EDSCR2

External register EDSCR2 bits [31:0] are architecturally mapped to AArch64 System register MDSCR_EL1[63:32].

This register is present only when FEAT_Debugv8p9 is implemented or FEAT_TRBE_EXT is implemented. Otherwise, direct accesses to EDSCR2 are RES0.

Attributes

Field descriptions

Bits [31:4]

EHBWE, bit [3]
When FEAT_Debugv8p9 is implemented:

Extended Halting Breakpoint and Watchpoint Enable. Enables use of additional breakpoints or watchpoints.

EHBWE	Meaning
0b0	Halting disabled for Breakpoint and Watchpoint debug events generated by each breakpoint <n> and Watchpoint <n>, where n is greater than or equal to 16.
0b1	Breakpoints and Watchpoint debug events are not affected by this mechanism.

When OSLSR_EL1.OSLK is 1, this field can be read and written through the MDSCR_EL1 System register.

It is IMPLEMENTATION DEFINED whether this field is implemented or is RES0 when 16 or fewer breakpoints are implemented, 16 or fewer watchpoints are implemented, and MDSELR_EL1 is implemented as RAZ/WI.

The reset behavior of this field is:

On a Cold reset, this field resets to 0.

Otherwise:

Bit [2]

TTA, bit [1]
When FEAT_TRBE_EXT is implemented or FEAT_ETEv1p3 is implemented:

Trap Trace Accesses.

Traps access to the following System registers:

AArch64: TRBBASER_EL1, TRBIDR_EL1, TRBLIMITR_EL1, TRBMAR_EL1, TRBMPAM_EL1, TRBPTR_EL1, TRBSR_EL1, TRBTRG_EL1, TRCACATR<n>, TRCACVR<n>, TRCAUTHSTATUS, TRCAUXCTLR, TRCBBCTLR, TRCCCCTLR, TRCCIDCCTLR0, TRCCIDCCTLR1, TRCCIDCVR<n>, TRCCLAIMCLR, TRCCLAIMSET, TRCCNTCTLR<n>, TRCCNTRLDVR<n>, TRCCNTVR<n>, TRCCONFIGR, TRCDEVARCH, TRCDEVID, TRCEVENTCTL0R, TRCEVENTCTL1R, TRCEXTINSELR<n>, TRCIDR0, TRCIDR1, TRCIDR2, TRCIDR3, TRCIDR4, TRCIDR5, TRCIDR6, TRCIDR7, TRCIDR8, TRCIDR9, TRCIDR10, TRCIDR11, TRCIDR12, TRCIDR13, TRCIMSPEC0, TRCIMSPEC<n>, TRCITEEDCR, TRCOSLSR, TRCPRGCTLR, TRCQCTLR, TRCRSCTLR<n>, TRCRSR, TRCSEQEVR<n>, TRCSEQRSTEVR, TRCSEQSTR, TRCSSCCR<n>, TRCSSCSR<n>, TRCSSPCICR<n>, TRCSTALLCTLR, TRCSTATR, TRCSYNCPR, TRCTRACEIDR, TRCTSCTLR, TRCVICTLR, TRCVIIECTLR, TRCVIPCSSCTLR, TRCVISSCTLR, TRCVMIDCCTLR0, TRCVMIDCCTLR1, and TRCVMIDCVR<n>.

TTA	Meaning
0b0	Accesses to trace System registers do not generate a Software Access debug event.
0b1	Accesses to trace System registers generate a Software Access debug event, if OSLSR_EL1.OSLK is 0 and if halting is allowed.

When OSLSR_EL1.OSLK is 1, this field can be read and written through the MDSCR_EL1 System register.

The reset behavior of this field is:

On a Cold reset, this field resets to 0.

Otherwise:

Bit [0]

Accessing EDSCR2

EDSCR2 can be accessed through the external debug interface:

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																												EHBWE	RES0	TTA	RES0

EDSCR2, External Debug Status and Control Register 2

Purpose

Configuration

Attributes

Field descriptions

Bits [31:4]

EHBWE, bit [3]
When FEAT_Debugv8p9 is implemented:

Otherwise:

Bit [2]

TTA, bit [1]
When FEAT_TRBE_EXT is implemented or FEAT_ETEv1p3 is implemented:

Otherwise:

Bit [0]

Accessing EDSCR2

EDSCR2 can be accessed through the external debug interface:

EDSCR2, External Debug Status and Control Register 2

Purpose

Configuration

Attributes

Field descriptions

Bits [31:4]

EHBWE, bit [3]When FEAT_Debugv8p9 is implemented:

Otherwise:

Bit [2]

TTA, bit [1]When FEAT_TRBE_EXT is implemented or FEAT_ETEv1p3 is implemented:

Otherwise:

Bit [0]

Accessing EDSCR2

EDSCR2 can be accessed through the external debug interface:

EHBWE, bit [3]
When FEAT_Debugv8p9 is implemented:

TTA, bit [1]
When FEAT_TRBE_EXT is implemented or FEAT_ETEv1p3 is implemented: