Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 1648

RSM—Resume from System Management Mode
Opcode
0F AA
Description
Returns program control from system management mode (SMM) to the application
program or operating system procedure that was interrupted when the processor
received an SSM interrupt. The processor's state is restored from the dump created
upon entering SMM. If the processor detects invalid state information during state
restoration, it enters the shutdown state. The following invalid information can cause a
shutdown:
• Any reserved bit of CR4 is set to 1.
• Any illegal combination of bits in CR0, such as (PG=1 and PE=0) or (NW=1 and
CD=0).
• (Intel Pentium and Intel486 only.) The value stored in the state dump base field is
not a 32-KByte aligned address.
The contents of the model-specific registers are not affected by a return from SMM.
See Chapter 9 in the Intel Architecture Software Developer's Manual, Volume 3 for
more information about SMM and the behavior of the RSM instruction.
Operation
IF Itanium System Environment THEN IA-32_Intercept(INST,RSM);
ReturnFromSSM;
ProcessorState  Restore(SSMDump);
Flags Affected
All.
Additional Itanium System Environment Exceptions
IA-32_Intercept
Protected Mode Exceptions
#UD
Real Address Mode Exceptions
#UD
Virtual 8086 Mode Exceptions
#UD
4:346
Instruction Description
RSM Resume operation of interrupted program
Mandatory Instruction Intercept.
If an attempt is made to execute this instruction when the processor
is not in SMM.
If an attempt is made to execute this instruction when the processor
is not in SMM.
If an attempt is made to execute this instruction when the processor
is not in SMM.
Volume 4: Base IA-32 Instruction Reference