Merge branch 'x86/setup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux...

* 'x86/setup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, setup: ACPI 3, BIOS workaround for E820-probing code
  x86, setup: preemptively save/restore edi and ebp around INT 15 E820
  x86, setup: mark %esi as clobbered in E820 BIOS call

diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index 8c3c25f35578a00c140440131a69ae539038f950..d5d2360763dc0e7e4512e9a63987d0aff89097d2 100644 (file)
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -2,6 +2,7 @@
  *
  *   Copyright (C) 1991, 1992 Linus Torvalds
  *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *   Copyright 2009 Intel Corporation; author H. Peter Anvin
  *
  *   This file is part of the Linux kernel, and is made available under
  *   the terms of the GNU General Public License version 2.
@@ -16,24 +17,32 @@
 
 #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;
        u32 next = 0;
-       u32 size, id;
+       u32 size, id, edi;
        u8 err;
        struct e820entry *desc = boot_params.e820_map;
+       static struct e820_ext_entry buf; /* static so it is zeroed */
 
        do {
-               size = sizeof(struct e820entry);
+               size = sizeof buf;
 
-               /* Important: %edx is clobbered by some BIOSes,
-                  so it must be either used for the error output
-                  or explicitly marked clobbered. */
-               asm("int $0x15; setc %0"
+               /* Important: %edx and %esi are clobbered by some BIOSes,
+                  so they must be either used for the error output
+                  or explicitly marked clobbered.  Given that, assume there
+                  is something out there clobbering %ebp and %edi, too. */
+               asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"
                    : "=d" (err), "+b" (next), "=a" (id), "+c" (size),
-                     "=m" (*desc)
-                   : "D" (desc), "d" (SMAP), "a" (0xe820));
+                     "=D" (edi), "+m" (buf)
+                   : "D" (&buf), "d" (SMAP), "a" (0xe820)
+                   : "esi");
 
                /* BIOSes which terminate the chain with CF = 1 as opposed
                   to %ebx = 0 don't always report the SMAP signature on
@@ -51,8 +60,14 @@ 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;
                count++;
-               desc++;
        } while (next && count < ARRAY_SIZE(boot_params.e820_map));
 
        return boot_params.e820_entries = count;