#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
static int __init set_graph_function(char *str)
{
func = strsep(&buf, ",");
/* we allow only one expression at a time */
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
- func);
+ FTRACE_GRAPH_MAX_FUNCS, func);
if (ret)
printk(KERN_DEBUG "ftrace: function %s not "
"traceable\n", func);
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
-int ftrace_graph_filter_enabled;
+int ftrace_graph_notrace_count;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+
+struct ftrace_graph_data {
+ unsigned long *table;
+ size_t size;
+ int *count;
+ const struct seq_operations *seq_ops;
+};
static void *
__g_next(struct seq_file *m, loff_t *pos)
{
- if (*pos >= ftrace_graph_count)
+ struct ftrace_graph_data *fgd = m->private;
+
+ if (*pos >= *fgd->count)
return NULL;
- return &ftrace_graph_funcs[*pos];
+ return &fgd->table[*pos];
}
static void *
static void *g_start(struct seq_file *m, loff_t *pos)
{
+ struct ftrace_graph_data *fgd = m->private;
+
mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */
- if (!ftrace_graph_filter_enabled && !*pos)
+ if (!*fgd->count && !*pos)
return (void *)1;
return __g_next(m, pos);
};
static int
-ftrace_graph_open(struct inode *inode, struct file *file)
+__ftrace_graph_open(struct inode *inode, struct file *file,
+ struct ftrace_graph_data *fgd)
{
int ret = 0;
- if (unlikely(ftrace_disabled))
- return -ENODEV;
-
mutex_lock(&graph_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC)) {
- ftrace_graph_filter_enabled = 0;
- ftrace_graph_count = 0;
- memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+ *fgd->count = 0;
+ memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
}
mutex_unlock(&graph_lock);
- if (file->f_mode & FMODE_READ)
- ret = seq_open(file, &ftrace_graph_seq_ops);
+ if (file->f_mode & FMODE_READ) {
+ ret = seq_open(file, fgd->seq_ops);
+ if (!ret) {
+ struct seq_file *m = file->private_data;
+ m->private = fgd;
+ }
+ } else
+ file->private_data = fgd;
return ret;
}
+static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_graph_data *fgd;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+ if (fgd == NULL)
+ return -ENOMEM;
+
+ fgd->table = ftrace_graph_funcs;
+ fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+ fgd->count = &ftrace_graph_count;
+ fgd->seq_ops = &ftrace_graph_seq_ops;
+
+ return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_graph_data *fgd;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+ if (fgd == NULL)
+ return -ENOMEM;
+
+ fgd->table = ftrace_graph_notrace_funcs;
+ fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+ fgd->count = &ftrace_graph_notrace_count;
+ fgd->seq_ops = &ftrace_graph_seq_ops;
+
+ return __ftrace_graph_open(inode, file, fgd);
+}
+
static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
- if (file->f_mode & FMODE_READ)
+ if (file->f_mode & FMODE_READ) {
+ struct seq_file *m = file->private_data;
+
+ kfree(m->private);
seq_release(inode, file);
+ } else {
+ kfree(file->private_data);
+ }
+
return 0;
}
static int
-ftrace_set_func(unsigned long *array, int *idx, char *buffer)
+ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
/* decode regex */
type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
- if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+ if (!not && *idx >= size)
return -EBUSY;
search_len = strlen(search);
fail = 0;
if (!exists) {
array[(*idx)++] = rec->ip;
- if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+ if (*idx >= size)
goto out;
}
} else {
if (fail)
return -EINVAL;
- ftrace_graph_filter_enabled = !!(*idx);
-
return 0;
}
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
- ssize_t read, ret;
+ ssize_t read, ret = 0;
+ struct ftrace_graph_data *fgd = file->private_data;
if (!cnt)
return 0;
- mutex_lock(&graph_lock);
-
- if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
- ret = -ENOMEM;
- goto out_unlock;
- }
+ if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
+ return -ENOMEM;
read = trace_get_user(&parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded((&parser))) {
parser.buffer[parser.idx] = 0;
+ mutex_lock(&graph_lock);
+
/* we allow only one expression at a time */
- ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
- parser.buffer);
- if (ret)
- goto out_free;
+ ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
+ parser.buffer);
+
+ mutex_unlock(&graph_lock);
}
- ret = read;
+ if (!ret)
+ ret = read;
-out_free:
trace_parser_put(&parser);
-out_unlock:
- mutex_unlock(&graph_lock);
return ret;
}
.llseek = ftrace_filter_lseek,
.release = ftrace_graph_release,
};
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+ .open = ftrace_graph_notrace_open,
+ .read = seq_read,
+ .write = ftrace_graph_write,
+ .llseek = ftrace_filter_lseek,
+ .release = ftrace_graph_release,
+};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
trace_create_file("set_graph_function", 0444, d_tracer,
NULL,
&ftrace_graph_fops);
+ trace_create_file("set_graph_notrace", 0444, d_tracer,
+ NULL,
+ &ftrace_graph_notrace_fops);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
return 0;
return -EBUSY;
}
+ /*
+ * The curr_ret_stack is an index to ftrace return stack of
+ * current task. Its value should be in [0, FTRACE_RETFUNC_
+ * DEPTH) when the function graph tracer is used. To support
+ * filtering out specific functions, it makes the index
+ * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+ * so when it sees a negative index the ftrace will ignore
+ * the record. And the index gets recovered when returning
+ * from the filtered function by adding the FTRACE_NOTRACE_
+ * DEPTH and then it'll continue to record functions normally.
+ *
+ * The curr_ret_stack is initialized to -1 and get increased
+ * in this function. So it can be less than -1 only if it was
+ * filtered out via ftrace_graph_notrace_addr() which can be
+ * set from set_graph_notrace file in debugfs by user.
+ */
+ if (current->curr_ret_stack < -1)
+ return -EBUSY;
+
calltime = trace_clock_local();
index = ++current->curr_ret_stack;
+ if (ftrace_graph_notrace_addr(func))
+ current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
barrier();
current->ret_stack[index].ret = ret;
current->ret_stack[index].func = func;
current->ret_stack[index].calltime = calltime;
current->ret_stack[index].subtime = 0;
current->ret_stack[index].fp = frame_pointer;
- *depth = index;
+ *depth = current->curr_ret_stack;
return 0;
}
index = current->curr_ret_stack;
- if (unlikely(index < 0)) {
+ /*
+ * A negative index here means that it's just returned from a
+ * notrace'd function. Recover index to get an original
+ * return address. See ftrace_push_return_trace().
+ *
+ * TODO: Need to check whether the stack gets corrupted.
+ */
+ if (index < 0)
+ index += FTRACE_NOTRACE_DEPTH;
+
+ if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
trace.rettime = trace_clock_local();
barrier();
current->curr_ret_stack--;
+ /*
+ * The curr_ret_stack can be less than -1 only if it was
+ * filtered out and it's about to return from the function.
+ * Recover the index and continue to trace normal functions.
+ */
+ if (current->curr_ret_stack < -1) {
+ current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+ return ret;
+ }
/*
* The trace should run after decrementing the ret counter
/* trace it when it is-nested-in or is a function enabled. */
if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
- ftrace_graph_ignore_irqs()) ||
+ ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
(max_depth && trace->depth >= max_depth))
return 0;
+ /*
+ * Do not trace a function if it's filtered by set_graph_notrace.
+ * Make the index of ret stack negative to indicate that it should
+ * ignore further functions. But it needs its own ret stack entry
+ * to recover the original index in order to continue tracing after
+ * returning from the function.
+ */
+ if (ftrace_graph_notrace_addr(trace->func))
+ return 1;
+
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
projects / karo-tx-linux.git / commitdiff