diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/printk.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index fe7eb2351610..1790a5521fd9 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -282,6 +282,47 @@ static inline void printk_safe_flush_on_panic(void) } #endif +#ifdef CONFIG_SMP +extern int __printk_cpu_trylock(void); +extern void __printk_wait_on_cpu_lock(void); +extern void __printk_cpu_unlock(void); + +/** + * printk_cpu_lock_irqsave() - Acquire the printk cpu-reentrant spinning + * lock and disable interrupts. + * @flags: Stack-allocated storage for saving local interrupt state, + * to be passed to printk_cpu_unlock_irqrestore(). + * + * If the lock is owned by another CPU, spin until it becomes available. + * Interrupts are restored while spinning. + */ +#define printk_cpu_lock_irqsave(flags) \ + for (;;) { \ + local_irq_save(flags); \ + if (__printk_cpu_trylock()) \ + break; \ + local_irq_restore(flags); \ + __printk_wait_on_cpu_lock(); \ + } + +/** + * printk_cpu_unlock_irqrestore() - Release the printk cpu-reentrant spinning + * lock and restore interrupts. + * @flags: Caller's saved interrupt state, from printk_cpu_lock_irqsave(). + */ +#define printk_cpu_unlock_irqrestore(flags) \ + do { \ + __printk_cpu_unlock(); \ + local_irq_restore(flags); \ + } while (0) \ + +#else + +#define printk_cpu_lock_irqsave(flags) ((void)flags) +#define printk_cpu_unlock_irqrestore(flags) ((void)flags) + +#endif /* CONFIG_SMP */ + extern int kptr_restrict; /** |