Changeset 2b4a9f26 in mainline for kernel/generic/src/synch/spinlock.c

Timestamp:

2010-05-20T19:30:18Z (14 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

42bbbe2

Parents:

b10e6e31

Message:

Add interrupts-disabled spinlocks whose purpose is the semantic distinction between spinlocks acquired always with interrupts disabled and normal spinlocks.
The compile-time distinction is implemented by the means of the type system and basic code correctness properties can be checked by the debugging assertions during run-time (with CONFIG_DEBUG)

• Correct bracketing of top-level interrupts-disabled spinlocks
• Correctness of the use of nested interrupts-disabled spinlocks (interrupts must be actually disabled)
• Basic consistency of places where the interrupt level is restored

The API encapsulates the physical manipulation with the interrupt levels and also two common locking patterns

• Sequential unlocking of spinlock A before locking of spinlock B without restoring original interrupt level (irq_spinlock_pass())
• Hand-over-hand locking of two locks in the correct locking order, e.g. if A precedes B, then locking of B before unlocking A (irq_spinlock_exchange())

A new HAL function interrupts_disabled() should be implemented in each port to support the run-time checks of correctly disabled interrupts while locking nested interrupts-disabled spinlocks
(only in debug builds, not used in non-debug builds).

File:

• kernel/generic/src/synch/spinlock.c (modified) (2 diffs)

kernel/generic/src/synch/spinlock.c

@@ -128 +128 @@
 void spinlock_unlock_debug(spinlock_t *lock)
 {
-        ASSERT(atomic_get(&lock->val) != 0);
+        ASSERT_SPINLOCK(atomic_get(&lock->val) != 0, lock);
         
         /*
@@ -143 +143 @@
 /** Lock spinlock conditionally
  *
- * Lock spinlock conditionally.
- * If the spinlock is not available at the moment,
- * signal failure.
+ * Lock spinlock conditionally. If the spinlock is not available
+ * at the moment, signal failure.
  *
  * @param lock Pointer to spinlock_t structure.