#ifndef LINUX_HARDIRQ_H #define LINUX_HARDIRQ_H #include #ifdef CONFIG_PREEMPT #include #endif #include #include #include #include /* * We put the hardirq and softirq counter into the preemption * counter. The bitmask has the following meaning: * * - bits 0-7 are the preemption count (max preemption depth: 256) * - bits 8-15 are the softirq count (max # of softirqs: 256) * * The hardirq count can in theory reach the same as NR_IRQS. * In reality, the number of nested IRQS is limited to the stack * size as well. For archs with over 1000 IRQS it is not practical * to expect that they will all nest. We give a max of 10 bits for * hardirq nesting. An arch may choose to give less than 10 bits. * m68k expects it to be 8. * * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) * - bit 26 is the NMI_MASK * - bit 28 is the PREEMPT_ACTIVE flag * * PREEMPT_MASK: 0x000000ff * SOFTIRQ_MASK: 0x0000ff00 * HARDIRQ_MASK: 0x03ff0000 * NMI_MASK: 0x04000000 */ #define PREEMPT_BITS 8 #define SOFTIRQ_BITS 8 #define NMI_BITS 1 #define MAX_HARDIRQ_BITS 10 #ifndef HARDIRQ_BITS # define HARDIRQ_BITS MAX_HARDIRQ_BITS #endif #if HARDIRQ_BITS > MAX_HARDIRQ_BITS #error HARDIRQ_BITS too high! #endif #define PREEMPT_SHIFT 0 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) #define __IRQ_MASK(x) ((1UL << (x))-1) #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) #define NMI_OFFSET (1UL << NMI_SHIFT) #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) #ifndef PREEMPT_ACTIVE #define PREEMPT_ACTIVE_BITS 1 #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) #endif #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) #error PREEMPT_ACTIVE is too low! #endif #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #define softirq_count() (preempt_count() & SOFTIRQ_MASK) #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ | NMI_MASK)) /* * Are we doing bottom half or hardware interrupt processing? * Are we in a softirq context? Interrupt context? * in_softirq - Are we currently processing softirq or have bh disabled? * in_serving_softirq - Are we currently processing softirq? */ #define in_irq() (hardirq_count()) #define in_softirq() (softirq_count()) #define in_interrupt() (irq_count()) #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) /* * Are we in NMI context? */ #define in_nmi() (preempt_count() & NMI_MASK) #if defined(CONFIG_PREEMPT) # define PREEMPT_INATOMIC_BASE kernel_locked() # define PREEMPT_CHECK_OFFSET 1 #else # define PREEMPT_INATOMIC_BASE 0 # define PREEMPT_CHECK_OFFSET 0 #endif /* * Are we running in atomic context? WARNING: this macro cannot * always detect atomic context; in particular, it cannot know about * held spinlocks in non-preemptible kernels. Thus it should not be * used in the general case to determine whether sleeping is possible. * Do not use in_atomic() in driver code. */ #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) /* * Check whether we were atomic before we did preempt_disable(): * (used by the scheduler, *after* releasing the kernel lock) */ #define in_atomic_preempt_off() \ ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) #ifdef CONFIG_PREEMPT # define preemptible() (preempt_count() == 0 && !irqs_disabled()) # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) #else # define preemptible() 0 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET #endif #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) extern void synchronize_irq(unsigned int irq); #else # define synchronize_irq(irq) barrier() #endif struct task_struct; #if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING) static inline void account_system_vtime(struct task_struct *tsk) { } #else extern void account_system_vtime(struct task_struct *tsk); #endif #if defined(CONFIG_NO_HZ) #if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) extern void rcu_enter_nohz(void); extern void rcu_exit_nohz(void); static inline void rcu_irq_enter(void) { rcu_exit_nohz(); } static inline void rcu_irq_exit(void) { rcu_enter_nohz(); } static inline void rcu_nmi_enter(void) { } static inline void rcu_nmi_exit(void) { } #else extern void rcu_irq_enter(void); extern void rcu_irq_exit(void); extern void rcu_nmi_enter(void); extern void rcu_nmi_exit(void); #endif #else # define rcu_irq_enter() do { } while (0) # define rcu_irq_exit() do { } while (0) # define rcu_nmi_enter() do { } while (0) # define rcu_nmi_exit() do { } while (0) #endif /* #if defined(CONFIG_NO_HZ) */ /* * It is safe to do non-atomic ops on ->hardirq_context, * because NMI handlers may not preempt and the ops are * always balanced, so the interrupted value of ->hardirq_context * will always be restored. */ #define __irq_enter() \ do { \ account_system_vtime(current); \ add_preempt_count(HARDIRQ_OFFSET); \ trace_hardirq_enter(); \ } while (0) /* * Enter irq context (on NO_HZ, update jiffies): */ extern void irq_enter(void); /* * Exit irq context without processing softirqs: */ #define __irq_exit() \ do { \ trace_hardirq_exit(); \ account_system_vtime(current); \ sub_preempt_count(HARDIRQ_OFFSET); \ } while (0) /* * Exit irq context and process softirqs if needed: */ extern void irq_exit(void); #define nmi_enter() \ do { \ ftrace_nmi_enter(); \ BUG_ON(in_nmi()); \ add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ lockdep_off(); \ rcu_nmi_enter(); \ trace_hardirq_enter(); \ } while (0) #define nmi_exit() \ do { \ trace_hardirq_exit(); \ rcu_nmi_exit(); \ lockdep_on(); \ BUG_ON(!in_nmi()); \ sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ ftrace_nmi_exit(); \ } while (0) #endif /* LINUX_HARDIRQ_H */