1 files changed, 38 insertions, 8 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 006281302925..7271fa33d791 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -617,7 +617,7 @@ __init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
  */
 __init void e820_setup_gap(void)
 {
-        unsigned long gapstart, gapsize, round;
+        unsigned long gapstart, gapsize;
         int found;
 
         gapstart = 0x10000000;
@@ -635,14 +635,9 @@ __init void e820_setup_gap(void)
 #endif
 
         /*
-         * See how much we want to round up: start off with
-         * rounding to the next 1MB area.
+         * e820_reserve_resources_late protect stolen RAM already
          */
-        round = 0x100000;
-        while ((gapsize >> 4) > round)
-                round += round;
-        /* Fun with two's complement */
-        pci_mem_start = (gapstart + round) & -round;
+        pci_mem_start = gapstart;
 
         printk(KERN_INFO
                "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
@@ -1371,6 +1366,23 @@ void __init e820_reserve_resources(void)
         }
 }
 
+/* How much should we pad RAM ending depending on where it is? */
+static unsigned long ram_alignment(resource_size_t pos)
+{
+        unsigned long mb = pos >> 20;
+
+        /* To 64kB in the first megabyte */
+        if (!mb)
+                return 64*1024;
+
+        /* To 1MB in the first 16MB */
+        if (mb < 16)
+                return 1024*1024;
+
+        /* To 32MB for anything above that */
+        return 32*1024*1024;
+}
+
 void __init e820_reserve_resources_late(void)
 {
         int i;
@@ -1382,6 +1394,24 @@ void __init e820_reserve_resources_late(void)
                         insert_resource_expand_to_fit(&iomem_resource, res);
                 res++;
         }
+
+        /*
+         * Try to bump up RAM regions to reasonable boundaries to
+         * avoid stolen RAM:
+         */
+        for (i = 0; i < e820.nr_map; i++) {
+                struct e820entry *entry = &e820_saved.map[i];
+                resource_size_t start, end;
+
+                if (entry->type != E820_RAM)
+                        continue;
+                start = entry->addr + entry->size;
+                end = round_up(start, ram_alignment(start));
+                if (start == end)
+                        continue;
+                reserve_region_with_split(&iomem_resource, start,
+                                                  end - 1, "RAM buffer");
+        }
 }
 
 char *__init default_machine_specific_memory_setup(void)