Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef LINUX_PREEMPT_MASK_H
2#define LINUX_PREEMPT_MASK_H
3
4#include <linux/preempt.h>
5#include <asm/hardirq.h>
6
7/*
8 * We put the hardirq and softirq counter into the preemption
9 * counter. The bitmask has the following meaning:
10 *
11 * - bits 0-7 are the preemption count (max preemption depth: 256)
12 * - bits 8-15 are the softirq count (max # of softirqs: 256)
13 *
14 * The hardirq count can in theory reach the same as NR_IRQS.
15 * In reality, the number of nested IRQS is limited to the stack
16 * size as well. For archs with over 1000 IRQS it is not practical
17 * to expect that they will all nest. We give a max of 10 bits for
18 * hardirq nesting. An arch may choose to give less than 10 bits.
19 * m68k expects it to be 8.
20 *
21 * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
22 * - bit 26 is the NMI_MASK
23 * - bit 27 is the PREEMPT_ACTIVE flag
24 *
25 * PREEMPT_MASK: 0x000000ff
26 * SOFTIRQ_MASK: 0x0000ff00
27 * HARDIRQ_MASK: 0x03ff0000
28 * NMI_MASK: 0x04000000
29 */
30#define PREEMPT_BITS 8
31#define SOFTIRQ_BITS 8
32#define NMI_BITS 1
33
34#define MAX_HARDIRQ_BITS 10
35
36#ifndef HARDIRQ_BITS
37# define HARDIRQ_BITS MAX_HARDIRQ_BITS
38#endif
39
40#if HARDIRQ_BITS > MAX_HARDIRQ_BITS
41#error HARDIRQ_BITS too high!
42#endif
43
44#define PREEMPT_SHIFT 0
45#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
46#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
47#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
48
49#define __IRQ_MASK(x) ((1UL << (x))-1)
50
51#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
52#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
53#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
54#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
55
56#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
57#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
58#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
59#define NMI_OFFSET (1UL << NMI_SHIFT)
60
61#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
62
63#ifndef PREEMPT_ACTIVE
64#define PREEMPT_ACTIVE_BITS 1
65#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
66#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
67#endif
68
69#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
70#error PREEMPT_ACTIVE is too low!
71#endif
72
73#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
74#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
75#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
76 | NMI_MASK))
77
78/*
79 * Are we doing bottom half or hardware interrupt processing?
80 * Are we in a softirq context? Interrupt context?
81 * in_softirq - Are we currently processing softirq or have bh disabled?
82 * in_serving_softirq - Are we currently processing softirq?
83 */
84#define in_irq() (hardirq_count())
85#define in_softirq() (softirq_count())
86#define in_interrupt() (irq_count())
87#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
88
89/*
90 * Are we in NMI context?
91 */
92#define in_nmi() (preempt_count() & NMI_MASK)
93
94#if defined(CONFIG_PREEMPT_COUNT)
95# define PREEMPT_CHECK_OFFSET 1
96#else
97# define PREEMPT_CHECK_OFFSET 0
98#endif
99
100/*
101 * Are we running in atomic context? WARNING: this macro cannot
102 * always detect atomic context; in particular, it cannot know about
103 * held spinlocks in non-preemptible kernels. Thus it should not be
104 * used in the general case to determine whether sleeping is possible.
105 * Do not use in_atomic() in driver code.
106 */
107#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
108
109/*
110 * Check whether we were atomic before we did preempt_disable():
111 * (used by the scheduler, *after* releasing the kernel lock)
112 */
113#define in_atomic_preempt_off() \
114 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
115
116#ifdef CONFIG_PREEMPT_COUNT
117# define preemptible() (preempt_count() == 0 && !irqs_disabled())
118#else
119# define preemptible() 0
120#endif
121
122#endif /* LINUX_PREEMPT_MASK_H */