DBGWVR<n>

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DBGWVR<n>_EL1, Debug Watchpoint Value Registers, n = 0 - 63

Purpose

Holds a data address value for use in watchpoint matching. Forms watchpoint n together with control register DBGWCR<n>_EL1.

Configuration

External register DBGWVR<n>_EL1 bits [63:0] are architecturally mapped to AArch64 System register DBGWVR<n>_EL1[63:0].

External register DBGWVR<n>_EL1 bits [31:0] are architecturally mapped to AArch32 System register DBGWVR<n>[31:0].

Attributes

Field descriptions

RESS[14:8], bits [63:57]

Reserved, Sign extended. Hardware and software must treat this field as RES0 if the most significant bit of VA is 0 or RES0, and as RES1 if the most significant bit of VA is 1.

Hardware always ignores the value of these bits and it is IMPLEMENTATION DEFINED whether:

The bits are hardwired to a copy of the most significant bit of VA, meaning writes to these bits are ignored, and reads to the bits always return the hardwired value.
The value in those bits can be written, and reads will return the last value written. The value held in those bits is ignored by hardware.

Bits[56:53]
When FEAT_LVA3 is implemented:

VA[56:53], bits [3:0] of bits [56:53]

Extension to VA[48:2]. For more information, see VA[48:2].

The reset behavior of this field is:

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

Otherwise:

RESS[7:4], bits [3:0] of bits [56:53]

Extension to RESS[14:8]. For more information, see RESS[14:8].

Bits[52:49]
When FEAT_LVA is implemented:

VA[52:49], bits [3:0] of bits [52:49]

Extension to VA[48:2]. For more information, see VA[48:2].

The reset behavior of this field is:

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

Otherwise:

RESS[3:0], bits [3:0] of bits [52:49]

Extension to RESS[14:8]. For more information, see RESS[14:8].

VA[48:2], bits [48:2]

Bits[48:2] of the address value for comparison.

When FEAT_LVA3 is implemented, (VA[56:53]:VA[52:49]) forms the upper part of the address value. If FEAT_LVA3 is not implemented, bits VA[56:53] are part of the RESS field.

When FEAT_LVA is implemented, VA[52:49] forms the upper part of the address value. If FEAT_LVA is not implemented, bits [52:49] are part of the RESS field.

Arm deprecates setting DBGWVR<n>_EL1[2] == 1.

The reset behavior of this field is:

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

Bits [1:0]

Accessing DBGWVR<n>_EL1

Note

SoftwareLockStatus() depends on the type of access attempted and AllowExternalDebugAccess() has a new definition from Armv8.4. Refer to the Pseudocode definitions for more information.

DBGWVR<n>_EL1 can be accessed through the external debug interface:

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
RESS[14:8]							Bits[56:53]				Bits[52:49]				VA[48:2]
VA[48:2]																														RES0

DBGWVR<n>_EL1, Debug Watchpoint Value Registers, n = 0 - 63

Purpose

Configuration

Attributes

Field descriptions

RESS[14:8], bits [63:57]

Bits[56:53]When FEAT_LVA3 is implemented:

VA[56:53], bits [3:0] of bits [56:53]

Otherwise:

RESS[7:4], bits [3:0] of bits [56:53]

Bits[52:49]When FEAT_LVA is implemented:

VA[52:49], bits [3:0] of bits [52:49]

Otherwise:

RESS[3:0], bits [3:0] of bits [52:49]

VA[48:2], bits [48:2]

Bits [1:0]

Accessing DBGWVR<n>_EL1

DBGWVR<n>_EL1 can be accessed through the external debug interface:

Bits[56:53]
When FEAT_LVA3 is implemented:

Bits[52:49]
When FEAT_LVA is implemented: