From patchwork Thu Apr 16 13:22:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 227507 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E105FC2BB55 for ; Thu, 16 Apr 2020 16:03:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF74B214AF for ; Thu, 16 Apr 2020 16:03:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587053007; bh=TjFmNk6idyfIeYrGysZ/y2DkV1ouIOtNI5z9UXMVK0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qR/ppxhZl7iJZB7xJsGk9dxBdBUHD/WhT0/vb3+c9D0ha0y27UgBnZAf/4tu7zJ4R isRv7FTkjvGkaqgg6zHj5xmaIabGKXuTzDUqfuwrz10jzvzyIdznc0nbkWTHZ/BbFv og1HCKYLkwBu6RnEK/sYv+bRJH1+PFyDBmT4G+1I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727918AbgDPQD0 (ORCPT ); Thu, 16 Apr 2020 12:03:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:34428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2895250AbgDPN0M (ORCPT ); Thu, 16 Apr 2020 09:26:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 33D8D206E9; Thu, 16 Apr 2020 13:26:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587043571; bh=TjFmNk6idyfIeYrGysZ/y2DkV1ouIOtNI5z9UXMVK0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SBMVJQW8UPyV6jVAs11SQDDdMbEy/ZrWCtjLN3UAcw10MzGaFDgm16TNGXZ0nlPeI xCcSBe5D0v4G6pfwyA1bVwb7XGItZAnEN/UZnWzhWUSuRX/qbFFsG4/yl8vfYPUtPF iTBIdIfZGA9T/2d0MyBzmmgol+7JplyGEl2hS95s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liguang Zhang , James Morse , Catalin Marinas , Sasha Levin Subject: [PATCH 4.19 012/146] firmware: arm_sdei: fix double-lock on hibernate with shared events Date: Thu, 16 Apr 2020 15:22:33 +0200 Message-Id: <20200416131244.205358079@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131242.353444678@linuxfoundation.org> References: <20200416131242.353444678@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: James Morse [ Upstream commit 6ded0b61cf638bf9f8efe60ab8ba23db60ea9763 ] SDEI has private events that must be registered on each CPU. When CPUs come and go they must re-register and re-enable their private events. Each event has flags to indicate whether this should happen to protect against an event being registered on a CPU coming online, while all the others are unregistering the event. These flags are protected by the sdei_list_lock spinlock, because the cpuhp callbacks can't take the mutex. Hibernate needs to unregister all events, but keep the in-memory re-register and re-enable as they are. sdei_unregister_shared() takes the spinlock to walk the list, then calls _sdei_event_unregister() on each shared event. _sdei_event_unregister() tries to take the same spinlock to update re-register and re-enable. This doesn't go so well. Push the re-register and re-enable updates out to their callers. sdei_unregister_shared() doesn't want these values updated, so doesn't need to do anything. This also fixes shared events getting lost over hibernate as this path made them look unregistered. Fixes: da351827240e ("firmware: arm_sdei: Add support for CPU and system power states") Reported-by: Liguang Zhang Signed-off-by: James Morse Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- drivers/firmware/arm_sdei.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index c64c7da738297..05b528c7ed8fd 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -489,11 +489,6 @@ static int _sdei_event_unregister(struct sdei_event *event) { lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_unregister(event->event_num); @@ -516,6 +511,11 @@ int sdei_event_unregister(u32 event_num) break; } + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + err = _sdei_event_unregister(event); if (err) break; @@ -583,26 +583,15 @@ static int _sdei_event_register(struct sdei_event *event) lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); - event->reregister = true; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_register(event->event_num, sdei_entry_point, event->registered, SDEI_EVENT_REGISTER_RM_ANY, 0); - err = sdei_do_cross_call(_local_event_register, event); - if (err) { - spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - + if (err) sdei_do_cross_call(_local_event_unregister, event); - } return err; } @@ -630,8 +619,17 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) break; } + spin_lock(&sdei_list_lock); + event->reregister = true; + spin_unlock(&sdei_list_lock); + err = _sdei_event_register(event); if (err) { + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + sdei_event_destroy(event); pr_warn("Failed to register event %u: %d\n", event_num, err);