From patchwork Fri May 19 14:57:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 684245 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C658C7EE26 for ; Fri, 19 May 2023 14:57:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231994AbjESO5o (ORCPT ); Fri, 19 May 2023 10:57:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231124AbjESO5n (ORCPT ); Fri, 19 May 2023 10:57:43 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E706AC4 for ; Fri, 19 May 2023 07:57:41 -0700 (PDT) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1684508259; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LldjaLfYb76ho80XKTV86hUVMPTppvWm3OJfAvriQ1E=; b=m+Lraj4jhQsFo6563+j1BDT13F83Csohj6lBkwKImBX6xGisyATDeieXMa56KWuiFpClOp DoBw9Tu4rkpCT5bMDdBP2CgktK1cfaAIkdzQhT2Qsxdq/4oeRxjxpIG7ReBMhWLtHDrNY0 E5feX0O9BoO1uQkXd5pXTtOEa6PbTH8ZSdUevx2bIytWc0Saz7BqXHhLDNBRkZSaS0ar9E 0B78OOJwbYq0IPbRMyKOnds2GFlzT6m/MgBrG3j278nlF8biKqXlAqzO339LJN3aApSLXL kSDPoIGTsAtDO6FjlcNL42irxL4oO1DMiqCEDhbRTostUN7sT55cC+KdX6jNQQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1684508259; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LldjaLfYb76ho80XKTV86hUVMPTppvWm3OJfAvriQ1E=; b=OCkVuzydKYV8IQcT7KmXlfPaecAv8Cl4WGmRWl4uDcVACybYaEQs7OA1yfnJlaQ1Hd1Rrt rG3xRWBP6pElZjAg== To: Ard Biesheuvel Cc: Pavel Pisa , linux-rt-users@vger.kernel.org, Pavel Hronek , Thomas Gleixner , Peter Zijlstra , Sebastian Andrzej Siewior Subject: [PATCH 2/3] ARM: vfp: Use vfp_lock() in vfp_sync_hwstate(). Date: Fri, 19 May 2023 16:57:30 +0200 Message-Id: <20230519145731.574867-3-bigeasy@linutronix.de> In-Reply-To: <20230519145731.574867-1-bigeasy@linutronix.de> References: <20230519145731.574867-1-bigeasy@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org vfp_sync_hwstate() uses preempt_disable() followed by local_bh_disable() to ensure that it won't get interrupted while checking the VFP state. This harms PREEMPT_RT because softirq handling can get preempted and local_bh_disable() synchronizes the related section with a sleeping lock which does not work with disabled preemption. Use the vfp_lock() to synchronize the access. Signed-off-by: Sebastian Andrzej Siewior --- arch/arm/vfp/vfpmodule.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index 57f9527d1e50e..543dc7f5a27e3 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -542,11 +542,9 @@ static inline void vfp_pm_init(void) { } */ void vfp_sync_hwstate(struct thread_info *thread) { - unsigned int cpu = get_cpu(); + vfp_lock(); - local_bh_disable(); - - if (vfp_state_in_hw(cpu, thread)) { + if (vfp_state_in_hw(raw_smp_processor_id(), thread)) { u32 fpexc = fmrx(FPEXC); /* @@ -557,8 +555,7 @@ void vfp_sync_hwstate(struct thread_info *thread) fmxr(FPEXC, fpexc); } - local_bh_enable(); - put_cpu(); + vfp_unlock(); } /* Ensure that the thread reloads the hardware VFP state on the next use. */