From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4D2A49B5C3 for ; Fri, 9 Oct 2026 10:08:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791540521; cv=none; b=gyGf5r+kBwp8Ww+fnLw2NB0d4BWNQph8y5Z6UCZUYIpo5xMfoIrvsWBkcdHCXkLPGwbFRJ9jTw+ngS0XH/LwaNueD2fPatPQ95+JdjX3XoTQw7O4fpO5vLygXBoWa+Cb2Yg4urGDRJOrbddBjCWVV6Uh+M5hasv6+2TfxLzqQc4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791540521; c=relaxed/simple; bh=SYLJTwuVBV7gzEU4OR4IQtvARl8eFPTxwnCz2PYU1+8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KyrkkO/gz9AA0R3X98mC6POmTbcCE5jr82SfLmpFV1aUHaPQpPuB8iFKcq2scj3whdsju2Lqpel4CPSu02QuiZLMsYRJtdm1bIYiq9PYlrOpMKVjHKmSEJjR3/tlaOdrOBwqa+h2kmVcjjwF0Rnjdpaj7gRB/X8tH6XsvHYyNew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ejB5Aap7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ejB5Aap7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 535461F00898; Fri, 9 Oct 2026 10:08:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791540520; bh=Ru0ZoHw/Kw/Oi/vluVCYpEmBr1d9awOz5x+e4Gf6Zco=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ejB5Aap7qJB0eLqC9SCRtQkfIzIVoxG+agEWiICmAbabgdIbGpLmahPjhX51KU6Ae Mm65RyqPdlWxbdMsnt/+vHbaYgaYtxQzrwvMD0I6m8FzIkifN6QwgdMEuVLNePLVZU QkoK6HuR00qeEbKKmCXOTreibk4W7VwYoZUbO2Y3CHJCF7rc0cyDMSwsi7m8d04goY Og4U9Rxrm8Tz1Inp963L/xP2rm/M2s5DNs4+I3STE7TfP+tUPPHcFNhzQsmjDtUMMv 2G96mwGkmW974dA6X/FKOO8CdjuVFHfOQTIr4iL6OgZxc8evyrEyubuJnsdDM8Vkef SS9Xk+mzxeJPA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Will Deacon , Thomas Gleixner , Ben Horgan , =?UTF-8?q?=C8=98tefania=20Ion?= , Catalin Marinas , Pankaj Patil , Borislav Petkov , Lorenzo Pieralisi , Jinjie Ruan , Mark Rutland , Tarun Sahu , Fuad Tabba , David Woodhouse , Peter Zijlstra , Marc Zyngier Subject: [PATCH v2 14/23] arm64: smp: Use generic HOTPLUG_CORE_SYNC_FULL machinery for CPU onlining Date: Fri, 9 Oct 2026 11:07:25 +0100 Message-ID: <20261009100738.31288-15-will@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261009100738.31288-1-will@kernel.org> References: <20261009100738.31288-1-will@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Select HOTPLUG_CORE_SYNC_FULL on arm64 to replace the 'cpu_running' completion with the generic code for synchronising with secondary CPUs during boot. Reviewed-by: Jinjie Ruan Signed-off-by: Will Deacon --- arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/smp.h | 1 - arch/arm64/kernel/smp.c | 39 +++++++++++++++++------------------- 3 files changed, 19 insertions(+), 23 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b5a51b0ef944..89d1f0f2269c 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -230,7 +230,7 @@ config ARM64 select HAVE_SYSCALL_TRACEPOINTS select HAVE_KPROBES select HAVE_KRETPROBES - select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU + select HOTPLUG_CORE_SYNC_FULL select HOTPLUG_SMT if HOTPLUG_CPU select IRQ_DOMAIN select IRQ_FORCED_THREADING diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 10ea4f543069..fe343c30d620 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -12,7 +12,6 @@ #define CPU_BOOT_STATUS_MASK ((UL(1) << CPU_STUCK_REASON_SHIFT) - 1) #define CPU_MMU_OFF (-1) -#define CPU_BOOT_SUCCESS (0) /* The cpu invoked ops->cpu_die, synchronise it with cpu_kill */ #define CPU_KILL_ME (1) /* The cpu couldn't die gracefully and is looping in the kernel */ diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 014b163ce658..d83ba5bbfd37 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -108,12 +108,9 @@ static int boot_secondary(unsigned int cpu, struct task_struct *idle) return -EOPNOTSUPP; } -static DECLARE_COMPLETION(cpu_running); - int __cpu_up(unsigned int cpu, struct task_struct *idle) { int ret; - long status; /* * We need to tell the secondary core where to find its stack and the @@ -124,27 +121,24 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) /* Now bring the CPU into our world */ ret = boot_secondary(cpu, idle); - if (ret) { - if (ret != -EPERM) - pr_err("CPU%u: failed to boot: %d\n", cpu, ret); - return ret; - } + if (ret && ret != -EPERM) + pr_err("CPU%u: failed to boot: %d\n", cpu, ret); + return ret; +} - /* - * CPU was successfully started, wait for it to come online or - * time out. - */ - wait_for_completion_timeout(&cpu_running, - msecs_to_jiffies(5000)); - if (cpu_online(cpu)) - return 0; +void arch_cpuhp_cleanup_kick_cpu(unsigned int cpu, bool is_alive) +{ + long status; + + if (is_alive) + return; - pr_crit("CPU%u: failed to come online\n", cpu); secondary_data.task = NULL; status = READ_ONCE(secondary_data.status); if (status == CPU_MMU_OFF) status = READ_ONCE(__early_cpu_boot_status); + /* A CPU has failed to boot. Try to figure out what happened. */ switch (status & CPU_BOOT_STATUS_MASK) { default: pr_err("CPU%u: failed in unknown state : 0x%lx\n", @@ -171,8 +165,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) case CPU_PANIC_KERNEL: panic("CPU%u detected unsupported configuration\n", cpu); } - - return -EIO; } static void init_gic_priority_masking(void) @@ -234,6 +226,13 @@ asmlinkage notrace void secondary_start_kernel(void) * Log the CPU info before it is marked online and might get read. */ cpuinfo_store_cpu(); + + /* + * Synchronise with the core bringing us online so that it knows + * we made it into the kernel. We're still not 'online'. + */ + cpuhp_ap_sync_alive(); + rcutree_report_cpu_starting(cpu); update_cpu_features(cpu); store_cpu_topology(cpu); @@ -256,9 +255,7 @@ asmlinkage notrace void secondary_start_kernel(void) pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n", cpu, (unsigned long)mpidr, read_cpuid_id()); - update_cpu_boot_status(CPU_BOOT_SUCCESS); set_cpu_online(cpu, true); - complete(&cpu_running); /* * Secondary CPUs enter the kernel with all DAIF exceptions masked. -- 2.56.0.385.gd3acb90ef8-goog