LXR linux/include/linux/context

   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
  11extern void context_tracking_cpu_set(int cpu);
  12
  13/* Called with interrupts disabled.  */
  14extern void __context_tracking_enter(enum ctx_state state);
  15extern void __context_tracking_exit(enum ctx_state state);
  16
  17extern void context_tracking_enter(enum ctx_state state);
  18extern void context_tracking_exit(enum ctx_state state);
  19extern void context_tracking_user_enter(void);
  20extern void context_tracking_user_exit(void);
  21
  22static inline void user_enter(void)
  23{
  24        if (context_tracking_is_enabled())
  25                context_tracking_enter(CONTEXT_USER);
  26
  27}
  28static 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.  */
  35static inline void user_enter_irqoff(void)
  36{
  37        if (context_tracking_is_enabled())
  38                __context_tracking_enter(CONTEXT_USER);
  39
  40}
  41static inline void user_exit_irqoff(void)
  42{
  43        if (context_tracking_is_enabled())
  44                __context_tracking_exit(CONTEXT_USER);
  45}
  46
  47static 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
  61static 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 */
  77static 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
  83static inline void user_enter(void) { }
  84static inline void user_exit(void) { }
  85static inline void user_enter_irqoff(void) { }
  86static inline void user_exit_irqoff(void) { }
  87static inline enum ctx_state exception_enter(void) { return 0; }
  88static inline void exception_exit(enum ctx_state prev_ctx) { }
  89static 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
  95extern void context_tracking_init(void);
  96#else
  97static 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 */
 103static 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
 124static 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
 136static 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
 148static 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
 156static 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
 165static 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
 175