1 #ifndef LINUX_PREEMPT_MASK_H
2 #define LINUX_PREEMPT_MASK_H
4 #include <linux/preempt.h>
7 * We put the hardirq and softirq counter into the preemption
8 * counter. The bitmask has the following meaning:
10 * - bits 0-7 are the preemption count (max preemption depth: 256)
11 * - bits 8-15 are the softirq count (max # of softirqs: 256)
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.
19 * PREEMPT_MASK: 0x000000ff
20 * SOFTIRQ_MASK: 0x0000ff00
21 * HARDIRQ_MASK: 0x000f0000
22 * NMI_MASK: 0x00100000
23 * PREEMPT_ACTIVE: 0x00200000
25 #define PREEMPT_BITS 8
26 #define SOFTIRQ_BITS 8
27 #define HARDIRQ_BITS 4
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)
35 #define __IRQ_MASK(x) ((1UL << (x))-1)
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)
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)
47 #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
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)
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 \
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?
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)
70 * Are we in NMI context?
72 #define in_nmi() (preempt_count() & NMI_MASK)
74 #if defined(CONFIG_PREEMPT_COUNT)
75 # define PREEMPT_CHECK_OFFSET 1
77 # define PREEMPT_CHECK_OFFSET 0
81 * The preempt_count offset needed for things like:
85 * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and
86 * softirqs, such that unlock sequences of:
93 #define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET)
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) != 0)
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_COUNT
112 # define preemptible() (preempt_count() == 0 && !irqs_disabled())
114 # define preemptible() 0
117 #endif /* LINUX_PREEMPT_MASK_H */
This page took 0.03309 seconds and 5 git commands to generate.