arm64: improved memory map handling for /dev/mem, ACPI etc

This series was split off from the UEFI virtmap for kexec series that I posted earlier today. The main purpose is to deal with the need to classify memory ranges as RAM or non-RAM in a consistent and comprehensive manner. This series applies on top of the other series.

Patch #1 avoids an early panic if the UEFI memory map is available but UEFI support itself fails to initialize. In this case, there is no need to panic early, and we have a better chance of being able to inform the user if we deal with this error condition at a later time.

Patch #2 adds iomem resource registration of UEFI memory regions. This is necessary because otherwise, drivers could potentially claim regions that are in active use by the firmware. This applies to both MMIO (NOR flash, RTC) and RAM ranges (runtime services code and data).

Patch #3-6 adds support to UEFI and non-UEFI code paths to record all memory known to the system in the 'physmem' memblock table (if enabled). This fulfils a need in the /dev/mem and (upcoming) ACPI layers to be able to classify ranges as being backed by normal RAM even if they are not covered by the 'memory' memblock table, and are hence not covered by the linear direct mapping. The physmem code is pre-existing code that only needs minor tweaking to be made suitable for this purpose.

Patch #7 enables the 'physmem' memblock table for arm64, and wires it into the handling of /dev/mem mappings, both to decide whether it should be mapped as MT_NORMAL, and whether read-write access can be allowed. (Non-RAM regions can be mapped read-write as long as they are not claimed by a driver in the iomem resource table. RAM regions can only be mapped read-only, and only if they are not covered by the 'memory' memblock table, and hence not covered by the linear mapping)

Finally, patch #8 changes the way the virtual memory map is handled by the early UEFI code. Specifically, it memblock_remove()s rather than _reserves() UEFI reserved RAM regions, so that they are removed entirely from the linear mapping.

Ard Biesheuvel (8):
arm64/efi: use UEFI memory map unconditionally if available arm64/efi: register UEFI reserved regions as iomem resources
memblock: add physmem to memblock_dump_all() output
memblock: introduce memblock_add_phys() and memblock_is_physmem()
of: fdt: register physmem in early_init_dt_scan_memory() arm64/efi: register physmem in reserve_regions()
arm64: use 'physmem' memblock to improve CONFIG_STRICT_DEVMEM handling arm64/efi: memblock_remove rather than _reserve UEFI reserved RAM