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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Thomas Bogendoerfer <tbogendoerfer@suse.de>,
        Paul Burton <paulburton@kernel.org>,
        Ralf Baechle <ralf@linux-mips.org>,
        James Hogan <jhogan@kernel.org>, linux-mips@vger.kernel.org
Subject: [PATCH 5.4 142/203] MIPS: SGI-IP27: Fix crash, when CPUs are disabled via nr_cpus parameter
Date:   Fri, 17 Jan 2020 00:17:39 +0100
Message-Id: <20200116231757.391207929@linuxfoundation.org>
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From: Thomas Bogendoerfer <tbogendoerfer@suse.de>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- 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_ir
 	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_d
 	/* 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);