From c3474b77222b02d8c1e0dbbd983dde013076ac8b Mon Sep 17 00:00:00 2001
From: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Date: Tue, 19 Nov 2019 12:08:56 +0100
Subject: [PATCH] MIPS: SGI-IP27: Fix crash, when CPUs are disabled via nr_cpus
 parameter

commit e3d765a941f6130fd94e47b2064cfee71f4cbadd upstream.

If number of CPUs are limited by the kernel commandline parameter nr_cpus
assignment of interrupts accourding to numa rules might not be possibe.
As a fallback use one of the online CPUs as interrupt destination.

Fixes: 69a07a41d908 ("MIPS: SGI-IP27: rework HUB interrupts")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
index 37be04975831..79a2f6bd2b5a 100644
--- a/arch/mips/sgi-ip27/ip27-irq.c
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -73,6 +73,9 @@ static void setup_hub_mask(struct hub_irq_data *hd, const struct cpumask *mask)
 	int cpu;
 
 	cpu = cpumask_first_and(mask, cpu_online_mask);
+	if (cpu >= nr_cpu_ids)
+		cpu = cpumask_any(cpu_online_mask);
+
 	nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
 	hd->cpu = cpu;
 	if (!cputoslice(cpu)) {
@@ -139,6 +142,7 @@ static int hub_domain_alloc(struct irq_domain *domain, unsigned int virq,
 	/* use CPU connected to nearest hub */
 	hub = hub_data(NASID_TO_COMPACT_NODEID(info->nasid));
 	setup_hub_mask(hd, &hub->h_cpus);
+	info->nasid = cpu_to_node(hd->cpu);
 
 	/* Make sure it's not already pending when we connect it. */
 	REMOTE_HUB_CLR_INTR(info->nasid, swlevel);
-- 
2.7.4