41-54 Vol. 3D

SGX INSTRUCTION REFERENCES

EREMOVE—Remove a page from the EPC 

Instruction Operand Encoding

Description

This leaf function causes an EPC page to be un-associated with its SECS and be marked as unused. This instruction 
leaf can only be executed when the current privilege level is 0.
The content of RCX is an effective address of an EPC page. The DS segment is used to create linear address. 
Segment override is not supported.
The instruction fails if the operand is not properly aligned or does not refer to an EPC page or the page is in use by 
another thread, or other threads are running in the enclave to which the page belongs. In addition the instruction 
fails if the operand refers to an SECS with associations.

EREMOVE Memory Parameter Semantics

The instruction faults if any of the following: 

EREMOVE Faulting Conditions

The error codes are: 

Opcode/

Instruction

Op/En

64/32 

bit Mode 

Support

CPUID 

Feature 

Flag

Description

 EAX = 03H

IR

V/V

SGX1

This leaf function removes a page from the EPC.

ENCLS[EREMOVE]

Op/En

EAX

RCX

IR

EREMOVE (In)

Effective address of the EPC page (In)

EPCPAGE

Write access permitted by Enclave

The memory operand is not properly aligned.

The memory operand does not resolve in an EPC page.

Refers to an invalid SECS.

Refers to an EPC page that is locked by another thread.

Another Intel SGX instruction is accessing the EPC page.

RCX does not contain an effective address of an EPC page.

the EPC page refers to an SECS with associations.

Table 41-36.  EREMOVE Return Value in RAX

 Error Code (see Table 41-3)

Description

No Error

EREMOVE successful

SGX_CHILD_PRESENT

If the SECS still have enclave pages loaded into EPC

SGX_ENCLAVE_ACT

If there are still logical processors executing inside the enclave