linux_dsm_epyc7002/include/linux/context_tracking.h
Frederic Weisbecker 56dd9470d7 context_tracking: Move exception handling to generic code
Exceptions handling on context tracking should share common
treatment: on entry we exit user mode if the exception triggered
in that context. Then on exception exit we return to that previous
context.

Generalize this to avoid duplication across archs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-07 17:09:25 +01:00

62 lines
1.5 KiB
C

#ifndef _LINUX_CONTEXT_TRACKING_H
#define _LINUX_CONTEXT_TRACKING_H
#include <linux/sched.h>
#include <linux/percpu.h>
#include <asm/ptrace.h>
#ifdef CONFIG_CONTEXT_TRACKING
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 {
IN_KERNEL = 0,
IN_USER,
} state;
};
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 user_enter(void);
extern void user_exit(void);
static inline void exception_enter(struct pt_regs *regs)
{
user_exit();
}
static inline void exception_exit(struct pt_regs *regs)
{
if (user_mode(regs))
user_enter();
}
extern void context_tracking_task_switch(struct task_struct *prev,
struct task_struct *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 void exception_enter(struct pt_regs *regs) { }
static inline void exception_exit(struct pt_regs *regs) { }
static inline void context_tracking_task_switch(struct task_struct *prev,
struct task_struct *next) { }
#endif /* !CONFIG_CONTEXT_TRACKING */
#endif