PMVCIDSR

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PMVCIDSR, CONTEXTIDR_EL1 and VMID Sample Register

Purpose

PC Sample-based Profiling Extension register that contains the sampled CONTEXTIDR_EL1 and VMID values that are captured on reading PMPCSR.

Configuration

External register PMVCIDSR bits [31:0] are architecturally mapped to External register PMCCIDSR[31:0].

This register is present only when FEAT_PMUv3_EXT64 is implemented and FEAT_PCSRv8p2 is implemented.

Attributes

Field descriptions

Bits [63:48]

VMID[15:8], bits [47:40]
When FEAT_VMID16 is implemented:

Extension to VMID[7:0]. For more information, see VMID[7:0].

The reset behavior of this field is:

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

Otherwise:

VMID, bits [39:32]

VMID sample. The VMID associated with the most recent PMPCSR sample. When the most recent PMPCSR sample was generated:

This field is set to an UNKNOWN value if any of the following apply:
- EL2 is disabled in the current Security state.
- The PE is executing at EL2.
- The PE is executing at EL0, and the Effective value of HCR_EL2.{E2H, TGE} is {1, 1}.
Otherwise:
- If EL2 is using AArch64 and either FEAT_VMID16 is not implemented or VTCR_EL2.VS is 1, this field is set to VTTBR_EL2.VMID.
- If EL2 is using AArch64, FEAT_VMID16 is implemented, and VTCR_EL2.VS is 0, PMVIDSR.VMID[7:0] is set to VTTBR_EL2.VMID[7:0] and PMVIDSR.VMID[15:8] is RES0.
- If EL2 is using AArch32, this field is set to VTTBR.VMID.

Because the value written to PMVIDSR is an indirect read of the VMID value, it is CONSTRAINED UNPREDICTABLE whether PMVIDSR is set to the original or new value if PMPCSR samples:

An instruction that writes to the VMID value.
The next Context synchronization event.
Any instruction executed between these two instructions.

The reset behavior of this field is:

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

CONTEXTIDR_EL1, bits [31:0]

Context ID. The value of CONTEXTIDR that is associated with the most recent PMPCSR sample. When the most recent PMPCSR sample is generated:

If EL1 is using AArch64, then the Context ID is sampled from CONTEXTIDR_EL1.
If EL1 is using AArch32, then the Context ID is sampled from CONTEXTIDR.
If EL3 is implemented and is using AArch32, then CONTEXTIDR is a banked register and this register samples the current banked copy of CONTEXTIDR for the Security state that is associated with the most recent PMPCSR sample.

Because the value written to this register is an indirect read of CONTEXTIDR, it is CONSTRAINED UNPREDICTABLE whether this register is set to the original or new value if PMPCSR samples:

An instruction that writes to CONTEXTIDR.
The next Context synchronization event.
Any instruction executed between these two instructions.

The reset behavior of this field is:

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

Accessing PMVCIDSR

If FEAT_PCSRv8p2 and FEAT_PMUv3_EXT32 are implemented, then the same content is present in the same locations, and can be accessed using PMVIDSR[31:0] and PMCID1SR[31:0].

IMPLEMENTATION DEFINED extensions to external debug might make the value of this register UNKNOWN, see 'Permitted behavior that might make the PC Sample-based profiling registers UNKNOWN'.

Accesses to this register use the following encodings:

Accessible at offset 0x208 from PMU

When DoubleLockStatus() or !IsCorePowered(), accesses to this register generate an error response.
When (FEAT_PMUv3_EXTPMN is not implemented, or !IsMostSecureAccess(addrdesc), or PMCCR().OSLO == '0') and OSLockStatus(), accesses to this register generate an error response.
Otherwise, accesses to this register are RO.

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
RES0																VMID[15:8]								VMID
CONTEXTIDR_EL1

PMVCIDSR, CONTEXTIDR_EL1 and VMID Sample Register

Purpose

Configuration

Attributes

Field descriptions

Bits [63:48]

VMID[15:8], bits [47:40]When FEAT_VMID16 is implemented:

Otherwise:

VMID, bits [39:32]

CONTEXTIDR_EL1, bits [31:0]

Accessing PMVCIDSR

VMID[15:8], bits [47:40]
When FEAT_VMID16 is implemented: