Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

Vol. 2B 4-265

INSTRUCTION SET REFERENCE, N-Z

RSM—Resume from System Management Mode

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 SMM 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™ processors 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.

The SMM state map used by RSM supports resuming processor context for non-

64-bit modes and 64-bit mode.

See Chapter 24, “System Management,” in the Intel

64 and IA-32 Architectures

Software Developer’s Manual, Volume 3B, for more information about SMM and the

behavior of the RSM instruction.

Operation

ReturnFromSMM;

IF (IA-32e mode supported)

THEN

ProcessorState ← Restore(SMMDump(IA-32e SMM STATE MAP));

Else

ProcessorState ← Restore(SMMDump(Non-32-Bit-Mode SMM STATE MAP));

Flags Affected

All.

Opcode Instruction

Non-

SMM

Mode SMM Mode Description

0F AA RSM Invalid Valid Resume operation of interrupted

program.