AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

# GCSSS2, Guarded Control Stack Switch Stack 2

The GCSSS2 characteristics are:

## Purpose

Validates that the most recent entry of the Guarded Control Stack that is getting switched to contains an In-progress cap entry, stores a Valid cap entry to the Guarded Control Stack that is getting switched from, and sets Xt to the address of that Valid cap entry.

## Configuration

This instruction is present only when FEAT_GCS is implemented. Otherwise, direct accesses to GCSSS2 are UNDEFINED.

## Attributes

GCSSS2 is a 64-bit System instruction.

## Field descriptions

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
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
Output address, for the outgoing Guarded Control Stack
Output address, for the outgoing Guarded Control Stack

#### Bits [63:0]

Output address, for the outgoing Guarded Control Stack.

## Executing GCSSS2

Accesses to this instruction use the following encodings in the System instruction encoding space:

#### GCSSS2 <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b01 | 0b011 | 0b0111 | 0b0111 | 0b011

if PSTATE.EL == EL0 then X[t, 64] = GCSSS2(); elsif PSTATE.EL == EL1 then X[t, 64] = GCSSS2(); elsif PSTATE.EL == EL2 then X[t, 64] = GCSSS2(); elsif PSTATE.EL == EL3 then X[t, 64] = GCSSS2();

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

Copyright © 2010-2024 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.