Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Thu, 26 Feb 2009 22:19:12 -0500
Commit: Steven Rostedt <srostedt@xxxxxxxxxx>
CommitDate: Thu, 26 Feb 2009 22:22:46 -0500
tracing: add options directory and core option files
This patch creates an options directory in the debugfs, that contains
the available tracing options. These files contain 1 or 0, where 1
is the option is enabled and 0 it is disabled.
Simply echoing in 1 will enable the option and 0 will disable it.
This patch only contains the core options, not the tracer options.
Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
---
kernel/trace/trace.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 117 insertions(+), 0 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bdaf60d..40e983e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3093,6 +3093,121 @@ static void tracing_init_debugfs_percpu(long cpu)
#include "trace_selftest.c"
#endif
+static ssize_t
+trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
+ loff_t *ppos)
+{
+ long index = (long)filp->private_data;
+ char *buf;
+
+ if (trace_flags & (1 << index))
+ buf = "1\n";
+ else
+ buf = "0\n";
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
+ loff_t *ppos)
+{
+ long index = (long)filp->private_data;
+ char buf[64];
+ unsigned long val;
+ int ret;
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ switch (val) {
+ case 0:
+ trace_flags &= ~(1 << index);
+ break;
+ case 1:
+ trace_flags |= 1 << index;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ *ppos += cnt;
+
+ return cnt;
+}
+
+
+static const struct file_operations trace_options_core_fops = {
+ .open = tracing_open_generic,
+ .read = trace_options_core_read,
+ .write = trace_options_core_write,
+};
+
+static struct dentry *trace_options_init_dentry(void)
+{
+ struct dentry *d_tracer;
+ static struct dentry *t_options;
+
+ if (t_options)
+ return t_options;
+
+ d_tracer = tracing_init_dentry();
+ if (!d_tracer)
+ return NULL;
+
+ t_options = debugfs_create_dir("options", d_tracer);
+ if (!t_options) {
+ pr_warning("Could not create debugfs directory 'options'\n");
+ return NULL;
+ }
+
+ return t_options;
+}
+
+static struct dentry *
+create_trace_option_core_file(const char *option, long index)
+{
+ struct dentry *t_options;
+ struct dentry *entry;
+
+ t_options = trace_options_init_dentry();
+ if (!t_options)
+ return NULL;
+
+ entry = debugfs_create_file(option, 0644, t_options, (void *)index,
+ &trace_options_core_fops);
+
+ return entry;
+}
+
+static __init void create_trace_options_dir(void)
+{
+ struct dentry *t_options;
+ struct dentry *entry;
+ int i;
+
+ t_options = trace_options_init_dentry();
+ if (!t_options)
+ return;
+
+ for (i = 0; trace_options[i]; i++) {
+ entry = create_trace_option_core_file(trace_options[i], i);
+ if (!entry)
+ pr_warning("Could not create debugfs %s entry\n",
+ trace_options[i]);
+ }
+}
+
static __init int tracer_init_debugfs(void)
{
struct dentry *d_tracer;
@@ -3111,6 +3226,8 @@ static __init int tracer_init_debugfs(void)
if (!entry)
pr_warning("Could not create debugfs 'trace_options' entry\n");
+ create_trace_options_dir();
+
entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
NULL, &tracing_cpumask_fops);
if (!entry)
--
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