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 19391521217 for ; Mon, 7 Sep 2026 16:41:04 +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=1788799265; cv=none; b=rFsxbndz0B66i/TfciRVM2XYpNgzS+wezpdhajy+rrQZjUWBtXs59x6shVSK3lYnNV77TcPwOyv0CMf5qH6irEGi+tUK20tUVDuyBo6IgYd7HzPhmIbzw1pC4eZ29DykMWCPdxI82abMBXNbhMtx41C8CkljTN5ET8oow+w5W3g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788799265; c=relaxed/simple; bh=ktl1ZCJhODHxHsQUeJgSo+99QiZHMC2VNxAPOmKVwxQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FQsw4TBCSgpUd0jAy13XbRSjsR4Gsx7mPApu3fJL3xOl2b00eUomk3btD5Rafi8/H12VWSadAlIuxAN0zMH5T+D1dP6ZpXpKItKc0SC1QX2oWkColf2T727x98thhdueqmXCMpHbJyEWP5XTGB1wKEq3Avqe3LPIpwSmlaXVJxQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BIM21oyM; 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="BIM21oyM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FE271F00A3A; Mon, 7 Sep 2026 16:41:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788799264; bh=yyPYTrxPqUtbU5EZK4JfbBiGHej8C5k7CQFXZsSwctE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BIM21oyMH2nqDROiqNNT5p3hi0dt+/D7eVoRyGqywawmePz9bjBhhkkq7SvrXrW7K auNkNIG2ZwcrIm8piTh2fH1zINZeRPh3tUKPzj+1byfod28aUmUhU9615HsrrPr5fD 6DmfzlmzdbSUjfE5OvsllyfjL+quIO0Evzpfe/0IAwpkoWIXsiVva9bux0skemtS+R HeN+/f1f8X0cIwDZKbGdlWrPO4gHKutOANOb0+NGJ+83daLleHPpj2kWHmL2tvEBVS HJuScroQaWhJCXsAz+8AhYtMg8TH4Kgws3giK6gvNgrdSsrnK2k+EA6jdZA6SDDbF9 h829IUqAkl03Q== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Will Deacon , Thomas Gleixner , Catalin Marinas , Borislav Petkov , Lorenzo Pieralisi , Jinjie Ruan , Mark Rutland , David Woodhouse , Peter Zijlstra , Marc Zyngier Subject: [PATCH 10/19] arm64: smp: Use generic HOTPLUG_CORE_SYNC_FULL machinery for CPU onlining Date: Mon, 7 Sep 2026 17:40:13 +0100 Message-ID: <20260907164024.17164-11-will@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260907164024.17164-1-will@kernel.org> References: <20260907164024.17164-1-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. 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 ff68640d0c0b..00362ed6e1ab 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(); + update_cpu_features(cpu); store_cpu_topology(cpu); @@ -255,9 +254,7 @@ 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. -- 2.55.0.979.g7e5102b832-goog