git: afca197f5240 - main - ofwbus: only allow unit number zero

The branch main has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=afca197f5240ce2c2c7abfe5c9fbc50ba55f178b

commit afca197f5240ce2c2c7abfe5c9fbc50ba55f178b
Author:     Mitchell Horne <mhorne@FreeBSD.org>
AuthorDate: 2023-02-13 17:44:03 +0000
Commit:     Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2023-02-13 17:45:01 +0000

    ofwbus: only allow unit number zero
    
    ofwbus has always been the root of attachment for OFW/FDT platforms. It
    may have simplebus children, but we expect only one instance of the
    ofwbus driver, added directly by nexus. We may as well ensure this
    remains the case.
    
    Reviewed by:    jhb
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D38493
---
 sys/dev/ofw/ofwbus.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/dev/ofw/ofwbus.c b/sys/dev/ofw/ofwbus.c
index cc8c66170cdb..80d013cd06ee 100644
--- a/sys/dev/ofw/ofwbus.c
+++ b/sys/dev/ofw/ofwbus.c
@@ -89,6 +89,11 @@ ofwbus_probe(device_t dev)
 	if (OF_peer(0) == 0)
 		return (ENXIO);
 
+	/* Only one instance of ofwbus. */
+	if (device_get_unit(dev) != 0)
+		panic("ofwbus added with non-zero unit number: %d\n",
+		    device_get_unit(dev));
+
 	device_set_desc(dev, "Open Firmware Device Tree");
 	return (BUS_PROBE_NOWILDCARD);
 }