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Rev | Author | Line No. | Line |
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5272 | serge | 1 | #ifndef LINUX_PREEMPT_MASK_H |
2 | #define LINUX_PREEMPT_MASK_H |
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3 | |||
4 | #include |
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5 | |||
6 | /* |
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7 | * We put the hardirq and softirq counter into the preemption |
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8 | * counter. The bitmask has the following meaning: |
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9 | * |
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10 | * - bits 0-7 are the preemption count (max preemption depth: 256) |
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11 | * - bits 8-15 are the softirq count (max # of softirqs: 256) |
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12 | * |
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13 | * The hardirq count could in theory be the same as the number of |
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14 | * interrupts in the system, but we run all interrupt handlers with |
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15 | * interrupts disabled, so we cannot have nesting interrupts. Though |
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16 | * there are a few palaeontologic drivers which reenable interrupts in |
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17 | * the handler, so we need more than one bit here. |
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18 | * |
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19 | * PREEMPT_MASK: 0x000000ff |
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20 | * SOFTIRQ_MASK: 0x0000ff00 |
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21 | * HARDIRQ_MASK: 0x000f0000 |
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22 | * NMI_MASK: 0x00100000 |
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23 | * PREEMPT_ACTIVE: 0x00200000 |
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24 | */ |
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25 | #define PREEMPT_BITS 8 |
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26 | #define SOFTIRQ_BITS 8 |
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27 | #define HARDIRQ_BITS 4 |
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28 | #define NMI_BITS 1 |
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29 | |||
30 | #define PREEMPT_SHIFT 0 |
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31 | #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) |
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32 | #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) |
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33 | #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) |
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34 | |||
35 | #define __IRQ_MASK(x) ((1UL << (x))-1) |
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36 | |||
37 | #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) |
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38 | #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) |
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39 | #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) |
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40 | #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) |
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41 | |||
42 | #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) |
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43 | #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) |
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44 | #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) |
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45 | #define NMI_OFFSET (1UL << NMI_SHIFT) |
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46 | |||
47 | #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) |
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48 | |||
49 | #define PREEMPT_ACTIVE_BITS 1 |
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50 | #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) |
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51 | #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) |
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52 | |||
53 | #define hardirq_count() (preempt_count() & HARDIRQ_MASK) |
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54 | #define softirq_count() (preempt_count() & SOFTIRQ_MASK) |
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55 | #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ |
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56 | | NMI_MASK)) |
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57 | |||
58 | /* |
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59 | * Are we doing bottom half or hardware interrupt processing? |
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60 | * Are we in a softirq context? Interrupt context? |
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61 | * in_softirq - Are we currently processing softirq or have bh disabled? |
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62 | * in_serving_softirq - Are we currently processing softirq? |
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63 | */ |
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64 | #define in_irq() (hardirq_count()) |
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65 | #define in_softirq() (softirq_count()) |
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66 | #define in_interrupt() (irq_count()) |
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67 | #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) |
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68 | |||
69 | /* |
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70 | * Are we in NMI context? |
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71 | */ |
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72 | #define in_nmi() (preempt_count() & NMI_MASK) |
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73 | |||
74 | #if defined(CONFIG_PREEMPT_COUNT) |
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75 | # define PREEMPT_CHECK_OFFSET 1 |
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76 | #else |
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77 | # define PREEMPT_CHECK_OFFSET 0 |
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78 | #endif |
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79 | |||
80 | /* |
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81 | * The preempt_count offset needed for things like: |
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82 | * |
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83 | * spin_lock_bh() |
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84 | * |
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85 | * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and |
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86 | * softirqs, such that unlock sequences of: |
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87 | * |
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88 | * spin_unlock(); |
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89 | * local_bh_enable(); |
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90 | * |
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91 | * Work as expected. |
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92 | */ |
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93 | #define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_CHECK_OFFSET) |
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94 | |||
95 | /* |
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96 | * Are we running in atomic context? WARNING: this macro cannot |
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97 | * always detect atomic context; in particular, it cannot know about |
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98 | * held spinlocks in non-preemptible kernels. Thus it should not be |
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99 | * used in the general case to determine whether sleeping is possible. |
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100 | * Do not use in_atomic() in driver code. |
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101 | */ |
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102 | #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) |
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103 | |||
104 | /* |
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105 | * Check whether we were atomic before we did preempt_disable(): |
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106 | * (used by the scheduler, *after* releasing the kernel lock) |
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107 | */ |
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108 | #define in_atomic_preempt_off() \ |
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109 | ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) |
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110 | |||
111 | #ifdef CONFIG_PREEMPT_COUNT |
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112 | # define preemptible() (preempt_count() == 0 && !irqs_disabled()) |
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113 | #else |
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114 | # define preemptible() 0 |
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115 | #endif |
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116 | |||
117 | #endif /* LINUX_PREEMPT_MASK_H */><>><>><>><>><>><>><>><>><>><> |