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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef LINUX_HARDIRQ_H
2#define LINUX_HARDIRQ_H
3
Randy Dunlap67bc4eb2005-07-12 13:58:36 -07004#include <linux/preempt.h>
Alexey Dobriyan405f5572009-07-11 22:08:37 +04005#ifdef CONFIG_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#include <linux/smp_lock.h>
Alexey Dobriyan405f5572009-07-11 22:08:37 +04007#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07008#include <linux/lockdep.h>
Steven Rostedt6a60dd12008-11-06 15:55:21 -05009#include <linux/ftrace_irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <asm/hardirq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
12/*
13 * We put the hardirq and softirq counter into the preemption
14 * counter. The bitmask has the following meaning:
15 *
16 * - bits 0-7 are the preemption count (max preemption depth: 256)
17 * - bits 8-15 are the softirq count (max # of softirqs: 256)
18 *
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050019 * The hardirq count can in theory reach the same as NR_IRQS.
20 * In reality, the number of nested IRQS is limited to the stack
21 * size as well. For archs with over 1000 IRQS it is not practical
22 * to expect that they will all nest. We give a max of 10 bits for
23 * hardirq nesting. An arch may choose to give less than 10 bits.
24 * m68k expects it to be 8.
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 *
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050026 * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
27 * - bit 26 is the NMI_MASK
28 * - bit 28 is the PREEMPT_ACTIVE flag
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 *
30 * PREEMPT_MASK: 0x000000ff
31 * SOFTIRQ_MASK: 0x0000ff00
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050032 * HARDIRQ_MASK: 0x03ff0000
33 * NMI_MASK: 0x04000000
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 */
35#define PREEMPT_BITS 8
36#define SOFTIRQ_BITS 8
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050037#define NMI_BITS 1
38
39#define MAX_HARDIRQ_BITS 10
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41#ifndef HARDIRQ_BITS
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050042# define HARDIRQ_BITS MAX_HARDIRQ_BITS
Eric W. Biederman23d0b8b2006-10-04 02:16:49 -070043#endif
44
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050045#if HARDIRQ_BITS > MAX_HARDIRQ_BITS
46#error HARDIRQ_BITS too high!
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#endif
48
49#define PREEMPT_SHIFT 0
50#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
51#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050052#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54#define __IRQ_MASK(x) ((1UL << (x))-1)
55
56#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
Paolo 'Blaisorblade' Giarrusso8f28e8f2005-05-28 15:52:02 -070058#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050059#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
62#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
63#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050064#define NMI_OFFSET (1UL << NMI_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Venkatesh Pallipadi75e10562010-10-04 17:03:16 -070066#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
67
Arnd Bergmann8e5b59a2009-08-06 16:02:50 -070068#ifndef PREEMPT_ACTIVE
69#define PREEMPT_ACTIVE_BITS 1
70#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
71#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
72#endif
73
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050074#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
Paolo 'Blaisorblade' Giarrusso8f28e8f2005-05-28 15:52:02 -070075#error PREEMPT_ACTIVE is too low!
76#endif
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
79#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050080#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
81 | NMI_MASK))
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
83/*
84 * Are we doing bottom half or hardware interrupt processing?
85 * Are we in a softirq context? Interrupt context?
Venkatesh Pallipadi75e10562010-10-04 17:03:16 -070086 * in_softirq - Are we currently processing softirq or have bh disabled?
87 * in_serving_softirq - Are we currently processing softirq?
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 */
89#define in_irq() (hardirq_count())
90#define in_softirq() (softirq_count())
91#define in_interrupt() (irq_count())
Venkatesh Pallipadi75e10562010-10-04 17:03:16 -070092#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Steven Rostedt375b38b2009-02-06 00:51:37 -050094/*
95 * Are we in NMI context?
96 */
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050097#define in_nmi() (preempt_count() & NMI_MASK)
Steven Rostedt375b38b2009-02-06 00:51:37 -050098
Arnd Bergmann7fe19da2010-10-28 16:12:33 +020099#if defined(CONFIG_PREEMPT) && defined(CONFIG_BKL)
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700100# define PREEMPT_INATOMIC_BASE kernel_locked()
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700101#else
102# define PREEMPT_INATOMIC_BASE 0
Arnd Bergmann7fe19da2010-10-28 16:12:33 +0200103#endif
104
105#if defined(CONFIG_PREEMPT)
106# define PREEMPT_CHECK_OFFSET 1
107#else
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700108# define PREEMPT_CHECK_OFFSET 0
109#endif
110
Jonathan Corbet8c703d32008-03-28 14:15:49 -0700111/*
112 * Are we running in atomic context? WARNING: this macro cannot
113 * always detect atomic context; in particular, it cannot know about
114 * held spinlocks in non-preemptible kernels. Thus it should not be
115 * used in the general case to determine whether sleeping is possible.
116 * Do not use in_atomic() in driver code.
117 */
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700118#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
Ingo Molnar4da1ce62007-07-09 18:51:58 +0200119
120/*
121 * Check whether we were atomic before we did preempt_disable():
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700122 * (used by the scheduler, *after* releasing the kernel lock)
Ingo Molnar4da1ce62007-07-09 18:51:58 +0200123 */
124#define in_atomic_preempt_off() \
125 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
126
127#ifdef CONFIG_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128# define preemptible() (preempt_count() == 0 && !irqs_disabled())
129# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
130#else
131# define preemptible() 0
132# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
133#endif
134
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100135#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136extern void synchronize_irq(unsigned int irq);
137#else
138# define synchronize_irq(irq) barrier()
139#endif
140
Al Virof0373602005-11-13 16:06:57 -0800141struct task_struct;
142
Venkatesh Pallipadib52bfee2010-10-04 17:03:19 -0700143#if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144static inline void account_system_vtime(struct task_struct *tsk)
145{
146}
Venkatesh Pallipadie1e10a22010-10-04 17:03:17 -0700147#else
148extern void account_system_vtime(struct task_struct *tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149#endif
150
Paul E. McKenneyb560d8a2009-08-21 22:08:51 -0700151#if defined(CONFIG_NO_HZ)
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700152#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700153extern void rcu_enter_nohz(void);
154extern void rcu_exit_nohz(void);
155
156static inline void rcu_irq_enter(void)
157{
158 rcu_exit_nohz();
159}
160
161static inline void rcu_irq_exit(void)
162{
163 rcu_enter_nohz();
164}
165
166static inline void rcu_nmi_enter(void)
167{
168}
169
170static inline void rcu_nmi_exit(void)
171{
172}
173
174#else
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100175extern void rcu_irq_enter(void);
176extern void rcu_irq_exit(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100177extern void rcu_nmi_enter(void);
178extern void rcu_nmi_exit(void);
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700179#endif
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100180#else
181# define rcu_irq_enter() do { } while (0)
182# define rcu_irq_exit() do { } while (0)
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100183# define rcu_nmi_enter() do { } while (0)
184# define rcu_nmi_exit() do { } while (0)
Paul E. McKenneyb560d8a2009-08-21 22:08:51 -0700185#endif /* #if defined(CONFIG_NO_HZ) */
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100186
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700187/*
188 * It is safe to do non-atomic ops on ->hardirq_context,
189 * because NMI handlers may not preempt and the ops are
190 * always balanced, so the interrupted value of ->hardirq_context
191 * will always be restored.
192 */
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800193#define __irq_enter() \
194 do { \
195 account_system_vtime(current); \
196 add_preempt_count(HARDIRQ_OFFSET); \
197 trace_hardirq_enter(); \
198 } while (0)
199
200/*
201 * Enter irq context (on NO_HZ, update jiffies):
202 */
Ingo Molnardde4b2b2007-02-16 01:27:45 -0800203extern void irq_enter(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700205/*
206 * Exit irq context without processing softirqs:
207 */
208#define __irq_exit() \
209 do { \
210 trace_hardirq_exit(); \
211 account_system_vtime(current); \
212 sub_preempt_count(HARDIRQ_OFFSET); \
213 } while (0)
214
215/*
216 * Exit irq context and process softirqs if needed:
217 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218extern void irq_exit(void);
219
Steven Rostedt2a7b8df2009-02-12 14:16:46 -0500220#define nmi_enter() \
221 do { \
222 ftrace_nmi_enter(); \
223 BUG_ON(in_nmi()); \
224 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
225 lockdep_off(); \
226 rcu_nmi_enter(); \
227 trace_hardirq_enter(); \
Steven Rostedt17666f02008-10-30 16:08:32 -0400228 } while (0)
Linus Torvalds5f34fe12008-12-30 16:10:19 -0800229
Steven Rostedt2a7b8df2009-02-12 14:16:46 -0500230#define nmi_exit() \
231 do { \
232 trace_hardirq_exit(); \
233 rcu_nmi_exit(); \
234 lockdep_on(); \
235 BUG_ON(!in_nmi()); \
236 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
237 ftrace_nmi_exit(); \
Steven Rostedt17666f02008-10-30 16:08:32 -0400238 } while (0)
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240#endif /* LINUX_HARDIRQ_H */