gcsss1

Guarded Control Stack Switch Stack 1

GCSSS1 <Xt>

First step to switch the GCS pointer.

Pseudocode Operation

if FEAT_GCS == '0' then
  UNDEFINED
else if PSTATE.EL == EL0 then
  UNDEFINED
else
  GCSSwitchStack1(X[t])

Example

GCSSS1 x3

Encoding

Binary Layout

1101010100

31:22

0

21

01

20:19

011

18:16

0111

15:12

0111

11:8

010

7:5

Rt

4:0

 

Format System

Opcode 0xD50B7740

Extension FEAT_GCS (Security)

Operands

• Xt
  New Stack Ptr

Related

More in FEAT_GCS (Security)

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xD50B7740	GCSSS1 <Xt>		A64		1101010100 | 0 | 01 | 011 | 0111 | 0111 | 010 | Rt

Description

Guarded Control Stack Switch Stack 1 validates that the stack being switched to contains a Valid cap entry, stores an In-progress cap entry to the stack that is being switched to, and sets the current Guarded control stack pointer to the stack that is being switched to. If the instruction generates a synchronous Data Abort exception, Watchpoint exception, GPC exception, or GCS Data Check exception, the value of GCSPR_ELx for the current Exception level is restored to the value held in the register before the instruction was executed.