1 files changed, 365 insertions, 0 deletions

diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
new file mode 100644
index 000000000000..63528086337c
--- /dev/null
+++ b/kernel/trace/trace_sysprof.c
@@ -0,0 +1,365 @@
+/*
+ * trace stack traces
+ *
+ * Copyright (C) 2004-2008, Soeren Sandmann
+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/kallsyms.h>
+#include <linux/debugfs.h>
+#include <linux/hrtimer.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/irq.h>
+#include <linux/fs.h>
+
+#include <asm/stacktrace.h>
+
+#include "trace.h"
+
+static struct trace_array       *sysprof_trace;
+static int __read_mostly        tracer_enabled;
+
+/*
+ * 1 msec sample interval by default:
+ */
+static unsigned long sample_period = 1000000;
+static const unsigned int sample_max_depth = 512;
+
+static DEFINE_MUTEX(sample_timer_lock);
+/*
+ * Per CPU hrtimers that do the profiling:
+ */
+static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
+
+struct stack_frame {
+        const void __user       *next_fp;
+        unsigned long           return_address;
+};
+
+static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
+{
+        int ret;
+
+        if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+                return 0;
+
+        ret = 1;
+        pagefault_disable();
+        if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+                ret = 0;
+        pagefault_enable();
+
+        return ret;
+}
+
+struct backtrace_info {
+        struct trace_array_cpu  *data;
+        struct trace_array      *tr;
+        int                     pos;
+};
+
+static void
+backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+        /* Ignore warnings */
+}
+
+static void backtrace_warning(void *data, char *msg)
+{
+        /* Ignore warnings */
+}
+
+static int backtrace_stack(void *data, char *name)
+{
+        /* Don't bother with IRQ stacks for now */
+        return -1;
+}
+
+static void backtrace_address(void *data, unsigned long addr, int reliable)
+{
+        struct backtrace_info *info = data;
+
+        if (info->pos < sample_max_depth && reliable) {
+                __trace_special(info->tr, info->data, 1, addr, 0);
+
+                info->pos++;
+        }
+}
+
+const static struct stacktrace_ops backtrace_ops = {
+        .warning                = backtrace_warning,
+        .warning_symbol         = backtrace_warning_symbol,
+        .stack                  = backtrace_stack,
+        .address                = backtrace_address,
+};
+
+static int
+trace_kernel(struct pt_regs *regs, struct trace_array *tr,
+             struct trace_array_cpu *data)
+{
+        struct backtrace_info info;
+        unsigned long bp;
+        char *stack;
+
+        info.tr = tr;
+        info.data = data;
+        info.pos = 1;
+
+        __trace_special(info.tr, info.data, 1, regs->ip, 0);
+
+        stack = ((char *)regs + sizeof(struct pt_regs));
+#ifdef CONFIG_FRAME_POINTER
+        bp = regs->bp;
+#else
+        bp = 0;
+#endif
+
+        dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
+
+        return info.pos;
+}
+
+static void timer_notify(struct pt_regs *regs, int cpu)
+{
+        struct trace_array_cpu *data;
+        struct stack_frame frame;
+        struct trace_array *tr;
+        const void __user *fp;
+        int is_user;
+        int i;
+
+        if (!regs)
+                return;
+
+        tr = sysprof_trace;
+        data = tr->data[cpu];
+        is_user = user_mode(regs);
+
+        if (!current || current->pid == 0)
+                return;
+
+        if (is_user && current->state != TASK_RUNNING)
+                return;
+
+        __trace_special(tr, data, 0, 0, current->pid);
+
+        if (!is_user)
+                i = trace_kernel(regs, tr, data);
+        else
+                i = 0;
+
+        /*
+         * Trace user stack if we are not a kernel thread
+         */
+        if (current->mm && i < sample_max_depth) {
+                regs = (struct pt_regs *)current->thread.sp0 - 1;
+
+                fp = (void __user *)regs->bp;
+
+                __trace_special(tr, data, 2, regs->ip, 0);
+
+                while (i < sample_max_depth) {
+                        frame.next_fp = 0;
+                        frame.return_address = 0;
+                        if (!copy_stack_frame(fp, &frame))
+                                break;
+                        if ((unsigned long)fp < regs->sp)
+                                break;
+
+                        __trace_special(tr, data, 2, frame.return_address,
+                                        (unsigned long)fp);
+                        fp = frame.next_fp;
+
+                        i++;
+                }
+
+        }
+
+        /*
+         * Special trace entry if we overflow the max depth:
+         */
+        if (i == sample_max_depth)
+                __trace_special(tr, data, -1, -1, -1);
+
+        __trace_special(tr, data, 3, current->pid, i);
+}
+
+static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
+{
+        /* trace here */
+        timer_notify(get_irq_regs(), smp_processor_id());
+
+        hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
+
+        return HRTIMER_RESTART;
+}
+
+static void start_stack_timer(int cpu)
+{
+        struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+
+        hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        hrtimer->function = stack_trace_timer_fn;
+        hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+
+        hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
+}
+
+static void start_stack_timers(void)
+{
+        cpumask_t saved_mask = current->cpus_allowed;
+        int cpu;
+
+        for_each_online_cpu(cpu) {
+                cpumask_of_cpu_ptr(new_mask, cpu);
+
+                set_cpus_allowed_ptr(current, new_mask);
+                start_stack_timer(cpu);
+        }
+        set_cpus_allowed_ptr(current, &saved_mask);
+}
+
+static void stop_stack_timer(int cpu)
+{
+        struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+
+        hrtimer_cancel(hrtimer);
+}
+
+static void stop_stack_timers(void)
+{
+        int cpu;
+
+        for_each_online_cpu(cpu)
+                stop_stack_timer(cpu);
+}
+
+static void stack_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 void start_stack_trace(struct trace_array *tr)
+{
+        mutex_lock(&sample_timer_lock);
+        stack_reset(tr);
+        start_stack_timers();
+        tracer_enabled = 1;
+        mutex_unlock(&sample_timer_lock);
+}
+
+static void stop_stack_trace(struct trace_array *tr)
+{
+        mutex_lock(&sample_timer_lock);
+        stop_stack_timers();
+        tracer_enabled = 0;
+        mutex_unlock(&sample_timer_lock);
+}
+
+static void stack_trace_init(struct trace_array *tr)
+{
+        sysprof_trace = tr;
+
+        if (tr->ctrl)
+                start_stack_trace(tr);
+}
+
+static void stack_trace_reset(struct trace_array *tr)
+{
+        if (tr->ctrl)
+                stop_stack_trace(tr);
+}
+
+static void stack_trace_ctrl_update(struct trace_array *tr)
+{
+        /* When starting a new trace, reset the buffers */
+        if (tr->ctrl)
+                start_stack_trace(tr);
+        else
+                stop_stack_trace(tr);
+}
+
+static struct tracer stack_trace __read_mostly =
+{
+        .name           = "sysprof",
+        .init           = stack_trace_init,
+        .reset          = stack_trace_reset,
+        .ctrl_update    = stack_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+        .selftest    = trace_selftest_startup_sysprof,
+#endif
+};
+
+__init static int init_stack_trace(void)
+{
+        return register_tracer(&stack_trace);
+}
+device_initcall(init_stack_trace);
+
+#define MAX_LONG_DIGITS 22
+
+static ssize_t
+sysprof_sample_read(struct file *filp, char __user *ubuf,
+                    size_t cnt, loff_t *ppos)
+{
+        char buf[MAX_LONG_DIGITS];
+        int r;
+
+        r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));
+
+        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+sysprof_sample_write(struct file *filp, const char __user *ubuf,
+                     size_t cnt, loff_t *ppos)
+{
+        char buf[MAX_LONG_DIGITS];
+        unsigned long val;
+
+        if (cnt > MAX_LONG_DIGITS-1)
+                cnt = MAX_LONG_DIGITS-1;
+
+        if (copy_from_user(&buf, ubuf, cnt))
+                return -EFAULT;
+
+        buf[cnt] = 0;
+
+        val = simple_strtoul(buf, NULL, 10);
+        /*
+         * Enforce a minimum sample period of 100 usecs:
+         */
+        if (val < 100)
+                val = 100;
+
+        mutex_lock(&sample_timer_lock);
+        stop_stack_timers();
+        sample_period = val * 1000;
+        start_stack_timers();
+        mutex_unlock(&sample_timer_lock);
+
+        return cnt;
+}
+
+static struct file_operations sysprof_sample_fops = {
+        .read           = sysprof_sample_read,
+        .write          = sysprof_sample_write,
+};
+
+void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
+{
+        struct dentry *entry;
+
+        entry = debugfs_create_file("sysprof_sample_period", 0644,
+                        d_tracer, NULL, &sysprof_sample_fops);
+        if (entry)
+                return;
+        pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");
+}