SP_EL3, Stack Pointer (EL3)

The SP_EL3 characteristics are:

Purpose

Holds the capability stack pointer associated with EL3. When executing at EL3, the values of SPSel.SP and the Executive bit of PCC determine the current capability stack pointer:

SPSel.SPExecutive bit of PCCCurrent stack pointer
0bx0b0RSP_EL0
0b00b1SP_EL0
0b10b1SP_EL3

Configuration

This register is present only when HaveEL(EL3). Otherwise, direct accesses to SP_EL3 are UNDEFINED.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

SP_EL3 is a 129-bit register.

Field descriptions

The SP_EL3 bit assignments are:

When Morello is implemented:

Bits [128:0]

Stack pointer

This field resets to an architecturally UNKNOWN value.

When Morello is not implemented:

6362616059585756555453525150494847464544434241403938373635343332
Stack pointer
Stack pointer
313029282726252423222120191817161514131211109876543210

Bits [63:0]

Stack pointer.

This field resets to an architecturally UNKNOWN value.

Accessing the SP_EL3

This register is not accessible using MRS and MSR instructions.

When the value of SPSel.SP is 1, this register is accessible at EL3 as the current stack pointer.

Note

When the value of SPSel.SP is 0, SP_EL0 is used as the current stack pointer at all Exception levels.




12/01/2022 09:56; 05a4944b4b04e7ab50def8c126b479d22136f35b

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