Merge branch 'topic/hdsp' into for-linus

[sfrench/cifs-2.6.git] / arch / x86 / boot / memory.c

diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index 5054c2ddd1a03471b4423e7c9eb1719dca667901..74b3d2ba84e90a39bb29f166278ce47bcf56437c 100644 (file)
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -17,11 +17,6 @@
 
 #define SMAP   0x534d4150      /* ASCII "SMAP" */
 
-struct e820_ext_entry {
-       struct e820entry std;
-       u32 ext_flags;
-} __attribute__((packed));
-
 static int detect_memory_e820(void)
 {
        int count = 0;
@@ -29,13 +24,21 @@ static int detect_memory_e820(void)
        u32 size, id, edi;
        u8 err;
        struct e820entry *desc = boot_params.e820_map;
-       static struct e820_ext_entry buf; /* static so it is zeroed */
+       static struct e820entry buf; /* static so it is zeroed */
 
        /*
-        * Set this here so that if the BIOS doesn't change this field
-        * but still doesn't change %ecx, we're still okay...
+        * Note: at least one BIOS is known which assumes that the
+        * buffer pointed to by one e820 call is the same one as
+        * the previous call, and only changes modified fields.  Therefore,
+        * we use a temporary buffer and copy the results entry by entry.
+        *
+        * This routine deliberately does not try to account for
+        * ACPI 3+ extended attributes.  This is because there are
+        * BIOSes in the field which report zero for the valid bit for
+        * all ranges, and we don't currently make any use of the
+        * other attribute bits.  Revisit this if we see the extended
+        * attribute bits deployed in a meaningful way in the future.
         */
-       buf.ext_flags = 1;
 
        do {
                size = sizeof buf;
@@ -66,13 +69,7 @@ static int detect_memory_e820(void)
                        break;
                }
 
-               /* ACPI 3.0 added the extended flags support.  If bit 0
-                  in the extended flags is zero, we're supposed to simply
-                  ignore the entry -- a backwards incompatible change! */
-               if (size > 20 && !(buf.ext_flags & 1))
-                       continue;
-
-               *desc++ = buf.std;
+               *desc++ = buf;
                count++;
        } while (next && count < ARRAY_SIZE(boot_params.e820_map));