summaryrefslogtreecommitdiff
path: root/include/linux/cpuidle.h
diff options
context:
space:
mode:
authorNeal Liu <neal.liu@mediatek.com>2020-07-27 06:25:46 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-07-29 19:38:30 +0300
commitefe9711214e6138a5a2a46ca4068bfce50c03444 (patch)
tree73343cbdd485268e6e4186b2c947a865895d0b00 /include/linux/cpuidle.h
parent81f94ddfeceddb3b8ffa6cfe5ddd3b896711d9ad (diff)
downloadlinux-efe9711214e6138a5a2a46ca4068bfce50c03444.tar.xz
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>
Diffstat (limited to 'include/linux/cpuidle.h')
-rw-r--r--include/linux/cpuidle.h9
1 files changed, 6 insertions, 3 deletions
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 */