Linux-ACPI Archive on lore.kernel.org
 help / color / Atom feed
From: Neal Liu <neal.liu@mediatek.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Sami Tolvanen <samitolvanen@google.com>
Cc: Neal Liu <neal.liu@mediatek.com>, <linux-acpi@vger.kernel.org>,
	<linux-pm@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	lkml <linux-kernel@vger.kernel.org>, <wsd_upstream@mediatek.com>
Subject: [PATCH v2] cpuidle: change enter_s2idle() prototype
Date: Mon, 6 Jul 2020 11:13:16 +0800
Message-ID: <1594005196-16327-2-git-send-email-neal.liu@mediatek.com> (raw)
In-Reply-To: <1594005196-16327-1-git-send-email-neal.liu@mediatek.com>

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 <neal.liu@mediatek.com>
---
 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

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-06  3:13 [PATCH v2] cpuidle: Fix CFI failure Neal Liu
2020-07-06  3:13 ` Neal Liu [this message]
2020-07-07 16:43   ` [PATCH v2] cpuidle: change enter_s2idle() prototype Sami Tolvanen
2020-07-09 12:18   ` Rafael J. Wysocki
2020-07-10  3:08     ` Neal Liu
2020-07-20  8:21       ` Neal Liu
2020-07-23 19:07         ` Sami Tolvanen
2020-07-24  9:57           ` Rafael J. Wysocki
2020-07-24 10:24             ` Neal Liu
2020-07-24 11:20               ` Rafael J. Wysocki
2020-07-24 11:49                 ` Neal Liu
2020-07-25 15:48                   ` Rafael J. Wysocki

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1594005196-16327-2-git-send-email-neal.liu@mediatek.com \
    --to=neal.liu@mediatek.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=jacob.jun.pan@linux.intel.com \
    --cc=jonathanh@nvidia.com \
    --cc=lenb@kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=matthias.bgg@gmail.com \
    --cc=rjw@rjwysocki.net \
    --cc=samitolvanen@google.com \
    --cc=thierry.reding@gmail.com \
    --cc=wsd_upstream@mediatek.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ACPI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-acpi/0 linux-acpi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-acpi linux-acpi/ https://lore.kernel.org/linux-acpi \
		linux-acpi@vger.kernel.org
	public-inbox-index linux-acpi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-acpi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git