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