Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup:
  [x86 setup] Handle case of improperly terminated E820 chain

1 files changed, 23 insertions, 7 deletions

diff --git a/arch/i386/boot/memory.c b/arch/i386/boot/memory.c
index 1a2e62db8bed..bccaa1cf6645 100644
--- a/arch/i386/boot/memory.c
+++ b/arch/i386/boot/memory.c
@@ -20,6 +20,7 @@
 
 static int detect_memory_e820(void)
 {
+        int count = 0;
         u32 next = 0;
         u32 size, id;
         u8 err;
@@ -33,14 +34,24 @@ static int detect_memory_e820(void)
                       "=m" (*desc)
                     : "D" (desc), "a" (0xe820));
 
-                if (err || id != SMAP)
+                /* Some BIOSes stop returning SMAP in the middle of
+                   the search loop.  We don't know exactly how the BIOS
+                   screwed up the map at that point, we might have a
+                   partial map, the full map, or complete garbage, so
+                   just return failure. */
+                if (id != SMAP) {
+                        count = 0;
                         break;
+                }
 
-                boot_params.e820_entries++;
+                if (err)
+                        break;
+
+                count++;
                 desc++;
-        } while (next && boot_params.e820_entries < E820MAX);
+        } while (next && count < E820MAX);
 
-        return boot_params.e820_entries;
+        return boot_params.e820_entries = count;
 }
 
 static int detect_memory_e801(void)
@@ -89,11 +100,16 @@ static int detect_memory_88(void)
 
 int detect_memory(void)
 {
+        int err = -1;
+
         if (detect_memory_e820() > 0)
-                return 0;
+                err = 0;
 
         if (!detect_memory_e801())
-                return 0;
+                err = 0;
+
+        if (!detect_memory_88())
+                err = 0;
 
-        return detect_memory_88();
+        return err;
 }