1 #ifndef LINUX_HARDIRQ_H
2 #define LINUX_HARDIRQ_H
4 #include <linux/preempt.h>
5 #include <linux/smp_lock.h>
6 #include <linux/lockdep.h>
7 #include <linux/ftrace_irq.h>
8 #include <asm/hardirq.h>
9 #include <asm/system.h>
12 * We put the hardirq and softirq counter into the preemption
13 * counter. The bitmask has the following meaning:
15 * - bits 0-7 are the preemption count (max preemption depth: 256)
16 * - bits 8-15 are the softirq count (max # of softirqs: 256)
18 * The hardirq count can be overridden per architecture, the default is:
20 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
21 * - ( bit 28 is the PREEMPT_ACTIVE flag. )
23 * PREEMPT_MASK: 0x000000ff
24 * SOFTIRQ_MASK: 0x0000ff00
25 * HARDIRQ_MASK: 0x0fff0000
27 #define PREEMPT_BITS 8
28 #define SOFTIRQ_BITS 8
31 #define HARDIRQ_BITS 12
33 #ifndef MAX_HARDIRQS_PER_CPU
34 #define MAX_HARDIRQS_PER_CPU NR_IRQS
38 * The hardirq mask has to be large enough to have space for potentially
39 * all IRQ sources in the system nesting on a single CPU.
41 #if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
42 # error HARDIRQ_BITS is too low!
46 #define PREEMPT_SHIFT 0
47 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
48 #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
50 #define __IRQ_MASK(x) ((1UL << (x))-1)
52 #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
53 #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
54 #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
56 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
57 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
58 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
60 #if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
61 #error PREEMPT_ACTIVE is too low!
64 #define NMI_OFFSET (PREEMPT_ACTIVE << 1)
66 #if NMI_OFFSET >= 0x80000000
67 #error PREEMPT_ACTIVE too high!
70 #define hardirq_count() (preempt_count() & HARDIRQ_MASK)
71 #define softirq_count() (preempt_count() & SOFTIRQ_MASK)
72 #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
75 * Are we doing bottom half or hardware interrupt processing?
76 * Are we in a softirq context? Interrupt context?
78 #define in_irq() (hardirq_count())
79 #define in_softirq() (softirq_count())
80 #define in_interrupt() (irq_count())
83 * Are we in NMI context?
85 #define in_nmi() (preempt_count() & NMI_OFFSET)
87 #if defined(CONFIG_PREEMPT)
88 # define PREEMPT_INATOMIC_BASE kernel_locked()
89 # define PREEMPT_CHECK_OFFSET 1
91 # define PREEMPT_INATOMIC_BASE 0
92 # define PREEMPT_CHECK_OFFSET 0
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.
102 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
105 * Check whether we were atomic before we did preempt_disable():
106 * (used by the scheduler, *after* releasing the kernel lock)
108 #define in_atomic_preempt_off() \
109 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
111 #ifdef CONFIG_PREEMPT
112 # define preemptible() (preempt_count() == 0 && !irqs_disabled())
113 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
115 # define preemptible() 0
116 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
120 extern void synchronize_irq(unsigned int irq);
122 # define synchronize_irq(irq) barrier()
127 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
128 static inline void account_system_vtime(struct task_struct *tsk)
133 #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
134 extern void rcu_irq_enter(void);
135 extern void rcu_irq_exit(void);
136 extern void rcu_nmi_enter(void);
137 extern void rcu_nmi_exit(void);
139 # define rcu_irq_enter() do { } while (0)
140 # define rcu_irq_exit() do { } while (0)
141 # 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) */
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.
151 #define __irq_enter() \
153 account_system_vtime(current); \
154 add_preempt_count(HARDIRQ_OFFSET); \
155 trace_hardirq_enter(); \
159 * Enter irq context (on NO_HZ, update jiffies):
161 extern void irq_enter(void);
164 * Exit irq context without processing softirqs:
166 #define __irq_exit() \
168 trace_hardirq_exit(); \
169 account_system_vtime(current); \
170 sub_preempt_count(HARDIRQ_OFFSET); \
174 * Exit irq context and process softirqs if needed:
176 extern void irq_exit(void);
178 #define nmi_enter() \
180 ftrace_nmi_enter(); \
182 add_preempt_count(NMI_OFFSET); \
194 sub_preempt_count(NMI_OFFSET); \
198 #endif /* LINUX_HARDIRQ_H */