Cheers,
--
Thomas E. Spanjaard
[EMAIL PROTECTED]
diff -r c74ab86802f6 -r 698fc3960f3f sys/kern/subr_diskmbr.c
--- a/sys/kern/subr_diskmbr.c Sat Nov 25 17:07:06 2006 +0000
+++ b/sys/kern/subr_diskmbr.c Sat Nov 25 20:02:05 2006 +0000
@@ -35,7 +35,7 @@
*
* from: @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91
* from: ufs_disksubr.c,v 1.8 1994/06/07 01:21:39 phk Exp $
- * $FreeBSD: src/sys/kern/subr_diskmbr.c,v 1.45 2000/01/28 10:22:07 bde Exp $
+ * $FreeBSD: src/sys/kern/subr_diskmbr.c,v 1.54 2001/12/11 05:35:43 peter Exp $
* $DragonFly: src/sys/kern/subr_diskmbr.c,v 1.13 2006/04/30 17:22:17 dillon Exp $
*/
@@ -57,11 +57,28 @@
static volatile u_char dsi_debug;
+/*
+ * This is what we have embedded in every boot1 for supporting the bogus
+ * "Dangerously Dedicated" mode. However, the old table is broken because
+ * it has an illegal geometry in it - it specifies 256 heads (heads = end
+ * head + 1) which causes nasty stuff when that wraps to zero in bios code.
+ * eg: divide by zero etc. This caused the dead-thinkpad problem, numerous
+ * SCSI bios crashes, EFI to crash, etc.
+ *
+ * We still have to recognize the old table though, even though we stopped
+ * inflicting it upon the world.
+ */
static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
+};
+static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
+ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
+ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
+ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
+ { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
};
static int check_part (char *sname, struct dos_partition *dp,
@@ -102,7 +119,8 @@ check_part(char *sname, struct dos_parti
* If ssector1 is on a cylinder >= 1024, then ssector can't be right.
* Allow the C/H/S for it to be 1023/ntracks-1/nsectors, or correct
* apart from the cylinder being reduced modulo 1024. Always allow
- * 1023/255/63.
+ * 1023/255/63, because this is the official way to represent
+ * pure-LBA for the starting position.
*/
if ((ssector < ssector1
&& ((chs_ssect == nsectors && dp->dp_shd == ntracks - 1
@@ -122,7 +140,12 @@ check_part(char *sname, struct dos_parti
+ mbr_offset;
esector1 = ssector1 + dp->dp_size - 1;
- /* Allow certain bogus C/H/S values for esector, as above. */
+ /*
+ * Allow certain bogus C/H/S values for esector, as above. However,
+ * heads == 255 isn't really legal and causes some BIOS crashes. The
+ * correct value to indicate a pure-LBA end is 1023/heads-1/sectors -
+ * usually 1023/254/63. "heads" is base 0, "sectors" is base 1.
+ */
if ((esector < esector1
&& ((chs_esect == nsectors && dp->dp_ehd == ntracks - 1
&& chs_ecyl == 1023)
@@ -220,9 +243,17 @@ reread_mbr:
}
if (bcmp(dp0, historical_bogus_partition_table,
- sizeof historical_bogus_partition_table) == 0) {
+ sizeof historical_bogus_partition_table) == 0 ||
+ bcmp(dp0, historical_bogus_partition_table_fixed,
+ sizeof historical_bogus_partition_table_fixed) == 0) {
+#if 0
TRACE(("%s: invalid primary partition table: historical\n",
sname));
+#endif /* 0 */
+ if (bootverbose)
+ printf(
+ "%s: invalid primary partition table: Dangerously Dedicated (ignored)\n",
+ sname);
error = EINVAL;
goto done;
}
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