Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
3#define _LINUX_CONTEXT_TRACKING_STATE_H
4
5#include <linux/percpu.h>
6#include <linux/static_key.h>
7
8struct context_tracking {
9 /*
10 * When active is false, probes are unset in order
11 * to minimize overhead: TIF flags are cleared
12 * and calls to user_enter/exit are ignored. This
13 * may be further optimized using static keys.
14 */
15 bool active;
16 int recursion;
17 enum ctx_state {
18 CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
19 CONTEXT_KERNEL = 0,
20 CONTEXT_USER,
21 CONTEXT_GUEST,
22 } state;
23};
24
25#ifdef CONFIG_CONTEXT_TRACKING
26extern struct static_key_false context_tracking_key;
27DECLARE_PER_CPU(struct context_tracking, context_tracking);
28
29static __always_inline bool context_tracking_enabled(void)
30{
31 return static_branch_unlikely(&context_tracking_key);
32}
33
34static __always_inline bool context_tracking_enabled_cpu(int cpu)
35{
36 return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
37}
38
39static inline bool context_tracking_enabled_this_cpu(void)
40{
41 return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
42}
43
44static __always_inline bool context_tracking_in_user(void)
45{
46 return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
47}
48#else
49static inline bool context_tracking_in_user(void) { return false; }
50static inline bool context_tracking_enabled(void) { return false; }
51static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
52static inline bool context_tracking_enabled_this_cpu(void) { return false; }
53#endif /* CONFIG_CONTEXT_TRACKING */
54
55#endif