Jeffrey Lee
authored
Detail: Modern ARMs (ARMv6+) introduce the possibility for the page table walk hardware to make use of the data cache(s) when performing memory accesses. This can significantly reduce the cost of a TLB miss on the system, and since the accesses are cache-coherent with the CPU it allows us to make the page tables cacheable for CPU (program) accesses also, improving the performance of page table manipulation by the OS. Even on ARMs where the page table walk can't use the data cache, it's been measured that page table manipulation operations can still benefit from placing the page tables in write-through or bufferable memory. So with that in mind, this set of changes updates the OS to allow cacheable/bufferable page tables to be used by the OS + MMU, using a system-appropriate cache policy. File changes: - hdr/KernelWS - Allocate workspace for storing the page flags that are to be used by the page tables - hdr/OSMem - Re-specify CP_CB_AlternativeDCache a...