1 /* $Id: hardirq.h,v 1.6 2000/03/07 15:45:42 ralf Exp $
2 *
3 * This file is subject to the terms and conditions of the GNU General Public
4 * License. See the file "COPYING" in the main directory of this archive
5 * for more details.
6 *
7 * Copyright (C) 1997 - 2000 by Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 */
10 #ifndef _ASM_HARDIRQ_H
11 #define _ASM_HARDIRQ_H
12
13 #include <linux/config.h>
14 #include <linux/threads.h>
15 #include <linux/irq.h>
16
17 /* entry.S is sensitive to the offsets of these fields */
18 typedef struct {
19 unsigned int __softirq_active;
20 unsigned int __softirq_mask;
21 unsigned int __local_irq_count;
22 unsigned int __local_bh_count;
23 unsigned int __syscall_count;
24 } ____cacheline_aligned irq_cpustat_t;
25
26 #include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
27
28 /*
29 * Are we in an interrupt context? Either doing bottom half
30 * or hardware interrupt processing?
31 */
32 #define in_interrupt() ({ int __cpu = smp_processor_id(); \
33 (local_irq_count(__cpu) + local_bh_count(__cpu) != 0); })
34 #define in_irq() (local_irq_count(smp_processor_id()) != 0)
35
36 #ifndef CONFIG_SMP
37
38 #define hardirq_trylock(cpu) (local_irq_count(cpu) == 0)
39 #define hardirq_endlock(cpu) do { } while (0)
40
41 #define irq_enter(cpu, irq) (local_irq_count(cpu)++)
42 #define irq_exit(cpu, irq) (local_irq_count(cpu)--)
43
44 #define synchronize_irq() barrier();
45
46 #else
47
48 #include <asm/atomic.h>
49 #include <linux/spinlock.h>
50 #include <asm/smp.h>
51
52 extern int global_irq_holder;
53 extern spinlock_t global_irq_lock;
54
55 static inline int irqs_running (void)
56 {
57 int i;
58
59 for (i = 0; i < smp_num_cpus; i++)
60 if (local_irq_count(i))
61 return 1;
62 return 0;
63 }
64
65 static inline void release_irqlock(int cpu)
66 {
67 /* if we didn't own the irq lock, just ignore.. */
68 if (global_irq_holder == cpu) {
69 global_irq_holder = NO_PROC_ID;
70 spin_unlock(&global_irq_lock);
71 }
72 }
73
74 static inline int hardirq_trylock(int cpu)
75 {
76 return !local_irq_count(cpu) && !spin_is_locked(&global_irq_lock);
77 }
78
79 #define hardirq_endlock(cpu) do { } while (0)
80
81 static inline void irq_enter(int cpu, int irq)
82 {
83 ++local_irq_count(cpu);
84
85 while (spin_is_locked(&global_irq_lock))
86 barrier();
87 }
88
89 static inline void irq_exit(int cpu, int irq)
90 {
91 --local_irq_count(cpu);
92 }
93
94 extern void synchronize_irq(void);
95
96 #endif /* CONFIG_SMP */
97
98 #endif /* _ASM_HARDIRQ_H */
99
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