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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 | #ifndef LINUX_HARDIRQ_H #define LINUX_HARDIRQ_H #include <linux/preempt.h> #ifdef CONFIG_PREEMPT #include <linux/smp_lock.h> #endif #include <linux/lockdep.h> #include <linux/ftrace_irq.h> #include <asm/hardirq.h> #include <asm/system.h> /* * We put the hardirq and softirq counter into the preemption * counter. The bitmask has the following meaning: * * - bits 0-7 are the preemption count (max preemption depth: 256) * - bits 8-15 are the softirq count (max # of softirqs: 256) * * The hardirq count can in theory reach the same as NR_IRQS. * In reality, the number of nested IRQS is limited to the stack * size as well. For archs with over 1000 IRQS it is not practical * to expect that they will all nest. We give a max of 10 bits for * hardirq nesting. An arch may choose to give less than 10 bits. * m68k expects it to be 8. * * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) * - bit 26 is the NMI_MASK * - bit 28 is the PREEMPT_ACTIVE flag * * PREEMPT_MASK: 0x000000ff * SOFTIRQ_MASK: 0x0000ff00 * HARDIRQ_MASK: 0x03ff0000 * NMI_MASK: 0x04000000 */ #define PREEMPT_BITS 8 #define SOFTIRQ_BITS 8 #define NMI_BITS 1 #define MAX_HARDIRQ_BITS 10 #ifndef HARDIRQ_BITS # define HARDIRQ_BITS MAX_HARDIRQ_BITS #endif #if HARDIRQ_BITS > MAX_HARDIRQ_BITS #error HARDIRQ_BITS too high! #endif #define PREEMPT_SHIFT 0 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) #define __IRQ_MASK(x) ((1UL << (x))-1) #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) #define NMI_OFFSET (1UL << NMI_SHIFT) #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) #ifndef PREEMPT_ACTIVE #define PREEMPT_ACTIVE_BITS 1 #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) #endif #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) #error PREEMPT_ACTIVE is too low! #endif #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #define softirq_count() (preempt_count() & SOFTIRQ_MASK) #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ | NMI_MASK)) /* * Are we doing bottom half or hardware interrupt processing? * Are we in a softirq context? Interrupt context? * in_softirq - Are we currently processing softirq or have bh disabled? * in_serving_softirq - Are we currently processing softirq? */ #define in_irq() (hardirq_count()) #define in_softirq() (softirq_count()) #define in_interrupt() (irq_count()) #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) /* * Are we in NMI context? */ #define in_nmi() (preempt_count() & NMI_MASK) #if defined(CONFIG_PREEMPT) # define PREEMPT_INATOMIC_BASE kernel_locked() # define PREEMPT_CHECK_OFFSET 1 #else # define PREEMPT_INATOMIC_BASE 0 # define PREEMPT_CHECK_OFFSET 0 #endif /* * Are we running in atomic context? WARNING: this macro cannot * always detect atomic context; in particular, it cannot know about * held spinlocks in non-preemptible kernels. Thus it should not be * used in the general case to determine whether sleeping is possible. * Do not use in_atomic() in driver code. */ #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE) /* * Check whether we were atomic before we did preempt_disable(): * (used by the scheduler, *after* releasing the kernel lock) */ #define in_atomic_preempt_off() \ ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET) #ifdef CONFIG_PREEMPT # define preemptible() (preempt_count() == 0 && !irqs_disabled()) # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) #else # define preemptible() 0 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET #endif #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) extern void synchronize_irq(unsigned int irq); #else # define synchronize_irq(irq) barrier() #endif struct task_struct; #if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING) static inline void account_system_vtime(struct task_struct *tsk) { } #else extern void account_system_vtime(struct task_struct *tsk); #endif #if defined(CONFIG_NO_HZ) #if defined(CONFIG_TINY_RCU) extern void rcu_enter_nohz(void); extern void rcu_exit_nohz(void); static inline void rcu_irq_enter(void) { rcu_exit_nohz(); } static inline void rcu_irq_exit(void) { rcu_enter_nohz(); } static inline void rcu_nmi_enter(void) { } static inline void rcu_nmi_exit(void) { } #else extern void rcu_irq_enter(void); extern void rcu_irq_exit(void); extern void rcu_nmi_enter(void); extern void rcu_nmi_exit(void); #endif #else # define rcu_irq_enter() do { } while (0) # define rcu_irq_exit() do { } while (0) # define rcu_nmi_enter() do { } while (0) # define rcu_nmi_exit() do { } while (0) #endif /* #if defined(CONFIG_NO_HZ) */ /* * It is safe to do non-atomic ops on ->hardirq_context, * because NMI handlers may not preempt and the ops are * always balanced, so the interrupted value of ->hardirq_context * will always be restored. */ #define __irq_enter() \ do { \ account_system_vtime(current); \ add_preempt_count(HARDIRQ_OFFSET); \ trace_hardirq_enter(); \ } while (0) /* * Enter irq context (on NO_HZ, update jiffies): */ extern void irq_enter(void); /* * Exit irq context without processing softirqs: */ #define __irq_exit() \ do { \ trace_hardirq_exit(); \ account_system_vtime(current); \ sub_preempt_count(HARDIRQ_OFFSET); \ } while (0) /* * Exit irq context and process softirqs if needed: */ extern void irq_exit(void); #define nmi_enter() \ do { \ ftrace_nmi_enter(); \ BUG_ON(in_nmi()); \ add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ lockdep_off(); \ rcu_nmi_enter(); \ trace_hardirq_enter(); \ } while (0) #define nmi_exit() \ do { \ trace_hardirq_exit(); \ rcu_nmi_exit(); \ lockdep_on(); \ BUG_ON(!in_nmi()); \ sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ ftrace_nmi_exit(); \ } while (0) #endif /* LINUX_HARDIRQ_H */ |