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Message-Id: <E1qvJ9B-00AqPS-9x@rmk-PC.armlinux.org.uk>
Date: Tue, 24 Oct 2023 16:16:45 +0100
From: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
To: linux-pm@...r.kernel.org, loongarch@...ts.linux.dev,
linux-acpi@...r.kernel.org, linux-arch@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-riscv@...ts.infradead.org, kvmarm@...ts.linux.dev,
x86@...nel.org, linux-csky@...r.kernel.org,
linux-doc@...r.kernel.org, linux-ia64@...r.kernel.org,
linux-parisc@...r.kernel.org
Cc: Salil Mehta <salil.mehta@...wei.com>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
jianyong.wu@....com, justin.he@....com,
James Morse <james.morse@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 07/39] drivers: base: Allow parts of GENERIC_CPU_DEVICES to be
overridden
From: James Morse <james.morse@....com>
Architectures often have extra per-cpu work that needs doing
before a CPU is registered, often to determine if a CPU is
hotpluggable.
To allow the ACPI architectures to use GENERIC_CPU_DEVICES, move
the cpu_register() call into arch_register_cpu(), which is made __weak
so architectures with extra work can override it.
This aligns with the way x86, ia64 and loongarch register hotplug CPUs
when they become present.
Signed-off-by: James Morse <james.morse@....com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
Changes since RFC:
* Dropped __init from x86/ia64 arch_register_cpu()
Changes since RFC v2:
* Dropped unnecessary Loongarch asm/cpu.h changes
---
drivers/base/cpu.c | 14 ++++++++++----
include/linux/cpu.h | 4 ++++
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 34b48f660b6b..579064fda97b 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -525,19 +525,25 @@ bool cpu_is_hotpluggable(unsigned int cpu)
EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
#ifdef CONFIG_GENERIC_CPU_DEVICES
-static DEFINE_PER_CPU(struct cpu, cpu_devices);
+DEFINE_PER_CPU(struct cpu, cpu_devices);
+
+int __weak arch_register_cpu(int cpu)
+{
+ return register_cpu(&per_cpu(cpu_devices, cpu), cpu);
+}
#endif
static void __init cpu_dev_register_generic(void)
{
-#ifdef CONFIG_GENERIC_CPU_DEVICES
int i;
+ if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
+ return;
+
for_each_present_cpu(i) {
- if (register_cpu(&per_cpu(cpu_devices, i), i))
+ if (arch_register_cpu(i))
panic("Failed to register CPU device");
}
-#endif
}
#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index eb768a866fe3..e117c06e0c6b 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -88,6 +88,10 @@ extern ssize_t arch_cpu_probe(const char *, size_t);
extern ssize_t arch_cpu_release(const char *, size_t);
#endif
+#ifdef CONFIG_GENERIC_CPU_DEVICES
+DECLARE_PER_CPU(struct cpu, cpu_devices);
+#endif
+
/*
* These states are not related to the core CPU hotplug mechanism. They are
* used by various (sub)architectures to track internal state
--
2.30.2
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