1 files changed, 108 insertions, 15 deletions

diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
index 65a60d3313b0..7b8433d5a8ef 100644
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -4,8 +4,28 @@
 
 #include <linux/percpu.h>
 #include <linux/static_key.h>
+#include <linux/context_tracking_irq.h>
+
+/* Offset to allow distinguishing irq vs. task-based idle entry/exit. */
+#define CT_NESTING_IRQ_NONIDLE	((LONG_MAX / 2) + 1)
+
+enum ctx_state {
+	CT_STATE_DISABLED	= -1,	/* returned by ct_state() if unknown */
+	CT_STATE_KERNEL		= 0,
+	CT_STATE_IDLE		= 1,
+	CT_STATE_USER		= 2,
+	CT_STATE_GUEST		= 3,
+	CT_STATE_MAX		= 4,
+};
+
+/* Odd value for watching, else even. */
+#define CT_RCU_WATCHING CT_STATE_MAX
+
+#define CT_STATE_MASK (CT_STATE_MAX - 1)
+#define CT_RCU_WATCHING_MASK (~CT_STATE_MASK)
 
 struct context_tracking {
+#ifdef CONFIG_CONTEXT_TRACKING_USER
 	/*
 	 * When active is false, probes are unset in order
 	 * to minimize overhead: TIF flags are cleared
@@ -14,17 +34,74 @@ struct context_tracking {
 	 */
 	bool active;
 	int recursion;
-	enum ctx_state {
-		CONTEXT_DISABLED = -1,	/* returned by ct_state() if unknown */
-		CONTEXT_KERNEL = 0,
-		CONTEXT_USER,
-		CONTEXT_GUEST,
-	} state;
+#endif
+#ifdef CONFIG_CONTEXT_TRACKING
+	atomic_t state;
+#endif
+#ifdef CONFIG_CONTEXT_TRACKING_IDLE
+	long nesting;		/* Track process nesting level. */
+	long nmi_nesting;	/* Track irq/NMI nesting level. */
+#endif
 };
 
 #ifdef CONFIG_CONTEXT_TRACKING
-extern struct static_key_false context_tracking_key;
 DECLARE_PER_CPU(struct context_tracking, context_tracking);
+#endif
+
+#ifdef CONFIG_CONTEXT_TRACKING_USER
+static __always_inline int __ct_state(void)
+{
+	return raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_STATE_MASK;
+}
+#endif
+
+#ifdef CONFIG_CONTEXT_TRACKING_IDLE
+static __always_inline int ct_rcu_watching(void)
+{
+	return atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING_MASK;
+}
+
+static __always_inline int ct_rcu_watching_cpu(int cpu)
+{
+	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
+
+	return atomic_read(&ct->state) & CT_RCU_WATCHING_MASK;
+}
+
+static __always_inline int ct_rcu_watching_cpu_acquire(int cpu)
+{
+	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
+
+	return atomic_read_acquire(&ct->state) & CT_RCU_WATCHING_MASK;
+}
+
+static __always_inline long ct_nesting(void)
+{
+	return __this_cpu_read(context_tracking.nesting);
+}
+
+static __always_inline long ct_nesting_cpu(int cpu)
+{
+	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
+
+	return ct->nesting;
+}
+
+static __always_inline long ct_nmi_nesting(void)
+{
+	return __this_cpu_read(context_tracking.nmi_nesting);
+}
+
+static __always_inline long ct_nmi_nesting_cpu(int cpu)
+{
+	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
+
+	return ct->nmi_nesting;
+}
+#endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */
+
+#ifdef CONFIG_CONTEXT_TRACKING_USER
+extern struct static_key_false context_tracking_key;
 
 static __always_inline bool context_tracking_enabled(void)
 {
@@ -36,20 +113,36 @@ static __always_inline bool context_tracking_enabled_cpu(int cpu)
 	return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
 }
 
-static inline bool context_tracking_enabled_this_cpu(void)
+static __always_inline bool context_tracking_enabled_this_cpu(void)
 {
 	return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
 }
 
-static __always_inline bool context_tracking_in_user(void)
+/**
+ * ct_state() - return the current context tracking state if known
+ *
+ * Returns the current cpu's context tracking state if context tracking
+ * is enabled.  If context tracking is disabled, returns
+ * CT_STATE_DISABLED.  This should be used primarily for debugging.
+ */
+static __always_inline int ct_state(void)
 {
-	return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
+	int ret;
+
+	if (!context_tracking_enabled())
+		return CT_STATE_DISABLED;
+
+	preempt_disable();
+	ret = __ct_state();
+	preempt_enable();
+
+	return ret;
 }
+
 #else
-static inline bool context_tracking_in_user(void) { return false; }
-static inline bool context_tracking_enabled(void) { return false; }
-static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
-static inline bool context_tracking_enabled_this_cpu(void) { return false; }
-#endif /* CONFIG_CONTEXT_TRACKING */
+static __always_inline bool context_tracking_enabled(void) { return false; }
+static __always_inline bool context_tracking_enabled_cpu(int cpu) { return false; }
+static __always_inline bool context_tracking_enabled_this_cpu(void) { return false; }
+#endif /* CONFIG_CONTEXT_TRACKING_USER */
 
 #endif