rt: core implementation

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 42 insertions, 14 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 12327b2bb785..8a2ddd3f0922 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -397,6 +397,8 @@ config DEBUG_RT_MUTEXES
 	help
 	 This allows rt mutex semantics violations and rt mutex related
 	 deadlocks (lockups) to be detected and reported automatically.
+	 When realtime preemption is enabled this includes spinlocks,
+	 rwlocks, mutexes and (rw)semaphores
 
 config DEBUG_PI_LIST
 	bool
@@ -420,7 +422,7 @@ config DEBUG_SPINLOCK
 
 config DEBUG_MUTEXES
 	bool "Mutex debugging: basic checks"
-	depends on DEBUG_KERNEL
+	depends on DEBUG_KERNEL && !PREEMPT_RT
 	help
 	 This feature allows mutex semantics violations to be detected and
 	 reported.
diff --git a/lib/Makefile b/lib/Makefile
index b6d1857bbf08..0d2ee155f4c9 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -34,7 +34,8 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
 obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
 obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
-lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
+obj-$(CONFIG_PREEMPT_RT) += plist.o
+obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
 lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o
 lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
index 54625bec6fb9..709c432b8a92 100644
--- a/lib/kernel_lock.c
+++ b/lib/kernel_lock.c
@@ -35,6 +35,8 @@ DEFINE_SEMAPHORE(kernel_sem);
  * about recursion, both due to the down() and due to the enabling of
  * preemption. schedule() will re-check the preemption flag after
  * reacquiring the semaphore.
+ *
+ * Called with interrupts disabled.
  */
 int __lockfunc __reacquire_kernel_lock(void)
 {
@@ -67,11 +69,15 @@ void __lockfunc lock_kernel(void)
 	struct task_struct *task = current;
 	int depth = task->lock_depth + 1;
 
-	if (likely(!depth))
+	if (likely(!depth)) {
 		/*
 		 * No recursion worries - we set up lock_depth _after_
 		 */
 		down(&kernel_sem);
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+		current->last_kernel_lock = __builtin_return_address(0);
+#endif
+	}
 
 	task->lock_depth = depth;
 }
@@ -82,8 +88,12 @@ void __lockfunc unlock_kernel(void)
 
 	BUG_ON(task->lock_depth < 0);
 
-	if (likely(--task->lock_depth < 0))
+	if (likely(--task->lock_depth < 0)) {
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+		current->last_kernel_lock = NULL;
+#endif
 		up(&kernel_sem);
+	}
 }
 
 EXPORT_SYMBOL(lock_kernel);
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 619313ed6c46..65e7eab8498e 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -158,7 +158,7 @@ static void init_shared_classes(void)
 		local_bh_disable();		\
 		local_irq_disable();		\
 		lockdep_softirq_enter();	\
-		WARN_ON(!in_softirq());
+		/* FIXME: preemptible softirqs. WARN_ON(!in_softirq()); */
 
 #define SOFTIRQ_EXIT()				\
 		lockdep_softirq_exit();		\
@@ -550,6 +550,11 @@ GENERATE_TESTCASE(init_held_rsem)
 #undef E
 
 /*
+ * FIXME: turns these into raw-spinlock tests on -rt
+ */
+#ifndef CONFIG_PREEMPT_RT
+
+/*
  * locking an irq-safe lock with irqs enabled:
  */
 #define E1()				\
@@ -890,6 +895,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft)
 #include "locking-selftest-softirq.h"
 // GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft)
 
+#endif /* !CONFIG_PREEMPT_RT */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define I_SPINLOCK(x)	lockdep_reset_lock(&lock_##x.dep_map)
 # define I_RWLOCK(x)	lockdep_reset_lock(&rwlock_##x.dep_map)
@@ -998,7 +1005,7 @@ static inline void print_testname(const char *testname)
 
 #define DO_TESTCASE_1(desc, name, nr)				\
 	print_testname(desc"/"#nr);				\
-	dotest(name##_##nr, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(name##_##nr, SUCCESS, LOCKTYPE_RWLOCK);	\
 	printk("\n");
 
 #define DO_TESTCASE_1B(desc, name, nr)				\
@@ -1006,17 +1013,17 @@ static inline void print_testname(const char *testname)
 	dotest(name##_##nr, FAILURE, LOCKTYPE_RWLOCK);		\
 	printk("\n");
 
-#define DO_TESTCASE_3(desc, name, nr)				\
-	print_testname(desc"/"#nr);				\
-	dotest(name##_spin_##nr, FAILURE, LOCKTYPE_SPIN);	\
-	dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK);	\
+#define DO_TESTCASE_3(desc, name, nr)					\
+	print_testname(desc"/"#nr);					\
+	dotest(name##_spin_##nr, FAILURE, LOCKTYPE_SPIN);		\
+	dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK);		\
 	dotest(name##_rlock_##nr, SUCCESS, LOCKTYPE_RWLOCK);	\
 	printk("\n");
 
-#define DO_TESTCASE_3RW(desc, name, nr)				\
-	print_testname(desc"/"#nr);				\
+#define DO_TESTCASE_3RW(desc, name, nr)					\
+	print_testname(desc"/"#nr);					\
 	dotest(name##_spin_##nr, FAILURE, LOCKTYPE_SPIN|LOCKTYPE_RWLOCK);\
-	dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK);	\
+	dotest(name##_wlock_##nr, FAILURE, LOCKTYPE_RWLOCK);		\
 	dotest(name##_rlock_##nr, SUCCESS, LOCKTYPE_RWLOCK);	\
 	printk("\n");
 
@@ -1047,7 +1054,7 @@ static inline void print_testname(const char *testname)
 	print_testname(desc);					\
 	dotest(name##_spin, FAILURE, LOCKTYPE_SPIN);		\
 	dotest(name##_wlock, FAILURE, LOCKTYPE_RWLOCK);		\
-	dotest(name##_rlock, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(name##_rlock, SUCCESS, LOCKTYPE_RWLOCK);	\
 	dotest(name##_mutex, FAILURE, LOCKTYPE_MUTEX);		\
 	dotest(name##_wsem, FAILURE, LOCKTYPE_RWSEM);		\
 	dotest(name##_rsem, FAILURE, LOCKTYPE_RWSEM);		\
@@ -1179,6 +1186,7 @@ void locking_selftest(void)
 	/*
 	 * irq-context testcases:
 	 */
+#ifndef CONFIG_PREEMPT_RT
 	DO_TESTCASE_2x6("irqs-on + irq-safe-A", irqsafe1);
 	DO_TESTCASE_2x3("sirq-safe-A => hirqs-on", irqsafe2A);
 	DO_TESTCASE_2x6("safe-A + irqs-on", irqsafe2B);
@@ -1188,6 +1196,7 @@ void locking_selftest(void)
 
 	DO_TESTCASE_6x2("irq read-recursion", irq_read_recursion);
 //	DO_TESTCASE_6x2B("irq read-recursion #2", irq_read_recursion2);
+#endif
 
 	if (unexpected_testcase_failures) {
 		printk("-----------------------------------------------------------------\n");
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 23abbd93cae1..e209012e5d31 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -157,12 +157,14 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 		 * succeed in getting a node here (and never reach
 		 * kmem_cache_alloc)
 		 */
+		rtp = &get_cpu_var(radix_tree_preloads);
 		rtp = &__get_cpu_var(radix_tree_preloads);
 		if (rtp->nr) {
 			ret = rtp->nodes[rtp->nr - 1];
 			rtp->nodes[rtp->nr - 1] = NULL;
 			rtp->nr--;
 		}
+		put_cpu_var(radix_tree_preloads);
 	}
 	if (ret == NULL)
 		ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
@@ -195,6 +197,8 @@ radix_tree_node_free(struct radix_tree_node *node)
 	call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
 }
 
+#ifndef CONFIG_PREEMPT_RT
+
 /*
  * Load up this CPU's radix_tree_node buffer with sufficient objects to
  * ensure that the addition of a single element in the tree cannot fail.  On
@@ -227,6 +231,8 @@ out:
 }
 EXPORT_SYMBOL(radix_tree_preload);
 
+#endif
+
 /*
  *	Return the maximum key which can be store into a
  *	radix tree with height HEIGHT.