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