forked from mirrors/linux
ed11a7f1b3
This is much less error-prone than the old code. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/812df7e64f120c5c7c08481f36a8caa9f53b2199.1447361906.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
49 lines
1.4 KiB
C
49 lines
1.4 KiB
C
#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;
|
|
int recursion;
|
|
enum ctx_state {
|
|
CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
|
|
CONTEXT_KERNEL = 0,
|
|
CONTEXT_USER,
|
|
CONTEXT_GUEST,
|
|
} state;
|
|
};
|
|
|
|
#ifdef CONFIG_CONTEXT_TRACKING
|
|
extern struct static_key_false context_tracking_enabled;
|
|
DECLARE_PER_CPU(struct context_tracking, context_tracking);
|
|
|
|
static inline bool context_tracking_is_enabled(void)
|
|
{
|
|
return static_branch_unlikely(&context_tracking_enabled);
|
|
}
|
|
|
|
static inline bool context_tracking_cpu_is_enabled(void)
|
|
{
|
|
return __this_cpu_read(context_tracking.active);
|
|
}
|
|
|
|
static inline bool context_tracking_in_user(void)
|
|
{
|
|
return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
|
|
}
|
|
#else
|
|
static inline bool context_tracking_in_user(void) { return false; }
|
|
static inline bool context_tracking_active(void) { return false; }
|
|
static inline bool context_tracking_is_enabled(void) { return false; }
|
|
static inline bool context_tracking_cpu_is_enabled(void) { return false; }
|
|
#endif /* CONFIG_CONTEXT_TRACKING */
|
|
|
|
#endif
|