#include <linux/list.h>
/*
- * We use the MSB mostly because its available; see <linux/preempt_mask.h> for
- * the other bits -- can't include that header due to inclusion hell.
+ * We put the hardirq and softirq counter into the preemption
+ * counter. The bitmask has the following meaning:
+ *
+ * - bits 0-7 are the preemption count (max preemption depth: 256)
+ * - bits 8-15 are the softirq count (max # of softirqs: 256)
+ *
+ * The hardirq count could in theory be the same as the number of
+ * interrupts in the system, but we run all interrupt handlers with
+ * interrupts disabled, so we cannot have nesting interrupts. Though
+ * there are a few palaeontologic drivers which reenable interrupts in
+ * the handler, so we need more than one bit here.
+ *
+ * PREEMPT_MASK: 0x000000ff
+ * SOFTIRQ_MASK: 0x0000ff00
+ * HARDIRQ_MASK: 0x000f0000
+ * NMI_MASK: 0x00100000
+ * PREEMPT_NEED_RESCHED: 0x80000000
*/
+#define PREEMPT_BITS 8
+#define SOFTIRQ_BITS 8
+#define HARDIRQ_BITS 4
+#define NMI_BITS 1
+
+#define PREEMPT_SHIFT 0
+#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
+#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
+
+#define __IRQ_MASK(x) ((1UL << (x))-1)
+
+#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
+#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
+#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
+#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
+
+#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
+#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
+#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
+#define NMI_OFFSET (1UL << NMI_SHIFT)
+
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
+#else
+# define SOFTIRQ_DISABLE_OFFSET (0)
+#endif
+
+/* We use the MSB mostly because its available */
#define PREEMPT_NEED_RESCHED 0x80000000
+/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
#include <asm/preempt.h>
+#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
+#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
+ | NMI_MASK))
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define softirq_count() (preempt_count() & SOFTIRQ_MASK)
+# define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
+#else
+# define softirq_count() (0UL)
+extern int in_serving_softirq(void);
+#endif
+
+/*
+ * Are we doing bottom half or hardware interrupt processing?
+ * Are we in a softirq context? Interrupt context?
+ * in_softirq - Are we currently processing softirq or have bh disabled?
+ * in_serving_softirq - Are we currently processing softirq?
+ */
+#define in_irq() (hardirq_count())
+#define in_softirq() (softirq_count())
+#define in_interrupt() (irq_count())
+
+/*
+ * Are we in NMI context?
+ */
+#define in_nmi() (preempt_count() & NMI_MASK)
+
+/*
+ * The preempt_count offset after preempt_disable();
+ */
+#if defined(CONFIG_PREEMPT_COUNT)
+# define PREEMPT_DISABLE_OFFSET PREEMPT_OFFSET
+#else
+# define PREEMPT_DISABLE_OFFSET 0
+#endif
+
+/*
+ * The preempt_count offset after spin_lock()
+ */
+#if !defined(CONFIG_PREEMPT_RT_FULL)
+#define PREEMPT_LOCK_OFFSET PREEMPT_DISABLE_OFFSET
+#else
+#define PREEMPT_LOCK_OFFSET 0
+#endif
+
+/*
+ * The preempt_count offset needed for things like:
+ *
+ * spin_lock_bh()
+ *
+ * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and
+ * softirqs, such that unlock sequences of:
+ *
+ * spin_unlock();
+ * local_bh_enable();
+ *
+ * Work as expected.
+ */
+#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_LOCK_OFFSET)
+
+/*
+ * Are we running in atomic context? WARNING: this macro cannot
+ * always detect atomic context; in particular, it cannot know about
+ * held spinlocks in non-preemptible kernels. Thus it should not be
+ * used in the general case to determine whether sleeping is possible.
+ * Do not use in_atomic() in driver code.
+ */
+#define in_atomic() (preempt_count() != 0)
+
+/*
+ * Check whether we were atomic before we did preempt_disable():
+ * (used by the scheduler)
+ */
+#define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
+
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
extern void preempt_count_add(int val);
extern void preempt_count_sub(int val);
-#define preempt_count_dec_and_test() ({ preempt_count_sub(1); should_resched(); })
+#define preempt_count_dec_and_test() \
+ ({ preempt_count_sub(1); should_resched(0); })
#else
#define preempt_count_add(val) __preempt_count_add(val)
#define preempt_count_sub(val) __preempt_count_sub(val)
# define preempt_check_resched_rt() barrier();
#endif
+#define preemptible() (preempt_count() == 0 && !irqs_disabled())
+
#ifdef CONFIG_PREEMPT
#define preempt_enable() \
do { \
__preempt_schedule(); \
} while (0)
+#define preempt_enable_notrace() \
+do { \
+ barrier(); \
+ if (unlikely(__preempt_count_dec_and_test())) \
+ __preempt_schedule_notrace(); \
+} while (0)
+
#define preempt_check_resched() \
do { \
- if (should_resched()) \
+ if (should_resched(0)) \
__preempt_schedule(); \
} while (0)
preempt_check_resched(); \
} while (0)
-#else
+#else /* !CONFIG_PREEMPT */
#define preempt_enable() \
do { \
barrier(); \
preempt_count_dec(); \
} while (0)
-#define preempt_check_resched() do { } while (0)
-#endif
-
-#define preempt_disable_notrace() \
-do { \
- __preempt_count_inc(); \
- barrier(); \
-} while (0)
-#define preempt_enable_no_resched_notrace() \
+#define preempt_enable_notrace() \
do { \
barrier(); \
__preempt_count_dec(); \
} while (0)
-#ifdef CONFIG_PREEMPT
-
-#ifndef CONFIG_CONTEXT_TRACKING
-#define __preempt_schedule_context() __preempt_schedule()
-#endif
+#define preempt_check_resched() do { } while (0)
+#endif /* CONFIG_PREEMPT */
-#define preempt_enable_notrace() \
+#define preempt_disable_notrace() \
do { \
+ __preempt_count_inc(); \
barrier(); \
- if (unlikely(__preempt_count_dec_and_test())) \
- __preempt_schedule_context(); \
} while (0)
-#else
-#define preempt_enable_notrace() \
+
+#define preempt_enable_no_resched_notrace() \
do { \
barrier(); \
__preempt_count_dec(); \
} while (0)
-#endif
#else /* !CONFIG_PREEMPT_COUNT */
#define preempt_enable_no_resched_notrace() barrier()
#define preempt_enable_notrace() barrier()
#define preempt_check_resched_rt() barrier()
+#define preemptible() 0
#endif /* CONFIG_PREEMPT_COUNT */
struct preempt_ops *ops;
};
+void preempt_notifier_inc(void);
+void preempt_notifier_dec(void);
void preempt_notifier_register(struct preempt_notifier *notifier);
void preempt_notifier_unregister(struct preempt_notifier *notifier);
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