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 <linux/ftrace_irq.h> 8 #include <asm/hardirq.h> 9 #include <asm/system.h> 10 11 /* 12 * We put the hardirq and softirq counter into the preemption 13 * counter. The bitmask has the following meaning: 14 * 15 * - bits 0-7 are the preemption count (max preemption depth: 256) 16 * - bits 8-15 are the softirq count (max # of softirqs: 256) 17 * 18 * The hardirq count can be overridden per architecture, the default is: 19 * 20 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096) 21 * - ( bit 28 is the PREEMPT_ACTIVE flag. ) 22 * 23 * PREEMPT_MASK: 0x000000ff 24 * SOFTIRQ_MASK: 0x0000ff00 25 * HARDIRQ_MASK: 0x0fff0000 26 */ 27 #define PREEMPT_BITS 8 28 #define SOFTIRQ_BITS 8 29 30 #ifndef HARDIRQ_BITS 31 #define HARDIRQ_BITS 12 32 33 #ifndef MAX_HARDIRQS_PER_CPU 34 #define MAX_HARDIRQS_PER_CPU NR_IRQS 35 #endif 36 37 /* 38 * The hardirq mask has to be large enough to have space for potentially 39 * all IRQ sources in the system nesting on a single CPU. 40 */ 41 #if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU 42 # error HARDIRQ_BITS is too low! 43 #endif 44 #endif 45 46 #define PREEMPT_SHIFT 0 47 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) 48 #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) 49 50 #define __IRQ_MASK(x) ((1UL << (x))-1) 51 52 #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) 53 #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) 54 #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) 55 56 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) 57 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) 58 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) 59 60 #if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS)) 61 #error PREEMPT_ACTIVE is too low! 62 #endif 63 64 #define hardirq_count() (preempt_count() & HARDIRQ_MASK) 65 #define softirq_count() (preempt_count() & SOFTIRQ_MASK) 66 #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK)) 67 68 /* 69 * Are we doing bottom half or hardware interrupt processing? 70 * Are we in a softirq context? Interrupt context? 71 */ 72 #define in_irq() (hardirq_count()) 73 #define in_softirq() (softirq_count()) 74 #define in_interrupt() (irq_count()) 75 76 #if defined(CONFIG_PREEMPT) 77 # define PREEMPT_INATOMIC_BASE kernel_locked() 78 # define PREEMPT_CHECK_OFFSET 1 79 #else 80 # define PREEMPT_INATOMIC_BASE 0 81 # define PREEMPT_CHECK_OFFSET 0 82 #endif 83 84 /* 85 * Are we running in atomic context? WARNING: this macro cannot 86 * always detect atomic context; in particular, it cannot know about 87 * held spinlocks in non-preemptible kernels. Thus it should not be 88 * used in the general case to determine whether sleeping is possible. 89 * Do not use in_atomic() in driver code. 90 */ 91 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) 92 93 /* 94 * Check whether we were atomic before we did preempt_disable(): 95 * (used by the scheduler, *after* releasing the kernel lock) 96 */ 97 #define in_atomic_preempt_off() \ 98 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 99 100 #ifdef CONFIG_PREEMPT 101 # define preemptible() (preempt_count() == 0 && !irqs_disabled()) 102 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 103 #else 104 # define preemptible() 0 105 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 106 #endif 107 108 #ifdef CONFIG_SMP 109 extern void synchronize_irq(unsigned int irq); 110 #else 111 # define synchronize_irq(irq) barrier() 112 #endif 113 114 struct task_struct; 115 116 #ifndef CONFIG_VIRT_CPU_ACCOUNTING account_system_vtime(struct task_struct * tsk)117static inline void account_system_vtime(struct task_struct *tsk) 118 { 119 } 120 #endif 121 122 #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) 123 extern void rcu_irq_enter(void); 124 extern void rcu_irq_exit(void); 125 extern void rcu_nmi_enter(void); 126 extern void rcu_nmi_exit(void); 127 #else 128 # define rcu_irq_enter() do { } while (0) 129 # define rcu_irq_exit() do { } while (0) 130 # define rcu_nmi_enter() do { } while (0) 131 # define rcu_nmi_exit() do { } while (0) 132 #endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */ 133 134 /* 135 * It is safe to do non-atomic ops on ->hardirq_context, 136 * because NMI handlers may not preempt and the ops are 137 * always balanced, so the interrupted value of ->hardirq_context 138 * will always be restored. 139 */ 140 #define __irq_enter() \ 141 do { \ 142 account_system_vtime(current); \ 143 add_preempt_count(HARDIRQ_OFFSET); \ 144 trace_hardirq_enter(); \ 145 } while (0) 146 147 /* 148 * Enter irq context (on NO_HZ, update jiffies): 149 */ 150 extern void irq_enter(void); 151 152 /* 153 * Exit irq context without processing softirqs: 154 */ 155 #define __irq_exit() \ 156 do { \ 157 trace_hardirq_exit(); \ 158 account_system_vtime(current); \ 159 sub_preempt_count(HARDIRQ_OFFSET); \ 160 } while (0) 161 162 /* 163 * Exit irq context and process softirqs if needed: 164 */ 165 extern void irq_exit(void); 166 167 #define nmi_enter() \ 168 do { \ 169 ftrace_nmi_enter(); \ 170 lockdep_off(); \ 171 rcu_nmi_enter(); \ 172 __irq_enter(); \ 173 } while (0) 174 175 #define nmi_exit() \ 176 do { \ 177 __irq_exit(); \ 178 rcu_nmi_exit(); \ 179 lockdep_on(); \ 180 ftrace_nmi_exit(); \ 181 } while (0) 182 183 #endif /* LINUX_HARDIRQ_H */ 184