4.8 Software configurable memory region locking

The HN-F supports variable size memory regions that can be locked in the L3 cache with way reservation.

These variable size memory regions ensure that locked lines are not evicted from the L3.

Software uses the following mechanism to program the HN-F configuration registers to enable region locking:

Note:

The locked regions do not comprehend Secure as opposed to Non-secure memory regions, so overlocking can occur if aliasing is performed between Secure and Non-secure regions.

The following tables specify various combinations of region size and the number of locked ways that software must program using the hnf_l3_lock_ways register and the hnf_l3_lock_base0 register to hnf_l3_lock_base3 register.

Table 4-2 hnf_l3_lock_ways register settings

L3 size Number of locked ways Total locked region size Locked ways Number of ways per region Region 0 Region 1 Region 2 Region 3
6XP/2HNF
256KB 1 16KB 0 1 16KB - - -
2 32KB 0-1 1, 1 16KB 16KB - -
4 64KB 0-3 1, 1, 1, 1 16KB 16KB 16KB 16KB
8 128KB 0-7 2, 2, 2, 2 32KB 32KB 32KB 32KB
12 192KB 0-11 2, 2, 4, 4 32KB 32KB 64KB 64KB
8XP/4HNF
512KB 1 32KB 0 1 32KB - - -
2 64KB 0-1 1, 1 32KB 32KB - -
4 128KB 0-3 1, 1, 1, 1 32KB 32KB 32KB 32KB
8 256KB 0-7 2, 2, 2, 2 64KB 64KB 64KB 64KB
12 384KB 0-11 2, 2, 4, 4 64KB 64KB 128KB 128KB
6XP/2HNF
1MB 1 64KB 0 1 64KB - - -
2 128KB 0-1 1, 1 64KB 64KB - -
4 256KB 0-3 1, 1, 1, 1 64KB 64KB 64KB 64KB
8 512KB 0-7 2, 2, 2, 2 128KB 128KB 128KB 128KB
12 768KB 0-11 2, 2, 4, 4 128KB 128KB 256KB 256KB
6XP/2HNF or 8XP/4HNF
2MB 1 128KB 0 1 128KB - - -
2 256KB 0-1 1, 1 128KB 128KB - -
4 512KB 0-3 1, 1, 1, 1 128KB 128KB 128KB 128KB
8 1MB 0-7 2, 2, 2, 2 256KB 256KB 256KB 256KB
12 1.5MB 0-11 2, 2, 4, 4 256KB 256KB 512KB 512KB
6XP/2HNF or 8XP/4HNF
4MB 1 256KB 0 1 256KB - - -
2 512KB 0-1 1, 1 256KB 256KB - -
4 1MB 0-3 1, 1, 1, 1 256KB 256KB 256KB 256KB
8 2MB 0-7 2, 2, 2, 2 512KB 512KB 512KB 512KB
12 3MB 0-11 2, 2, 4, 4 512KB 512KB 1MB 1MB
8XP/4HNF
8MB 1 512KB 0 1 512KB - - -
2 1MB 0-1 1, 1 512KB 512KB - -
4 2MB 0-3 1, 1, 1, 1 512KB 512KB 512KB 512KB
8 4MB 0-7 2, 2, 2, 2 1MB 1MB 1MB 1MB
12 6MB 0-11 2, 2, 4, 4 1MB 1MB 2MB 2MB
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