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Commit 476c942d authored by Neal Liu's avatar Neal Liu Committed by Sami Tolvanen
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BACKPORT: FROMLIST: cpuidle: change enter_s2idle() prototype 

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.

Bug: 159445192
Bug: 159672235
Change-Id: Iffc9e1b6a17471ca4291865ab3dc8803303a38ce
Link: https://lore.kernel.org/lkml/1595820346-4361-2-git-send-email-neal.liu@mediatek.com/


Signed-off-by: default avatarNeal Liu <neal.liu@mediatek.com>
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent 261a54f3

arch/arm/mach-tegra/cpuidle-tegra114.c

+3 −1
Original line number Diff line number Diff line
@@ -51,11 +51,13 @@ static int tegra114_idle_power_down(struct cpuidle_device *dev, 
	return index;

}



static void tegra114_idle_enter_s2idle(struct cpuidle_device *dev,

static int tegra114_idle_enter_s2idle(struct cpuidle_device *dev,

				       struct cpuidle_driver *drv,

				       int index)

{

       tegra114_idle_power_down(dev, drv, index);



       return 0;

}

#endif

drivers/acpi/processor_idle.c

+6 −4
Original line number Diff line number Diff line
@@ -791,7 +791,7 @@ static int acpi_idle_enter(struct cpuidle_device *dev, 
	return index;

}



static void acpi_idle_enter_s2idle(struct cpuidle_device *dev,

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);
@@ -800,16 +800,18 @@ static void acpi_idle_enter_s2idle(struct cpuidle_device *dev, 
		struct acpi_processor *pr = __this_cpu_read(processors);



		if (unlikely(!pr))

			return;

			return 0;



		if (pr->flags.bm_check) {

			acpi_idle_enter_bm(pr, cx, false);

			return;

			return 0;

		} else {

			ACPI_FLUSH_CPU_CACHE();

		}

	}

	acpi_idle_do_entry(cx);



	return 0;

}



static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,

drivers/idle/intel_idle.c

+4 −2
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ static const struct idle_cpu *icpu; 
static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;

static int intel_idle(struct cpuidle_device *dev,

			struct cpuidle_driver *drv, int index);

static void intel_idle_s2idle(struct cpuidle_device *dev,

static int intel_idle_s2idle(struct cpuidle_device *dev,

			      struct cpuidle_driver *drv, int index);

static struct cpuidle_state *cpuidle_state_table;
@@ -935,13 +935,15 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, 
 * @drv: cpuidle driver

 * @index: state index

 */

static void intel_idle_s2idle(struct cpuidle_device *dev,

static int intel_idle_s2idle(struct cpuidle_device *dev,

			     struct cpuidle_driver *drv, int index)

{

	unsigned long ecx = 1; /* break on interrupt flag */

	unsigned long eax = flg2MWAIT(drv->states[index].flags);



	mwait_idle_with_hints(eax, ecx);



	return 0;

}



static void __setup_broadcast_timer(bool on)

include/linux/cpuidle.h

+6 −3
Original line number Diff line number Diff line
@@ -61,8 +61,11 @@ 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,

	int (*enter_s2idle)(struct cpuidle_device *dev,

			    struct cpuidle_driver *drv,

			    int index);

};