LXR linux/include/linux/context

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_CONTEXT_TRACKING_H
   3#define _LINUX_CONTEXT_TRACKING_H
   4
   5#include <linux/sched.h>
   6#include <linux/vtime.h>
   7#include <linux/context_tracking_state.h>
   8#include <linux/instrumentation.h>
   9
  10#include <asm/ptrace.h>
  11
  12
  13#ifdef CONFIG_CONTEXT_TRACKING
  14extern void context_tracking_cpu_set(int cpu);
  15
  16/* Called with interrupts disabled.  */
  17extern void __context_tracking_enter(enum ctx_state state);
  18extern void __context_tracking_exit(enum ctx_state state);
  19
  20extern void context_tracking_enter(enum ctx_state state);
  21extern void context_tracking_exit(enum ctx_state state);
  22extern void context_tracking_user_enter(void);
  23extern void context_tracking_user_exit(void);
  24
  25static inline void user_enter(void)
  26{
  27        if (context_tracking_enabled())
  28                context_tracking_enter(CONTEXT_USER);
  29
  30}
  31static inline void user_exit(void)
  32{
  33        if (context_tracking_enabled())
  34                context_tracking_exit(CONTEXT_USER);
  35}
  36
  37/* Called with interrupts disabled.  */
  38static __always_inline void user_enter_irqoff(void)
  39{
  40        if (context_tracking_enabled())
  41                __context_tracking_enter(CONTEXT_USER);
  42
  43}
  44static __always_inline void user_exit_irqoff(void)
  45{
  46        if (context_tracking_enabled())
  47                __context_tracking_exit(CONTEXT_USER);
  48}
  49
  50static inline enum ctx_state exception_enter(void)
  51{
  52        enum ctx_state prev_ctx;
  53
  54        if (!context_tracking_enabled())
  55                return 0;
  56
  57        prev_ctx = this_cpu_read(context_tracking.state);
  58        if (prev_ctx != CONTEXT_KERNEL)
  59                context_tracking_exit(prev_ctx);
  60
  61        return prev_ctx;
  62}
  63
  64static inline void exception_exit(enum ctx_state prev_ctx)
  65{
  66        if (context_tracking_enabled()) {
  67                if (prev_ctx != CONTEXT_KERNEL)
  68                        context_tracking_enter(prev_ctx);
  69        }
  70}
  71
  72
  73/**
  74 * ct_state() - return the current context tracking state if known
  75 *
  76 * Returns the current cpu's context tracking state if context tracking
  77 * is enabled.  If context tracking is disabled, returns
  78 * CONTEXT_DISABLED.  This should be used primarily for debugging.
  79 */
  80static __always_inline enum ctx_state ct_state(void)
  81{
  82        return context_tracking_enabled() ?
  83                this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
  84}
  85#else
  86static inline void user_enter(void) { }
  87static inline void user_exit(void) { }
  88static inline void user_enter_irqoff(void) { }
  89static inline void user_exit_irqoff(void) { }
  90static inline enum ctx_state exception_enter(void) { return 0; }
  91static inline void exception_exit(enum ctx_state prev_ctx) { }
  92static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
  93#endif /* !CONFIG_CONTEXT_TRACKING */
  94
  95#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
  96
  97#ifdef CONFIG_CONTEXT_TRACKING_FORCE
  98extern void context_tracking_init(void);
  99#else
 100static inline void context_tracking_init(void) { }
 101#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
 102
 103
 104#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 105/* must be called with irqs disabled */
 106static __always_inline void guest_enter_irqoff(void)
 107{
 108        instrumentation_begin();
 109        if (vtime_accounting_enabled_this_cpu())
 110                vtime_guest_enter(current);
 111        else
 112                current->flags |= PF_VCPU;
 113        instrumentation_end();
 114
 115        if (context_tracking_enabled())
 116                __context_tracking_enter(CONTEXT_GUEST);
 117
 118        /* KVM does not hold any references to rcu protected data when it
 119         * switches CPU into a guest mode. In fact switching to a guest mode
 120         * is very similar to exiting to userspace from rcu point of view. In
 121         * addition CPU may stay in a guest mode for quite a long time (up to
 122         * one time slice). Lets treat guest mode as quiescent state, just like
 123         * we do with user-mode execution.
 124         */
 125        if (!context_tracking_enabled_this_cpu()) {
 126                instrumentation_begin();
 127                rcu_virt_note_context_switch(smp_processor_id());
 128                instrumentation_end();
 129        }
 130}
 131
 132static __always_inline void guest_exit_irqoff(void)
 133{
 134        if (context_tracking_enabled())
 135                __context_tracking_exit(CONTEXT_GUEST);
 136
 137        instrumentation_begin();
 138        if (vtime_accounting_enabled_this_cpu())
 139                vtime_guest_exit(current);
 140        else
 141                current->flags &= ~PF_VCPU;
 142        instrumentation_end();
 143}
 144
 145#else
 146static __always_inline void guest_enter_irqoff(void)
 147{
 148        /*
 149         * This is running in ioctl context so its safe
 150         * to assume that it's the stime pending cputime
 151         * to flush.
 152         */
 153        instrumentation_begin();
 154        vtime_account_kernel(current);
 155        current->flags |= PF_VCPU;
 156        rcu_virt_note_context_switch(smp_processor_id());
 157        instrumentation_end();
 158}
 159
 160static __always_inline void guest_exit_irqoff(void)
 161{
 162        instrumentation_begin();
 163        /* Flush the guest cputime we spent on the guest */
 164        vtime_account_kernel(current);
 165        current->flags &= ~PF_VCPU;
 166        instrumentation_end();
 167}
 168#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
 169
 170static inline void guest_exit(void)
 171{
 172        unsigned long flags;
 173
 174        local_irq_save(flags);
 175        guest_exit_irqoff();
 176        local_irq_restore(flags);
 177}
 178
 179#endif
 180