lockdep/selftest: Add wait context selftests

These tests are added for two purposes:

*	Test the implementation of wait context checks and related
	annotations.

*	Semi-document the rules for wait context nesting when
	PROVE_RAW_LOCK_NESTING=y.

The test cases are only avaible for PROVE_RAW_LOCK_NESTING=y, as wait
context checking makes more sense for that configuration.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201208103112.2838119-5-boqun.feng@gmail.com

lib/locking-selftest.c

@@ -64,6 +64,9 @@ static DEFINE_SPINLOCK(lock_B);
 static DEFINE_SPINLOCK(lock_C);
 static DEFINE_SPINLOCK(lock_D);
 
+static DEFINE_RAW_SPINLOCK(raw_lock_A);
+static DEFINE_RAW_SPINLOCK(raw_lock_B);
+
 static DEFINE_RWLOCK(rwlock_A);
 static DEFINE_RWLOCK(rwlock_B);
 static DEFINE_RWLOCK(rwlock_C);
@@ -1306,6 +1309,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define I_SPINLOCK(x)	lockdep_reset_lock(&lock_##x.dep_map)
+# define I_RAW_SPINLOCK(x)	lockdep_reset_lock(&raw_lock_##x.dep_map)
 # define I_RWLOCK(x)	lockdep_reset_lock(&rwlock_##x.dep_map)
 # define I_MUTEX(x)	lockdep_reset_lock(&mutex_##x.dep_map)
 # define I_RWSEM(x)	lockdep_reset_lock(&rwsem_##x.dep_map)
@@ -1315,6 +1319,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock)
 #endif
 #else
 # define I_SPINLOCK(x)
+# define I_RAW_SPINLOCK(x)
 # define I_RWLOCK(x)
 # define I_MUTEX(x)
 # define I_RWSEM(x)
@@ -1358,9 +1363,12 @@ static void reset_locks(void)
 	I1(A); I1(B); I1(C); I1(D);
 	I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
 	I_WW(t); I_WW(t2); I_WW(o.base); I_WW(o2.base); I_WW(o3.base);
+	I_RAW_SPINLOCK(A); I_RAW_SPINLOCK(B);
 	lockdep_reset();
 	I2(A); I2(B); I2(C); I2(D);
 	init_shared_classes();
+	raw_spin_lock_init(&raw_lock_A);
+	raw_spin_lock_init(&raw_lock_B);
 
 	ww_mutex_init(&o, &ww_lockdep); ww_mutex_init(&o2, &ww_lockdep); ww_mutex_init(&o3, &ww_lockdep);
 	memset(&t, 0, sizeof(t)); memset(&t2, 0, sizeof(t2));
@@ -2419,6 +2427,226 @@ static void fs_reclaim_tests(void)
 	pr_cont("\n");
 }
 
+#define __guard(cleanup) __maybe_unused __attribute__((__cleanup__(cleanup)))
+
+static void hardirq_exit(int *_)
+{
+	HARDIRQ_EXIT();
+}
+
+#define HARDIRQ_CONTEXT(name, ...)					\
+	int hardirq_guard_##name __guard(hardirq_exit);			\
+	HARDIRQ_ENTER();
+
+#define NOTTHREADED_HARDIRQ_CONTEXT(name, ...)				\
+	int notthreaded_hardirq_guard_##name __guard(hardirq_exit);	\
+	local_irq_disable();						\
+	__irq_enter();							\
+	WARN_ON(!in_irq());
+
+static void softirq_exit(int *_)
+{
+	SOFTIRQ_EXIT();
+}
+
+#define SOFTIRQ_CONTEXT(name, ...)				\
+	int softirq_guard_##name __guard(softirq_exit);		\
+	SOFTIRQ_ENTER();
+
+static void rcu_exit(int *_)
+{
+	rcu_read_unlock();
+}
+
+#define RCU_CONTEXT(name, ...)					\
+	int rcu_guard_##name __guard(rcu_exit);			\
+	rcu_read_lock();
+
+static void rcu_bh_exit(int *_)
+{
+	rcu_read_unlock_bh();
+}
+
+#define RCU_BH_CONTEXT(name, ...)				\
+	int rcu_bh_guard_##name __guard(rcu_bh_exit);		\
+	rcu_read_lock_bh();
+
+static void rcu_sched_exit(int *_)
+{
+	rcu_read_unlock_sched();
+}
+
+#define RCU_SCHED_CONTEXT(name, ...)				\
+	int rcu_sched_guard_##name __guard(rcu_sched_exit);	\
+	rcu_read_lock_sched();
+
+static void rcu_callback_exit(int *_)
+{
+	rcu_lock_release(&rcu_callback_map);
+}
+
+#define RCU_CALLBACK_CONTEXT(name, ...)					\
+	int rcu_callback_guard_##name __guard(rcu_callback_exit);	\
+	rcu_lock_acquire(&rcu_callback_map);
+
+
+static void raw_spinlock_exit(raw_spinlock_t **lock)
+{
+	raw_spin_unlock(*lock);
+}
+
+#define RAW_SPINLOCK_CONTEXT(name, lock)						\
+	raw_spinlock_t *raw_spinlock_guard_##name __guard(raw_spinlock_exit) = &(lock);	\
+	raw_spin_lock(&(lock));
+
+static void spinlock_exit(spinlock_t **lock)
+{
+	spin_unlock(*lock);
+}
+
+#define SPINLOCK_CONTEXT(name, lock)						\
+	spinlock_t *spinlock_guard_##name __guard(spinlock_exit) = &(lock);	\
+	spin_lock(&(lock));
+
+static void mutex_exit(struct mutex **lock)
+{
+	mutex_unlock(*lock);
+}
+
+#define MUTEX_CONTEXT(name, lock)					\
+	struct mutex *mutex_guard_##name __guard(mutex_exit) = &(lock);	\
+	mutex_lock(&(lock));
+
+#define GENERATE_2_CONTEXT_TESTCASE(outer, outer_lock, inner, inner_lock)	\
+										\
+static void __maybe_unused inner##_in_##outer(void)				\
+{										\
+	outer##_CONTEXT(_, outer_lock);						\
+	{									\
+		inner##_CONTEXT(_, inner_lock);					\
+	}									\
+}
+
+/*
+ * wait contexts (considering PREEMPT_RT)
+ *
+ * o: inner is allowed in outer
+ * x: inner is disallowed in outer
+ *
+ *       \  inner |  RCU  | RAW_SPIN | SPIN | MUTEX
+ * outer  \       |       |          |      |
+ * ---------------+-------+----------+------+-------
+ * HARDIRQ        |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * NOTTHREADED_IRQ|   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * SOFTIRQ        |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU            |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_BH         |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_CALLBACK   |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * RCU_SCHED      |   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * RAW_SPIN       |   o   |    o     |  x   |  x
+ * ---------------+-------+----------+------+-------
+ * SPIN           |   o   |    o     |  o   |  x
+ * ---------------+-------+----------+------+-------
+ * MUTEX          |   o   |    o     |  o   |  o
+ * ---------------+-------+----------+------+-------
+ */
+
+#define GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(HARDIRQ, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(NOTTHREADED_HARDIRQ, , inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(SOFTIRQ, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU, , inner, inner_lock)				\
+GENERATE_2_CONTEXT_TESTCASE(RCU_BH, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU_CALLBACK, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RCU_SCHED, , inner, inner_lock)			\
+GENERATE_2_CONTEXT_TESTCASE(RAW_SPINLOCK, raw_lock_A, inner, inner_lock)	\
+GENERATE_2_CONTEXT_TESTCASE(SPINLOCK, lock_A, inner, inner_lock)		\
+GENERATE_2_CONTEXT_TESTCASE(MUTEX, mutex_A, inner, inner_lock)
+
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RCU, )
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(RAW_SPINLOCK, raw_lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(SPINLOCK, lock_B)
+GENERATE_2_CONTEXT_TESTCASE_FOR_ALL_OUTER(MUTEX, mutex_B)
+
+/* the outer context allows all kinds of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(outer)			\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, SUCCESS, LOCKTYPE_MUTEX);		\
+
+/*
+ * the outer context only allows the preemption introduced by spinlock_t (which
+ * is a sleepable lock for PREEMPT_RT)
+ */
+#define DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(outer)		\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX);		\
+
+/* the outer doesn't allows any kind of preemption */
+#define DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(outer)			\
+	dotest(RCU_in_##outer, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(RAW_SPINLOCK_in_##outer, SUCCESS, LOCKTYPE_SPIN);	\
+	dotest(SPINLOCK_in_##outer, FAILURE, LOCKTYPE_SPIN);		\
+	dotest(MUTEX_in_##outer, FAILURE, LOCKTYPE_MUTEX);		\
+
+static void wait_context_tests(void)
+{
+	printk("  --------------------------------------------------------------------------\n");
+	printk("  | wait context tests |\n");
+	printk("  --------------------------------------------------------------------------\n");
+	printk("                                 | rcu  | raw  | spin |mutex |\n");
+	printk("  --------------------------------------------------------------------------\n");
+	print_testname("in hardirq context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(HARDIRQ);
+	pr_cont("\n");
+
+	print_testname("in hardirq context (not threaded)");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(NOTTHREADED_HARDIRQ);
+	pr_cont("\n");
+
+	print_testname("in softirq context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SOFTIRQ);
+	pr_cont("\n");
+
+	print_testname("in RCU context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU);
+	pr_cont("\n");
+
+	print_testname("in RCU-bh context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_BH);
+	pr_cont("\n");
+
+	print_testname("in RCU callback context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(RCU_CALLBACK);
+	pr_cont("\n");
+
+	print_testname("in RCU-sched context");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RCU_SCHED);
+	pr_cont("\n");
+
+	print_testname("in RAW_SPINLOCK context");
+	DO_CONTEXT_TESTCASE_OUTER_NOT_PREEMPTIBLE(RAW_SPINLOCK);
+	pr_cont("\n");
+
+	print_testname("in SPINLOCK context");
+	DO_CONTEXT_TESTCASE_OUTER_LIMITED_PREEMPTIBLE(SPINLOCK);
+	pr_cont("\n");
+
+	print_testname("in MUTEX context");
+	DO_CONTEXT_TESTCASE_OUTER_PREEMPTIBLE(MUTEX);
+	pr_cont("\n");
+}
+
 void locking_selftest(void)
 {
 	/*
@@ -2542,6 +2770,10 @@ void locking_selftest(void)
 
 	fs_reclaim_tests();
 
+	/* Wait context test cases that are specific for RAW_LOCK_NESTING */
+	if (IS_ENABLED(CONFIG_PROVE_RAW_LOCK_NESTING))
+		wait_context_tests();
+
 	if (unexpected_testcase_failures) {
 		printk("-----------------------------------------------------------------\n");
 		debug_locks = 0;