13 files changed, 531 insertions, 31 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e2319f39988b..dd349c92f051 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -165,7 +165,10 @@ void cpu_idle(void)
                          */
                         local_irq_disable();
                         enter_idle();
+                        /* Don't trace irqs off for idle */
+                        stop_critical_timings();
                         idle();
+                        start_critical_timings();
                         /* In many cases the interrupt that ended idle
                            has already called exit_idle. But some idle
                            loops can be woken up without interrupt. */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 76f60f52a885..84aa2883fe15 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_SMP) := msr-on-cpu.o
 
 lib-y := delay_$(BITS).o
+lib-y += thunk_$(BITS).o
 lib-y += usercopy_$(BITS).o getuser_$(BITS).o putuser_$(BITS).o
 lib-y += memcpy_$(BITS).o
 
diff --git a/arch/x86/lib/thunk_32.S b/arch/x86/lib/thunk_32.S
new file mode 100644
index 000000000000..650b11e00ecc
--- /dev/null
+++ b/arch/x86/lib/thunk_32.S
@@ -0,0 +1,47 @@
+/*
+ * Trampoline to trace irqs off. (otherwise CALLER_ADDR1 might crash)
+ * Copyright 2008 by Steven Rostedt, Red Hat, Inc
+ *  (inspired by Andi Kleen's thunk_64.S)
+ * Subject to the GNU public license, v.2. No warranty of any kind.
+ */
+
+        #include <linux/linkage.h>
+
+#define ARCH_TRACE_IRQS_ON                      \
+        pushl %eax;                             \
+        pushl %ecx;                             \
+        pushl %edx;                             \
+        call trace_hardirqs_on;                 \
+        popl %edx;                              \
+        popl %ecx;                              \
+        popl %eax;
+
+#define ARCH_TRACE_IRQS_OFF                     \
+        pushl %eax;                             \
+        pushl %ecx;                             \
+        pushl %edx;                             \
+        call trace_hardirqs_off;                \
+        popl %edx;                              \
+        popl %ecx;                              \
+        popl %eax;
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+        /* put return address in eax (arg1) */
+        .macro thunk_ra name,func
+        .globl \name
+\name:
+        pushl %eax
+        pushl %ecx
+        pushl %edx
+        /* Place EIP in the arg1 */
+        movl 3*4(%esp), %eax
+        call \func
+        popl %edx
+        popl %ecx
+        popl %eax
+        ret
+        .endm
+
+        thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller
+        thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller
+#endif
diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S
index e009251d4e9f..bf9a7d5a5428 100644
--- a/arch/x86/lib/thunk_64.S
+++ b/arch/x86/lib/thunk_64.S
@@ -2,6 +2,7 @@
  * Save registers before calling assembly functions. This avoids
  * disturbance of register allocation in some inline assembly constructs.
  * Copyright 2001,2002 by Andi Kleen, SuSE Labs.
+ * Added trace_hardirqs callers - Copyright 2007 Steven Rostedt, Red Hat, Inc.
  * Subject to the GNU public license, v.2. No warranty of any kind.
  */
 
@@ -42,8 +43,22 @@
 #endif  
         
 #ifdef CONFIG_TRACE_IRQFLAGS
-        thunk trace_hardirqs_on_thunk,trace_hardirqs_on
-        thunk trace_hardirqs_off_thunk,trace_hardirqs_off
+        /* put return address in rdi (arg1) */
+        .macro thunk_ra name,func
+        .globl \name
+\name:
+        CFI_STARTPROC
+        SAVE_ARGS
+        /* SAVE_ARGS pushs 9 elements */
+        /* the next element would be the rip */
+        movq 9*8(%rsp), %rdi
+        call \func
+        jmp  restore
+        CFI_ENDPROC
+        .endm
+
+        thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller
+        thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller
 #endif
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/include/asm-x86/irqflags.h b/include/asm-x86/irqflags.h
index c242527f970e..24d71b1eb189 100644
--- a/include/asm-x86/irqflags.h
+++ b/include/asm-x86/irqflags.h
@@ -179,8 +179,6 @@ static inline void trace_hardirqs_fixup(void)
  * have a reliable stack. x86_64 only.
  */
 #define SWAPGS_UNSAFE_STACK     swapgs
-#define ARCH_TRACE_IRQS_ON              call trace_hardirqs_on_thunk
-#define ARCH_TRACE_IRQS_OFF             call trace_hardirqs_off_thunk
 #define ARCH_LOCKDEP_SYS_EXIT           call lockdep_sys_exit_thunk
 #define ARCH_LOCKDEP_SYS_EXIT_IRQ       \
         TRACE_IRQS_ON; \
@@ -192,24 +190,6 @@ static inline void trace_hardirqs_fixup(void)
         TRACE_IRQS_OFF;
 
 #else
-#define ARCH_TRACE_IRQS_ON                      \
-        pushl %eax;                             \
-        pushl %ecx;                             \
-        pushl %edx;                             \
-        call trace_hardirqs_on;                 \
-        popl %edx;                              \
-        popl %ecx;                              \
-        popl %eax;
-
-#define ARCH_TRACE_IRQS_OFF                     \
-        pushl %eax;                             \
-        pushl %ecx;                             \
-        pushl %edx;                             \
-        call trace_hardirqs_off;                \
-        popl %edx;                              \
-        popl %ecx;                              \
-        popl %eax;
-
 #define ARCH_LOCKDEP_SYS_EXIT                   \
         pushl %eax;                             \
         pushl %ecx;                             \
@@ -223,8 +203,8 @@ static inline void trace_hardirqs_fixup(void)
 #endif
 
 #ifdef CONFIG_TRACE_IRQFLAGS
-#  define TRACE_IRQS_ON         ARCH_TRACE_IRQS_ON
-#  define TRACE_IRQS_OFF        ARCH_TRACE_IRQS_OFF
+#  define TRACE_IRQS_ON         call trace_hardirqs_on_thunk;
+#  define TRACE_IRQS_OFF        call trace_hardirqs_off_thunk;
 #else
 #  define TRACE_IRQS_ON
 #  define TRACE_IRQS_OFF
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index db8a5e7abe41..0a20445dcbcc 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -50,4 +50,12 @@ extern void mcount(void);
 # define CALLER_ADDR5 0UL
 #endif
 
+#ifdef CONFIG_IRQSOFF_TRACER
+  extern void notrace time_hardirqs_on(unsigned long a0, unsigned long a1);
+  extern void notrace time_hardirqs_off(unsigned long a0, unsigned long a1);
+#else
+# define time_hardirqs_on(a0, a1)               do { } while (0)
+# define time_hardirqs_off(a0, a1)              do { } while (0)
+#endif
+
 #endif /* _LINUX_FTRACE_H */
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index e600c4e9b8c5..5b711d4e9fd9 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -12,10 +12,10 @@
 #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);
+  extern void trace_hardirqs_on(void);
+  extern void trace_hardirqs_off(void);
 # define trace_hardirq_context(p)       ((p)->hardirq_context)
 # define trace_softirq_context(p)       ((p)->softirq_context)
 # define trace_hardirqs_enabled(p)      ((p)->hardirqs_enabled)
@@ -41,6 +41,14 @@
 # define INIT_TRACE_IRQFLAGS
 #endif
 
+#ifdef CONFIG_IRQSOFF_TRACER
+ extern void stop_critical_timings(void);
+ extern void start_critical_timings(void);
+#else
+# define stop_critical_timings() do { } while (0)
+# define start_critical_timings() do { } while (0)
+#endif
+
 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
 
 #include <asm/irqflags.h>
diff --git a/kernel/fork.c b/kernel/fork.c
index 19908b26cf80..d66d676dc362 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -909,7 +909,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
         rt_mutex_init_task(p);
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_LOCKDEP)
         DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
         DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
 #endif
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 81a4e4a3f087..e21924365ea3 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -39,6 +39,7 @@
 #include <linux/irqflags.h>
 #include <linux/utsname.h>
 #include <linux/hash.h>
+#include <linux/ftrace.h>
 
 #include <asm/sections.h>
 
@@ -982,7 +983,7 @@ check_noncircular(struct lock_class *source, unsigned int depth)
         return 1;
 }
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
 /*
  * Forwards and backwards subgraph searching, for the purposes of
  * proving that two subgraphs can be connected by a new dependency
@@ -1680,7 +1681,7 @@ valid_state(struct task_struct *curr, struct held_lock *this,
 static int mark_lock(struct task_struct *curr, struct held_lock *this,
                      enum lock_usage_bit new_bit);
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
 
 /*
  * print irq inversion bug:
@@ -2013,11 +2014,13 @@ void early_boot_irqs_on(void)
 /*
  * Hardirqs will be enabled:
  */
-void trace_hardirqs_on(void)
+void notrace trace_hardirqs_on_caller(unsigned long a0)
 {
         struct task_struct *curr = current;
         unsigned long ip;
 
+        time_hardirqs_on(CALLER_ADDR0, a0);
+
         if (unlikely(!debug_locks || current->lockdep_recursion))
                 return;
 
@@ -2055,16 +2058,23 @@ void trace_hardirqs_on(void)
         curr->hardirq_enable_event = ++curr->irq_events;
         debug_atomic_inc(&hardirqs_on_events);
 }
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
 
+void notrace trace_hardirqs_on(void)
+{
+        trace_hardirqs_on_caller(CALLER_ADDR0);
+}
 EXPORT_SYMBOL(trace_hardirqs_on);
 
 /*
  * Hardirqs were disabled:
  */
-void trace_hardirqs_off(void)
+void notrace trace_hardirqs_off_caller(unsigned long a0)
 {
         struct task_struct *curr = current;
 
+        time_hardirqs_off(CALLER_ADDR0, a0);
+
         if (unlikely(!debug_locks || current->lockdep_recursion))
                 return;
 
@@ -2082,7 +2092,12 @@ void trace_hardirqs_off(void)
         } else
                 debug_atomic_inc(&redundant_hardirqs_off);
 }
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
 
+void notrace trace_hardirqs_off(void)
+{
+        trace_hardirqs_off_caller(CALLER_ADDR0);
+}
 EXPORT_SYMBOL(trace_hardirqs_off);
 
 /*
diff --git a/kernel/printk.c b/kernel/printk.c
index 8fb01c32aa3b..ae7d5b9e535d 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1041,7 +1041,9 @@ void release_console_sem(void)
                 _log_end = log_end;
                 con_start = log_end;            /* Flush */
                 spin_unlock(&logbuf_lock);
+                stop_critical_timings();        /* don't trace print latency */
                 call_console_drivers(_con_start, _log_end);
+                start_critical_timings();
                 local_irq_restore(flags);
         }
         console_locked = 0;
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 892ecc94a82b..896df1cf6adc 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -26,6 +26,24 @@ config FTRACE
           (the bootup default), then the overhead of the instructions is very
           small and not measurable even in micro-benchmarks.
 
+config IRQSOFF_TRACER
+        bool "Interrupts-off Latency Tracer"
+        default n
+        depends on TRACE_IRQFLAGS_SUPPORT
+        depends on GENERIC_TIME
+        select TRACE_IRQFLAGS
+        select TRACING
+        select TRACER_MAX_TRACE
+        help
+          This option measures the time spent in irqs-off critical
+          sections, with microsecond accuracy.
+
+          The default measurement method is a maximum search, which is
+          disabled by default and can be runtime (re-)started
+          via:
+
+              echo 0 > /debugfs/tracing/tracing_max_latency
+
 config SCHED_TRACER
         bool "Scheduling Latency Tracer"
         depends on DEBUG_KERNEL
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 5508cdb19aea..46be8647fb65 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_FTRACE) += libftrace.o
 obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_FTRACE) += trace_functions.o
+obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
 
 libftrace-y := ftrace.o
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
new file mode 100644
index 000000000000..a9131b0cf1a5
--- /dev/null
+++ b/kernel/trace/trace_irqsoff.c
@@ -0,0 +1,402 @@
+/*
+ * trace irqs off criticall timings
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * From code in the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 William Lee Irwin III
+ */
+#include <linux/kallsyms.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/fs.h>
+
+#include "trace.h"
+
+static struct trace_array               *irqsoff_trace __read_mostly;
+static int                              tracer_enabled __read_mostly;
+
+/*
+ * Sequence count - we record it when starting a measurement and
+ * skip the latency if the sequence has changed - some other section
+ * did a maximum and could disturb our measurement with serial console
+ * printouts, etc. Truly coinciding maximum latencies should be rare
+ * and what happens together happens separately as well, so this doesnt
+ * decrease the validity of the maximum found:
+ */
+static __cacheline_aligned_in_smp       unsigned long max_sequence;
+
+#ifdef CONFIG_FTRACE
+/*
+ * irqsoff uses its own tracer function to keep the overhead down:
+ */
+static void notrace
+irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
+{
+        struct trace_array *tr = irqsoff_trace;
+        struct trace_array_cpu *data;
+        unsigned long flags;
+        long disabled;
+        int cpu;
+
+        if (likely(!tracer_enabled))
+                return;
+
+        local_save_flags(flags);
+
+        if (!irqs_disabled_flags(flags))
+                return;
+
+        cpu = raw_smp_processor_id();
+        data = tr->data[cpu];
+        disabled = atomic_inc_return(&data->disabled);
+
+        if (likely(disabled == 1))
+                ftrace(tr, data, ip, parent_ip, flags);
+
+        atomic_dec(&data->disabled);
+}
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+        .func = irqsoff_tracer_call,
+};
+#endif /* CONFIG_FTRACE */
+
+/*
+ * Should this new latency be reported/recorded?
+ */
+static int notrace report_latency(cycle_t delta)
+{
+        if (tracing_thresh) {
+                if (delta < tracing_thresh)
+                        return 0;
+        } else {
+                if (delta <= tracing_max_latency)
+                        return 0;
+        }
+        return 1;
+}
+
+static void notrace
+check_critical_timing(struct trace_array *tr,
+                      struct trace_array_cpu *data,
+                      unsigned long parent_ip,
+                      int cpu)
+{
+        unsigned long latency, t0, t1;
+        cycle_t T0, T1, T2, delta;
+        unsigned long flags;
+
+        /*
+         * usecs conversion is slow so we try to delay the conversion
+         * as long as possible:
+         */
+        T0 = data->preempt_timestamp;
+        T1 = now(cpu);
+        delta = T1-T0;
+
+        local_save_flags(flags);
+
+        if (!report_latency(delta))
+                goto out;
+
+        ftrace(tr, data, CALLER_ADDR0, parent_ip, flags);
+        /*
+         * Update the timestamp, because the trace entry above
+         * might change it (it can only get larger so the latency
+         * is fair to be reported):
+         */
+        T2 = now(cpu);
+
+        delta = T2-T0;
+
+        latency = nsecs_to_usecs(delta);
+
+        if (data->critical_sequence != max_sequence)
+                goto out;
+
+        tracing_max_latency = delta;
+        t0 = nsecs_to_usecs(T0);
+        t1 = nsecs_to_usecs(T1);
+
+        data->critical_end = parent_ip;
+
+        update_max_tr_single(tr, current, cpu);
+
+        if (tracing_thresh)
+                printk(KERN_INFO "(%16s-%-5d|#%d): %lu us critical section "
+                       "violates %lu us threshold.\n"
+                       " => started at timestamp %lu: ",
+                                current->comm, current->pid,
+                                raw_smp_processor_id(),
+                                latency, nsecs_to_usecs(tracing_thresh), t0);
+        else
+                printk(KERN_INFO "(%16s-%-5d|#%d):"
+                       " new %lu us maximum-latency "
+                       "critical section.\n => started at timestamp %lu: ",
+                                current->comm, current->pid,
+                                raw_smp_processor_id(),
+                                latency, t0);
+
+        print_symbol(KERN_CONT "<%s>\n", data->critical_start);
+        printk(KERN_CONT " =>   ended at timestamp %lu: ", t1);
+        print_symbol(KERN_CONT "<%s>\n", data->critical_end);
+        dump_stack();
+        t1 = nsecs_to_usecs(now(cpu));
+        printk(KERN_CONT " =>   dump-end timestamp %lu\n\n", t1);
+
+        max_sequence++;
+
+out:
+        data->critical_sequence = max_sequence;
+        data->preempt_timestamp = now(cpu);
+        tracing_reset(data);
+        ftrace(tr, data, CALLER_ADDR0, parent_ip, flags);
+}
+
+static inline void notrace
+start_critical_timing(unsigned long ip, unsigned long parent_ip)
+{
+        int cpu;
+        struct trace_array *tr = irqsoff_trace;
+        struct trace_array_cpu *data;
+        unsigned long flags;
+
+        if (likely(!tracer_enabled))
+                return;
+
+        cpu = raw_smp_processor_id();
+        data = tr->data[cpu];
+
+        if (unlikely(!data) || unlikely(!data->trace) ||
+            data->critical_start || atomic_read(&data->disabled))
+                return;
+
+        atomic_inc(&data->disabled);
+
+        data->critical_sequence = max_sequence;
+        data->preempt_timestamp = now(cpu);
+        data->critical_start = parent_ip;
+        tracing_reset(data);
+
+        local_save_flags(flags);
+        ftrace(tr, data, ip, parent_ip, flags);
+
+        atomic_dec(&data->disabled);
+}
+
+static inline void notrace
+stop_critical_timing(unsigned long ip, unsigned long parent_ip)
+{
+        int cpu;
+        struct trace_array *tr = irqsoff_trace;
+        struct trace_array_cpu *data;
+        unsigned long flags;
+
+        if (likely(!tracer_enabled))
+                return;
+
+        cpu = raw_smp_processor_id();
+        data = tr->data[cpu];
+
+        if (unlikely(!data) || unlikely(!data->trace) ||
+            !data->critical_start || atomic_read(&data->disabled))
+                return;
+
+        atomic_inc(&data->disabled);
+        local_save_flags(flags);
+        ftrace(tr, data, ip, parent_ip, flags);
+        check_critical_timing(tr, data, parent_ip, cpu);
+        data->critical_start = 0;
+        atomic_dec(&data->disabled);
+}
+
+void notrace start_critical_timings(void)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+
+void notrace stop_critical_timings(void)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+void notrace time_hardirqs_on(unsigned long a0, unsigned long a1)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                stop_critical_timing(a0, a1);
+}
+
+void notrace time_hardirqs_off(unsigned long a0, unsigned long a1)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                start_critical_timing(a0, a1);
+}
+
+#else /* !CONFIG_PROVE_LOCKING */
+
+/*
+ * Stubs:
+ */
+
+void early_boot_irqs_off(void)
+{
+}
+
+void early_boot_irqs_on(void)
+{
+}
+
+void trace_softirqs_on(unsigned long ip)
+{
+}
+
+void trace_softirqs_off(unsigned long ip)
+{
+}
+
+inline void print_irqtrace_events(struct task_struct *curr)
+{
+}
+
+/*
+ * We are only interested in hardirq on/off events:
+ */
+void notrace trace_hardirqs_on(void)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+void notrace trace_hardirqs_off(void)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+void notrace trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                stop_critical_timing(CALLER_ADDR0, caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+void notrace trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+        unsigned long flags;
+
+        local_save_flags(flags);
+
+        if (irqs_disabled_flags(flags))
+                start_critical_timing(CALLER_ADDR0, caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+
+#endif /* CONFIG_PROVE_LOCKING */
+
+static void start_irqsoff_tracer(struct trace_array *tr)
+{
+        tracer_enabled = 1;
+        register_ftrace_function(&trace_ops);
+}
+
+static void stop_irqsoff_tracer(struct trace_array *tr)
+{
+        unregister_ftrace_function(&trace_ops);
+        tracer_enabled = 0;
+}
+
+static void irqsoff_tracer_init(struct trace_array *tr)
+{
+        irqsoff_trace = tr;
+        /* make sure that the tracer is visibel */
+        smp_wmb();
+
+        if (tr->ctrl)
+                start_irqsoff_tracer(tr);
+}
+
+static void irqsoff_tracer_reset(struct trace_array *tr)
+{
+        if (tr->ctrl)
+                stop_irqsoff_tracer(tr);
+}
+
+static void irqsoff_tracer_ctrl_update(struct trace_array *tr)
+{
+        if (tr->ctrl)
+                start_irqsoff_tracer(tr);
+        else
+                stop_irqsoff_tracer(tr);
+}
+
+static void notrace irqsoff_tracer_open(struct trace_iterator *iter)
+{
+        /* stop the trace while dumping */
+        if (iter->tr->ctrl)
+                stop_irqsoff_tracer(iter->tr);
+}
+
+static void notrace irqsoff_tracer_close(struct trace_iterator *iter)
+{
+        if (iter->tr->ctrl)
+                start_irqsoff_tracer(iter->tr);
+}
+
+static struct tracer irqsoff_tracer __read_mostly =
+{
+        .name           = "irqsoff",
+        .init           = irqsoff_tracer_init,
+        .reset          = irqsoff_tracer_reset,
+        .open           = irqsoff_tracer_open,
+        .close          = irqsoff_tracer_close,
+        .ctrl_update    = irqsoff_tracer_ctrl_update,
+        .print_max      = 1,
+};
+
+__init static int init_irqsoff_tracer(void)
+{
+        register_tracer(&irqsoff_tracer);
+
+        return 0;
+}
+device_initcall(init_irqsoff_tracer);