Change Details

When the memory reported from EFI isn't on a 1G boundary we still use 1G mappings. On some hardware this can cause issues as the core may still access this memory. Reduce this limit down to a 2M boundary. With this patch, DMAP is mapped with L2 (2MiB) resolution. Implementation of pmap_mapbios and pmap_unmapbios had to be updated as some regions containing ACPI tables are no longer in DMAP (as they are not in the physmap reported by EFI). This implementation is similar to what we have on amd64. Caveats (only first revision of patch): - Maximum 2MiB mapbios mapping in early boot stage (also, the mapping cannot cross L2 boundary) Acknowledgements: part of the code was taken from @andrew 's WIP code (pmap_bootstrap_dmap).

Previously DMAP VA range was used for this purpose but the address range of ACPI tables may not be covered by DMAP. This change is a prerequisite before switching to L2-block based DMAP.

When the memory reported from EFI isn't on a 1G boundary we still use 1G mappings. On some hardware this can cause issues as the core may still access this memory. Reduce this limit down to a 2M boundary. With this patch, DMAP is mapped with L2 (2MiB) resolutionPreviously DMAP VA range was used for this purpose but the address range of ACPI tables may not be covered by DMAP. Implementation of pmap_mapbios and pmap_unmapbios had to be updated as some regions containing ACPI tables are no longer in DMAP (as they are not in the physmap reported by EFI)This change is a prerequisite before switching to L2-block based DMAP. This implementation is similar to what we have on amd64. Caveats (only first revision of patch): - Maximum 2MiB mapbios mapping in early boot stage (also, the mapping cannot cross L2 boundary) Acknowledgements: part of the code was taken from @andrew 's WIP code (pmap_bootstrap_dmap).