diff options
Diffstat (limited to 'kernel/trace/trace_events.c')
| -rw-r--r-- | kernel/trace/trace_events.c | 94 |
1 files changed, 92 insertions, 2 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 1d07f800a9ce..210e71ff82db 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3,6 +3,9 @@ * * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> * + * - Added format output of fields of the trace point. + * This was based off of work by Tom Zanussi <tzanussi@gmail.com>. + * */ #include <linux/debugfs.h> @@ -10,10 +13,12 @@ #include <linux/module.h> #include <linux/ctype.h> -#include "trace.h" +#include "trace_output.h" #define TRACE_SYSTEM "TRACE_SYSTEM" +static DEFINE_MUTEX(event_mutex); + #define events_for_each(event) \ for (event = __start_ftrace_events; \ (unsigned long)event < (unsigned long)__stop_ftrace_events; \ @@ -104,6 +109,7 @@ static int ftrace_set_clr_event(char *buf, int set) event = NULL; } + mutex_lock(&event_mutex); events_for_each(call) { if (!call->name) @@ -124,6 +130,8 @@ static int ftrace_set_clr_event(char *buf, int set) ret = 0; } + mutex_unlock(&event_mutex); + return ret; } @@ -324,7 +332,9 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, switch (val) { case 0: case 1: + mutex_lock(&event_mutex); ftrace_event_enable_disable(call, val); + mutex_unlock(&event_mutex); break; default: @@ -437,6 +447,71 @@ event_available_types_read(struct file *filp, char __user *ubuf, size_t cnt, return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } +#undef FIELD +#define FIELD(type, name) \ + #type, #name, offsetof(typeof(field), name), sizeof(field.name) + +static int trace_write_header(struct trace_seq *s) +{ + struct trace_entry field; + + /* struct trace_entry */ + return trace_seq_printf(s, + "\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n" + "\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n" + "\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n" + "\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n" + "\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n" + "\n", + FIELD(unsigned char, type), + FIELD(unsigned char, flags), + FIELD(unsigned char, preempt_count), + FIELD(int, pid), + FIELD(int, tgid)); +} +static ssize_t +event_format_read(struct file *filp, char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct ftrace_event_call *call = filp->private_data; + struct trace_seq *s; + char *buf; + int r; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + trace_seq_init(s); + + if (*ppos) + return 0; + + /* If any of the first writes fail, so will the show_format. */ + + trace_seq_printf(s, "name: %s\n", call->name); + trace_seq_printf(s, "ID: %d\n", call->id); + trace_seq_printf(s, "format:\n"); + trace_write_header(s); + + r = call->show_format(s); + if (!r) { + /* + * ug! The format output is bigger than a PAGE!! + */ + buf = "FORMAT TOO BIG\n"; + r = simple_read_from_buffer(ubuf, cnt, ppos, + buf, strlen(buf)); + goto out; + } + + r = simple_read_from_buffer(ubuf, cnt, ppos, + s->buffer, s->len); + out: + kfree(s); + return r; +} + static const struct seq_operations show_event_seq_ops = { .start = t_start, .next = t_next, @@ -483,6 +558,11 @@ static const struct file_operations ftrace_available_types_fops = { .read = event_available_types_read, }; +static const struct file_operations ftrace_event_format_fops = { + .open = tracing_open_generic, + .read = event_format_read, +}; + static struct dentry *event_trace_events_dir(void) { static struct dentry *d_tracer; @@ -595,7 +675,17 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) &ftrace_available_types_fops); if (!entry) pr_warning("Could not create debugfs " - "'%s/type' available_types\n", call->name); + "'%s/available_types' entry\n", call->name); + + /* A trace may not want to export its format */ + if (!call->show_format) + return 0; + + entry = debugfs_create_file("format", 0444, call->dir, call, + &ftrace_event_format_fops); + if (!entry) + pr_warning("Could not create debugfs " + "'%s/format' entry\n", call->name); return 0; } |
