67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
#ifndef _LINUX_CONTEXT_TRACKING_H
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#define _LINUX_CONTEXT_TRACKING_H
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#include <linux/sched.h>
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#include <linux/percpu.h>
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#include <asm/ptrace.h>
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struct context_tracking {
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/*
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* When active is false, probes are unset in order
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* to minimize overhead: TIF flags are cleared
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* and calls to user_enter/exit are ignored. This
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* may be further optimized using static keys.
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*/
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bool active;
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enum ctx_state {
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IN_KERNEL = 0,
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IN_USER,
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} state;
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};
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#ifdef CONFIG_CONTEXT_TRACKING
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DECLARE_PER_CPU(struct context_tracking, context_tracking);
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static inline bool context_tracking_in_user(void)
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{
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return __this_cpu_read(context_tracking.state) == IN_USER;
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}
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static inline bool context_tracking_active(void)
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{
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return __this_cpu_read(context_tracking.active);
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}
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extern void user_enter(void);
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extern void user_exit(void);
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static inline enum ctx_state exception_enter(void)
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{
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enum ctx_state prev_ctx;
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prev_ctx = this_cpu_read(context_tracking.state);
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user_exit();
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return prev_ctx;
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}
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static inline void exception_exit(enum ctx_state prev_ctx)
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{
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if (prev_ctx == IN_USER)
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user_enter();
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}
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extern void context_tracking_task_switch(struct task_struct *prev,
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struct task_struct *next);
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#else
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static inline bool context_tracking_in_user(void) { return false; }
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static inline void user_enter(void) { }
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static inline void user_exit(void) { }
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static inline enum ctx_state exception_enter(void) { return 0; }
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static inline void exception_exit(enum ctx_state prev_ctx) { }
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static inline void context_tracking_task_switch(struct task_struct *prev,
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struct task_struct *next) { }
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#endif /* !CONFIG_CONTEXT_TRACKING */
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#endif
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