memdisk: Calculate mBFT checksum later

We were calculating the mBFT checksum too early; dpt_ptr could
change after checksumming, so we now do it after that possibility.

Signed-off-by: Shao Miller <shao.miller@yrdsb.edu.on.ca>

diff --git a/memdisk/setup.c b/memdisk/setup.c
index cec25ad..db1c4bc 100644 (file)
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -1,8 +1,9 @@
 /* ----------------------------------------------------------------------- *
  *
  *   Copyright 2001-2009 H. Peter Anvin - All Rights Reserved
- *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
- *   Portions copyright 2009 Shao Miller [El Torito code, mBFT, safe hook]
+ *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *   Portions copyright 2009-2010 Shao Miller
+ *                               [El Torito code, mBFT, "safe hook"]
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -1212,18 +1213,6 @@ void setup(const struct real_mode_args *rm_args_ptr)
     /* Re-fill the "safe hook" mBFT field with the physical address */
     safe_hook->mBFT += (uint32_t)hptr;
 
-    /* Complete the mBFT */
-    {
-       struct mBFT *mBFT = (struct mBFT *)safe_hook->mBFT;
-
-       mBFT->acpi.signature[0] = 'm';  /* "mBFT" */
-       mBFT->acpi.signature[1] = 'B';
-       mBFT->acpi.signature[2] = 'F';
-       mBFT->acpi.signature[3] = 'T';
-       mBFT->safe_hook = (uint32_t)safe_hook;
-       mBFT->acpi.checksum = -checksum_buf(mBFT, mBFT->acpi.length);
-    }
-
     /* Update various BIOS magic data areas (gotta love this shit) */
 
     if (geometry->driveno & 0x80) {
@@ -1257,6 +1246,18 @@ void setup(const struct real_mode_args *rm_args_ptr)
        }
     }
 
+    /* Complete the mBFT */
+    {
+       struct mBFT *mBFT = (struct mBFT *)safe_hook->mBFT;
+
+       mBFT->acpi.signature[0] = 'm';  /* "mBFT" */
+       mBFT->acpi.signature[1] = 'B';
+       mBFT->acpi.signature[2] = 'F';
+       mBFT->acpi.signature[3] = 'T';
+       mBFT->safe_hook = (uint32_t)safe_hook;
+       mBFT->acpi.checksum = -checksum_buf(mBFT, mBFT->acpi.length);
+    }
+
     /* Install the interrupt handlers */
     printf("old: int13 = %08x  int15 = %08x  int1e = %08x\n",
           rdz_32(BIOS_INT13), rdz_32(BIOS_INT15), rdz_32(BIOS_INT1E));