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authorGustavo Padovan <gustavo.padovan@collabora.co.uk>2013-09-27 11:56:14 -0300
committerGustavo Padovan <gustavo.padovan@collabora.co.uk>2013-09-27 11:56:14 -0300
commit1025c04cecd19882e28f16c4004034b475c372c5 (patch)
tree2b7402887e86d54bff5a123228c9059eae5e32bd /include/linux/context_tracking_state.h
parent4375f1037d52602413142e290608d0d84671ad36 (diff)
parent5bcecf325378218a8e248bb6bcae96ec7362f8ef (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth
Conflicts: net/bluetooth/hci_core.c
Diffstat (limited to 'include/linux/context_tracking_state.h')
-rw-r--r--include/linux/context_tracking_state.h39
1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
new file mode 100644
index 00000000000..0f1979d0674
--- /dev/null
+++ b/include/linux/context_tracking_state.h
@@ -0,0 +1,39 @@
+#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