[RFC] arm64: mm: update max_pfn after memory hotplug

[Chris Goldsworthy <quic_cgoldswo@quicinc.com>]

From: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com>

After new memory blocks have been hotplugged, max_pfn and max_low_pfn
needs updating to reflect on new PFNs being hot added to system.

Signed-off-by: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com>
Signed-off-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com>
---
 arch/arm64/mm/mmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index cfd9deb..fd85b51 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1499,6 +1499,11 @@ int arch_add_memory(int nid, u64 start, u64 size,
 	if (ret)
 		__remove_pgd_mapping(swapper_pg_dir,
 				     __phys_to_virt(start), size);
+	else {
+		max_pfn = PFN_UP(start + size);
+		max_low_pfn = max_pfn;
+	}
+
 	return ret;
 }
 
-- 
2.7.4