1 files changed, 30 insertions, 13 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 8b08fb955274..7b61036427df 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -333,11 +333,23 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
                                               req_type & _PAGE_CACHE_MASK);
         }
 
-        is_range_ram = pagerange_is_ram(start, end);
-        if (is_range_ram == 1)
-                return reserve_ram_pages_type(start, end, req_type, new_type);
-        else if (is_range_ram < 0)
-                return -EINVAL;
+        if (new_type)
+                *new_type = actual_type;
+
+        /*
+         * For legacy reasons, some parts of the physical address range in the
+         * legacy 1MB region is treated as non-RAM (even when listed as RAM in
+         * the e820 tables).  So we will track the memory attributes of this
+         * legacy 1MB region using the linear memtype_list always.
+         */
+        if (end >= ISA_END_ADDRESS) {
+                is_range_ram = pagerange_is_ram(start, end);
+                if (is_range_ram == 1)
+                        return reserve_ram_pages_type(start, end, req_type,
+                                                      new_type);
+                else if (is_range_ram < 0)
+                        return -EINVAL;
+        }
 
         new  = kmalloc(sizeof(struct memtype), GFP_KERNEL);
         if (!new)
@@ -347,9 +359,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
         new->end        = end;
         new->type       = actual_type;
 
-        if (new_type)
-                *new_type = actual_type;
-
         spin_lock(&memtype_lock);
 
         if (cached_entry && start >= cached_start)
@@ -437,11 +446,19 @@ int free_memtype(u64 start, u64 end)
         if (is_ISA_range(start, end - 1))
                 return 0;
 
-        is_range_ram = pagerange_is_ram(start, end);
-        if (is_range_ram == 1)
-                return free_ram_pages_type(start, end);
-        else if (is_range_ram < 0)
-                return -EINVAL;
+        /*
+         * For legacy reasons, some parts of the physical address range in the
+         * legacy 1MB region is treated as non-RAM (even when listed as RAM in
+         * the e820 tables).  So we will track the memory attributes of this
+         * legacy 1MB region using the linear memtype_list always.
+         */
+        if (end >= ISA_END_ADDRESS) {
+                is_range_ram = pagerange_is_ram(start, end);
+                if (is_range_ram == 1)
+                        return free_ram_pages_type(start, end);
+                else if (is_range_ram < 0)
+                        return -EINVAL;
+        }
 
         spin_lock(&memtype_lock);
         list_for_each_entry(entry, &memtype_list, nd) {