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cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE

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The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
enabled. Commit c8cc7d4de7 ("sched/idle: Reorganize the idle loop")
removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
compiler optimising away __this_cpu_read(cpuidle_devices). However, with
CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
and the kernel fails to link since cpuidle_devices is not defined.

This patch introduces an accessor function for the current CPU cpuidle
device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
cpuidle_idle_call().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: 4.5+ <stable@vger.kernel.org> # 4.5+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Catalin Marinas 2016-06-01 18:52:16 +01:00 committed by Rafael J. Wysocki
parent e7387da520
commit 9bd616e3db
2 changed files with 4 additions and 1 deletions
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3
include/linux/cpuidle.h
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@ -152,6 +152,8 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev);
extern int cpuidle_play_dead(void);
extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
static inline struct cpuidle_device *cpuidle_get_device(void)
{return __this_cpu_read(cpuidle_devices); }
#else
static inline void disable_cpuidle(void) { }
static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
@ -187,6 +189,7 @@ static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
static inline int cpuidle_play_dead(void) {return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
struct cpuidle_device *dev) {return NULL; }
static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
#endif
#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_SUSPEND)

2
kernel/sched/idle.c
View File

@ -127,7 +127,7 @@ static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
*/
static void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_device *dev = cpuidle_get_device();
struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
int next_state, entered_state;