Merge branch 'linus' into stackprotector

Conflicts:
	arch/x86/include/asm/pda.h
	kernel/fork.c

1 files changed, 103 insertions, 149 deletions

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index cb817a209aa0..df175cb4564f 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -9,25 +9,27 @@
 #include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
-#include <linux/marker.h>
 #include <linux/ftrace.h>
+#include <trace/sched.h>
 
 #include "trace.h"
 
 static struct trace_array       *ctx_trace;
 static int __read_mostly        tracer_enabled;
-static atomic_t                 sched_ref;
+static int                      sched_ref;
+static DEFINE_MUTEX(sched_register_mutex);
 
 static void
-sched_switch_func(void *private, void *__rq, struct task_struct *prev,
+probe_sched_switch(struct rq *__rq, struct task_struct *prev,
                         struct task_struct *next)
 {
-        struct trace_array **ptr = private;
-        struct trace_array *tr = *ptr;
         struct trace_array_cpu *data;
         unsigned long flags;
-        long disabled;
         int cpu;
+        int pc;
+
+        if (!sched_ref)
+                return;
 
         tracing_record_cmdline(prev);
         tracing_record_cmdline(next);
@@ -35,183 +37,95 @@ sched_switch_func(void *private, void *__rq, struct task_struct *prev,
         if (!tracer_enabled)
                 return;
 
+        pc = preempt_count();
         local_irq_save(flags);
         cpu = raw_smp_processor_id();
-        data = tr->data[cpu];
-        disabled = atomic_inc_return(&data->disabled);
+        data = ctx_trace->data[cpu];
 
-        if (likely(disabled == 1))
-                tracing_sched_switch_trace(tr, data, prev, next, flags);
+        if (likely(!atomic_read(&data->disabled)))
+                tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
 
-        atomic_dec(&data->disabled);
         local_irq_restore(flags);
 }
 
-static notrace void
-sched_switch_callback(void *probe_data, void *call_data,
-                      const char *format, va_list *args)
-{
-        struct task_struct *prev;
-        struct task_struct *next;
-        struct rq *__rq;
-
-        if (!atomic_read(&sched_ref))
-                return;
-
-        /* skip prev_pid %d next_pid %d prev_state %ld */
-        (void)va_arg(*args, int);
-        (void)va_arg(*args, int);
-        (void)va_arg(*args, long);
-        __rq = va_arg(*args, typeof(__rq));
-        prev = va_arg(*args, typeof(prev));
-        next = va_arg(*args, typeof(next));
-
-        /*
-         * If tracer_switch_func only points to the local
-         * switch func, it still needs the ptr passed to it.
-         */
-        sched_switch_func(probe_data, __rq, prev, next);
-}
-
 static void
-wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct
-                        task_struct *curr)
+probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 {
-        struct trace_array **ptr = private;
-        struct trace_array *tr = *ptr;
         struct trace_array_cpu *data;
         unsigned long flags;
-        long disabled;
-        int cpu;
+        int cpu, pc;
 
-        if (!tracer_enabled)
+        if (!likely(tracer_enabled))
                 return;
 
-        tracing_record_cmdline(curr);
+        pc = preempt_count();
+        tracing_record_cmdline(current);
 
         local_irq_save(flags);
         cpu = raw_smp_processor_id();
-        data = tr->data[cpu];
-        disabled = atomic_inc_return(&data->disabled);
+        data = ctx_trace->data[cpu];
 
-        if (likely(disabled == 1))
-                tracing_sched_wakeup_trace(tr, data, wakee, curr, flags);
+        if (likely(!atomic_read(&data->disabled)))
+                tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
+                                           flags, pc);
 
-        atomic_dec(&data->disabled);
         local_irq_restore(flags);
 }
 
-static notrace void
-wake_up_callback(void *probe_data, void *call_data,
-                 const char *format, va_list *args)
-{
-        struct task_struct *curr;
-        struct task_struct *task;
-        struct rq *__rq;
-
-        if (likely(!tracer_enabled))
-                return;
-
-        /* Skip pid %d state %ld */
-        (void)va_arg(*args, int);
-        (void)va_arg(*args, long);
-        /* now get the meat: "rq %p task %p rq->curr %p" */
-        __rq = va_arg(*args, typeof(__rq));
-        task = va_arg(*args, typeof(task));
-        curr = va_arg(*args, typeof(curr));
-
-        tracing_record_cmdline(task);
-        tracing_record_cmdline(curr);
-
-        wakeup_func(probe_data, __rq, task, curr);
-}
-
-static void sched_switch_reset(struct trace_array *tr)
-{
-        int cpu;
-
-        tr->time_start = ftrace_now(tr->cpu);
-
-        for_each_online_cpu(cpu)
-                tracing_reset(tr->data[cpu]);
-}
-
 static int tracing_sched_register(void)
 {
         int ret;
 
-        ret = marker_probe_register("kernel_sched_wakeup",
-                        "pid %d state %ld ## rq %p task %p rq->curr %p",
-                        wake_up_callback,
-                        &ctx_trace);
+        ret = register_trace_sched_wakeup(probe_sched_wakeup);
         if (ret) {
-                pr_info("wakeup trace: Couldn't add marker"
+                pr_info("wakeup trace: Couldn't activate tracepoint"
                         " probe to kernel_sched_wakeup\n");
                 return ret;
         }
 
-        ret = marker_probe_register("kernel_sched_wakeup_new",
-                        "pid %d state %ld ## rq %p task %p rq->curr %p",
-                        wake_up_callback,
-                        &ctx_trace);
+        ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
         if (ret) {
-                pr_info("wakeup trace: Couldn't add marker"
+                pr_info("wakeup trace: Couldn't activate tracepoint"
                         " probe to kernel_sched_wakeup_new\n");
                 goto fail_deprobe;
         }
 
-        ret = marker_probe_register("kernel_sched_schedule",
-                "prev_pid %d next_pid %d prev_state %ld "
-                "## rq %p prev %p next %p",
-                sched_switch_callback,
-                &ctx_trace);
+        ret = register_trace_sched_switch(probe_sched_switch);
         if (ret) {
-                pr_info("sched trace: Couldn't add marker"
+                pr_info("sched trace: Couldn't activate tracepoint"
                         " probe to kernel_sched_schedule\n");
                 goto fail_deprobe_wake_new;
         }
 
         return ret;
 fail_deprobe_wake_new:
-        marker_probe_unregister("kernel_sched_wakeup_new",
-                                wake_up_callback,
-                                &ctx_trace);
+        unregister_trace_sched_wakeup_new(probe_sched_wakeup);
 fail_deprobe:
-        marker_probe_unregister("kernel_sched_wakeup",
-                                wake_up_callback,
-                                &ctx_trace);
+        unregister_trace_sched_wakeup(probe_sched_wakeup);
         return ret;
 }
 
 static void tracing_sched_unregister(void)
 {
-        marker_probe_unregister("kernel_sched_schedule",
-                                sched_switch_callback,
-                                &ctx_trace);
-        marker_probe_unregister("kernel_sched_wakeup_new",
-                                wake_up_callback,
-                                &ctx_trace);
-        marker_probe_unregister("kernel_sched_wakeup",
-                                wake_up_callback,
-                                &ctx_trace);
+        unregister_trace_sched_switch(probe_sched_switch);
+        unregister_trace_sched_wakeup_new(probe_sched_wakeup);
+        unregister_trace_sched_wakeup(probe_sched_wakeup);
 }
 
 static void tracing_start_sched_switch(void)
 {
-        long ref;
-
-        ref = atomic_inc_return(&sched_ref);
-        if (ref == 1)
+        mutex_lock(&sched_register_mutex);
+        if (!(sched_ref++))
                 tracing_sched_register();
+        mutex_unlock(&sched_register_mutex);
 }
 
 static void tracing_stop_sched_switch(void)
 {
-        long ref;
-
-        ref = atomic_dec_and_test(&sched_ref);
-        if (ref)
+        mutex_lock(&sched_register_mutex);
+        if (!(--sched_ref))
                 tracing_sched_unregister();
+        mutex_unlock(&sched_register_mutex);
 }
 
 void tracing_start_cmdline_record(void)
@@ -224,40 +138,86 @@ void tracing_stop_cmdline_record(void)
         tracing_stop_sched_switch();
 }
 
+/**
+ * tracing_start_sched_switch_record - start tracing context switches
+ *
+ * Turns on context switch tracing for a tracer.
+ */
+void tracing_start_sched_switch_record(void)
+{
+        if (unlikely(!ctx_trace)) {
+                WARN_ON(1);
+                return;
+        }
+
+        tracing_start_sched_switch();
+
+        mutex_lock(&sched_register_mutex);
+        tracer_enabled++;
+        mutex_unlock(&sched_register_mutex);
+}
+
+/**
+ * tracing_stop_sched_switch_record - start tracing context switches
+ *
+ * Turns off context switch tracing for a tracer.
+ */
+void tracing_stop_sched_switch_record(void)
+{
+        mutex_lock(&sched_register_mutex);
+        tracer_enabled--;
+        WARN_ON(tracer_enabled < 0);
+        mutex_unlock(&sched_register_mutex);
+
+        tracing_stop_sched_switch();
+}
+
+/**
+ * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
+ * @tr: trace array pointer to assign
+ *
+ * Some tracers might want to record the context switches in their
+ * trace. This function lets those tracers assign the trace array
+ * to use.
+ */
+void tracing_sched_switch_assign_trace(struct trace_array *tr)
+{
+        ctx_trace = tr;
+}
+
 static void start_sched_trace(struct trace_array *tr)
 {
-        sched_switch_reset(tr);
-        tracing_start_cmdline_record();
-        tracer_enabled = 1;
+        tracing_reset_online_cpus(tr);
+        tracing_start_sched_switch_record();
 }
 
 static void stop_sched_trace(struct trace_array *tr)
 {
-        tracer_enabled = 0;
-        tracing_stop_cmdline_record();
+        tracing_stop_sched_switch_record();
 }
 
-static void sched_switch_trace_init(struct trace_array *tr)
+static int sched_switch_trace_init(struct trace_array *tr)
 {
         ctx_trace = tr;
-
-        if (tr->ctrl)
-                start_sched_trace(tr);
+        start_sched_trace(tr);
+        return 0;
 }
 
 static void sched_switch_trace_reset(struct trace_array *tr)
 {
-        if (tr->ctrl)
+        if (sched_ref)
                 stop_sched_trace(tr);
 }
 
-static void sched_switch_trace_ctrl_update(struct trace_array *tr)
+static void sched_switch_trace_start(struct trace_array *tr)
 {
-        /* When starting a new trace, reset the buffers */
-        if (tr->ctrl)
-                start_sched_trace(tr);
-        else
-                stop_sched_trace(tr);
+        tracing_reset_online_cpus(tr);
+        tracing_start_sched_switch();
+}
+
+static void sched_switch_trace_stop(struct trace_array *tr)
+{
+        tracing_stop_sched_switch();
 }
 
 static struct tracer sched_switch_trace __read_mostly =
@@ -265,7 +225,8 @@ static struct tracer sched_switch_trace __read_mostly =
         .name           = "sched_switch",
         .init           = sched_switch_trace_init,
         .reset          = sched_switch_trace_reset,
-        .ctrl_update    = sched_switch_trace_ctrl_update,
+        .start          = sched_switch_trace_start,
+        .stop           = sched_switch_trace_stop,
 #ifdef CONFIG_FTRACE_SELFTEST
         .selftest    = trace_selftest_startup_sched_switch,
 #endif
@@ -273,14 +234,7 @@ static struct tracer sched_switch_trace __read_mostly =
 
 __init static int init_sched_switch_trace(void)
 {
-        int ret = 0;
-
-        if (atomic_read(&sched_ref))
-                ret = tracing_sched_register();
-        if (ret) {
-                pr_info("error registering scheduler trace\n");
-                return ret;
-        }
         return register_tracer(&sched_switch_trace);
 }
 device_initcall(init_sched_switch_trace);
+