From efe9711214e6138a5a2a46ca4068bfce50c03444 Mon Sep 17 00:00:00 2001 From: Neal Liu Date: Mon, 27 Jul 2020 11:25:46 +0800 Subject: 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 Reviewed-by: Sami Tolvanen Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/idle') 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; } /* -- cgit v1.2.3