Merge tag 'devicetree-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / arch / arm64 / mm / init.c

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 4e90a1d170587376a41278820a0d0fc0e76fb8cf..edc8e950badaacac8ecf0f2b44879b02b121feeb 100644 (file)
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -168,6 +168,43 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
        free_area_init(max_zone_pfns);
 }
 
+int pfn_valid(unsigned long pfn)
+{
+       phys_addr_t addr = PFN_PHYS(pfn);
+       struct mem_section *ms;
+
+       /*
+        * Ensure the upper PAGE_SHIFT bits are clear in the
+        * pfn. Else it might lead to false positives when
+        * some of the upper bits are set, but the lower bits
+        * match a valid pfn.
+        */
+       if (PHYS_PFN(addr) != pfn)
+               return 0;
+
+       if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
+               return 0;
+
+       ms = __pfn_to_section(pfn);
+       if (!valid_section(ms))
+               return 0;
+
+       /*
+        * ZONE_DEVICE memory does not have the memblock entries.
+        * memblock_is_map_memory() check for ZONE_DEVICE based
+        * addresses will always fail. Even the normal hotplugged
+        * memory will never have MEMBLOCK_NOMAP flag set in their
+        * memblock entries. Skip memblock search for all non early
+        * memory sections covering all of hotplug memory including
+        * both normal and ZONE_DEVICE based.
+        */
+       if (!early_section(ms))
+               return pfn_section_valid(ms, pfn);
+
+       return memblock_is_memory(addr);
+}
+EXPORT_SYMBOL(pfn_valid);
+
 int pfn_is_map_memory(unsigned long pfn)
 {
        phys_addr_t addr = PFN_PHYS(pfn);