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From:   "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
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Cc:     Salil Mehta <salil.mehta@huawei.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
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Subject: [PATCH 09/21] drivers: base: add arch_cpu_is_hotpluggable()
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Message-Id: <E1r5R3M-00CszH-6r@rmk-PC.armlinux.org.uk>
Sender: Russell King <rmk@armlinux.org.uk>
Date:   Tue, 21 Nov 2023 13:44:36 +0000
Precedence: bulk

The differences between architecture specific implementations of
arch_register_cpu() are down to whether the CPU is hotpluggable or not.
Rather than overriding the weak version of arch_register_cpu(), provide
a function that can be used to provide this detail instead.

Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/base/cpu.c  | 11 ++++++++++-
 include/linux/cpu.h |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 58bb86091b34..221ffbeb1c9b 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -527,9 +527,18 @@ EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 #ifdef CONFIG_GENERIC_CPU_DEVICES
 DEFINE_PER_CPU(struct cpu, cpu_devices);
 
+bool __weak arch_cpu_is_hotpluggable(int cpu)
+{
+	return false;
+}
+
 int __weak arch_register_cpu(int cpu)
 {
-	return register_cpu(&per_cpu(cpu_devices, cpu), cpu);
+	struct cpu *c = &per_cpu(cpu_devices, cpu);
+
+	c->hotpluggable = arch_cpu_is_hotpluggable(cpu);
+
+	return register_cpu(c, cpu);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 1e982d63eae8..dcb89c987164 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -80,6 +80,7 @@ extern __printf(4, 5)
 struct device *cpu_device_create(struct device *parent, void *drvdata,
 				 const struct attribute_group **groups,
 				 const char *fmt, ...);
+extern bool arch_cpu_is_hotpluggable(int cpu);
 extern int arch_register_cpu(int cpu);
 extern void arch_unregister_cpu(int cpu);
 #ifdef CONFIG_HOTPLUG_CPU
-- 
2.30.2