static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
+function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
+function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs);
static struct tracer_flags func_flags;
/* Our option */
enum {
- TRACE_FUNC_OPT_STACK = 0x1,
+
+ TRACE_FUNC_NO_OPTS = 0x0, /* No flags set. */
+ TRACE_FUNC_OPT_STACK = 0x1,
+ TRACE_FUNC_OPT_NO_REPEATS = 0x2,
+
+ /* Update this to next highest bit. */
+ TRACE_FUNC_OPT_HIGHEST_BIT = 0x4
};
+#define TRACE_FUNC_OPT_MASK (TRACE_FUNC_OPT_HIGHEST_BIT - 1)
+
int ftrace_allocate_ftrace_ops(struct trace_array *tr)
{
struct ftrace_ops *ops;
ftrace_free_ftrace_ops(tr);
}
+static ftrace_func_t select_trace_function(u32 flags_val)
+{
+ switch (flags_val & TRACE_FUNC_OPT_MASK) {
+ case TRACE_FUNC_NO_OPTS:
+ return function_trace_call;
+ case TRACE_FUNC_OPT_STACK:
+ return function_stack_trace_call;
+ case TRACE_FUNC_OPT_NO_REPEATS:
+ return function_no_repeats_trace_call;
+ case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS:
+ return function_stack_no_repeats_trace_call;
+ default:
+ return NULL;
+ }
+}
+
+static bool handle_func_repeats(struct trace_array *tr, u32 flags_val)
+{
+ if (!tr->last_func_repeats &&
+ (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) {
+ tr->last_func_repeats = alloc_percpu(struct trace_func_repeats);
+ if (!tr->last_func_repeats)
+ return false;
+ }
+
+ return true;
+}
+
static int function_trace_init(struct trace_array *tr)
{
ftrace_func_t func;
if (!tr->ops)
return -ENOMEM;
- /* Currently only the global instance can do stack tracing */
- if (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
- func_flags.val & TRACE_FUNC_OPT_STACK)
- func = function_stack_trace_call;
- else
- func = function_trace_call;
+ func = select_trace_function(func_flags.val);
+ if (!func)
+ return -EINVAL;
+
+ if (!handle_func_repeats(tr, func_flags.val))
+ return -ENOMEM;
ftrace_init_array_ops(tr, func);
local_irq_restore(flags);
}
+static inline bool is_repeat_check(struct trace_array *tr,
+ struct trace_func_repeats *last_info,
+ unsigned long ip, unsigned long parent_ip)
+{
+ if (last_info->ip == ip &&
+ last_info->parent_ip == parent_ip &&
+ last_info->count < U16_MAX) {
+ last_info->ts_last_call =
+ ring_buffer_time_stamp(tr->array_buffer.buffer);
+ last_info->count++;
+ return true;
+ }
+
+ return false;
+}
+
+static inline void process_repeats(struct trace_array *tr,
+ unsigned long ip, unsigned long parent_ip,
+ struct trace_func_repeats *last_info,
+ unsigned int trace_ctx)
+{
+ if (last_info->count) {
+ trace_last_func_repeats(tr, last_info, trace_ctx);
+ last_info->count = 0;
+ }
+
+ last_info->ip = ip;
+ last_info->parent_ip = parent_ip;
+}
+
+static void
+function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs)
+{
+ struct trace_func_repeats *last_info;
+ struct trace_array *tr = op->private;
+ struct trace_array_cpu *data;
+ unsigned int trace_ctx;
+ unsigned long flags;
+ int bit;
+ int cpu;
+
+ if (unlikely(!tr->function_enabled))
+ return;
+
+ bit = ftrace_test_recursion_trylock(ip, parent_ip);
+ if (bit < 0)
+ return;
+
+ preempt_disable_notrace();
+
+ cpu = smp_processor_id();
+ data = per_cpu_ptr(tr->array_buffer.data, cpu);
+ if (atomic_read(&data->disabled))
+ goto out;
+
+ /*
+ * An interrupt may happen at any place here. But as far as I can see,
+ * the only damage that this can cause is to mess up the repetition
+ * counter without valuable data being lost.
+ * TODO: think about a solution that is better than just hoping to be
+ * lucky.
+ */
+ last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
+ if (is_repeat_check(tr, last_info, ip, parent_ip))
+ goto out;
+
+ local_save_flags(flags);
+ trace_ctx = tracing_gen_ctx_flags(flags);
+ process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
+
+ trace_function(tr, ip, parent_ip, trace_ctx);
+
+out:
+ ftrace_test_recursion_unlock(bit);
+ preempt_enable_notrace();
+}
+
+static void
+function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs)
+{
+ struct trace_func_repeats *last_info;
+ struct trace_array *tr = op->private;
+ struct trace_array_cpu *data;
+ unsigned long flags;
+ long disabled;
+ int cpu;
+ unsigned int trace_ctx;
+
+ if (unlikely(!tr->function_enabled))
+ return;
+
+ /*
+ * Need to use raw, since this must be called before the
+ * recursive protection is performed.
+ */
+ local_irq_save(flags);
+ cpu = raw_smp_processor_id();
+ data = per_cpu_ptr(tr->array_buffer.data, cpu);
+ disabled = atomic_inc_return(&data->disabled);
+
+ if (likely(disabled == 1)) {
+ last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
+ if (is_repeat_check(tr, last_info, ip, parent_ip))
+ goto out;
+
+ trace_ctx = tracing_gen_ctx_flags(flags);
+ process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
+
+ trace_function(tr, ip, parent_ip, trace_ctx);
+ __trace_stack(tr, trace_ctx, STACK_SKIP);
+ }
+
+ out:
+ atomic_dec(&data->disabled);
+ local_irq_restore(flags);
+}
+
static struct tracer_opt func_opts[] = {
#ifdef CONFIG_STACKTRACE
{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
#endif
+ { TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
{ } /* Always set a last empty entry */
};
static struct tracer_flags func_flags = {
- .val = 0, /* By default: all flags disabled */
+ .val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */
.opts = func_opts
};
static int
func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
{
- switch (bit) {
- case TRACE_FUNC_OPT_STACK:
- /* do nothing if already set */
- if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
- break;
-
- /* We can change this flag when not running. */
- if (tr->current_trace != &function_trace)
- break;
+ ftrace_func_t func;
+ u32 new_flags;
- unregister_ftrace_function(tr->ops);
+ /* Do nothing if already set. */
+ if (!!set == !!(func_flags.val & bit))
+ return 0;
- if (set) {
- tr->ops->func = function_stack_trace_call;
- register_ftrace_function(tr->ops);
- } else {
- tr->ops->func = function_trace_call;
- register_ftrace_function(tr->ops);
- }
+ /* We can change this flag only when not running. */
+ if (tr->current_trace != &function_trace)
+ return 0;
- break;
- default:
+ new_flags = (func_flags.val & ~bit) | (set ? bit : 0);
+ func = select_trace_function(new_flags);
+ if (!func)
return -EINVAL;
- }
+
+ /* Check if there's anything to change. */
+ if (tr->ops->func == func)
+ return 0;
+
+ if (!handle_func_repeats(tr, new_flags))
+ return -ENOMEM;
+
+ unregister_ftrace_function(tr->ops);
+ tr->ops->func = func;
+ register_ftrace_function(tr->ops);
return 0;
}
projects / linux-2.6-microblaze.git / blobdiff