include/linux/context_tracking.h

   1 #ifndef _LINUX_CONTEXT_TRACKING_H
   2 #define _LINUX_CONTEXT_TRACKING_H
   3
   4 #include <linux/sched.h>
   5 #include <linux/vtime.h>
   6 #include <linux/context_tracking_state.h>
   7 #include <asm/ptrace.h>
   8
   9
  10 #ifdef CONFIG_CONTEXT_TRACKING
  11 extern void context_tracking_cpu_set(int cpu);
  12
  13 /* Called with interrupts disabled.  */
  14 extern void __context_tracking_enter(enum ctx_state state);
  15 extern void __context_tracking_exit(enum ctx_state state);
  16
  17 extern void context_tracking_enter(enum ctx_state state);
  18 extern void context_tracking_exit(enum ctx_state state);
  19 extern void context_tracking_user_enter(void);
  20 extern void context_tracking_user_exit(void);
  21
  22 static inline void user_enter(void)
  23 {
  24         if (context_tracking_is_enabled())
  25                 context_tracking_enter(CONTEXT_USER);
  26
  27 }
  28 static inline void user_exit(void)
  29 {
  30         if (context_tracking_is_enabled())
  31                 context_tracking_exit(CONTEXT_USER);
  32 }
  33
  34 /* Called with interrupts disabled.  */
  35 static inline void user_enter_irqoff(void)
  36 {
  37         if (context_tracking_is_enabled())
  38                 __context_tracking_enter(CONTEXT_USER);
  39
  40 }
  41 static inline void user_exit_irqoff(void)
  42 {
  43         if (context_tracking_is_enabled())
  44                 __context_tracking_exit(CONTEXT_USER);
  45 }
  46
  47 static inline enum ctx_state exception_enter(void)
  48 {
  49         enum ctx_state prev_ctx;
  50
  51         if (!context_tracking_is_enabled())
  52                 return 0;
  53
  54         prev_ctx = this_cpu_read(context_tracking.state);
  55         if (prev_ctx != CONTEXT_KERNEL)
  56                 context_tracking_exit(prev_ctx);
  57
  58         return prev_ctx;
  59 }
  60
  61 static inline void exception_exit(enum ctx_state prev_ctx)
  62 {
  63         if (context_tracking_is_enabled()) {
  64                 if (prev_ctx != CONTEXT_KERNEL)
  65                         context_tracking_enter(prev_ctx);
  66         }
  67 }
  68
  69
  70 /**
  71  * ct_state() - return the current context tracking state if known
  72  *
  73  * Returns the current cpu's context tracking state if context tracking
  74  * is enabled.  If context tracking is disabled, returns
  75  * CONTEXT_DISABLED.  This should be used primarily for debugging.
  76  */
  77 static inline enum ctx_state ct_state(void)
  78 {
  79         return context_tracking_is_enabled() ?
  80                 this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
  81 }
  82 #else
  83 static inline void user_enter(void) { }
  84 static inline void user_exit(void) { }
  85 static inline void user_enter_irqoff(void) { }
  86 static inline void user_exit_irqoff(void) { }
  87 static inline enum ctx_state exception_enter(void) { return 0; }
  88 static inline void exception_exit(enum ctx_state prev_ctx) { }
  89 static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
  90 #endif /* !CONFIG_CONTEXT_TRACKING */
  91
  92 #define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond))
  93
  94 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
  95 extern void context_tracking_init(void);
  96 #else
  97 static inline void context_tracking_init(void) { }
  98 #endif /* CONFIG_CONTEXT_TRACKING_FORCE */
  99
 100
 101 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 102 /* must be called with irqs disabled */
 103 static inline void guest_enter_irqoff(void)
 104 {
 105         if (vtime_accounting_cpu_enabled())
 106                 vtime_guest_enter(current);
 107         else
 108                 current->flags |= PF_VCPU;
 109
 110         if (context_tracking_is_enabled())
 111                 __context_tracking_enter(CONTEXT_GUEST);
 112
 113         /* KVM does not hold any references to rcu protected data when it
 114          * switches CPU into a guest mode. In fact switching to a guest mode
 115          * is very similar to exiting to userspace from rcu point of view. In
 116          * addition CPU may stay in a guest mode for quite a long time (up to
 117          * one time slice). Lets treat guest mode as quiescent state, just like
 118          * we do with user-mode execution.
 119          */
 120         if (!context_tracking_cpu_is_enabled())
 121                 rcu_virt_note_context_switch(smp_processor_id());
 122 }
 123
 124 static inline void guest_exit_irqoff(void)
 125 {
 126         if (context_tracking_is_enabled())
 127                 __context_tracking_exit(CONTEXT_GUEST);
 128
 129         if (vtime_accounting_cpu_enabled())
 130                 vtime_guest_exit(current);
 131         else
 132                 current->flags &= ~PF_VCPU;
 133 }
 134
 135 #else
 136 static inline void guest_enter_irqoff(void)
 137 {
 138         /*
 139          * This is running in ioctl context so its safe
 140          * to assume that it's the stime pending cputime
 141          * to flush.
 142          */
 143         vtime_account_system(current);
 144         current->flags |= PF_VCPU;
 145         rcu_virt_note_context_switch(smp_processor_id());
 146 }
 147
 148 static inline void guest_exit_irqoff(void)
 149 {
 150         /* Flush the guest cputime we spent on the guest */
 151         vtime_account_system(current);
 152         current->flags &= ~PF_VCPU;
 153 }
 154 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
 155
 156 static inline void guest_enter(void)
 157 {
 158         unsigned long flags;
 159
 160         local_irq_save(flags);
 161         guest_enter_irqoff();
 162         local_irq_restore(flags);
 163 }
 164
 165 static inline void guest_exit(void)
 166 {
 167         unsigned long flags;
 168
 169         local_irq_save(flags);
 170         guest_exit_irqoff();
 171         local_irq_restore(flags);
 172 }
 173
 174 #endif