package/boot/grub/usb-cd.patch

   1 # --- T2-COPYRIGHT-NOTE-BEGIN ---
   2 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
   3 #
   4 # T2 SDE: package/.../grub/usb-cd.patch
   5 # Copyright (C) 2011 The T2 SDE Project
   6 #
   7 # More information can be found in the files COPYING and README.
   8 #
   9 # This patch file is dual-licensed. It is available under the license the
  10 # patched project is licensed under, as long as it is an OpenSource license
  11 # as defined at http://www.opensource.org/ (e.g. BSD, X11) or under the terms
  12 # of the GNU General Public License as published by the Free Software
  13 # Foundation; either version 2 of the License, or (at your option) any later
  14 # version.
  15 # --- T2-COPYRIGHT-NOTE-END ---
  16
  17 Some Phoenix / Award BIOS does corrupt itself, if the disk system reset
  18 or version query is called when booting from an USB CD-ROM. Strangely,
  19 however, those Phoenix/Award BIOS did work fine booting from an internal
  20 IDE CD. Whatever.
  21
  22 Avoid said calls and additionally incorporated another Award BIOS
  23 fix, searching for an instruction sequence and extracting the
  24 call address, as well as hardened reading (retry including decreased
  25 sizes, also inspired by isolinux) and check the carry flag to pro-
  26 actively further help potentially broken BIOSes, as there are so
  27 many of those, ...
  28
  29   - Rene Rebe <rene@exactcode.de>
  30
  31 diff -ur grub-0.97/stage2/asm.S grub-0.97-fixed/stage2/asm.S
  32 --- grub-0.97/stage2/asm.S      2004-06-19 18:55:22.000000000 +0200
  33 +++ grub-0.97-fixed/stage2/asm.S        2007-09-30 15:35:34.000000000 +0200
  34 @@ -139,7 +139,7 @@
  35         ADDR32  movb    %dl, EXT_C(boot_drive)
  36
  37         /* reset disk system (%ah = 0) */
  38 -       int     $0x13
  39 +       /* int  $0x13 */ /* appears to confuse Phoenix/Award BIOS with USB CDs -ReneR */
  40  #endif
  41
  42         /* transition to protected mode */
  43 @@ -971,7 +1060,10 @@
  44         movw    %bx, %ax
  45         movw    %cx, %ds
  46         int     $0x13           /* do the operation */
  47 -       movb    %ah, %dl        /* save return value */
  48 +       jc      1f              /* carry flag indicates error -ReneR */
  49 +       xor     %ah, %ah        /* no error: clearn ah just in case, ... */
  50 +1:     movb    %ah, %dl        /* save return value */
  51 +
  52         /* clear the data segment */
  53         xorw    %ax, %ax
  54         movw    %ax, %ds
  55 diff -ur grub-0.97/stage2/bios.c grub-0.97-fixed/stage2/bios.c
  56 --- grub-0.97/stage2/bios.c     2004-03-27 17:34:04.000000000 +0100
  57 +++ grub-0.97-fixed/stage2/bios.c       2007-09-30 15:40:29.000000000 +0200
  58 @@ -61,27 +61,54 @@
  59         unsigned long buffer;
  60         unsigned long long block;
  61        } __attribute__ ((packed)) dap;
  62 +
  63 +      int retry_count = 4;
  64 +
  65 +      while (nsec > 0 && retry_count > 0) {
  66
  67 -      /* XXX: Don't check the geometry by default, because some buggy
  68 -        BIOSes don't return the number of total sectors correctly,
  69 -        even if they have working LBA support. Hell.  */
  70 +       /* XXX: Don't check the geometry by default, because some buggy
  71 +          BIOSes don't return the number of total sectors correctly,
  72 +          even if they have working LBA support. Hell.  */
  73  #ifdef NO_BUGGY_BIOS_IN_THE_WORLD
  74 -      if (sector >= geometry->total_sectors)
  75 -       return BIOSDISK_ERROR_GEOMETRY;
  76 +       if (sector >= geometry->total_sectors)
  77 +         return BIOSDISK_ERROR_GEOMETRY;
  78  #endif /* NO_BUGGY_BIOS_IN_THE_WORLD */
  79 -
  80 -      /* FIXME: sizeof (DAP) must be 0x10. Should assert that the compiler
  81 -        can't add any padding.  */
  82 -      dap.length = sizeof (dap);
  83 -      dap.block = sector;
  84 -      dap.blocks = nsec;
  85 -      dap.reserved = 0;
  86 -      /* This is undocumented part. The address is formated in
  87 -        SEGMENT:ADDRESS.  */
  88 -      dap.buffer = segment << 16;
  89 +
  90 +
  91 +       /* FIXME: sizeof (DAP) must be 0x10. Should assert that the compiler
  92 +          can't add any padding.  */
  93 +       dap.length = sizeof (dap);
  94 +       dap.block = sector;
  95 +       switch (retry_count) {
  96 +       case 1:
  97 +         dap.blocks = 1; break;
  98 +       case 2:
  99 +         dap.blocks = nsec / 2; break;
 100 +       default:
 101 +         dap.blocks = nsec;
 102 +       }
 103 +       dap.reserved = 0;
 104 +       /* This is undocumented part. The address is formated in
 105 +          SEGMENT:ADDRESS.  */
 106 +       dap.buffer = segment << 16;
 107 +
 108 +       err = biosdisk_int13_extensions ((read + 0x42) << 8, drive, &dap);
 109 +
 110 +       if (err && ! geometry->flags & BIOSDISK_FLAG_CDROM)
 111 +         break; /* only retry for CD-ROMs */
 112 +       if (err) {
 113 +         printf ("biosdisk: err: %x\n", (int) err);
 114 +         --retry_count;
 115 +       }
 116 +
 117 +       if (!err) {
 118 +         sector += dap.blocks;
 119 +         nsec -= dap.blocks;
 120 +         segment += geometry->sector_size / 16; /* 16 bytes per segment */
 121 +         retry_count = 3; /* refresh on success */
 122 +       }
 123 +      }
 124
 125 -      err = biosdisk_int13_extensions ((read + 0x42) << 8, drive, &dap);
 126 -
 127  /* #undef NO_INT13_FALLBACK */
 128  #ifndef NO_INT13_FALLBACK
 129        if (err)
 130 @@ -142,11 +168,42 @@
 131      unsigned char heads;
 132
 133      unsigned char dummy[16];
 134 -  } __attribute__ ((packed)) cdrp;
 135 +  } __attribute__ ((packed)) cdrp __attribute__ ((aligned(8)));
 136
 137    grub_memset (&cdrp, 0, sizeof (cdrp));
 138    cdrp.size = sizeof (cdrp) - sizeof (cdrp.dummy);
 139    err = biosdisk_int13_extensions (0x4B01, drive, &cdrp);
 140 +
 141 +  /* On error try to find a broken Award BIOS, idea and signature from isolinux.
 142 +     -ReneR */
 143 +#if !defined(NO_BUGGY_BIOS_IN_THE_WORLD) && defined(FSYS_ISO9660)
 144 +  if (err || cdrp.drive_no != drive)
 145 +    {
 146 +      const char award_string [] = { 0xb8,1,2,0xbb,0,0x7c,0xb9,6,0,0xba,0x80,1,0x9c,0x9a };
 147 +      char* bios_addr;
 148 +
 149 +      /* printf ("get_cdinfo: failed. Searching for broken Award BIOS signature ...\n"); */
 150 +      for (bios_addr = (char*)0xf0000; bios_addr < (char*) 0xfffff; ++bios_addr)
 151 +       if (grub_memcmp (bios_addr, award_string, sizeof (award_string)) == 0)
 152 +         break;
 153 +
 154 +      if (bios_addr != (void*)0xfffff)
 155 +       {
 156 +         void** int13_vector = (void**) (0x13 * 4);
 157 +         void** call_addr = (void**)(bios_addr + 0x0e);
 158 +
 159 +         /* printf ("get_cdinfo: found Award signature @ %x\n", bios_addr); */
 160 +         if (*int13_vector != *call_addr) {
 161 +           printf ("get_cdinfo: patching INT13 old: %x new: %x\n", *int13_vector, *call_addr);
 162 +
 163 +           *int13_vector = *call_addr;
 164 +           err = biosdisk_int13_extensions (0x4B01, drive, &cdrp);
 165 +         }
 166 +         /* else
 167 +           printf ("get_cdinfo: INT13 already pointing to same entry.\n"); */
 168 +       }
 169 +    }
 170 +#endif
 171    if (! err && cdrp.drive_no == drive)
 172      {
 173        if ((cdrp.media_type & 0x0F) == 0)