Commit e7358b3b authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

context_tracking: Split low level state headers 



We plan to use the context tracking static key on inline
vtime APIs. For this we need to include the context tracking
headers from those of vtime.

However vtime headers need to stay low level because they are
included in hardirq.h that mostly contains standalone
definitions. But context_tracking.h includes sched.h for
a few task_struct references, therefore it wouldn't be sensible
to include it from vtime.h

To solve this, lets split the context tracking headers and move
out the pure state definitions that only require a few low level
headers. We can safely include that small part in vtime.h later.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
parent 54461562

include/linux/context_tracking.h

+1 −30
Original line number Diff line number Diff line
@@ -2,40 +2,12 @@ 
#define _LINUX_CONTEXT_TRACKING_H



#include <linux/sched.h>

#include <linux/percpu.h>

#include <linux/vtime.h>

#include <linux/static_key.h>

#include <linux/context_tracking_state.h>

#include <asm/ptrace.h>



struct context_tracking {

	/*

	 * When active is false, probes are unset in order

	 * to minimize overhead: TIF flags are cleared

	 * and calls to user_enter/exit are ignored. This

	 * may be further optimized using static keys.

	 */

	bool active;

	enum ctx_state {

		IN_KERNEL = 0,

		IN_USER,

	} state;

};





#ifdef CONFIG_CONTEXT_TRACKING

extern struct static_key context_tracking_enabled;

DECLARE_PER_CPU(struct context_tracking, context_tracking);



static inline bool context_tracking_in_user(void)

{

	return __this_cpu_read(context_tracking.state) == IN_USER;

}



static inline bool context_tracking_active(void)

{

	return __this_cpu_read(context_tracking.active);

}



extern void context_tracking_cpu_set(int cpu);



extern void context_tracking_user_enter(void);
@@ -83,7 +55,6 @@ static inline void context_tracking_task_switch(struct task_struct *prev, 
		__context_tracking_task_switch(prev, next);

}

#else

static inline bool context_tracking_in_user(void) { return false; }

static inline void user_enter(void) { }

static inline void user_exit(void) { }

static inline enum ctx_state exception_enter(void) { return 0; }

include/linux/context_tracking_state.h

0 → 100644
+39 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_CONTEXT_TRACKING_STATE_H

#define _LINUX_CONTEXT_TRACKING_STATE_H



#include <linux/percpu.h>

#include <linux/static_key.h>



struct context_tracking {

	/*

	 * When active is false, probes are unset in order

	 * to minimize overhead: TIF flags are cleared

	 * and calls to user_enter/exit are ignored. This

	 * may be further optimized using static keys.

	 */

	bool active;

	enum ctx_state {

		IN_KERNEL = 0,

		IN_USER,

	} state;

};



#ifdef CONFIG_CONTEXT_TRACKING

extern struct static_key context_tracking_enabled;

DECLARE_PER_CPU(struct context_tracking, context_tracking);



static inline bool context_tracking_in_user(void)

{

	return __this_cpu_read(context_tracking.state) == IN_USER;

}



static inline bool context_tracking_active(void)

{

	return __this_cpu_read(context_tracking.active);

}

#else

static inline bool context_tracking_in_user(void) { return false; }

static inline bool context_tracking_active(void) { return false; }

#endif /* CONFIG_CONTEXT_TRACKING */



#endif

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