kernel - Change legacy MBR partition type from 0xA5 to 0x6C

* Should have done this years ago but finally change the legacy MBR partition type DragonFlyBSD uses from 0xA5 (which was shared with FreeBSD), to something different 0x6C. * Makes it less confusing for Grub. * Does not change EFI boot, which uses 16-byte UUIDs (we already have our own) and does not use 8-bit partition ids. * Boot code and kernel now recognize both 0xA5 and 0x6C. Existing users do *NOT* need to reinstall their boot code.
DragonFlyBSD · Sep 12, 2017 · 794d80a · 794d80a
1 parent 2116b62
commit 794d80a
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Showing 9 changed files with 49 additions and 32 deletions.
diff --git a/sbin/fdisk/fdisk.c b/sbin/fdisk/fdisk.c
@@ -174,6 +174,7 @@ struct part_type
 	,{0x63, "ISC UNIX, other System V/386, GNU HURD or Mach"}
 	,{0x64, "Novell Netware 2.xx"}
 	,{0x65, "Novell Netware 3.xx"}
+	,{0x6C, "DragonFlyBSD"}
 	,{0x70, "DiskSecure Multi-Boot"}
 	,{0x75, "PCIX"}
 	,{0x77, "QNX4.x"}
@@ -363,7 +364,7 @@ main(int argc, char *argv[])
 		read_s0();
 		reset_boot();
 		partp = (struct dos_partition *) (&mboot.parts[0]);
-		partp->dp_typ = DOSPTYP_386BSD;
+		partp->dp_typ = DOSPTYP_DFLYBSD;
 		partp->dp_flag = ACTIVE;
 		partp->dp_start = dos_sectors;
 		if (disksecs - dos_sectors > 0xFFFFFFFFU) {
@@ -559,7 +560,7 @@ struct dos_partition *partp = (struct dos_partition *) (&mboot.parts[3]);
 
 	init_boot();
 
-	partp->dp_typ = DOSPTYP_386BSD;
+	partp->dp_typ = DOSPTYP_DFLYBSD;
 	partp->dp_flag = ACTIVE;
 	start = roundup(start, dos_sectors);
 	if (start == 0)

diff --git a/sys/boot/pc32/boot0/boot0.S b/sys/boot/pc32/boot0/boot0.S
@@ -516,8 +516,8 @@ tables:
 		/*
 		 * These values indicate bootable types we know the names of.
 		 */
-		.byte 0x1, 0x6, 0x7, 0xb, 0xc, 0xe, 0x83
-		.byte 0x9f, 0xa5, 0xa6, 0xa9
+		.byte 0x1, 0x6, 0x7, 0xc, 0xe, 0x6c, 0x83, 0x9f
+		.byte 0xa5, 0xa6, 0xa9
 
 		/*
 		 * These are offsets that match the known names above and
@@ -529,10 +529,10 @@ tables:
 		.byte os_dos-.			# Windows
 		.byte os_dos-.			# Windows
 		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
+		.byte os_dfbsd-.		# DragonFly (new)
 		.byte os_linux-.		# Linux
 		.byte os_bsd-.			# BSD/OS
-		.byte os_dfbsd-.		# DragonFly/FreeBSD
+		.byte os_dfbsd-.		# DragonFly (old) / FreeBSD
 		.byte os_bsd-.			# OpenBSD
 		.byte os_bsd-.			# NetBSD
 

diff --git a/sys/boot/pc32/boot2/boot1.S b/sys/boot/pc32/boot2/boot1.S
@@ -54,6 +54,7 @@
 		.set PRT_OFF,0x1be		// Partition offset
 		.set PRT_NUM,0x4		// Partitions
 		.set PRT_BSD,0xa5		// Partition type
+		.set PRT_DFLY,0x6c		// Partition type
 
 // Flag Bits
 		.set FL_PACKET,0x80		// Packet mode
@@ -178,9 +179,11 @@ main:		cld				// String ops inc
 		mov $0x1,%cx	 		// Two passes
 main.1: 	mov $BOOT2_LOAD_BUF+PRT_OFF,%si	// Partition table
 		movb $0x1,%dh			// Partition
-main.2: 	cmpb $PRT_BSD,0x4(%si)		// Our partition type?
+main.2: 	cmpb $PRT_BSD,0x4(%si)		// FreeBSD / old DFly
+		je main.2a
+		cmpb $PRT_DFLY,0x4(%si)		// New DFly
 		jne main.3			// No
-		jcxz main.5			// If second pass
+main.2a:	jcxz main.5			// If second pass
 		testb $0x80,(%si)		// Active?
 		jnz main.5			// Yes
 main.3: 	add $0x10,%si	 		// Next entry
@@ -193,7 +196,6 @@ main.3: 	add $0x10,%si	 		// Next entry
 // If we get here, we didn't find any FreeBSD slices at all, so print an
 // error message and die.
 // 
-		mov $msg_part,%si		// Message
 		jmp error			// Error
 //
 // Floppies use partition 0 of drive 0.
@@ -299,14 +301,12 @@ nread_alt:
 		push %cs			// Read from
 		callw xread.1	 		//  disk
 		jnc return			// If success, return
-		mov $msg_read,%si		// Otherwise, set the error
-						//  message and fall through to
-						//  the error routine
-// 
-// Print out the error message pointed to by %ds:(%si) followed
-// by a prompt, wait for a keypress, and then reboot the machine.
+
+// Print that an error occured (no room to determine which error
+// occured) and the prompt.  Then wait for a keypress, then reboot the
+// machine.
 // 
-error:		callw putstr			// Display message
+error:
 		mov $prompt,%si			// Display
 		callw putstr			//  prompt
 		xorb %ah,%ah			// BIOS: Get
@@ -440,9 +440,6 @@ read.6: 	retw				// To caller
 
 // Messages
 
-msg_read:	.asciz "Read"
-msg_part:	.asciz "Boot"
-
 prompt: 	.asciz " error\r\n"
 
 flags:		.byte FLAGS			// Flags

diff --git a/sys/boot/pc32/boot2/boot2.c b/sys/boot/pc32/boot2/boot2.c
@@ -539,7 +539,8 @@ dskprobe(void)
     sl = dsk.slice;
     if (sl < BASE_SLICE) {
 	for (i = 0; i < NDOSPART; i++)
-	    if (dp[i].dp_typ == DOSPTYP_386BSD &&
+	    if ((dp[i].dp_typ == DOSPTYP_386BSD ||
+		 dp[i].dp_typ == DOSPTYP_DFLYBSD) &&
 		(dp[i].dp_flag & 0x80 || sl < BASE_SLICE)) {
 		sl = BASE_SLICE + i;
 		if (dp[i].dp_flag & 0x80 ||
@@ -552,7 +553,7 @@ dskprobe(void)
     if (sl != WHOLE_DISK_SLICE) {
 	if (sl != COMPATIBILITY_SLICE)
 	    dp += sl - BASE_SLICE;
-	if (dp->dp_typ != DOSPTYP_386BSD) {
+	if (dp->dp_typ != DOSPTYP_386BSD && dp->dp_typ != DOSPTYP_DFLYBSD) {
 	    printf(INVALID_S, "slice");
 	    return -1;
 	}

diff --git a/sys/boot/pc32/libi386/biosdisk.c b/sys/boot/pc32/libi386/biosdisk.c
@@ -277,8 +277,9 @@ bd_print(int verbose)
 		dptr = &od->od_slicetab[0];
 
 		/* Check for a "dedicated" disk */
-		if (((dptr[3].dp_typ == DOSPTYP_386BSD) ||
-			(dptr[3].dp_typ == DOSPTYP_NETBSD)) &&
+		if ((dptr[3].dp_typ == DOSPTYP_386BSD ||
+		     dptr[3].dp_typ == DOSPTYP_NETBSD ||
+		     dptr[3].dp_typ == DOSPTYP_DFLYBSD) &&
 		    (dptr[3].dp_start == 0) &&
 		    (dptr[3].dp_size == 50000)) {
 		    sprintf(line, "      disk%d", i);
@@ -306,6 +307,7 @@ bd_printslice(struct open_disk *od, struct dos_partition *dp, char *prefix,
 	char line[80];
 
 	switch (dp->dp_typ) {
+	case DOSPTYP_DFLYBSD:
 	case DOSPTYP_386BSD:
 	case DOSPTYP_NETBSD:
 	/* XXX: possibly add types 0 and 1, as in subr_disk, for gpt magic */
@@ -637,7 +639,8 @@ bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev)
     /*
      * Check for the historically bogus MBR found on true dedicated disks
      */
-    if ((dptr[3].dp_typ == DOSPTYP_386BSD) &&
+    if ((dptr[3].dp_typ == DOSPTYP_386BSD ||
+	 dptr[3].dp_typ == DOSPTYP_DFLYBSD) &&
       (dptr[3].dp_start == 0) &&
       (dptr[3].dp_size == 50000)) {
         sector = 0;
@@ -664,10 +667,14 @@ bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev)
     DEBUG("slice entry %d at %d, %d sectors", dev->d_kind.biosdisk.slice - 1, sector, dptr->dp_size);
 
     /*
-     * If we are looking at a BSD slice, and the partition is < 0, assume the 'a' partition
+     * If we are looking at a BSD slice, and the partition is < 0,
+     * assume the 'a' partition
      */
-    if ((dptr->dp_typ == DOSPTYP_386BSD) && (dev->d_kind.biosdisk.partition < 0))
+    if ((dptr->dp_typ == DOSPTYP_386BSD ||
+	 dptr->dp_typ == DOSPTYP_DFLYBSD) &&
+        dev->d_kind.biosdisk.partition < 0) {
 	dev->d_kind.biosdisk.partition = 0;
+    }
 
 unsliced:
     /* 
@@ -878,7 +885,8 @@ bd_bestslice(struct open_disk *od)
 	dp = &od->od_slicetab[0];
 	for (i = 0; i < od->od_nslices; i++, dp++) {
 		switch (dp->dp_typ) {
-		case DOSPTYP_386BSD:		/* FreeBSD */
+		case DOSPTYP_DFLYBSD:		/* DragonFlyBSD */
+		case DOSPTYP_386BSD:		/* FreeBSD and old DFlyBSD */
 			pref = dp->dp_flag & 0x80 ? PREF_FBSD_ACT : PREF_FBSD;
 			break;
 

diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
@@ -290,7 +290,8 @@ disk_probe_slice(struct disk *dp, cdev_t dev, int slice, int reprobe)
 	} else {
 		if (sp->ds_type == DOSPTYP_386BSD || /* XXX */
 		    sp->ds_type == DOSPTYP_NETBSD ||
-		    sp->ds_type == DOSPTYP_OPENBSD) {
+		    sp->ds_type == DOSPTYP_OPENBSD ||
+		    sp->ds_type == DOSPTYP_DFLYBSD) {
 			log(LOG_WARNING, "%s: cannot find label (%s)\n",
 			    dev->si_name, msg);
 		}
@@ -453,6 +454,7 @@ disk_probe(struct disk *dp, int reprobe)
 		if (sp->ds_type == DOSPTYP_386BSD ||
 		    sp->ds_type == DOSPTYP_NETBSD ||
 		    sp->ds_type == DOSPTYP_OPENBSD ||
+		    sp->ds_type == DOSPTYP_DFLYBSD ||
 		    sp->ds_type == 0 ||
 		    sp->ds_type == 1) {
 			if (dp->d_slice->dss_first_bsd_slice == 0)

diff --git a/sys/kern/subr_diskmbr.c b/sys/kern/subr_diskmbr.c
@@ -67,13 +67,13 @@ 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, },
+	{ 0x80, 0, 1, 0, DOSPTYP_DFLYBSD, 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, },
+	{ 0x80, 0, 1, 0, DOSPTYP_DFLYBSD, 254, 255, 255, 0, 50000, },
 };
 
 static int check_part (char *sname, struct dos_partition *dp,
@@ -205,7 +205,8 @@ mbrinit(cdev_t dev, struct disk_info *info, struct diskslices **sspp)
 	/*
 	 * TODO:
 	 * Perhaps skip entries with 0 size.
-	 * Perhaps only look at entries of type DOSPTYP_386BSD.
+	 * Perhaps only look at entries of type DOSPTYP_386BSD or
+	 * DOSPTYP_DFLYBSD
 	 */
 	max_ncyls = 0;
 	max_nsectors = 0;

diff --git a/sys/kern/subr_diskslice.c b/sys/kern/subr_diskslice.c
@@ -778,9 +778,11 @@ dsreadandsetlabel(cdev_t dev, u_int flags,
 		lp = ops->op_clone_label(info, sp);
 	}
 	if (msg != NULL) {
-		if (sp->ds_type == DOSPTYP_386BSD /* XXX */)
+		if (sp->ds_type == DOSPTYP_386BSD ||
+		    sp->ds_type == DOSPTYP_DFLYBSD) {
 			log(LOG_WARNING, "%s: cannot find label (%s)\n",
 			    sname, msg);
+		}
 		if (lp.opaque)
 			kfree(lp.opaque, M_DEVBUF);
 	} else {

diff --git a/sys/sys/diskmbr.h b/sys/sys/diskmbr.h
@@ -47,6 +47,11 @@
 #define	DOSMAGICOFFSET	510
 #define	DOSMAGIC	0xAA55
 
+/*
+ * NOTE: DragonFlyBSD had been using 0xA5 forever but after many years
+ *	 we're finally shifting to our own as A5 causes conflicts in grub.
+ */
+#define	DOSPTYP_DFLYBSD	0x6c	/* DragonFlyBSD partition type */
 #define	DOSPTYP_386BSD	0xa5	/* 386BSD partition type */
 #define	DOSPTYP_OPENBSD	0xa6	/* OpenBSD partition type */
 #define	DOSPTYP_NETBSD	0xa9	/* NetBSD partition type */