[PATCH 5.10 286/575] arm64: mm: update max_pfn after memory hotplug

[Greg Kroah-Hartman]

From: Sudarshan Rajagopalan <quic_sudaraja@xxxxxxxxxxx>

[ Upstream commit 8fac67ca236b961b573355e203dbaf62a706a2e5 ]

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.
Without this patch, debug-related functions that use max_pfn such as
get_max_dump_pfn() or read_page_owner() will not work with any page in
memory that is hot-added after boot.

Fixes: 4ab215061554 ("arm64: Add memory hotplug support")
Signed-off-by: Sudarshan Rajagopalan <quic_sudaraja@xxxxxxxxxxx>
Signed-off-by: Chris Goldsworthy <quic_cgoldswo@xxxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Florian Fainelli <f.fainelli@xxxxxxxxx>
Cc: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx>
Tested-by: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/a51a27ee7be66024b5ce626310d673f24107bcb8.1632853776.git.quic_cgoldswo@xxxxxxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 58dc93e566179..2601a514d8c4a 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1492,6 +1492,11 @@ 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;
 }
 
-- 
2.33.0