1 #ifndef LINUX_HARDIRQ_H 2 #define LINUX_HARDIRQ_H 3 4 #include <linux/preempt.h> 5 #include <linux/lockdep.h> 6 #include <linux/ftrace_irq.h> 7 #include <asm/hardirq.h> 8 9 /* 10 * We put the hardirq and softirq counter into the preemption 11 * counter. The bitmask has the following meaning: 12 * 13 * - bits 0-7 are the preemption count (max preemption depth: 256) 14 * - bits 8-15 are the softirq count (max # of softirqs: 256) 15 * 16 * The hardirq count can in theory reach the same as NR_IRQS. 17 * In reality, the number of nested IRQS is limited to the stack 18 * size as well. For archs with over 1000 IRQS it is not practical 19 * to expect that they will all nest. We give a max of 10 bits for 20 * hardirq nesting. An arch may choose to give less than 10 bits. 21 * m68k expects it to be 8. 22 * 23 * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) 24 * - bit 26 is the NMI_MASK 25 * - bit 28 is the PREEMPT_ACTIVE flag 26 * 27 * PREEMPT_MASK: 0x000000ff 28 * SOFTIRQ_MASK: 0x0000ff00 29 * HARDIRQ_MASK: 0x03ff0000 30 * NMI_MASK: 0x04000000 31 */ 32 #define PREEMPT_BITS 8 33 #define SOFTIRQ_BITS 8 34 #define NMI_BITS 1 35 36 #define MAX_HARDIRQ_BITS 10 37 38 #ifndef HARDIRQ_BITS 39 # define HARDIRQ_BITS MAX_HARDIRQ_BITS 40 #endif 41 42 #if HARDIRQ_BITS > MAX_HARDIRQ_BITS 43 #error HARDIRQ_BITS too high! 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 #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) 50 51 #define __IRQ_MASK(x) ((1UL << (x))-1) 52 53 #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) 54 #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) 55 #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) 56 #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) 57 58 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) 59 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) 60 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) 61 #define NMI_OFFSET (1UL << NMI_SHIFT) 62 63 #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) 64 65 #ifndef PREEMPT_ACTIVE 66 #define PREEMPT_ACTIVE_BITS 1 67 #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) 68 #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) 69 #endif 70 71 #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) 72 #error PREEMPT_ACTIVE is too low! 73 #endif 74 75 #define hardirq_count() (preempt_count() & HARDIRQ_MASK) 76 #define softirq_count() (preempt_count() & SOFTIRQ_MASK) 77 #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ 78 | NMI_MASK)) 79 80 /* 81 * Are we doing bottom half or hardware interrupt processing? 82 * Are we in a softirq context? Interrupt context? 83 * in_softirq - Are we currently processing softirq or have bh disabled? 84 * in_serving_softirq - Are we currently processing softirq? 85 */ 86 #define in_irq() (hardirq_count()) 87 #define in_softirq() (softirq_count()) 88 #define in_interrupt() (irq_count()) 89 #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) 90 91 /* 92 * Are we in NMI context? 93 */ 94 #define in_nmi() (preempt_count() & NMI_MASK) 95 96 #if defined(CONFIG_PREEMPT_COUNT) 97 # define PREEMPT_CHECK_OFFSET 1 98 #else 99 # define PREEMPT_CHECK_OFFSET 0 100 #endif 101 102 /* 103 * Are we running in atomic context? WARNING: this macro cannot 104 * always detect atomic context; in particular, it cannot know about 105 * held spinlocks in non-preemptible kernels. Thus it should not be 106 * used in the general case to determine whether sleeping is possible. 107 * Do not use in_atomic() in driver code. 108 */ 109 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) 110 111 /* 112 * Check whether we were atomic before we did preempt_disable(): 113 * (used by the scheduler, *after* releasing the kernel lock) 114 */ 115 #define in_atomic_preempt_off() \ 116 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 117 118 #ifdef CONFIG_PREEMPT_COUNT 119 # define preemptible() (preempt_count() == 0 && !irqs_disabled()) 120 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 121 #else 122 # define preemptible() 0 123 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 124 #endif 125 126 #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) 127 extern void synchronize_irq(unsigned int irq); 128 #else 129 # define synchronize_irq(irq) barrier() 130 #endif 131 132 struct task_struct; 133 134 #if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING) account_system_vtime(struct task_struct * tsk)135static inline void account_system_vtime(struct task_struct *tsk) 136 { 137 } 138 #else 139 extern void account_system_vtime(struct task_struct *tsk); 140 #endif 141 142 #if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) 143 rcu_nmi_enter(void)144static inline void rcu_nmi_enter(void) 145 { 146 } 147 rcu_nmi_exit(void)148static inline void rcu_nmi_exit(void) 149 { 150 } 151 152 #else 153 extern void rcu_nmi_enter(void); 154 extern void rcu_nmi_exit(void); 155 #endif 156 157 /* 158 * It is safe to do non-atomic ops on ->hardirq_context, 159 * because NMI handlers may not preempt and the ops are 160 * always balanced, so the interrupted value of ->hardirq_context 161 * will always be restored. 162 */ 163 #define __irq_enter() \ 164 do { \ 165 account_system_vtime(current); \ 166 add_preempt_count(HARDIRQ_OFFSET); \ 167 trace_hardirq_enter(); \ 168 } while (0) 169 170 /* 171 * Enter irq context (on NO_HZ, update jiffies): 172 */ 173 extern void irq_enter(void); 174 175 /* 176 * Exit irq context without processing softirqs: 177 */ 178 #define __irq_exit() \ 179 do { \ 180 trace_hardirq_exit(); \ 181 account_system_vtime(current); \ 182 sub_preempt_count(HARDIRQ_OFFSET); \ 183 } while (0) 184 185 /* 186 * Exit irq context and process softirqs if needed: 187 */ 188 extern void irq_exit(void); 189 190 #define nmi_enter() \ 191 do { \ 192 ftrace_nmi_enter(); \ 193 BUG_ON(in_nmi()); \ 194 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 195 lockdep_off(); \ 196 rcu_nmi_enter(); \ 197 trace_hardirq_enter(); \ 198 } while (0) 199 200 #define nmi_exit() \ 201 do { \ 202 trace_hardirq_exit(); \ 203 rcu_nmi_exit(); \ 204 lockdep_on(); \ 205 BUG_ON(!in_nmi()); \ 206 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 207 ftrace_nmi_exit(); \ 208 } while (0) 209 210 #endif /* LINUX_HARDIRQ_H */ 211