include/linux/hardirq.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef LINUX_HARDIRQ_H
   3 #define LINUX_HARDIRQ_H
   4
   5 #include <linux/context_tracking_state.h>
   6 #include <linux/preempt.h>
   7 #include <linux/lockdep.h>
   8 #include <linux/ftrace_irq.h>
   9 #include <linux/sched.h>
  10 #include <linux/vtime.h>
  11 #include <asm/hardirq.h>
  12
  13 extern void synchronize_irq(unsigned int irq);
  14 extern bool synchronize_hardirq(unsigned int irq);
  15
  16 #ifdef CONFIG_NO_HZ_FULL
  17 void __rcu_irq_enter_check_tick(void);
  18 #else
  19 static inline void __rcu_irq_enter_check_tick(void) { }
  20 #endif
  21
  22 static __always_inline void rcu_irq_enter_check_tick(void)
  23 {
  24         if (context_tracking_enabled())
  25                 __rcu_irq_enter_check_tick();
  26 }
  27
  28 /*
  29  * It is safe to do non-atomic ops on ->hardirq_context,
  30  * because NMI handlers may not preempt and the ops are
  31  * always balanced, so the interrupted value of ->hardirq_context
  32  * will always be restored.
  33  */
  34 #define __irq_enter()                                   \
  35         do {                                            \
  36                 preempt_count_add(HARDIRQ_OFFSET);      \
  37                 lockdep_hardirq_enter();                \
  38                 account_hardirq_enter(current);         \
  39         } while (0)
  40
  41 /*
  42  * Like __irq_enter() without time accounting for fast
  43  * interrupts, e.g. reschedule IPI where time accounting
  44  * is more expensive than the actual interrupt.
  45  */
  46 #define __irq_enter_raw()                               \
  47         do {                                            \
  48                 preempt_count_add(HARDIRQ_OFFSET);      \
  49                 lockdep_hardirq_enter();                \
  50         } while (0)
  51
  52 /*
  53  * Enter irq context (on NO_HZ, update jiffies):
  54  */
  55 void irq_enter(void);
  56 /*
  57  * Like irq_enter(), but RCU is already watching.
  58  */
  59 void irq_enter_rcu(void);
  60
  61 /*
  62  * Exit irq context without processing softirqs:
  63  */
  64 #define __irq_exit()                                    \
  65         do {                                            \
  66                 account_hardirq_exit(current);          \
  67                 lockdep_hardirq_exit();                 \
  68                 preempt_count_sub(HARDIRQ_OFFSET);      \
  69         } while (0)
  70
  71 /*
  72  * Like __irq_exit() without time accounting
  73  */
  74 #define __irq_exit_raw()                                \
  75         do {                                            \
  76                 lockdep_hardirq_exit();                 \
  77                 preempt_count_sub(HARDIRQ_OFFSET);      \
  78         } while (0)
  79
  80 /*
  81  * Exit irq context and process softirqs if needed:
  82  */
  83 void irq_exit(void);
  84
  85 /*
  86  * Like irq_exit(), but return with RCU watching.
  87  */
  88 void irq_exit_rcu(void);
  89
  90 #ifndef arch_nmi_enter
  91 #define arch_nmi_enter()        do { } while (0)
  92 #define arch_nmi_exit()         do { } while (0)
  93 #endif
  94
  95 #ifdef CONFIG_TINY_RCU
  96 static inline void rcu_nmi_enter(void) { }
  97 static inline void rcu_nmi_exit(void) { }
  98 #else
  99 extern void rcu_nmi_enter(void);
 100 extern void rcu_nmi_exit(void);
 101 #endif
 102
 103 /*
 104  * NMI vs Tracing
 105  * --------------
 106  *
 107  * We must not land in a tracer until (or after) we've changed preempt_count
 108  * such that in_nmi() becomes true. To that effect all NMI C entry points must
 109  * be marked 'notrace' and call nmi_enter() as soon as possible.
 110  */
 111
 112 /*
 113  * nmi_enter() can nest up to 15 times; see NMI_BITS.
 114  */
 115 #define __nmi_enter()                                           \
 116         do {                                                    \
 117                 lockdep_off();                                  \
 118                 arch_nmi_enter();                               \
 119                 BUG_ON(in_nmi() == NMI_MASK);                   \
 120                 __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET);       \
 121         } while (0)
 122
 123 #define nmi_enter()                                             \
 124         do {                                                    \
 125                 __nmi_enter();                                  \
 126                 lockdep_hardirq_enter();                        \
 127                 rcu_nmi_enter();                                \
 128                 instrumentation_begin();                        \
 129                 ftrace_nmi_enter();                             \
 130                 instrumentation_end();                          \
 131         } while (0)
 132
 133 #define __nmi_exit()                                            \
 134         do {                                                    \
 135                 BUG_ON(!in_nmi());                              \
 136                 __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET);       \
 137                 arch_nmi_exit();                                \
 138                 lockdep_on();                                   \
 139         } while (0)
 140
 141 #define nmi_exit()                                              \
 142         do {                                                    \
 143                 instrumentation_begin();                        \
 144                 ftrace_nmi_exit();                              \
 145                 instrumentation_end();                          \
 146                 rcu_nmi_exit();                                 \
 147                 lockdep_hardirq_exit();                         \
 148                 __nmi_exit();                                   \
 149         } while (0)
 150
 151 #endif /* LINUX_HARDIRQ_H */