locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
to sleepable rt_spin_lock().  This means that the interrupt related
suffixes for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect
the CPU's interrupt state. This commit therefore adds raw spin-lock
torture tests.  This in turn permits pure spin locks to be tested in
PREEMPT_RT kernels.

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/locking/locktorture.c

@@ -55,7 +55,7 @@ torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
 /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
 #define MAX_NESTED_LOCKS 8
 
-static char *torture_type = "spin_lock";
+static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock";
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type,
 		 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
@@ -257,6 +257,59 @@ static struct lock_torture_ops spin_lock_irq_ops = {
 	.name		= "spin_lock_irq"
 };
 
+static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
+
+static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	raw_spin_lock(&torture_raw_spinlock);
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock(&torture_raw_spinlock);
+}
+
+static struct lock_torture_ops raw_spin_lock_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock"
+};
+
+static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops raw_spin_lock_irq_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock_irq"
+};
+
 static DEFINE_RWLOCK(torture_rwlock);
 
 static int torture_rwlock_write_lock(int tid __maybe_unused)
@@ -1017,6 +1070,7 @@ static int __init lock_torture_init(void)
 	static struct lock_torture_ops *torture_ops[] = {
 		&lock_busted_ops,
 		&spin_lock_ops, &spin_lock_irq_ops,
+		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
 		&rw_lock_ops, &rw_lock_irq_ops,
 		&mutex_lock_ops,
 		&ww_mutex_lock_ops,