1 #ifndef LINUX_PREEMPT_MASK_H
2 #define LINUX_PREEMPT_MASK_H
4 #include <linux/preempt.h>
5 #include <asm/hardirq.h>
8 * We put the hardirq and softirq counter into the preemption
9 * counter. The bitmask has the following meaning:
11 * - bits 0-7 are the preemption count (max preemption depth: 256)
12 * - bits 8-15 are the softirq count (max # of softirqs: 256)
14 * The hardirq count could in theory be the same as the number of
15 * interrupts in the system, but we run all interrupt handlers with
16 * interrupts disabled, so we cannot have nesting interrupts. Though
17 * there are a few palaeontologic drivers which reenable interrupts in
18 * the handler, so we need more than one bit here.
20 * PREEMPT_MASK: 0x000000ff
21 * SOFTIRQ_MASK: 0x0000ff00
22 * HARDIRQ_MASK: 0x000f0000
23 * NMI_MASK: 0x00100000
24 * PREEMPT_ACTIVE: 0x00200000
26 #define PREEMPT_BITS 8
27 #define SOFTIRQ_BITS 8
28 #define HARDIRQ_BITS 4
31 #define PREEMPT_SHIFT 0
32 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
33 #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
34 #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
36 #define __IRQ_MASK(x) ((1UL << (x))-1)
38 #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
39 #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
40 #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
41 #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
43 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
44 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
45 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
46 #define NMI_OFFSET (1UL << NMI_SHIFT)
48 #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
50 #define PREEMPT_ACTIVE_BITS 1
51 #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
52 #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
54 #define hardirq_count() (preempt_count() & HARDIRQ_MASK)
55 #define softirq_count() (preempt_count() & SOFTIRQ_MASK)
56 #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
60 * Are we doing bottom half or hardware interrupt processing?
61 * Are we in a softirq context? Interrupt context?
62 * in_softirq - Are we currently processing softirq or have bh disabled?
63 * in_serving_softirq - Are we currently processing softirq?
65 #define in_irq() (hardirq_count())
66 #define in_softirq() (softirq_count())
67 #define in_interrupt() (irq_count())
68 #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
71 * Are we in NMI context?
73 #define in_nmi() (preempt_count() & NMI_MASK)
75 #if defined(CONFIG_PREEMPT_COUNT)
76 # define PREEMPT_CHECK_OFFSET 1
78 # define PREEMPT_CHECK_OFFSET 0
82 * Are we running in atomic context? WARNING: this macro cannot
83 * always detect atomic context; in particular, it cannot know about
84 * held spinlocks in non-preemptible kernels. Thus it should not be
85 * used in the general case to determine whether sleeping is possible.
86 * Do not use in_atomic() in driver code.
88 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
91 * Check whether we were atomic before we did preempt_disable():
92 * (used by the scheduler, *after* releasing the kernel lock)
94 #define in_atomic_preempt_off() \
95 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
97 #ifdef CONFIG_PREEMPT_COUNT
98 # define preemptible() (preempt_count() == 0 && !irqs_disabled())
100 # define preemptible() 0
103 #endif /* LINUX_PREEMPT_MASK_H */