1 #ifndef LINUX_HARDIRQ_H 2 #define LINUX_HARDIRQ_H 3 4 #include <linux/preempt.h> 5 #include <linux/smp_lock.h> 6 #include <linux/lockdep.h> 7 #include <asm/hardirq.h> 8 #include <asm/system.h> 9 10 /* 11 * We put the hardirq and softirq counter into the preemption 12 * counter. The bitmask has the following meaning: 13 * 14 * - bits 0-7 are the preemption count (max preemption depth: 256) 15 * - bits 8-15 are the softirq count (max # of softirqs: 256) 16 * 17 * The hardirq count can be overridden per architecture, the default is: 18 * 19 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096) 20 * - ( bit 28 is the PREEMPT_ACTIVE flag. ) 21 * 22 * PREEMPT_MASK: 0x000000ff 23 * SOFTIRQ_MASK: 0x0000ff00 24 * HARDIRQ_MASK: 0x0fff0000 25 */ 26 #define PREEMPT_BITS 8 27 #define SOFTIRQ_BITS 8 28 29 #ifndef HARDIRQ_BITS 30 #define HARDIRQ_BITS 12 31 32 #ifndef MAX_HARDIRQS_PER_CPU 33 #define MAX_HARDIRQS_PER_CPU NR_IRQS 34 #endif 35 36 /* 37 * The hardirq mask has to be large enough to have space for potentially 38 * all IRQ sources in the system nesting on a single CPU. 39 */ 40 #if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU 41 # error HARDIRQ_BITS is too low! 42 #endif 43 #endif 44 45 #define PREEMPT_SHIFT 0 46 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) 47 #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_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 55 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) 56 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) 57 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) 58 59 #if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS)) 60 #error PREEMPT_ACTIVE is too low! 61 #endif 62 63 #define hardirq_count() (preempt_count() & HARDIRQ_MASK) 64 #define softirq_count() (preempt_count() & SOFTIRQ_MASK) 65 #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK)) 66 67 /* 68 * Are we doing bottom half or hardware interrupt processing? 69 * Are we in a softirq context? Interrupt context? 70 */ 71 #define in_irq() (hardirq_count()) 72 #define in_softirq() (softirq_count()) 73 #define in_interrupt() (irq_count()) 74 75 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) 76 77 #ifdef CONFIG_PREEMPT 78 # define PREEMPT_CHECK_OFFSET 1 79 #else 80 # define PREEMPT_CHECK_OFFSET 0 81 #endif 82 83 /* 84 * Check whether we were atomic before we did preempt_disable(): 85 * (used by the scheduler) 86 */ 87 #define in_atomic_preempt_off() \ 88 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 89 90 #ifdef CONFIG_PREEMPT 91 # define preemptible() (preempt_count() == 0 && !irqs_disabled()) 92 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 93 #else 94 # define preemptible() 0 95 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 96 #endif 97 98 #ifdef CONFIG_SMP 99 extern void synchronize_irq(unsigned int irq); 100 #else 101 # define synchronize_irq(irq) barrier() 102 #endif 103 104 struct task_struct; 105 106 #ifndef CONFIG_VIRT_CPU_ACCOUNTING 107 static inline void account_system_vtime(struct task_struct *tsk) 108 { 109 } 110 #endif 111 112 /* 113 * It is safe to do non-atomic ops on ->hardirq_context, 114 * because NMI handlers may not preempt and the ops are 115 * always balanced, so the interrupted value of ->hardirq_context 116 * will always be restored. 117 */ 118 #define __irq_enter() \ 119 do { \ 120 account_system_vtime(current); \ 121 add_preempt_count(HARDIRQ_OFFSET); \ 122 trace_hardirq_enter(); \ 123 } while (0) 124 125 /* 126 * Enter irq context (on NO_HZ, update jiffies): 127 */ 128 extern void irq_enter(void); 129 130 /* 131 * Exit irq context without processing softirqs: 132 */ 133 #define __irq_exit() \ 134 do { \ 135 trace_hardirq_exit(); \ 136 account_system_vtime(current); \ 137 sub_preempt_count(HARDIRQ_OFFSET); \ 138 } while (0) 139 140 /* 141 * Exit irq context and process softirqs if needed: 142 */ 143 extern void irq_exit(void); 144 145 #define nmi_enter() do { lockdep_off(); __irq_enter(); } while (0) 146 #define nmi_exit() do { __irq_exit(); lockdep_on(); } while (0) 147 148 #endif /* LINUX_HARDIRQ_H */ 149