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 #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) 76 # define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked()) 77 #else 78 # define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) 79 #endif 80 81 #ifdef CONFIG_PREEMPT 82 # define PREEMPT_CHECK_OFFSET 1 83 #else 84 # define PREEMPT_CHECK_OFFSET 0 85 #endif 86 87 /* 88 * Check whether we were atomic before we did preempt_disable(): 89 * (used by the scheduler) 90 */ 91 #define in_atomic_preempt_off() \ 92 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 93 94 #ifdef CONFIG_PREEMPT 95 # define preemptible() (preempt_count() == 0 && !irqs_disabled()) 96 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 97 #else 98 # define preemptible() 0 99 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 100 #endif 101 102 #ifdef CONFIG_SMP 103 extern void synchronize_irq(unsigned int irq); 104 #else 105 # define synchronize_irq(irq) barrier() 106 #endif 107 108 struct task_struct; 109 110 #ifndef CONFIG_VIRT_CPU_ACCOUNTING 111 static inline void account_system_vtime(struct task_struct *tsk) 112 { 113 } 114 #endif 115 116 /* 117 * It is safe to do non-atomic ops on ->hardirq_context, 118 * because NMI handlers may not preempt and the ops are 119 * always balanced, so the interrupted value of ->hardirq_context 120 * will always be restored. 121 */ 122 #define __irq_enter() \ 123 do { \ 124 account_system_vtime(current); \ 125 add_preempt_count(HARDIRQ_OFFSET); \ 126 trace_hardirq_enter(); \ 127 } while (0) 128 129 /* 130 * Enter irq context (on NO_HZ, update jiffies): 131 */ 132 extern void irq_enter(void); 133 134 /* 135 * Exit irq context without processing softirqs: 136 */ 137 #define __irq_exit() \ 138 do { \ 139 trace_hardirq_exit(); \ 140 account_system_vtime(current); \ 141 sub_preempt_count(HARDIRQ_OFFSET); \ 142 } while (0) 143 144 /* 145 * Exit irq context and process softirqs if needed: 146 */ 147 extern void irq_exit(void); 148 149 #define nmi_enter() do { lockdep_off(); __irq_enter(); } while (0) 150 #define nmi_exit() do { __irq_exit(); lockdep_on(); } while (0) 151 152 #endif /* LINUX_HARDIRQ_H */ 153