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