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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A51F6C433EB for ; Mon, 27 Jul 2020 12:10:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 838B820786 for ; Mon, 27 Jul 2020 12:10:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595851815; bh=bgk7Y9im7YZxJP9DpB6e0mBf+rOiEEuKPptHOfIQpO0=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=CUal1deDhjpbe5MdUjEpuuF2A4Y3R1WZI/kIhK5g4D/BWmKyHRIQ4Wi/EPZhLRM6d 0Th/O9/0Wbb1eTqHcy+8RDLAjq+5mIPwsj293gPFK0Y+Ivu2/fHf/AgeXy+IaKi8jx yAOSRbCAtQOF8IKui3/xYkg/TF5ssBhQLrRWokgg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728129AbgG0MKL (ORCPT ); Mon, 27 Jul 2020 08:10:11 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:36411 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728046AbgG0MKK (ORCPT ); Mon, 27 Jul 2020 08:10:10 -0400 Received: by mail-oi1-f196.google.com with SMTP id s144so4183976oie.3; Mon, 27 Jul 2020 05:10:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=MY8NFYemyusLitbLbaMoVSrE9YgFZMePGaF7pe3X/ig=; b=faVciNUS/lZe/q44gVqtjyTGYoXpiyBzS48vs5p6TVGDaSPzoIUiEvbfe/uWJw+tM/ T5inF/dVm4YyICu9IafwEAK0LGPqmZItdeC42GaTYm+PFJwd75SW++3r4SfZ6VSu2Aco Mo6r8eXrv67p6caTop1vFJcqWv5/hclJmeYQ8iDCO4tmxtUPn90eyh/xcYKjc29flVzE Ph5THp3A/edojAYaqr6WfOku2qKMLSVfonTDcwFJTTjXZVGhE2PU0rj7vgyd/5ZQ51KN MvotOfveZwGDtq4kh11gg+Tun3e0NS0CVzOr3KivTIZUmeShlrqskkO1rLTfsbL6J67P QWmQ== X-Gm-Message-State: AOAM533Z/H+EzQeAMhfHd1MgW5gb1IU89b6En6YbS8QplWERnRxQuAgs YiZW2MC/9LyYk6KiedmcVgXnf+2FBOupWBujPDs= X-Google-Smtp-Source: ABdhPJx+eJ2XZmKmc1yyOWlaMremLljLAQsKfx87QRnMm2/D3J76CmRbkiallwCViQ1xjwchuuWJJxzfrCmDO0Cn0+U= X-Received: by 2002:aca:4a89:: with SMTP id x131mr18642621oia.103.1595851808250; Mon, 27 Jul 2020 05:10:08 -0700 (PDT) MIME-Version: 1.0 References: <1595820346-4361-1-git-send-email-neal.liu@mediatek.com> <1595820346-4361-2-git-send-email-neal.liu@mediatek.com> In-Reply-To: <1595820346-4361-2-git-send-email-neal.liu@mediatek.com> From: "Rafael J. Wysocki" Date: Mon, 27 Jul 2020 14:09:39 +0200 Message-ID: Subject: Re: [PATCH v3] cpuidle: change enter_s2idle() prototype To: Neal Liu Cc: "Rafael J. Wysocki" , Len Brown , Daniel Lezcano , Thierry Reding , Jonathan Hunter , Jacob Pan , Matthias Brugger , Sami Tolvanen , ACPI Devel Maling List , Linux PM , linux-tegra , Linux ARM , "moderated list:ARM/Mediatek SoC..." , lkml , wsd_upstream Content-Type: text/plain; charset="UTF-8" Sender: linux-tegra-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On Mon, Jul 27, 2020 at 5:25 AM 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() assign same function callback to different > function pointer declarations. > > static int init_state_node(struct cpuidle_state *idle_state, > const struct of_device_id *matches, > struct device_node *state_node) { ... > idle_state->enter = match_id->data; ... > idle_state->enter_s2idle = match_id->data; } > > Function declarations: > > struct cpuidle_state { ... > int (*enter) (struct cpuidle_device *dev, > struct cpuidle_driver *drv, > int index); > > void (*enter_s2idle) (struct cpuidle_device *dev, > struct cpuidle_driver *drv, > int index); }; > > In this case, either enter() or enter_s2idle() would cause CFI check > failed since they use same callee. > > Align function prototype of enter() since it needs return value for > some use cases. The return value of enter_s2idle() is no > need currently. > > Signed-off-by: Neal Liu > Reviewed-by: Sami Tolvanen > --- > drivers/acpi/processor_idle.c | 6 ++++-- > drivers/cpuidle/cpuidle-tegra.c | 8 +++++--- > drivers/idle/intel_idle.c | 6 ++++-- > include/linux/cpuidle.h | 9 ++++++--- > 4 files changed, 19 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..b65909a 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -65,10 +65,13 @@ struct cpuidle_state { > * CPUs execute ->enter_s2idle with the local tick or entire timekeeping > * suspended, so it must not re-enable interrupts at any point (even > * temporarily) or attempt to change states of clock event devices. > + * > + * This callback may point to the same function as ->enter if all of > + * the above requirements are met by it. > */ > - 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 */ > -- Applied as 5.9 material, thanks!