linux-kernel - [PATCH 4.4 027/312] MIPS: SMP: Update cpu_foreign

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Date:   Fri,  8 May 2020 14:30:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, James Hogan <james.hogan@...tec.com>,
        Paul Burton <paul.burton@...tec.com>,
        David Daney <david.daney@...ium.com>,
        Kevin Cernekee <cernekee@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Huacai Chen <chenhc@...ote.com>,
        Hongliang Tao <taohl@...ote.com>, Hua Yan <yanh@...ote.com>,
        linux-mips@...ux-mips.org, Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH 4.4 027/312] MIPS: SMP: Update cpu_foreign_map on CPU disable

From: James Hogan <james.hogan@...tec.com>

commit 826e99be6ab5189dbfb096389016ffb8d20a683e upstream.

When a CPU is disabled via CPU hotplug, cpu_foreign_map is not updated.
This could result in cache management SMP calls being sent to offline
CPUs instead of online siblings in the same core.

Add a call to calculate_cpu_foreign_map() in the various MIPS cpu
disable callbacks after set_cpu_online(). All cases are updated for
consistency and to keep cpu_foreign_map strictly up to date, not just
those which may support hardware multithreading.

Fixes: cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores")
Signed-off-by: James Hogan <james.hogan@...tec.com>
Cc: Paul Burton <paul.burton@...tec.com>
Cc: David Daney <david.daney@...ium.com>
Cc: Kevin Cernekee <cernekee@...il.com>
Cc: Florian Fainelli <f.fainelli@...il.com>
Cc: Huacai Chen <chenhc@...ote.com>
Cc: Hongliang Tao <taohl@...ote.com>
Cc: Hua Yan <yanh@...ote.com>
Cc: linux-mips@...ux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13799/
Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/mips/cavium-octeon/smp.c         |    1 +
 arch/mips/include/asm/smp.h           |    2 ++
 arch/mips/kernel/smp-bmips.c          |    1 +
 arch/mips/kernel/smp-cps.c            |    1 +
 arch/mips/kernel/smp.c                |    2 +-
 arch/mips/loongson64/loongson-3/smp.c |    1 +
 6 files changed, 7 insertions(+), 1 deletion(-)

--- a/arch/mips/cavium-octeon/smp.c
+++ b/arch/mips/cavium-octeon/smp.c
@@ -239,6 +239,7 @@ static int octeon_cpu_disable(void)
 		return -ENOTSUPP;
 
 	set_cpu_online(cpu, false);
+	calculate_cpu_foreign_map();
 	cpumask_clear_cpu(cpu, &cpu_callin_map);
 	octeon_fixup_irqs();
 
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -63,6 +63,8 @@ extern cpumask_t cpu_coherent_mask;
 
 extern void asmlinkage smp_bootstrap(void);
 
+extern void calculate_cpu_foreign_map(void);
+
 /*
  * this function sends a 'reschedule' IPI to another CPU.
  * it goes straight through and wastes no time serializing
--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -362,6 +362,7 @@ static int bmips_cpu_disable(void)
 	pr_info("SMP: CPU%d is offline\n", cpu);
 
 	set_cpu_online(cpu, false);
+	calculate_cpu_foreign_map();
 	cpumask_clear_cpu(cpu, &cpu_callin_map);
 	clear_c0_status(IE_IRQ5);
 
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -338,6 +338,7 @@ static int cps_cpu_disable(void)
 	atomic_sub(1 << cpu_vpe_id(&current_cpu_data), &core_cfg->vpe_mask);
 	smp_mb__after_atomic();
 	set_cpu_online(cpu, false);
+	calculate_cpu_foreign_map();
 	cpumask_clear_cpu(cpu, &cpu_callin_map);
 
 	return 0;
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -118,7 +118,7 @@ static inline void set_cpu_core_map(int
  * Calculate a new cpu_foreign_map mask whenever a
  * new cpu appears or disappears.
  */
-static inline void calculate_cpu_foreign_map(void)
+void calculate_cpu_foreign_map(void)
 {
 	int i, k, core_present;
 	cpumask_t temp_foreign_map;
--- a/arch/mips/loongson64/loongson-3/smp.c
+++ b/arch/mips/loongson64/loongson-3/smp.c
@@ -417,6 +417,7 @@ static int loongson3_cpu_disable(void)
 		return -EBUSY;
 
 	set_cpu_online(cpu, false);
+	calculate_cpu_foreign_map();
 	cpumask_clear_cpu(cpu, &cpu_callin_map);
 	local_irq_save(flags);
 	fixup_irqs();