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authorNeal Liu <neal.liu@mediatek.com>2020-07-27 11:25:46 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-07-29 18:38:30 +0200
commitefe9711214e6138a5a2a46ca4068bfce50c03444 (patch)
tree73343cbdd485268e6e4186b2c947a865895d0b00
parent81f94ddfeceddb3b8ffa6cfe5ddd3b896711d9ad (diff)
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>
-rw-r--r--drivers/acpi/processor_idle.c6
-rw-r--r--drivers/cpuidle/cpuidle-tegra.c8
-rw-r--r--drivers/idle/intel_idle.c6
-rw-r--r--include/linux/cpuidle.h9
4 files changed, 19 insertions, 10 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 75534c5b5433..6ffb6c99c2de 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 150045849d78..a12fb141875a 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 fa23a7ea01ac..3f86f36dab2b 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -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;
}
/*
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index ec2ef63771f0..b65909ae4e20 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 */