Changes in kernel/generic/src/synch/spinlock.c [2b264c4:95d45482] in mainline

File:

• kernel/generic/src/synch/spinlock.c (modified) (10 diffs)

kernel/generic/src/synch/spinlock.c

@@ -1 +1 @@
 /*
  * Copyright (c) 2001-2004 Jakub Jermar
- * Copyright (c) 2023 Jiří Zárevúcky
  * All rights reserved.
  *
@@ -37 +36 @@
  */
 
-#include <arch/asm.h>
 #include <synch/spinlock.h>
 #include <atomic.h>
@@ -49 +47 @@
 #include <cpu.h>
 
-#ifndef ARCH_SPIN_HINT
-#define ARCH_SPIN_HINT() ((void)0)
-#endif
+#ifdef CONFIG_SMP
 
 /** Initialize spinlock
@@ -60 +56 @@
 void spinlock_initialize(spinlock_t *lock, const char *name)
 {
-#ifdef CONFIG_SMP
         atomic_flag_clear_explicit(&lock->flag, memory_order_relaxed);
 #ifdef CONFIG_DEBUG_SPINLOCK
         lock->name = name;
 #endif
-#endif
-}
+}
+
+#ifdef CONFIG_DEBUG_SPINLOCK
 
 /** Lock spinlock
  *
+ * Lock spinlock.
+ * This version has limitted ability to report
+ * possible occurence of deadlock.
+ *
  * @param lock Pointer to spinlock_t structure.
  *
  */
-void spinlock_lock(spinlock_t *lock)
-{
+void spinlock_lock_debug(spinlock_t *lock)
+{
+        size_t i = 0;
+        bool deadlock_reported = false;
+
         preemption_disable();
-
-#ifdef CONFIG_SMP
-        bool deadlock_reported = false;
-        size_t i = 0;
-
         while (atomic_flag_test_and_set_explicit(&lock->flag, memory_order_acquire)) {
-                ARCH_SPIN_HINT();
-
-#ifdef CONFIG_DEBUG_SPINLOCK
                 /*
                  * We need to be careful about particular locks
@@ -116 +111 @@
                         deadlock_reported = true;
                 }
-#endif
-        }
-
-        /* Avoid compiler warning with debug disabled. */
-        (void) i;
+        }
 
         if (deadlock_reported)
                 printf("cpu%u: not deadlocked\n", CPU->id);
+}
+
+/** Unlock spinlock
+ *
+ * Unlock spinlock.
+ *
+ * @param sl Pointer to spinlock_t structure.
+ */
+void spinlock_unlock_debug(spinlock_t *lock)
+{
+        ASSERT_SPINLOCK(spinlock_locked(lock), lock);
+
+        atomic_flag_clear_explicit(&lock->flag, memory_order_release);
+        preemption_enable();
+}
 
 #endif
-}
-
-/** Unlock spinlock
- *
- * @param sl Pointer to spinlock_t structure.
- */
-void spinlock_unlock(spinlock_t *lock)
-{
-#ifdef CONFIG_SMP
-#ifdef CONFIG_DEBUG_SPINLOCK
-        ASSERT_SPINLOCK(spinlock_locked(lock), lock);
-#endif
-
-        atomic_flag_clear_explicit(&lock->flag, memory_order_release);
-#endif
-
-        preemption_enable();
-}
-
-/**
+
+/** Lock spinlock conditionally
+ *
  * Lock spinlock conditionally. If the spinlock is not available
  * at the moment, signal failure.
@@ -151 +140 @@
  * @param lock Pointer to spinlock_t structure.
  *
- * @return true on success.
+ * @return Zero on failure, non-zero otherwise.
  *
  */
@@ -157 +146 @@
 {
         preemption_disable();
-
-#ifdef CONFIG_SMP
         bool ret = !atomic_flag_test_and_set_explicit(&lock->flag, memory_order_acquire);
 
@@ -165 +152 @@
 
         return ret;
-#else
-        return true;
-#endif
 }
 
@@ -177 +161 @@
 bool spinlock_locked(spinlock_t *lock)
 {
-#ifdef CONFIG_SMP
         // NOTE: Atomic flag doesn't support simple atomic read (by design),
         //       so instead we test_and_set and then clear if necessary.
@@ -187 +170 @@
                 atomic_flag_clear_explicit(&lock->flag, memory_order_relaxed);
         return ret;
-#else
-        return true;
+}
+
 #endif
+
+/** Initialize interrupts-disabled spinlock
+ *
+ * @param lock IRQ spinlock to be initialized.
+ * @param name IRQ spinlock name.
+ *
+ */
+void irq_spinlock_initialize(irq_spinlock_t *lock, const char *name)
+{
+        spinlock_initialize(&(lock->lock), name);
+        lock->guard = false;
+        lock->ipl = 0;
+}
+
+/** Lock interrupts-disabled spinlock
+ *
+ * Lock a spinlock which requires disabled interrupts.
+ *
+ * @param lock    IRQ spinlock to be locked.
+ * @param irq_dis If true, disables interrupts before locking the spinlock.
+ *                If false, interrupts are expected to be already disabled.
+ *
+ */
+void irq_spinlock_lock(irq_spinlock_t *lock, bool irq_dis)
+{
+        if (irq_dis) {
+                ipl_t ipl = interrupts_disable();
+                spinlock_lock(&(lock->lock));
+
+                lock->guard = true;
+                lock->ipl = ipl;
+        } else {
+                ASSERT_IRQ_SPINLOCK(interrupts_disabled(), lock);
+
+                spinlock_lock(&(lock->lock));
+                ASSERT_IRQ_SPINLOCK(!lock->guard, lock);
+        }
+}
+
+/** Unlock interrupts-disabled spinlock
+ *
+ * Unlock a spinlock which requires disabled interrupts.
+ *
+ * @param lock    IRQ spinlock to be unlocked.
+ * @param irq_res If true, interrupts are restored to previously
+ *                saved interrupt level.
+ *
+ */
+void irq_spinlock_unlock(irq_spinlock_t *lock, bool irq_res)
+{
+        ASSERT_IRQ_SPINLOCK(interrupts_disabled(), lock);
+
+        if (irq_res) {
+                ASSERT_IRQ_SPINLOCK(lock->guard, lock);
+
+                lock->guard = false;
+                ipl_t ipl = lock->ipl;
+
+                spinlock_unlock(&(lock->lock));
+                interrupts_restore(ipl);
+        } else {
+                ASSERT_IRQ_SPINLOCK(!lock->guard, lock);
+                spinlock_unlock(&(lock->lock));
+        }
+}
+
+/** Lock interrupts-disabled spinlock
+ *
+ * Lock an interrupts-disabled spinlock conditionally. If the
+ * spinlock is not available at the moment, signal failure.
+ * Interrupts are expected to be already disabled.
+ *
+ * @param lock IRQ spinlock to be locked conditionally.
+ *
+ * @return Zero on failure, non-zero otherwise.
+ *
+ */
+bool irq_spinlock_trylock(irq_spinlock_t *lock)
+{
+        ASSERT_IRQ_SPINLOCK(interrupts_disabled(), lock);
+        bool ret = spinlock_trylock(&(lock->lock));
+
+        ASSERT_IRQ_SPINLOCK((!ret) || (!lock->guard), lock);
+        return ret;
+}
+
+/** Pass lock from one interrupts-disabled spinlock to another
+ *
+ * Pass lock from one IRQ spinlock to another IRQ spinlock
+ * without enabling interrupts during the process.
+ *
+ * The first IRQ spinlock is supposed to be locked.
+ *
+ * @param unlock IRQ spinlock to be unlocked.
+ * @param lock   IRQ spinlock to be locked.
+ *
+ */
+void irq_spinlock_pass(irq_spinlock_t *unlock, irq_spinlock_t *lock)
+{
+        ASSERT_IRQ_SPINLOCK(interrupts_disabled(), unlock);
+
+        /* Pass guard from unlock to lock */
+        bool guard = unlock->guard;
+        ipl_t ipl = unlock->ipl;
+        unlock->guard = false;
+
+        spinlock_unlock(&(unlock->lock));
+        spinlock_lock(&(lock->lock));
+
+        ASSERT_IRQ_SPINLOCK(!lock->guard, lock);
+
+        if (guard) {
+                lock->guard = true;
+                lock->ipl = ipl;
+        }
+}
+
+/** Hand-over-hand locking of interrupts-disabled spinlocks
+ *
+ * Implement hand-over-hand locking between two interrupts-disabled
+ * spinlocks without enabling interrupts during the process.
+ *
+ * The first IRQ spinlock is supposed to be locked.
+ *
+ * @param unlock IRQ spinlock to be unlocked.
+ * @param lock   IRQ spinlock to be locked.
+ *
+ */
+void irq_spinlock_exchange(irq_spinlock_t *unlock, irq_spinlock_t *lock)
+{
+        ASSERT_IRQ_SPINLOCK(interrupts_disabled(), unlock);
+
+        spinlock_lock(&(lock->lock));
+        ASSERT_IRQ_SPINLOCK(!lock->guard, lock);
+
+        /* Pass guard from unlock to lock */
+        if (unlock->guard) {
+                lock->guard = true;
+                lock->ipl = unlock->ipl;
+                unlock->guard = false;
+        }
+
+        spinlock_unlock(&(unlock->lock));
+}
+
+/** Find out whether the IRQ spinlock is currently locked.
+ *
+ * @param lock          IRQ spinlock.
+ * @return              True if the IRQ spinlock is locked, false otherwise.
+ */
+bool irq_spinlock_locked(irq_spinlock_t *ilock)
+{
+        return spinlock_locked(&ilock->lock);
 }