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Date:   Tue, 16 May 2023 09:09:57 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
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Subject: [tip: smp/core] arm64: smp: Switch to hotplug core state synchronization
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Michael Kelley <mikelley@microsoft.com>,
        Oleksandr Natalenko <oleksandr@natalenko.name>,
        Helge Deller <deller@gmx.de>,
        "Guilherme G. Piccoli" <gpiccoli@igalia.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
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The following commit has been merged into the smp/core branch of tip:

Commit-ID:     b3091f172fed63ee59d1746f088bdcc76a79a79c
Gitweb:        https://git.kernel.org/tip/b3091f172fed63ee59d1746f088bdcc76a79a79c
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Fri, 12 May 2023 23:07:33 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 15 May 2023 13:44:57 +02:00

arm64: smp: Switch to hotplug core state synchronization

Switch to the CPU hotplug core state tracking and synchronization
mechanim. No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.690926018@linutronix.de
---
 arch/arm64/Kconfig           |  1 +
 arch/arm64/include/asm/smp.h |  2 +-
 arch/arm64/kernel/smp.c      | 14 +++++---------
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1201d2..fcb945b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -222,6 +222,7 @@ config ARM64
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_GENERIC_VDSO
+	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
 	select KASAN_VMALLOC if KASAN
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index f2d2623..9b31e6d 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 
 extern int __cpu_disable(void);
 
-extern void __cpu_die(unsigned int cpu);
+static inline void __cpu_die(unsigned int cpu) { }
 extern void __noreturn cpu_die(void);
 extern void __noreturn cpu_die_early(void);
 
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index d00d4cb..edd6389 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -332,17 +332,13 @@ static int op_cpu_kill(unsigned int cpu)
 }
 
 /*
- * called on the thread which is asking for a CPU to be shutdown -
- * waits until shutdown has completed, or it is timed out.
+ * Called on the thread which is asking for a CPU to be shutdown after the
+ * shutdown completed.
  */
-void __cpu_die(unsigned int cpu)
+void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
 {
 	int err;
 
-	if (!cpu_wait_death(cpu, 5)) {
-		pr_crit("CPU%u: cpu didn't die\n", cpu);
-		return;
-	}
 	pr_debug("CPU%u: shutdown\n", cpu);
 
 	/*
@@ -369,8 +365,8 @@ void __noreturn cpu_die(void)
 
 	local_daif_mask();
 
-	/* Tell __cpu_die() that this CPU is now safe to dispose of */
-	(void)cpu_report_death();
+	/* Tell cpuhp_bp_sync_dead() that this CPU is now safe to dispose of */
+	cpuhp_ap_report_dead();
 
 	/*
 	 * Actually shutdown the CPU. This must never fail. The specific hotplug