[PATCH] MIPS: SGI-IP27: print the NMI dump on an nbcon console

[Imre Kaloz]

Since the 8250 console became nbcon, printk() in nmi_dump() only queues
records for the printer thread, which never runs because no CPU leaves
the NMI handler before the hub reset. Print the dump from an emergency
section.

Fixes: d3539347022a ("serial: 8250: Switch to nbcon console, take 2")
Signed-off-by: Imre Kaloz <kaloz@xxxxxxxxxx>
---
 arch/mips/sgi-ip27/ip27-nmi.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/mips/sgi-ip27/ip27-nmi.c b/arch/mips/sgi-ip27/ip27-nmi.c
index fc2816398d0c..4447c0bec8b4 100644
--- a/arch/mips/sgi-ip27/ip27-nmi.c
+++ b/arch/mips/sgi-ip27/ip27-nmi.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/console.h>
 #include <linux/kernel.h>
 #include <linux/mmzone.h>
 #include <linux/nodemask.h>
@@ -183,6 +184,12 @@ static void nmi_dump(void)
 	 */
 	arch_spin_lock(&nmi_lock);
 
+	/*
+	 * No CPU leaves the NMI handler before the hub reset below, so an
+	 * nbcon console's printer thread would never print the dump.
+	 */
+	nbcon_cpu_emergency_enter();
+
 #ifdef REAL_NMI_SIGNAL
 	/*
 	 * Wait up to 15 seconds for the other cpus to respond to the NMI.

base-commit: 5dd1818b15d98d4a20806cd00b1b40320b06004f
-- 
2.47.3