From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8921EC433E0 for ; Mon, 29 Jun 2020 19:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EBD4206A5 for ; Mon, 29 Jun 2020 19:17:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731041AbgF2TRe (ORCPT ); Mon, 29 Jun 2020 15:17:34 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:46260 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728039AbgF2TRc (ORCPT ); Mon, 29 Jun 2020 15:17:32 -0400 Received: from 89-64-84-69.dynamic.chello.pl (89.64.84.69) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.415) id 60876454d392fc4c; Mon, 29 Jun 2020 17:17:29 +0200 From: "Rafael J. Wysocki" To: Neal Liu Cc: Len Brown , Daniel Lezcano , Thierry Reding , Jonathan Hunter , Jacob Pan , Matthias Brugger , Sami Tolvanen , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com Subject: Re: [PATCH] cpuidle: change enter_s2idle() prototype Date: Mon, 29 Jun 2020 17:17:28 +0200 Message-ID: <9963896.lEaLCsxmBZ@kreacher> In-Reply-To: <1593421540-7397-2-git-send-email-neal.liu@mediatek.com> References: <1593421540-7397-1-git-send-email-neal.liu@mediatek.com> <1593421540-7397-2-git-send-email-neal.liu@mediatek.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Monday, June 29, 2020 11:05:40 AM CEST Neal Liu wrote: > Control Flow Integrity(CFI) is a security mechanism that disallows > changes to the original control flow graph of a compiled binary, > making it significantly harder to perform such attacks. > > init_state_node() assigns same function pointer to idle_state->enter > and idle_state->enter_s2idle. This definitely causes CFI failure > when calling either enter() or enter_s2idle(). > > Align enter_s2idle() with enter() function prototype to fix CFI > failure. That needs to be documented somewhere close to the definition of the callbacks in question. Otherwise it is completely unclear why this is a good idea. > Signed-off-by: Neal Liu > --- > drivers/acpi/processor_idle.c | 6 ++++-- > drivers/cpuidle/cpuidle-tegra.c | 8 +++++--- > drivers/idle/intel_idle.c | 6 ++++-- > include/linux/cpuidle.h | 6 +++--- > 4 files changed, 16 insertions(+), 10 deletions(-) > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index 75534c5..6ffb6c9 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -655,8 +655,8 @@ static int acpi_idle_enter(struct cpuidle_device *dev, > return index; > } > > -static void acpi_idle_enter_s2idle(struct cpuidle_device *dev, > - struct cpuidle_driver *drv, int index) > +static int acpi_idle_enter_s2idle(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > { > struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu); > > @@ -674,6 +674,8 @@ static void acpi_idle_enter_s2idle(struct cpuidle_device *dev, > } > } > acpi_idle_do_entry(cx); > + > + return 0; > } > > static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr, > diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c > index 1500458..a12fb14 100644 > --- a/drivers/cpuidle/cpuidle-tegra.c > +++ b/drivers/cpuidle/cpuidle-tegra.c > @@ -253,11 +253,13 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev, > return err ? -1 : index; > } > > -static void tegra114_enter_s2idle(struct cpuidle_device *dev, > - struct cpuidle_driver *drv, > - int index) > +static int tegra114_enter_s2idle(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, > + int index) > { > tegra_cpuidle_enter(dev, drv, index); > + > + return 0; > } > > /* > diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c > index f449584..b178da3 100644 > --- a/drivers/idle/intel_idle.c > +++ b/drivers/idle/intel_idle.c > @@ -175,13 +175,15 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, > * Invoked as a suspend-to-idle callback routine with frozen user space, frozen > * scheduler tick and suspended scheduler clock on the target CPU. > */ > -static __cpuidle void intel_idle_s2idle(struct cpuidle_device *dev, > - struct cpuidle_driver *drv, int index) > +static __cpuidle int intel_idle_s2idle(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > { > unsigned long eax = flg2MWAIT(drv->states[index].flags); > unsigned long ecx = 1; /* break on interrupt flag */ > > mwait_idle_with_hints(eax, ecx); > + > + return 0; > } > > /* > diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h > index ec2ef63..bee10c0 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -66,9 +66,9 @@ struct cpuidle_state { > * suspended, so it must not re-enable interrupts at any point (even > * temporarily) or attempt to change states of clock event devices. > */ > - void (*enter_s2idle) (struct cpuidle_device *dev, > - struct cpuidle_driver *drv, > - int index); > + int (*enter_s2idle)(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, > + int index); > }; > > /* Idle State Flags */ > -- > 1.7.9.5 >