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From:   Thomas Bogendoerfer <tbogendoerfer@suse.de>
To:     Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paulburton@kernel.org>,
        James Hogan <jhogan@kernel.org>, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] MIPS: SGI-IP27: Fix crash, when CPUs are disabled via nr_cpus parameter
Date:   Tue, 19 Nov 2019 12:08:56 +0100
Message-Id: <20191119110857.28540-1-tbogendoerfer@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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>
---
 arch/mips/sgi-ip27/ip27-irq.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
index 5aef06e28a5b..c72ae330ea93 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 = 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(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);
-- 
2.16.4