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2d4b8473 FW |
1 | #ifndef LINUX_PREEMPT_MASK_H |
2 | #define LINUX_PREEMPT_MASK_H | |
3 | ||
4 | #include <linux/preempt.h> | |
2d4b8473 FW |
5 | |
6 | /* | |
7 | * We put the hardirq and softirq counter into the preemption | |
8 | * counter. The bitmask has the following meaning: | |
9 | * | |
10 | * - bits 0-7 are the preemption count (max preemption depth: 256) | |
11 | * - bits 8-15 are the softirq count (max # of softirqs: 256) | |
12 | * | |
54197e43 TG |
13 | * The hardirq count could in theory be the same as the number of |
14 | * interrupts in the system, but we run all interrupt handlers with | |
15 | * interrupts disabled, so we cannot have nesting interrupts. Though | |
16 | * there are a few palaeontologic drivers which reenable interrupts in | |
17 | * the handler, so we need more than one bit here. | |
2d4b8473 | 18 | * |
00d1a39e TG |
19 | * PREEMPT_MASK: 0x000000ff |
20 | * SOFTIRQ_MASK: 0x0000ff00 | |
21 | * HARDIRQ_MASK: 0x000f0000 | |
22 | * NMI_MASK: 0x00100000 | |
23 | * PREEMPT_ACTIVE: 0x00200000 | |
2d4b8473 FW |
24 | */ |
25 | #define PREEMPT_BITS 8 | |
26 | #define SOFTIRQ_BITS 8 | |
54197e43 | 27 | #define HARDIRQ_BITS 4 |
2d4b8473 FW |
28 | #define NMI_BITS 1 |
29 | ||
2d4b8473 FW |
30 | #define PREEMPT_SHIFT 0 |
31 | #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) | |
32 | #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) | |
33 | #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) | |
34 | ||
35 | #define __IRQ_MASK(x) ((1UL << (x))-1) | |
36 | ||
37 | #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) | |
38 | #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) | |
39 | #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) | |
40 | #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) | |
41 | ||
42 | #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) | |
43 | #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) | |
44 | #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) | |
45 | #define NMI_OFFSET (1UL << NMI_SHIFT) | |
46 | ||
47 | #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) | |
48 | ||
2d4b8473 FW |
49 | #define PREEMPT_ACTIVE_BITS 1 |
50 | #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) | |
51 | #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) | |
2d4b8473 FW |
52 | |
53 | #define hardirq_count() (preempt_count() & HARDIRQ_MASK) | |
54 | #define softirq_count() (preempt_count() & SOFTIRQ_MASK) | |
55 | #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ | |
56 | | NMI_MASK)) | |
57 | ||
58 | /* | |
59 | * Are we doing bottom half or hardware interrupt processing? | |
60 | * Are we in a softirq context? Interrupt context? | |
61 | * in_softirq - Are we currently processing softirq or have bh disabled? | |
62 | * in_serving_softirq - Are we currently processing softirq? | |
63 | */ | |
64 | #define in_irq() (hardirq_count()) | |
65 | #define in_softirq() (softirq_count()) | |
66 | #define in_interrupt() (irq_count()) | |
67 | #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) | |
68 | ||
69 | /* | |
70 | * Are we in NMI context? | |
71 | */ | |
72 | #define in_nmi() (preempt_count() & NMI_MASK) | |
73 | ||
74 | #if defined(CONFIG_PREEMPT_COUNT) | |
75 | # define PREEMPT_CHECK_OFFSET 1 | |
76 | #else | |
77 | # define PREEMPT_CHECK_OFFSET 0 | |
78 | #endif | |
79 | ||
9ea4c380 PZ |
80 | /* |
81 | * The preempt_count offset needed for things like: | |
82 | * | |
83 | * spin_lock_bh() | |
84 | * | |
85 | * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and | |
86 | * softirqs, such that unlock sequences of: | |
87 | * | |
88 | * spin_unlock(); | |
89 | * local_bh_enable(); | |
90 | * | |
91 | * Work as expected. | |
92 | */ | |
93 | #define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET) | |
94 | ||
2d4b8473 FW |
95 | /* |
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 | */ | |
102 | #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) | |
103 | ||
104 | /* | |
105 | * Check whether we were atomic before we did preempt_disable(): | |
106 | * (used by the scheduler, *after* releasing the kernel lock) | |
107 | */ | |
108 | #define in_atomic_preempt_off() \ | |
109 | ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) | |
110 | ||
111 | #ifdef CONFIG_PREEMPT_COUNT | |
112 | # define preemptible() (preempt_count() == 0 && !irqs_disabled()) | |
113 | #else | |
114 | # define preemptible() 0 | |
115 | #endif | |
116 | ||
117 | #endif /* LINUX_PREEMPT_MASK_H */ |