HTPIDR

Provides a location where software running in Hyp mode can store thread identifying information that is not visible to Non-secure software executing at EL0 or EL1, for hypervisor management purposes.

Configuration

AArch32 System register HTPIDR bits [31:0] are architecturally mapped to AArch64 System register TPIDR_EL2[31:0].

This register is present only when EL2 is capable of using AArch32. Otherwise, direct accesses to HTPIDR are UNDEFINED.

Attributes

Field descriptions

Bits [31:0]

Thread ID. Thread identifying information stored by software running at this Exception level.

The reset behavior of this field is:

On a Warm reset, this field resets to an architecturally UNKNOWN value.

Accessing HTPIDR

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

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc	opc1	CRn	CRm	opc2
0b1111	0b100	0b1101	0b0000	0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T13 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T13 == '1' then AArch32.TakeHypTrapException(0x03); else UNDEFINED; elsif PSTATE.EL == EL2 then R[t] = HTPIDR; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else R[t] = HTPIDR;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc	opc1	CRn	CRm	opc2
0b1111	0b100	0b1101	0b0000	0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T13 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T13 == '1' then AArch32.TakeHypTrapException(0x03); else UNDEFINED; elsif PSTATE.EL == EL2 then HTPIDR = R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else HTPIDR = R[t];

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Thread ID

HTPIDR, Hyp Software Thread ID Register