1 #ifndef LINUX_HARDIRQ_H
2 #define LINUX_HARDIRQ_H
4 #include <linux/preempt.h>
6 #include <linux/smp_lock.h>
8 #include <linux/lockdep.h>
9 #include <linux/ftrace_irq.h>
10 #include <asm/hardirq.h>
13 * We put the hardirq and softirq counter into the preemption
14 * counter. The bitmask has the following meaning:
16 * - bits 0-7 are the preemption count (max preemption depth: 256)
17 * - bits 8-15 are the softirq count (max # of softirqs: 256)
19 * 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.
26 * - 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
30 * PREEMPT_MASK: 0x000000ff
31 * SOFTIRQ_MASK: 0x0000ff00
32 * HARDIRQ_MASK: 0x03ff0000
33 * NMI_MASK: 0x04000000
35 #define PREEMPT_BITS 8
36 #define SOFTIRQ_BITS 8
39 #define MAX_HARDIRQ_BITS 10
42 # define HARDIRQ_BITS MAX_HARDIRQ_BITS
45 #if HARDIRQ_BITS > MAX_HARDIRQ_BITS
46 #error HARDIRQ_BITS too high!
49 #define PREEMPT_SHIFT 0
50 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
51 #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
52 #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
54 #define __IRQ_MASK(x) ((1UL << (x))-1)
56 #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
57 #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
58 #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
59 #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
61 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
62 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
63 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
64 #define NMI_OFFSET (1UL << NMI_SHIFT)
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)
72 #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
73 #error PREEMPT_ACTIVE is too low!
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 \
82 * Are we doing bottom half or hardware interrupt processing?
83 * Are we in a softirq context? Interrupt context?
85 #define in_irq() (hardirq_count())
86 #define in_softirq() (softirq_count())
87 #define in_interrupt() (irq_count())
90 * Are we in NMI context?
92 #define in_nmi() (preempt_count() & NMI_MASK)
94 #if defined(CONFIG_PREEMPT)
95 # define PREEMPT_INATOMIC_BASE kernel_locked()
96 # define PREEMPT_CHECK_OFFSET 1
98 # define PREEMPT_INATOMIC_BASE 0
99 # define PREEMPT_CHECK_OFFSET 0
103 * Are we running in atomic context? WARNING: this macro cannot
104 * always detect atomic context; in particular, it cannot know about
105 * held spinlocks in non-preemptible kernels. Thus it should not be
106 * used in the general case to determine whether sleeping is possible.
107 * Do not use in_atomic() in driver code.
109 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
112 * Check whether we were atomic before we did preempt_disable():
113 * (used by the scheduler, *after* releasing the kernel lock)
115 #define in_atomic_preempt_off() \
116 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
118 #ifdef CONFIG_PREEMPT
119 # define preemptible() (preempt_count() == 0 && !irqs_disabled())
120 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
122 # define preemptible() 0
123 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
126 #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
127 extern void synchronize_irq(unsigned int irq);
129 # define synchronize_irq(irq) barrier()
134 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
135 static inline void account_system_vtime(struct task_struct *tsk)
140 #if defined(CONFIG_NO_HZ)
141 #if defined(CONFIG_TINY_RCU)
142 extern void rcu_enter_nohz(void);
143 extern void rcu_exit_nohz(void);
145 static inline void rcu_irq_enter(void)
150 static inline void rcu_irq_exit(void)
155 static inline void rcu_nmi_enter(void)
159 static inline void rcu_nmi_exit(void)
164 extern void rcu_irq_enter(void);
165 extern void rcu_irq_exit(void);
166 extern void rcu_nmi_enter(void);
167 extern void rcu_nmi_exit(void);
170 # define rcu_irq_enter() do { } while (0)
171 # define rcu_irq_exit() do { } while (0)
172 # define rcu_nmi_enter() do { } while (0)
173 # define rcu_nmi_exit() do { } while (0)
174 #endif /* #if defined(CONFIG_NO_HZ) */
177 * It is safe to do non-atomic ops on ->hardirq_context,
178 * because NMI handlers may not preempt and the ops are
179 * always balanced, so the interrupted value of ->hardirq_context
180 * will always be restored.
182 #define __irq_enter() \
184 account_system_vtime(current); \
185 add_preempt_count(HARDIRQ_OFFSET); \
186 trace_hardirq_enter(); \
190 * Enter irq context (on NO_HZ, update jiffies):
192 extern void irq_enter(void);
195 * Exit irq context without processing softirqs:
197 #define __irq_exit() \
199 trace_hardirq_exit(); \
200 account_system_vtime(current); \
201 sub_preempt_count(HARDIRQ_OFFSET); \
205 * Exit irq context and process softirqs if needed:
207 extern void irq_exit(void);
209 #define nmi_enter() \
211 ftrace_nmi_enter(); \
213 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
216 trace_hardirq_enter(); \
221 trace_hardirq_exit(); \
225 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
229 #endif /* LINUX_HARDIRQ_H */