From d8c216cfa57e8a579f41729cbb88c97835d9ac8d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 8 Jan 2011 00:29:20 +0100 Subject: cpuidle: Make cpuidle_enable_device() call poll_idle_init() The following scenario is possible with the current cpuidle code and the ACPI cpuidle driver: (1) acpi_processor_cst_has_changed() is called, (2) cpuidle_disable_device() is called, (3) cpuidle_remove_state_sysfs() is called to remove the (presumably outdated) states info from sysfs, (3) acpi_processor_get_power_info() is called, the first entry in the pr->power.states[] table is filled with zeros, (4) acpi_processor_setup_cpuidle() is called and it doesn't fill the first entry in pr->power.states[], (5) cpuidle_enable_device() is called, (6) __cpuidle_register_device() is _not_ called, since the device has already been registered, (7) Consequently, poll_idle_init() is _not_ called either, (8) cpuidle_add_state_sysfs() is called to create the sysfs attributes for the new states and it uses the bogus first table entry from acpi_processor_get_power_info() for creating state0. This problem is avoided if cpuidle_enable_device() unconditionally calls poll_idle_init(). Reported-by: Len Brown Signed-off-by: Rafael J. Wysocki Signed-off-by: Len Brown cc: stable@kernel.org --- drivers/cpuidle/cpuidle.c | 82 +++++++++++++++++++++++------------------------ 1 file changed, 41 insertions(+), 41 deletions(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index a507108..97df791 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -154,6 +154,45 @@ void cpuidle_resume_and_unlock(void) EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); +#ifdef CONFIG_ARCH_HAS_CPU_RELAX +static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st) +{ + ktime_t t1, t2; + s64 diff; + int ret; + + t1 = ktime_get(); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + + t2 = ktime_get(); + diff = ktime_to_us(ktime_sub(t2, t1)); + if (diff > INT_MAX) + diff = INT_MAX; + + ret = (int) diff; + return ret; +} + +static void poll_idle_init(struct cpuidle_device *dev) +{ + struct cpuidle_state *state = &dev->states[0]; + + cpuidle_set_statedata(state, NULL); + + snprintf(state->name, CPUIDLE_NAME_LEN, "C0"); + snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); + state->exit_latency = 0; + state->target_residency = 0; + state->power_usage = -1; + state->flags = CPUIDLE_FLAG_POLL; + state->enter = poll_idle; +} +#else +static void poll_idle_init(struct cpuidle_device *dev) {} +#endif /* CONFIG_ARCH_HAS_CPU_RELAX */ + /** * cpuidle_enable_device - enables idle PM for a CPU * @dev: the CPU @@ -178,6 +217,8 @@ int cpuidle_enable_device(struct cpuidle_device *dev) return ret; } + poll_idle_init(dev); + if ((ret = cpuidle_add_state_sysfs(dev))) return ret; @@ -232,45 +273,6 @@ void cpuidle_disable_device(struct cpuidle_device *dev) EXPORT_SYMBOL_GPL(cpuidle_disable_device); -#ifdef CONFIG_ARCH_HAS_CPU_RELAX -static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st) -{ - ktime_t t1, t2; - s64 diff; - int ret; - - t1 = ktime_get(); - local_irq_enable(); - while (!need_resched()) - cpu_relax(); - - t2 = ktime_get(); - diff = ktime_to_us(ktime_sub(t2, t1)); - if (diff > INT_MAX) - diff = INT_MAX; - - ret = (int) diff; - return ret; -} - -static void poll_idle_init(struct cpuidle_device *dev) -{ - struct cpuidle_state *state = &dev->states[0]; - - cpuidle_set_statedata(state, NULL); - - snprintf(state->name, CPUIDLE_NAME_LEN, "C0"); - snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); - state->exit_latency = 0; - state->target_residency = 0; - state->power_usage = -1; - state->flags = CPUIDLE_FLAG_POLL; - state->enter = poll_idle; -} -#else -static void poll_idle_init(struct cpuidle_device *dev) {} -#endif /* CONFIG_ARCH_HAS_CPU_RELAX */ - /** * __cpuidle_register_device - internal register function called before register * and enable routines @@ -291,8 +293,6 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) init_completion(&dev->kobj_unregister); - poll_idle_init(dev); - /* * cpuidle driver should set the dev->power_specified bit * before registering the device if the driver provides -- cgit v1.1