[deliverable/linux.git] / include / linux / hardirq.h

#ifndef LINUX_HARDIRQ_H
#define LINUX_HARDIRQ_H

#include <linux/preempt.h>
#include <linux/lockdep.h>
#include <linux/ftrace_irq.h>
#include <linux/vtime.h>
#include <asm/hardirq.h>

/*
 * 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 27 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_COUNT)
# define PREEMPT_CHECK_OFFSET 1
#else
# 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) != 0)

/*
 * 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_COUNT
# define preemptible()	(preempt_count() == 0 && !irqs_disabled())
#else
# define preemptible()	0
#endif

#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
extern void synchronize_irq(unsigned int irq);
#else
# define synchronize_irq(irq)	barrier()
#endif

#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)

static inline void rcu_nmi_enter(void)
{
}

static inline void rcu_nmi_exit(void)
{
}

#else
extern void rcu_nmi_enter(void);
extern void rcu_nmi_exit(void);
#endif

/*
 * 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_irq_enter_time(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_irq_exit_time(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 {							\
		lockdep_off();					\
		ftrace_nmi_enter();				\
		BUG_ON(in_nmi());				\
		add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
		rcu_nmi_enter();				\
		trace_hardirq_enter();				\
	} while (0)

#define nmi_exit()						\
	do {							\
		trace_hardirq_exit();				\
		rcu_nmi_exit();					\
		BUG_ON(!in_nmi());				\
		sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
		ftrace_nmi_exit();				\
		lockdep_on();					\
	} while (0)

#endif /* LINUX_HARDIRQ_H */
Commit	Line	Data
	1	#ifndef LINUX_HARDIRQ_H
	2	#define LINUX_HARDIRQ_H
	3
	4	#include <linux/preempt.h>
	5	#include <linux/lockdep.h>
	6	#include <linux/ftrace_irq.h>
	7	#include <linux/vtime.h>
	8	#include <asm/hardirq.h>
	9
	10	/*
	11	* We put the hardirq and softirq counter into the preemption
	12	* counter. The bitmask has the following meaning:
	13	*
	14	* - bits 0-7 are the preemption count (max preemption depth: 256)
	15	* - bits 8-15 are the softirq count (max # of softirqs: 256)
	16	*
	17	* The hardirq count can in theory reach the same as NR_IRQS.
	18	* In reality, the number of nested IRQS is limited to the stack
	19	* size as well. For archs with over 1000 IRQS it is not practical
	20	* to expect that they will all nest. We give a max of 10 bits for
	21	* hardirq nesting. An arch may choose to give less than 10 bits.
	22	* m68k expects it to be 8.
	23	*
	24	* - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
	25	* - bit 26 is the NMI_MASK
	26	* - bit 27 is the PREEMPT_ACTIVE flag
	27	*
	28	* PREEMPT_MASK: 0x000000ff
	29	* SOFTIRQ_MASK: 0x0000ff00
	30	* HARDIRQ_MASK: 0x03ff0000
	31	* NMI_MASK: 0x04000000
	32	*/
	33	#define PREEMPT_BITS 8
	34	#define SOFTIRQ_BITS 8
	35	#define NMI_BITS 1
	36
	37	#define MAX_HARDIRQ_BITS 10
	38
	39	#ifndef HARDIRQ_BITS
	40	# define HARDIRQ_BITS MAX_HARDIRQ_BITS
	41	#endif
	42
	43	#if HARDIRQ_BITS > MAX_HARDIRQ_BITS
	44	#error HARDIRQ_BITS too high!
	45	#endif
	46
	47	#define PREEMPT_SHIFT 0
	48	#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
	49	#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
	50	#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
	51
	52	#define __IRQ_MASK(x) ((1UL << (x))-1)
	53
	54	#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
	55	#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
	56	#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
	57	#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
	58
	59	#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
	60	#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
	61	#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
	62	#define NMI_OFFSET (1UL << NMI_SHIFT)
	63
	64	#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
	65
	66	#ifndef PREEMPT_ACTIVE
	67	#define PREEMPT_ACTIVE_BITS 1
	68	#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
	69	#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
	70	#endif
	71
	72	#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
	73	#error PREEMPT_ACTIVE is too low!
	74	#endif
	75
	76	#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
	77	#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
	78	#define irq_count() (preempt_count() & (HARDIRQ_MASK \| SOFTIRQ_MASK \
	79	\| NMI_MASK))
	80
	81	/*
	82	* Are we doing bottom half or hardware interrupt processing?
	83	* Are we in a softirq context? Interrupt context?
	84	* in_softirq - Are we currently processing softirq or have bh disabled?
	85	* in_serving_softirq - Are we currently processing softirq?
	86	*/
	87	#define in_irq() (hardirq_count())
	88	#define in_softirq() (softirq_count())
	89	#define in_interrupt() (irq_count())
	90	#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
	91
	92	/*
	93	* Are we in NMI context?
	94	*/
	95	#define in_nmi() (preempt_count() & NMI_MASK)
	96
	97	#if defined(CONFIG_PREEMPT_COUNT)
	98	# define PREEMPT_CHECK_OFFSET 1
	99	#else
	100	# define PREEMPT_CHECK_OFFSET 0
	101	#endif
	102
	103	/*
	104	* Are we running in atomic context? WARNING: this macro cannot
	105	* always detect atomic context; in particular, it cannot know about
	106	* held spinlocks in non-preemptible kernels. Thus it should not be
	107	* used in the general case to determine whether sleeping is possible.
	108	* Do not use in_atomic() in driver code.
	109	*/
	110	#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
	111
	112	/*
	113	* Check whether we were atomic before we did preempt_disable():
	114	* (used by the scheduler, after releasing the kernel lock)
	115	*/
	116	#define in_atomic_preempt_off() \
	117	((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
	118
	119	#ifdef CONFIG_PREEMPT_COUNT
	120	# define preemptible() (preempt_count() == 0 && !irqs_disabled())
	121	#else
	122	# define preemptible() 0
	123	#endif
	124
	125	#if defined(CONFIG_SMP) \|\| defined(CONFIG_GENERIC_HARDIRQS)
	126	extern void synchronize_irq(unsigned int irq);
	127	#else
	128	# define synchronize_irq(irq) barrier()
	129	#endif
	130
	131	#if defined(CONFIG_TINY_RCU) \|\| defined(CONFIG_TINY_PREEMPT_RCU)
	132
	133	static inline void rcu_nmi_enter(void)
	134	{
	135	}
	136
	137	static inline void rcu_nmi_exit(void)
	138	{
	139	}
	140
	141	#else
	142	extern void rcu_nmi_enter(void);
	143	extern void rcu_nmi_exit(void);
	144	#endif
	145
	146	/*
	147	* It is safe to do non-atomic ops on ->hardirq_context,
	148	* because NMI handlers may not preempt and the ops are
	149	* always balanced, so the interrupted value of ->hardirq_context
	150	* will always be restored.
	151	*/
	152	#define __irq_enter() \
	153	do { \
	154	account_irq_enter_time(current); \
	155	add_preempt_count(HARDIRQ_OFFSET); \
	156	trace_hardirq_enter(); \
	157	} while (0)
	158
	159	/*
	160	* Enter irq context (on NO_HZ, update jiffies):
	161	*/
	162	extern void irq_enter(void);
	163
	164	/*
	165	* Exit irq context without processing softirqs:
	166	*/
	167	#define __irq_exit() \
	168	do { \
	169	trace_hardirq_exit(); \
	170	account_irq_exit_time(current); \
	171	sub_preempt_count(HARDIRQ_OFFSET); \
	172	} while (0)
	173
	174	/*
	175	* Exit irq context and process softirqs if needed:
	176	*/
	177	extern void irq_exit(void);
	178
	179	#define nmi_enter() \
	180	do { \
	181	lockdep_off(); \
	182	ftrace_nmi_enter(); \
	183	BUG_ON(in_nmi()); \
	184	add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
	185	rcu_nmi_enter(); \
	186	trace_hardirq_enter(); \
	187	} while (0)
	188
	189	#define nmi_exit() \
	190	do { \
	191	trace_hardirq_exit(); \
	192	rcu_nmi_exit(); \
	193	BUG_ON(!in_nmi()); \
	194	sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
	195	ftrace_nmi_exit(); \
	196	lockdep_on(); \
	197	} while (0)
	198
	199	#endif /* LINUX_HARDIRQ_H */