Fix -current builds on alpha. Recent changes in device handling caused

subtle problems with how alpha was handling the promcons device.  This
moves the call to make_dev() for the promcons device to a later point of
the boot-up sequence than where promcons initially gets attached, make_dev()
called during the first attach crashes due to kernel stack issues.

Reviewed by:	gallatin, marcel, phk
Discussed on:	-current@, -alpha@
Approved by:	rwatson (mentor)

2 files changed, 29 insertions, 2 deletions

diff --git a/sys/alpha/alpha/machdep.c b/sys/alpha/alpha/machdep.c
index 9bd1f5b..227c7fb 100644
--- a/sys/alpha/alpha/machdep.c
+++ b/sys/alpha/alpha/machdep.c
@@ -201,6 +201,9 @@ long	unusedmem;		/* amount of memory for OS that we don't use */
 long	unknownmem;		/* amount of memory with an unknown use */
 int	ncpus;			/* number of cpus */
 
+int	promcons_dly_mkdev = 1;	/* need to delay call to make_dev() */
+void	promcons_delayed_makedev(void);
+
 vm_offset_t phys_avail[10];
 
 /* must be 2 less so 0 0 can signal end of chunks */
@@ -889,6 +892,14 @@ alpha_init(pfn, ptb, bim, bip, biv)
 	}
 
 	/*
+	 * Check to see if promcons needs to make_dev() now,
+	 * doing it before now crashes with kernel stack issues.
+	 */
+	if (promcons_dly_mkdev > 1)
+		promcons_delayed_makedev();
+	promcons_dly_mkdev = 0;
+
+	/*
 	 * Initialize the virtual memory system, and set the
 	 * page table base register in proc 0's PCB.
 	 */
diff --git a/sys/alpha/alpha/promcons.c b/sys/alpha/alpha/promcons.c
index 4d41abc..35cda1b 100644
--- a/sys/alpha/alpha/promcons.c
+++ b/sys/alpha/alpha/promcons.c
@@ -83,6 +83,9 @@ void	promtimeout(void *);
 int	promparam(struct tty *, struct termios *);
 void	promstop(struct tty *, int);
 
+extern	int promcons_dly_mkdev;
+void	promcons_delayed_makedev(void);
+
 int
 promopen(dev, flag, mode, td)
 	dev_t dev;
@@ -248,12 +251,25 @@ promcnattach(int alpha_console)
 {
 	prom_consdev.cn_pri = CN_NORMAL;
 	sprintf(prom_consdev.cn_name, "promcons");
-	make_dev(&prom_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "promcons");
-	cnadd(&prom_consdev);
+	if (promcons_dly_mkdev)
+		promcons_dly_mkdev++;
+	else {
+		make_dev(&prom_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "promcons");
+		cnadd(&prom_consdev);
+	}
 	promcn_attached = 1;
 }
 
 void
+promcons_delayed_makedev(void)
+{
+	if (promcn_attached) {
+		make_dev(&prom_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "promcons");
+		cnadd(&prom_consdev);
+	}
+}
+
+void
 promcndetach(void)
 {
 	if (promcn_attached) {