1 files changed, 44 insertions, 17 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dade4c9559cc..8696ce6bf2f6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1047,7 +1047,7 @@ void disable_trace_on_warning(void)
  *
  * Shows real state of the ring buffer if it is enabled or not.
  */
-static int tracer_tracing_is_on(struct trace_array *tr)
+int tracer_tracing_is_on(struct trace_array *tr)
 {
         if (tr->trace_buffer.buffer)
                 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
@@ -4123,6 +4123,30 @@ static const char readme_msg[] =
         "\t\t\t  traces\n"
 #endif
 #endif /* CONFIG_STACK_TRACER */
+#ifdef CONFIG_KPROBE_EVENT
+        "  kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
+        "\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENT
+        "  uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
+        "\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#if defined(CONFIG_KPROBE_EVENT) || defined(CONFIG_UPROBE_EVENT)
+        "\t  accepts: event-definitions (one definition per line)\n"
+        "\t   Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
+        "\t           -:[<group>/]<event>\n"
+#ifdef CONFIG_KPROBE_EVENT
+        "\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENT
+        "\t    place: <path>:<offset>\n"
+#endif
+        "\t     args: <name>=fetcharg[:type]\n"
+        "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
+        "\t           $stack<index>, $stack, $retval, $comm\n"
+        "\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
+        "\t           b<bit-width>@<bit-offset>/<container-size>\n"
+#endif
         "  events/\t\t- Directory containing all trace event subsystems:\n"
         "      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
         "  events/<system>/\t- Directory containing all trace events for <system>:\n"
@@ -4945,7 +4969,7 @@ out:
         return ret;
 }
 
-#ifdef CONFIG_TRACER_MAX_TRACE
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
 
 static ssize_t
 tracing_max_lat_read(struct file *filp, char __user *ubuf,
@@ -5124,19 +5148,20 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
         struct trace_iterator *iter = filp->private_data;
         ssize_t sret;
 
-        /* return any leftover data */
-        sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
-        if (sret != -EBUSY)
-                return sret;
-
-        trace_seq_init(&iter->seq);
-
         /*
          * Avoid more than one consumer on a single file descriptor
          * This is just a matter of traces coherency, the ring buffer itself
          * is protected.
          */
         mutex_lock(&iter->mutex);
+
+        /* return any leftover data */
+        sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+        if (sret != -EBUSY)
+                goto out;
+
+        trace_seq_init(&iter->seq);
+
         if (iter->trace->read) {
                 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
                 if (sret)
@@ -5867,7 +5892,7 @@ static const struct file_operations tracing_thresh_fops = {
         .llseek         = generic_file_llseek,
 };
 
-#ifdef CONFIG_TRACER_MAX_TRACE
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
 static const struct file_operations tracing_max_lat_fops = {
         .open           = tracing_open_generic,
         .read           = tracing_max_lat_read,
@@ -6163,9 +6188,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                 return -EBUSY;
 #endif
 
-        if (splice_grow_spd(pipe, &spd))
-                return -ENOMEM;
-
         if (*ppos & (PAGE_SIZE - 1))
                 return -EINVAL;
 
@@ -6175,6 +6197,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                 len &= PAGE_MASK;
         }
 
+        if (splice_grow_spd(pipe, &spd))
+                return -ENOMEM;
+
  again:
         trace_access_lock(iter->cpu_file);
         entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
@@ -6232,19 +6257,21 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
         /* did we read anything? */
         if (!spd.nr_pages) {
                 if (ret)
-                        return ret;
+                        goto out;
 
+                ret = -EAGAIN;
                 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
-                        return -EAGAIN;
+                        goto out;
 
                 ret = wait_on_pipe(iter, true);
                 if (ret)
-                        return ret;
+                        goto out;
 
                 goto again;
         }
 
         ret = splice_to_pipe(pipe, &spd);
+out:
         splice_shrink_spd(&spd);
 
         return ret;
@@ -7195,7 +7222,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 
         create_trace_options_dir(tr);
 
-#ifdef CONFIG_TRACER_MAX_TRACE
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
         trace_create_file("tracing_max_latency", 0644, d_tracer,
                         &tr->max_latency, &tracing_max_lat_fops);
 #endif