Secure Monitor Call exception, recording it in ESR_ELx, using the EC syndrome value 0x17, that is taken to EL3.

If the value of HCR_EL2.TSC is 1 and EL2 is enabled in the current Security state, execution of an SMC instruction at EL1 generates an exception that is taken to EL2, regardless of the value of SCR_EL3.SMD.

If the value of HCR_EL2.TSC is 0 and the value of SCR_EL3.SMD is 1, the SMC instruction is UNDEFINED.

Encoding: System

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
1	1	0	1	0	1	0	0	0	0	0																	0	0	0	1	1
								opc			imm16																op2			LL

SMC #<imm>

Decoding algorithm

constant bits(16) imm = imm16;

Operation

if PSTATE.EL == EL0 then UNDEFINED;
AArch64.CheckForSMCUndefOrTrap(imm);
AArch64.CallSecureMonitor(imm);

Explanations

<imm>: Is a 16-bit unsigned immediate, in the range 0 to 65535, encoded in the "imm16" field.