10.4.12. OS Lock Status Register

The DBGOSLSR characteristics are:

Purpose

Provides status information for the OS Lock. Software can read this register to detect whether the OS Save and Restore mechanism is implemented. If it is not implemented, the read of DBGOSLSR.OSLM returns zero.

Usage constraints

There are no usage constraints.

Configurations

Available in all configurations.

Attributes

See the register summary in Table 10.1.

Figure 10.14 shows the DBGOSLSR bit assignments.

Figure 10.14. DBGOSLSR bit assignments

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Table 10.14 shows the DBGOSLSR bit assignments.

Table 10.14. DBGOSLSR bit assignments

BitsNameFunction
[31:4]-

Reserved, UNK.

[3]OSLM[1]

OS Lock Model implemented bit. This field identifies the form of OS Save and Restore mechanism implemented:

0b10

The processor implements the OS Lock Model but does not implement DBGOSSRR.

Note

This field splits across the two non-contiguous bits in the register.

[2]nTT

This bit is always RAZ. It indicates that a 32-bit access is needed to write the key to the OS Lock Access Register.

[1]OSLK

This bit indicates the status of the OS Lock:

0

Lock not set.

1

Lock set.

The OS Lock is set or cleared by writing to the DBGOSLAR, see OS Lock Access Register. The OS Lock is set to 1 on a core power up reset.

Setting the OS Lock restricts access to Debug registers. See the ARM Architecture Reference Manual for more information.

[0]OSLM[0]

OS Lock Model implemented bit. This field identifies the form of OS Save and Restore mechanism implemented:

0b10

The processor implements the OS Lock Model but does not implement DBGOSSRR.

Note

This field splits across the two non-contiguous bits in the register.


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