I'm trying to understand how to enable ACTLR.SMP and the SCU on our own secure OS, and the Cortex-A9 TRM states that:
For the primary processor:
• the SCU duplicate tags for all processors
• the data cache.
2. Enable the SCU.
3. Enable the data cache, set the SMP mode with ACTLR.SMP=1.
While reading Linux code, I found that the SCU is enabled quite late in the boot process (mmu is already on, and L1/L2 caches are already configured), and the only bit set at this time are ENABLE and STANDBY_ENABLE. I can't find any invalidation of the SCU tags.
- Is not invalidating the SCU before enabling an issue ?
- Why does Linux enables the SCU so late in the boot process ?