1 files changed, 33 insertions, 17 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ad38648bddbd..ebe1811e5b1e 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -671,12 +671,13 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
         unsigned long last_map_addr = 0;
         unsigned long page_size_mask = 0;
         unsigned long start_pfn, end_pfn;
+        unsigned long pos;
 
         struct map_range mr[NR_RANGE_MR];
         int nr_range, i;
         int use_pse, use_gbpages;
 
-        printk(KERN_INFO "init_memory_mapping\n");
+        printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 
         /*
          * Find space for the kernel direct mapping tables.
@@ -710,35 +711,50 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 
         /* head if not big page alignment ?*/
         start_pfn = start >> PAGE_SHIFT;
-        end_pfn = ((start + (PMD_SIZE - 1)) >> PMD_SHIFT)
+        pos = start_pfn << PAGE_SHIFT;
+        end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
                         << (PMD_SHIFT - PAGE_SHIFT);
-        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+        if (start_pfn < end_pfn) {
+                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+                pos = end_pfn << PAGE_SHIFT;
+        }
 
         /* big page (2M) range*/
-        start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+        start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                          << (PMD_SHIFT - PAGE_SHIFT);
-        end_pfn = ((start + (PUD_SIZE - 1))>>PUD_SHIFT)
+        end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
                          << (PUD_SHIFT - PAGE_SHIFT);
-        if (end_pfn > ((end>>PUD_SHIFT)<<(PUD_SHIFT - PAGE_SHIFT)))
-                end_pfn = ((end>>PUD_SHIFT)<<(PUD_SHIFT - PAGE_SHIFT));
-        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
-                        page_size_mask & (1<<PG_LEVEL_2M));
+        if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
+                end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
+        if (start_pfn < end_pfn) {
+                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+                                page_size_mask & (1<<PG_LEVEL_2M));
+                pos = end_pfn << PAGE_SHIFT;
+        }
 
         /* big page (1G) range */
-        start_pfn = end_pfn;
-        end_pfn = (end>>PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
-        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+        start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
+                         << (PUD_SHIFT - PAGE_SHIFT);
+        end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
+        if (start_pfn < end_pfn) {
+                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
                                 page_size_mask &
                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
+                pos = end_pfn << PAGE_SHIFT;
+        }
 
         /* tail is not big page (1G) alignment */
-        start_pfn = end_pfn;
-        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
-        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
-                        page_size_mask & (1<<PG_LEVEL_2M));
+        start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
+                         << (PMD_SHIFT - PAGE_SHIFT);
+        end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
+        if (start_pfn < end_pfn) {
+                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+                                page_size_mask & (1<<PG_LEVEL_2M));
+                pos = end_pfn << PAGE_SHIFT;
+        }
 
         /* tail is not big page (2M) alignment */
-        start_pfn = end_pfn;
+        start_pfn = pos>>PAGE_SHIFT;
         end_pfn = end>>PAGE_SHIFT;
         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);