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) && defined(CONFIG_BKL) 97 # include <linux/sched.h> 98 # define PREEMPT_INATOMIC_BASE (current->lock_depth >= 0) 99 #else 100 # define PREEMPT_INATOMIC_BASE 0 101 #endif 102 103 #if defined(CONFIG_PREEMPT) 104 # define PREEMPT_CHECK_OFFSET 1 105 #else 106 # define PREEMPT_CHECK_OFFSET 0 107 #endif 108 109 /* 110 * Are we running in atomic context? WARNING: this macro cannot 111 * always detect atomic context; in particular, it cannot know about 112 * held spinlocks in non-preemptible kernels. Thus it should not be 113 * used in the general case to determine whether sleeping is possible. 114 * Do not use in_atomic() in driver code. 115 */ 116 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) 117 118 /* 119 * Check whether we were atomic before we did preempt_disable(): 120 * (used by the scheduler, *after* releasing the kernel lock) 121 */ 122 #define in_atomic_preempt_off() \ 123 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) 124 125 #ifdef CONFIG_PREEMPT 126 # define preemptible() (preempt_count() == 0 && !irqs_disabled()) 127 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) 128 #else 129 # define preemptible() 0 130 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET 131 #endif 132 133 #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) 134 extern void synchronize_irq(unsigned int irq); 135 #else 136 # define synchronize_irq(irq) barrier() 137 #endif 138 139 struct task_struct; 140 141 #if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING) 142 static inline void account_system_vtime(struct task_struct *tsk) 143 { 144 } 145 #else 146 extern void account_system_vtime(struct task_struct *tsk); 147 #endif 148 149 #if defined(CONFIG_NO_HZ) 150 #if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) 151 extern void rcu_enter_nohz(void); 152 extern void rcu_exit_nohz(void); 153 154 static inline void rcu_irq_enter(void) 155 { 156 rcu_exit_nohz(); 157 } 158 159 static inline void rcu_irq_exit(void) 160 { 161 rcu_enter_nohz(); 162 } 163 164 static inline void rcu_nmi_enter(void) 165 { 166 } 167 168 static inline void rcu_nmi_exit(void) 169 { 170 } 171 172 #else 173 extern void rcu_irq_enter(void); 174 extern void rcu_irq_exit(void); 175 extern void rcu_nmi_enter(void); 176 extern void rcu_nmi_exit(void); 177 #endif 178 #else 179 # define rcu_irq_enter() do { } while (0) 180 # define rcu_irq_exit() do { } while (0) 181 # define rcu_nmi_enter() do { } while (0) 182 # define rcu_nmi_exit() do { } while (0) 183 #endif /* #if defined(CONFIG_NO_HZ) */ 184 185 /* 186 * It is safe to do non-atomic ops on ->hardirq_context, 187 * because NMI handlers may not preempt and the ops are 188 * always balanced, so the interrupted value of ->hardirq_context 189 * will always be restored. 190 */ 191 #define __irq_enter() \ 192 do { \ 193 account_system_vtime(current); \ 194 add_preempt_count(HARDIRQ_OFFSET); \ 195 trace_hardirq_enter(); \ 196 } while (0) 197 198 /* 199 * Enter irq context (on NO_HZ, update jiffies): 200 */ 201 extern void irq_enter(void); 202 203 /* 204 * Exit irq context without processing softirqs: 205 */ 206 #define __irq_exit() \ 207 do { \ 208 trace_hardirq_exit(); \ 209 account_system_vtime(current); \ 210 sub_preempt_count(HARDIRQ_OFFSET); \ 211 } while (0) 212 213 /* 214 * Exit irq context and process softirqs if needed: 215 */ 216 extern void irq_exit(void); 217 218 #define nmi_enter() \ 219 do { \ 220 ftrace_nmi_enter(); \ 221 BUG_ON(in_nmi()); \ 222 add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 223 lockdep_off(); \ 224 rcu_nmi_enter(); \ 225 trace_hardirq_enter(); \ 226 } while (0) 227 228 #define nmi_exit() \ 229 do { \ 230 trace_hardirq_exit(); \ 231 rcu_nmi_exit(); \ 232 lockdep_on(); \ 233 BUG_ON(!in_nmi()); \ 234 sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ 235 ftrace_nmi_exit(); \ 236 } while (0) 237 238 #endif /* LINUX_HARDIRQ_H */ 239