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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005#include <linux/smp_lock.h>
Ingo Molnarfbb9ce92006-07-03 00:24:50 -07006#include <linux/lockdep.h>
Steven Rostedt6a60dd12008-11-06 15:55:21 -05007#include <linux/ftrace_irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <asm/hardirq.h>
9#include <asm/system.h>
10
11/*
12 * We put the hardirq and softirq counter into the preemption
13 * counter. The bitmask has the following meaning:
14 *
15 * - bits 0-7 are the preemption count (max preemption depth: 256)
16 * - bits 8-15 are the softirq count (max # of softirqs: 256)
17 *
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050018 * The hardirq count can in theory reach the same as NR_IRQS.
19 * In reality, the number of nested IRQS is limited to the stack
20 * size as well. For archs with over 1000 IRQS it is not practical
21 * to expect that they will all nest. We give a max of 10 bits for
22 * hardirq nesting. An arch may choose to give less than 10 bits.
23 * m68k expects it to be 8.
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 *
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050025 * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
26 * - bit 26 is the NMI_MASK
27 * - bit 28 is the PREEMPT_ACTIVE flag
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 *
29 * PREEMPT_MASK: 0x000000ff
30 * SOFTIRQ_MASK: 0x0000ff00
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050031 * HARDIRQ_MASK: 0x03ff0000
32 * NMI_MASK: 0x04000000
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 */
34#define PREEMPT_BITS 8
35#define SOFTIRQ_BITS 8
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050036#define NMI_BITS 1
37
38#define MAX_HARDIRQ_BITS 10
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40#ifndef HARDIRQ_BITS
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050041# define HARDIRQ_BITS MAX_HARDIRQ_BITS
Eric W. Biederman23d0b8b2006-10-04 02:16:49 -070042#endif
43
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050044#if HARDIRQ_BITS > MAX_HARDIRQ_BITS
45#error HARDIRQ_BITS too high!
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#endif
47
48#define PREEMPT_SHIFT 0
49#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
50#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050051#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#define __IRQ_MASK(x) ((1UL << (x))-1)
54
55#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
Paolo 'Blaisorblade' Giarrusso8f28e8f2005-05-28 15:52:02 -070057#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050058#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
61#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
62#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050063#define NMI_OFFSET (1UL << NMI_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050065#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
Paolo 'Blaisorblade' Giarrusso8f28e8f2005-05-28 15:52:02 -070066#error PREEMPT_ACTIVE is too low!
67#endif
68
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
70#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050071#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
72 | NMI_MASK))
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74/*
75 * Are we doing bottom half or hardware interrupt processing?
76 * Are we in a softirq context? Interrupt context?
77 */
78#define in_irq() (hardirq_count())
79#define in_softirq() (softirq_count())
80#define in_interrupt() (irq_count())
81
Steven Rostedt375b38b2009-02-06 00:51:37 -050082/*
83 * Are we in NMI context?
84 */
Steven Rostedt5a5fb7d2009-02-12 10:53:37 -050085#define in_nmi() (preempt_count() & NMI_MASK)
Steven Rostedt375b38b2009-02-06 00:51:37 -050086
Linus Torvalds8e3e0762008-05-10 20:58:02 -070087#if defined(CONFIG_PREEMPT)
88# define PREEMPT_INATOMIC_BASE kernel_locked()
89# define PREEMPT_CHECK_OFFSET 1
90#else
91# define PREEMPT_INATOMIC_BASE 0
92# define PREEMPT_CHECK_OFFSET 0
93#endif
94
Jonathan Corbet8c703d32008-03-28 14:15:49 -070095/*
96 * Are we running in atomic context? WARNING: this macro cannot
97 * always detect atomic context; in particular, it cannot know about
98 * held spinlocks in non-preemptible kernels. Thus it should not be
99 * used in the general case to determine whether sleeping is possible.
100 * Do not use in_atomic() in driver code.
101 */
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700102#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
Ingo Molnar4da1ce62007-07-09 18:51:58 +0200103
104/*
105 * Check whether we were atomic before we did preempt_disable():
Linus Torvalds8e3e0762008-05-10 20:58:02 -0700106 * (used by the scheduler, *after* releasing the kernel lock)
Ingo Molnar4da1ce62007-07-09 18:51:58 +0200107 */
108#define in_atomic_preempt_off() \
109 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
110
111#ifdef CONFIG_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112# define preemptible() (preempt_count() == 0 && !irqs_disabled())
113# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
114#else
115# define preemptible() 0
116# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
117#endif
118
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100119#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120extern void synchronize_irq(unsigned int irq);
121#else
122# define synchronize_irq(irq) barrier()
123#endif
124
Al Virof0373602005-11-13 16:06:57 -0800125struct task_struct;
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127#ifndef CONFIG_VIRT_CPU_ACCOUNTING
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128static inline void account_system_vtime(struct task_struct *tsk)
129{
130}
131#endif
132
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100133#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100134extern void rcu_irq_enter(void);
135extern void rcu_irq_exit(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100136extern void rcu_nmi_enter(void);
137extern void rcu_nmi_exit(void);
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100138#else
139# define rcu_irq_enter() do { } while (0)
140# define rcu_irq_exit() do { } while (0)
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100141# define rcu_nmi_enter() do { } while (0)
142# define rcu_nmi_exit() do { } while (0)
143#endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */
Steven Rostedt2232c2d2008-02-29 18:46:50 +0100144
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700145/*
146 * It is safe to do non-atomic ops on ->hardirq_context,
147 * because NMI handlers may not preempt and the ops are
148 * always balanced, so the interrupted value of ->hardirq_context
149 * will always be restored.
150 */
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800151#define __irq_enter() \
152 do { \
153 account_system_vtime(current); \
154 add_preempt_count(HARDIRQ_OFFSET); \
155 trace_hardirq_enter(); \
156 } while (0)
157
158/*
159 * Enter irq context (on NO_HZ, update jiffies):
160 */
Ingo Molnardde4b2b2007-02-16 01:27:45 -0800161extern void irq_enter(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700163/*
164 * Exit irq context without processing softirqs:
165 */
166#define __irq_exit() \
167 do { \
168 trace_hardirq_exit(); \
169 account_system_vtime(current); \
170 sub_preempt_count(HARDIRQ_OFFSET); \
171 } while (0)
172
173/*
174 * Exit irq context and process softirqs if needed:
175 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176extern void irq_exit(void);
177
Steven Rostedt2a7b8df2009-02-12 14:16:46 -0500178#define nmi_enter() \
179 do { \
180 ftrace_nmi_enter(); \
181 BUG_ON(in_nmi()); \
182 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
183 lockdep_off(); \
184 rcu_nmi_enter(); \
185 trace_hardirq_enter(); \
Steven Rostedt17666f02008-10-30 16:08:32 -0400186 } while (0)
Linus Torvalds5f34fe12008-12-30 16:10:19 -0800187
Steven Rostedt2a7b8df2009-02-12 14:16:46 -0500188#define nmi_exit() \
189 do { \
190 trace_hardirq_exit(); \
191 rcu_nmi_exit(); \
192 lockdep_on(); \
193 BUG_ON(!in_nmi()); \
194 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
195 ftrace_nmi_exit(); \
Steven Rostedt17666f02008-10-30 16:08:32 -0400196 } while (0)
Ingo Molnarde30a2b2006-07-03 00:24:42 -0700197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198#endif /* LINUX_HARDIRQ_H */