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