[PATCH] lockdep: irqtrace subsystem, core
Accurate hard-IRQ-flags and softirq-flags state tracing.
This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 8f03e3b..584609b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -62,6 +62,119 @@
}
/*
+ * This one is for softirq.c-internal use,
+ * where hardirqs are disabled legitimately:
+ */
+static void __local_bh_disable(unsigned long ip)
+{
+ unsigned long flags;
+
+ WARN_ON_ONCE(in_irq());
+
+ raw_local_irq_save(flags);
+ add_preempt_count(SOFTIRQ_OFFSET);
+ /*
+ * Were softirqs turned off above:
+ */
+ if (softirq_count() == SOFTIRQ_OFFSET)
+ trace_softirqs_off(ip);
+ raw_local_irq_restore(flags);
+}
+
+void local_bh_disable(void)
+{
+ __local_bh_disable((unsigned long)__builtin_return_address(0));
+}
+
+EXPORT_SYMBOL(local_bh_disable);
+
+void __local_bh_enable(void)
+{
+ WARN_ON_ONCE(in_irq());
+
+ /*
+ * softirqs should never be enabled by __local_bh_enable(),
+ * it always nests inside local_bh_enable() sections:
+ */
+ WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET);
+
+ sub_preempt_count(SOFTIRQ_OFFSET);
+}
+EXPORT_SYMBOL_GPL(__local_bh_enable);
+
+/*
+ * Special-case - softirqs can safely be enabled in
+ * cond_resched_softirq(), or by __do_softirq(),
+ * without processing still-pending softirqs:
+ */
+void _local_bh_enable(void)
+{
+ WARN_ON_ONCE(in_irq());
+ WARN_ON_ONCE(!irqs_disabled());
+
+ if (softirq_count() == SOFTIRQ_OFFSET)
+ trace_softirqs_on((unsigned long)__builtin_return_address(0));
+ sub_preempt_count(SOFTIRQ_OFFSET);
+}
+
+EXPORT_SYMBOL(_local_bh_enable);
+
+void local_bh_enable(void)
+{
+ unsigned long flags;
+
+ WARN_ON_ONCE(in_irq());
+ WARN_ON_ONCE(irqs_disabled());
+
+ local_irq_save(flags);
+ /*
+ * Are softirqs going to be turned on now:
+ */
+ if (softirq_count() == SOFTIRQ_OFFSET)
+ trace_softirqs_on((unsigned long)__builtin_return_address(0));
+ /*
+ * Keep preemption disabled until we are done with
+ * softirq processing:
+ */
+ sub_preempt_count(SOFTIRQ_OFFSET - 1);
+
+ if (unlikely(!in_interrupt() && local_softirq_pending()))
+ do_softirq();
+
+ dec_preempt_count();
+ local_irq_restore(flags);
+ preempt_check_resched();
+}
+EXPORT_SYMBOL(local_bh_enable);
+
+void local_bh_enable_ip(unsigned long ip)
+{
+ unsigned long flags;
+
+ WARN_ON_ONCE(in_irq());
+
+ local_irq_save(flags);
+ /*
+ * Are softirqs going to be turned on now:
+ */
+ if (softirq_count() == SOFTIRQ_OFFSET)
+ trace_softirqs_on(ip);
+ /*
+ * Keep preemption disabled until we are done with
+ * softirq processing:
+ */
+ sub_preempt_count(SOFTIRQ_OFFSET - 1);
+
+ if (unlikely(!in_interrupt() && local_softirq_pending()))
+ do_softirq();
+
+ dec_preempt_count();
+ local_irq_restore(flags);
+ preempt_check_resched();
+}
+EXPORT_SYMBOL(local_bh_enable_ip);
+
+/*
* We restart softirq processing MAX_SOFTIRQ_RESTART times,
* and we fall back to softirqd after that.
*
@@ -80,8 +193,9 @@
int cpu;
pending = local_softirq_pending();
+ __local_bh_disable((unsigned long)__builtin_return_address(0));
+ trace_softirq_enter();
- local_bh_disable();
cpu = smp_processor_id();
restart:
/* Reset the pending bitmask before enabling irqs */
@@ -109,7 +223,8 @@
if (pending)
wakeup_softirqd();
- __local_bh_enable();
+ trace_softirq_exit();
+ _local_bh_enable();
}
#ifndef __ARCH_HAS_DO_SOFTIRQ
@@ -136,23 +251,6 @@
#endif
-void local_bh_enable(void)
-{
- WARN_ON(irqs_disabled());
- /*
- * Keep preemption disabled until we are done with
- * softirq processing:
- */
- sub_preempt_count(SOFTIRQ_OFFSET - 1);
-
- if (unlikely(!in_interrupt() && local_softirq_pending()))
- do_softirq();
-
- dec_preempt_count();
- preempt_check_resched();
-}
-EXPORT_SYMBOL(local_bh_enable);
-
#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
# define invoke_softirq() __do_softirq()
#else
@@ -165,6 +263,7 @@
void irq_exit(void)
{
account_system_vtime(current);
+ trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();