[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>

1 files changed, 96 insertions, 0 deletions

diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
new file mode 100644
index 00000000000..412e025bc5c
--- /dev/null
+++ b/include/linux/irqflags.h
@@ -0,0 +1,96 @@
+/*
+ * include/linux/irqflags.h
+ *
+ * IRQ flags tracing: follow the state of the hardirq and softirq flags and
+ * provide callbacks for transitions between ON and OFF states.
+ *
+ * This file gets included from lowlevel asm headers too, to provide
+ * wrapped versions of the local_irq_*() APIs, based on the
+ * raw_local_irq_*() macros from the lowlevel headers.
+ */
+#ifndef _LINUX_TRACE_IRQFLAGS_H
+#define _LINUX_TRACE_IRQFLAGS_H
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+  extern void trace_hardirqs_on(void);
+  extern void trace_hardirqs_off(void);
+  extern void trace_softirqs_on(unsigned long ip);
+  extern void trace_softirqs_off(unsigned long ip);
+# define trace_hardirq_context(p)	((p)->hardirq_context)
+# define trace_softirq_context(p)	((p)->softirq_context)
+# define trace_hardirqs_enabled(p)	((p)->hardirqs_enabled)
+# define trace_softirqs_enabled(p)	((p)->softirqs_enabled)
+# define trace_hardirq_enter()	do { current->hardirq_context++; } while (0)
+# define trace_hardirq_exit()	do { current->hardirq_context--; } while (0)
+# define trace_softirq_enter()	do { current->softirq_context++; } while (0)
+# define trace_softirq_exit()	do { current->softirq_context--; } while (0)
+# define INIT_TRACE_IRQFLAGS	.softirqs_enabled = 1,
+#else
+# define trace_hardirqs_on()		do { } while (0)
+# define trace_hardirqs_off()		do { } while (0)
+# define trace_softirqs_on(ip)		do { } while (0)
+# define trace_softirqs_off(ip)		do { } while (0)
+# define trace_hardirq_context(p)	0
+# define trace_softirq_context(p)	0
+# define trace_hardirqs_enabled(p)	0
+# define trace_softirqs_enabled(p)	0
+# define trace_hardirq_enter()		do { } while (0)
+# define trace_hardirq_exit()		do { } while (0)
+# define trace_softirq_enter()		do { } while (0)
+# define trace_softirq_exit()		do { } while (0)
+# define INIT_TRACE_IRQFLAGS
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+
+#include <asm/irqflags.h>
+
+#define local_irq_enable() \
+	do { trace_hardirqs_on(); raw_local_irq_enable(); } while (0)
+#define local_irq_disable() \
+	do { raw_local_irq_disable(); trace_hardirqs_off(); } while (0)
+#define local_irq_save(flags) \
+	do { raw_local_irq_save(flags); trace_hardirqs_off(); } while (0)
+
+#define local_irq_restore(flags)				\
+	do {							\
+		if (raw_irqs_disabled_flags(flags)) {		\
+			raw_local_irq_restore(flags);		\
+			trace_hardirqs_off();			\
+		} else {					\
+			trace_hardirqs_on();			\
+			raw_local_irq_restore(flags);		\
+		}						\
+	} while (0)
+#else /* !CONFIG_TRACE_IRQFLAGS_SUPPORT */
+/*
+ * The local_irq_*() APIs are equal to the raw_local_irq*()
+ * if !TRACE_IRQFLAGS.
+ */
+# define raw_local_irq_disable()	local_irq_disable()
+# define raw_local_irq_enable()		local_irq_enable()
+# define raw_local_irq_save(flags)	local_irq_save(flags)
+# define raw_local_irq_restore(flags)	local_irq_restore(flags)
+#endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */
+
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+#define safe_halt()						\
+	do {							\
+		trace_hardirqs_on();				\
+		raw_safe_halt();				\
+	} while (0)
+
+#define local_save_flags(flags)		raw_local_save_flags(flags)
+
+#define irqs_disabled()						\
+({								\
+	unsigned long flags;					\
+								\
+	raw_local_save_flags(flags);				\
+	raw_irqs_disabled_flags(flags);				\
+})
+
+#define irqs_disabled_flags(flags)	raw_irqs_disabled_flags(flags)
+#endif		/* CONFIG_X86 */
+
+#endif