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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.

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Neal Liu 2020-07-27 11:25:46 +08:00 committed by Rafael J. Wysocki
parent 81f94ddfec
commit efe9711214
4 changed files with 19 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/acpi/processor_idle.c
View File

@ -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,

8
drivers/cpuidle/cpuidle-tegra.c
View File

@ -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;
}
/*

6
drivers/idle/intel_idle.c
View File

@ -173,13 +173,15 @@ 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;
}
/*

9
include/linux/cpuidle.h
View File

@ -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 */