Fix booting from an IDE block device on the Sun Blade 100. Apparently

writing to disk using the Open Firmware interfaces is buggy and causes
corruption of the disk.  While it isn't entirely clear what versions
of Open Firmware are affected, but it seems to only affect IDE drives.
So if we detect an IDE drive, disable writing to it.  This results in
a small lose of bootloader functionality (bsd.upgrade loop prevention
and flagging /etc/random.seed re-use) but that is better than losing
the ability to run OpenBSD at all.

Based on a diff by Ted Bullock (who did all the hard work of debugging
this and coming up with a viable fix).

ok deraadt@

2 files changed, 20 insertions, 9 deletions

diff --git a/sys/arch/sparc64/stand/ofwboot/ofdev.c b/sys/arch/sparc64/stand/ofwboot/ofdev.c
index c23b4129c66..2a4a37e2f78 100644
--- a/sys/arch/sparc64/stand/ofwboot/ofdev.c
+++ b/sys/arch/sparc64/stand/ofwboot/ofdev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ofdev.c,v 1.31 2020/12/09 18:10:19 krw Exp $	*/
+/*	$OpenBSD: ofdev.c,v 1.32 2021/12/01 17:25:35 kettenis Exp $	*/
 /*	$NetBSD: ofdev.c,v 1.1 2000/08/20 14:58:41 mrg Exp $	*/
 
 /*
@@ -520,7 +520,7 @@ devopen(struct open_file *of, const char *name, char **file)
 	char fname[256];
 	char buf[DEV_BSIZE];
 	struct disklabel label;
-	int handle, part;
+	int dhandle, ihandle, part, parent;
 	int error = 0;
 #ifdef SOFTRAID
 	char volno;
@@ -647,23 +647,24 @@ devopen(struct open_file *of, const char *name, char **file)
 		return 0;
 	}
 #endif
-	if ((handle = OF_finddevice(fname)) == -1)
+	if ((dhandle = OF_finddevice(fname)) == -1)
 		return ENOENT;
+
 	DNPRINTF(BOOT_D_OFDEV, "devopen: found %s\n", fname);
-	if (OF_getprop(handle, "name", buf, sizeof buf) < 0)
+	if (OF_getprop(dhandle, "name", buf, sizeof buf) < 0)
 		return ENXIO;
 	DNPRINTF(BOOT_D_OFDEV, "devopen: %s is called %s\n", fname, buf);
-	if (OF_getprop(handle, "device_type", buf, sizeof buf) < 0)
+	if (OF_getprop(dhandle, "device_type", buf, sizeof buf) < 0)
 		return ENXIO;
 	DNPRINTF(BOOT_D_OFDEV, "devopen: %s is a %s device\n", fname, buf);
 	DNPRINTF(BOOT_D_OFDEV, "devopen: opening %s\n", fname);
-	if ((handle = OF_open(fname)) == -1) {
+	if ((ihandle = OF_open(fname)) == -1) {
 		DNPRINTF(BOOT_D_OFDEV, "devopen: open of %s failed\n", fname);
 		return ENXIO;
 	}
 	DNPRINTF(BOOT_D_OFDEV, "devopen: %s is now open\n", fname);
 	bzero(&ofdev, sizeof ofdev);
-	ofdev.handle = handle;
+	ofdev.handle = ihandle;
 	ofdev.type = OFDEV_DISK;
 	ofdev.bsize = DEV_BSIZE;
 	if (!strcmp(buf, "block")) {
@@ -685,6 +686,16 @@ devopen(struct open_file *of, const char *name, char **file)
 
 		of->f_dev = devsw;
 		of->f_devdata = &ofdev;
+
+		/* Some PROMS have buggy writing code for IDE block devices */
+		parent = OF_parent(dhandle);
+		if (parent && OF_getprop(parent, "device_type", buf,
+		    sizeof(buf)) > 0 && strcmp(buf, "ide") == 0) {
+			DNPRINTF(BOOT_D_OFDEV, 
+			    "devopen: Disable writing for IDE block device\n");
+			of->f_flags |= F_NOWRITE;
+		}
+
 #ifdef SPARC_BOOT_UFS
 		bcopy(&file_system_ufs, &file_system[nfsys++], sizeof file_system[0]);
 		bcopy(&file_system_ufs2, &file_system[nfsys++], sizeof file_system[0]);
@@ -712,7 +723,7 @@ devopen(struct open_file *of, const char *name, char **file)
 bad:
 	DNPRINTF(BOOT_D_OFDEV, "devopen: error %d, cannot open device\n",
 	    error);
-	OF_close(handle);
+	OF_close(ihandle);
 	ofdev.handle = -1;
 	return error;
 }
diff --git a/sys/arch/sparc64/stand/ofwboot/vers.c b/sys/arch/sparc64/stand/ofwboot/vers.c
index 3ca4ec8093b..78466bad3c0 100644
--- a/sys/arch/sparc64/stand/ofwboot/vers.c
+++ b/sys/arch/sparc64/stand/ofwboot/vers.c
@@ -1 +1 @@
-const char version[] = "1.21";
+const char version[] = "1.22";