/* Current function tracing op */
struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
+/* What to set function_trace_op to */
+static struct ftrace_ops *set_function_trace_op;
/* List for set_ftrace_pid's pids. */
LIST_HEAD(ftrace_pids);
global_ops.func = func;
}
+static void ftrace_sync(struct work_struct *work)
+{
+ /*
+ * This function is just a stub to implement a hard force
+ * of synchronize_sched(). This requires synchronizing
+ * tasks even in userspace and idle.
+ *
+ * Yes, function tracing is rude.
+ */
+}
+
+static void ftrace_sync_ipi(void *data)
+{
+ /* Probably not needed, but do it anyway */
+ smp_rmb();
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static void update_function_graph_func(void);
+#else
+static inline void update_function_graph_func(void) { }
+#endif
+
static void update_ftrace_function(void)
{
ftrace_func_t func;
!FTRACE_FORCE_LIST_FUNC)) {
/* Set the ftrace_ops that the arch callback uses */
if (ftrace_ops_list == &global_ops)
- function_trace_op = ftrace_global_list;
+ set_function_trace_op = ftrace_global_list;
else
- function_trace_op = ftrace_ops_list;
+ set_function_trace_op = ftrace_ops_list;
func = ftrace_ops_list->func;
} else {
/* Just use the default ftrace_ops */
- function_trace_op = &ftrace_list_end;
+ set_function_trace_op = &ftrace_list_end;
func = ftrace_ops_list_func;
}
+ update_function_graph_func();
+
+ /* If there's no change, then do nothing more here */
+ if (ftrace_trace_function == func)
+ return;
+
+ /*
+ * If we are using the list function, it doesn't care
+ * about the function_trace_ops.
+ */
+ if (func == ftrace_ops_list_func) {
+ ftrace_trace_function = func;
+ /*
+ * Don't even bother setting function_trace_ops,
+ * it would be racy to do so anyway.
+ */
+ return;
+ }
+
+#ifndef CONFIG_DYNAMIC_FTRACE
+ /*
+ * For static tracing, we need to be a bit more careful.
+ * The function change takes affect immediately. Thus,
+ * we need to coorditate the setting of the function_trace_ops
+ * with the setting of the ftrace_trace_function.
+ *
+ * Set the function to the list ops, which will call the
+ * function we want, albeit indirectly, but it handles the
+ * ftrace_ops and doesn't depend on function_trace_op.
+ */
+ ftrace_trace_function = ftrace_ops_list_func;
+ /*
+ * Make sure all CPUs see this. Yes this is slow, but static
+ * tracing is slow and nasty to have enabled.
+ */
+ schedule_on_each_cpu(ftrace_sync);
+ /* Now all cpus are using the list ops. */
+ function_trace_op = set_function_trace_op;
+ /* Make sure the function_trace_op is visible on all CPUs */
+ smp_wmb();
+ /* Nasty way to force a rmb on all cpus */
+ smp_call_function(ftrace_sync_ipi, NULL, 1);
+ /* OK, we are all set to update the ftrace_trace_function now! */
+#endif /* !CONFIG_DYNAMIC_FTRACE */
+
ftrace_trace_function = func;
}
static int __register_ftrace_function(struct ftrace_ops *ops)
{
- if (unlikely(ftrace_disabled))
- return -ENODEV;
-
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
{
int ret;
- if (ftrace_disabled)
- return -ENODEV;
-
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
ret = remove_ftrace_list_ops(&ftrace_control_list,
&control_ops, ops);
- if (!ret) {
- /*
- * The ftrace_ops is now removed from the list,
- * so there'll be no new users. We must ensure
- * all current users are done before we free
- * the control data.
- */
- synchronize_sched();
- control_ops_free(ops);
- }
} else
ret = remove_ftrace_ops(&ftrace_ops_list, ops);
if (ftrace_enabled)
update_ftrace_function();
- /*
- * Dynamic ops may be freed, we must make sure that all
- * callers are done before leaving this function.
- */
- if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
- synchronize_sched();
-
return 0;
}
int cpu;
int ret = 0;
- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
ret = ftrace_profile_init_cpu(cpu);
if (ret)
break;
* the hashes are freed with call_rcu_sched().
*/
static int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
struct ftrace_hash *filter_hash;
struct ftrace_hash *notrace_hash;
int ret;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ /*
+ * There's a small race when adding ops that the ftrace handler
+ * that wants regs, may be called without them. We can not
+ * allow that handler to be called if regs is NULL.
+ */
+ if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+ return 0;
+#endif
+
filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
else if (command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(0);
- if (command & FTRACE_UPDATE_TRACE_FUNC)
+ if (command & FTRACE_UPDATE_TRACE_FUNC) {
+ function_trace_op = set_function_trace_op;
+ smp_wmb();
+ /* If irqs are disabled, we are in stop machine */
+ if (!irqs_disabled())
+ smp_call_function(ftrace_sync_ipi, NULL, 1);
ftrace_update_ftrace_func(ftrace_trace_function);
+ }
if (command & FTRACE_START_FUNC_RET)
ftrace_enable_ftrace_graph_caller();
static int ftrace_startup(struct ftrace_ops *ops, int command)
{
bool hash_enable = true;
+ int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
+ ret = __register_ftrace_function(ops);
+ if (ret)
+ return ret;
+
ftrace_start_up++;
command |= FTRACE_UPDATE_CALLS;
return 0;
}
-static void ftrace_shutdown(struct ftrace_ops *ops, int command)
+static int ftrace_shutdown(struct ftrace_ops *ops, int command)
{
bool hash_disable = true;
+ int ret;
if (unlikely(ftrace_disabled))
- return;
+ return -ENODEV;
+
+ ret = __unregister_ftrace_function(ops);
+ if (ret)
+ return ret;
ftrace_start_up--;
/*
command |= FTRACE_UPDATE_TRACE_FUNC;
}
- if (!command || !ftrace_enabled)
- return;
+ if (!command || !ftrace_enabled) {
+ /*
+ * If these are control ops, they still need their
+ * per_cpu field freed. Since, function tracing is
+ * not currently active, we can just free them
+ * without synchronizing all CPUs.
+ */
+ if (ops->flags & FTRACE_OPS_FL_CONTROL)
+ control_ops_free(ops);
+ return 0;
+ }
ftrace_run_update_code(command);
+
+ /*
+ * Dynamic ops may be freed, we must make sure that all
+ * callers are done before leaving this function.
+ * The same goes for freeing the per_cpu data of the control
+ * ops.
+ *
+ * Again, normal synchronize_sched() is not good enough.
+ * We need to do a hard force of sched synchronization.
+ * This is because we use preempt_disable() to do RCU, but
+ * the function tracers can be called where RCU is not watching
+ * (like before user_exit()). We can not rely on the RCU
+ * infrastructure to do the synchronization, thus we must do it
+ * ourselves.
+ */
+ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
+ schedule_on_each_cpu(ftrace_sync);
+
+ if (ops->flags & FTRACE_OPS_FL_CONTROL)
+ control_ops_free(ops);
+ }
+
+ return 0;
}
static void ftrace_startup_sysctl(void)
static unsigned long ftrace_update_cnt;
unsigned long ftrace_update_tot_cnt;
-static int ops_traces_mod(struct ftrace_ops *ops)
+static inline int ops_traces_mod(struct ftrace_ops *ops)
{
- struct ftrace_hash *hash;
+ /*
+ * Filter_hash being empty will default to trace module.
+ * But notrace hash requires a test of individual module functions.
+ */
+ return ftrace_hash_empty(ops->filter_hash) &&
+ ftrace_hash_empty(ops->notrace_hash);
+}
- hash = ops->filter_hash;
- return ftrace_hash_empty(hash);
+/*
+ * Check if the current ops references the record.
+ *
+ * If the ops traces all functions, then it was already accounted for.
+ * If the ops does not trace the current record function, skip it.
+ * If the ops ignores the function via notrace filter, skip it.
+ */
+static inline bool
+ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+{
+ /* If ops isn't enabled, ignore it */
+ if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+ return 0;
+
+ /* If ops traces all mods, we already accounted for it */
+ if (ops_traces_mod(ops))
+ return 0;
+
+ /* The function must be in the filter */
+ if (!ftrace_hash_empty(ops->filter_hash) &&
+ !ftrace_lookup_ip(ops->filter_hash, rec->ip))
+ return 0;
+
+ /* If in notrace hash, we ignore it too */
+ if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
+ return 0;
+
+ return 1;
+}
+
+static int referenced_filters(struct dyn_ftrace *rec)
+{
+ struct ftrace_ops *ops;
+ int cnt = 0;
+
+ for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
+ if (ops_references_rec(ops, rec))
+ cnt++;
+ }
+
+ return cnt;
}
static int ftrace_update_code(struct module *mod)
struct dyn_ftrace *p;
cycle_t start, stop;
unsigned long ref = 0;
+ bool test = false;
int i;
/*
for (ops = ftrace_ops_list;
ops != &ftrace_list_end; ops = ops->next) {
- if (ops->flags & FTRACE_OPS_FL_ENABLED &&
- ops_traces_mod(ops))
- ref++;
+ if (ops->flags & FTRACE_OPS_FL_ENABLED) {
+ if (ops_traces_mod(ops))
+ ref++;
+ else
+ test = true;
+ }
}
}
for (pg = ftrace_new_pgs; pg; pg = pg->next) {
for (i = 0; i < pg->index; i++) {
+ int cnt = ref;
+
/* If something went wrong, bail without enabling anything */
if (unlikely(ftrace_disabled))
return -1;
p = &pg->records[i];
- p->flags = ref;
+ if (test)
+ cnt += referenced_filters(p);
+ p->flags = cnt;
/*
* Do the initial record conversion from mcount jump
* conversion puts the module to the correct state, thus
* passing the ftrace_make_call check.
*/
- if (ftrace_start_up && ref) {
+ if (ftrace_start_up && cnt) {
int failed = __ftrace_replace_code(p, 1);
if (failed)
ftrace_bug(failed, p->ip);
if (i == FTRACE_FUNC_HASHSIZE)
return;
- ret = __register_ftrace_function(&trace_probe_ops);
- if (!ret)
- ret = ftrace_startup(&trace_probe_ops, 0);
+ ret = ftrace_startup(&trace_probe_ops, 0);
ftrace_probe_registered = 1;
}
static void __disable_ftrace_function_probe(void)
{
- int ret;
int i;
if (!ftrace_probe_registered)
}
/* no more funcs left */
- ret = __unregister_ftrace_function(&trace_probe_ops);
- if (!ret)
- ftrace_shutdown(&trace_probe_ops, 0);
+ ftrace_shutdown(&trace_probe_ops, 0);
ftrace_probe_registered = 0;
}
ftrace_process_locs(mod, start, end);
}
-static int ftrace_module_notify_enter(struct notifier_block *self,
- unsigned long val, void *data)
+void ftrace_module_init(struct module *mod)
{
- struct module *mod = data;
-
- if (val == MODULE_STATE_COMING)
- ftrace_init_module(mod, mod->ftrace_callsites,
- mod->ftrace_callsites +
- mod->num_ftrace_callsites);
- return 0;
+ ftrace_init_module(mod, mod->ftrace_callsites,
+ mod->ftrace_callsites +
+ mod->num_ftrace_callsites);
}
static int ftrace_module_notify_exit(struct notifier_block *self,
return 0;
}
#else
-static int ftrace_module_notify_enter(struct notifier_block *self,
- unsigned long val, void *data)
-{
- return 0;
-}
static int ftrace_module_notify_exit(struct notifier_block *self,
unsigned long val, void *data)
{
}
#endif /* CONFIG_MODULES */
-struct notifier_block ftrace_module_enter_nb = {
- .notifier_call = ftrace_module_notify_enter,
- .priority = INT_MAX, /* Run before anything that can use kprobes */
-};
-
struct notifier_block ftrace_module_exit_nb = {
.notifier_call = ftrace_module_notify_exit,
.priority = INT_MIN, /* Run after anything that can remove kprobes */
__start_mcount_loc,
__stop_mcount_loc);
- ret = register_module_notifier(&ftrace_module_enter_nb);
- if (ret)
- pr_warning("Failed to register trace ftrace module enter notifier\n");
-
ret = register_module_notifier(&ftrace_module_exit_nb);
if (ret)
pr_warning("Failed to register trace ftrace module exit notifier\n");
static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
static inline void ftrace_startup_enable(int command) { }
/* Keep as macros so we do not need to define the commands */
-# define ftrace_startup(ops, command) \
- ({ \
- (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
- 0; \
+# define ftrace_startup(ops, command) \
+ ({ \
+ int ___ret = __register_ftrace_function(ops); \
+ if (!___ret) \
+ (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
+ ___ret; \
})
-# define ftrace_shutdown(ops, command) do { } while (0)
+# define ftrace_shutdown(ops, command) __unregister_ftrace_function(ops)
+
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
return 1;
}
do_for_each_ftrace_op(op, ftrace_control_list) {
if (!(op->flags & FTRACE_OPS_FL_STUB) &&
!ftrace_function_local_disabled(op) &&
- ftrace_ops_test(op, ip))
+ ftrace_ops_test(op, ip, regs))
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
trace_recursion_clear(TRACE_CONTROL_BIT);
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (ftrace_ops_test(op, ip))
+ if (ftrace_ops_test(op, ip, regs))
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
preempt_enable_notrace();
mutex_lock(&ftrace_lock);
- ret = __register_ftrace_function(ops);
- if (!ret)
- ret = ftrace_startup(ops, 0);
+ ret = ftrace_startup(ops, 0);
mutex_unlock(&ftrace_lock);
int ret;
mutex_lock(&ftrace_lock);
- ret = __unregister_ftrace_function(ops);
- if (!ret)
- ftrace_shutdown(ops, 0);
+ ret = ftrace_shutdown(ops, 0);
mutex_unlock(&ftrace_lock);
return ret;
trace_func_graph_ret_t ftrace_graph_return =
(trace_func_graph_ret_t)ftrace_stub;
trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
+static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
return NOTIFY_DONE;
}
+/* Just a place holder for function graph */
+static struct ftrace_ops fgraph_ops __read_mostly = {
+ .func = ftrace_stub,
+ .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
+ FTRACE_OPS_FL_RECURSION_SAFE,
+};
+
+static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
+{
+ if (!ftrace_ops_test(&global_ops, trace->func, NULL))
+ return 0;
+ return __ftrace_graph_entry(trace);
+}
+
+/*
+ * The function graph tracer should only trace the functions defined
+ * by set_ftrace_filter and set_ftrace_notrace. If another function
+ * tracer ops is registered, the graph tracer requires testing the
+ * function against the global ops, and not just trace any function
+ * that any ftrace_ops registered.
+ */
+static void update_function_graph_func(void)
+{
+ if (ftrace_ops_list == &ftrace_list_end ||
+ (ftrace_ops_list == &global_ops &&
+ global_ops.next == &ftrace_list_end))
+ ftrace_graph_entry = __ftrace_graph_entry;
+ else
+ ftrace_graph_entry = ftrace_graph_entry_test;
+}
+
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
trace_func_graph_ent_t entryfunc)
{
}
ftrace_graph_return = retfunc;
- ftrace_graph_entry = entryfunc;
- ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
+ /*
+ * Update the indirect function to the entryfunc, and the
+ * function that gets called to the entry_test first. Then
+ * call the update fgraph entry function to determine if
+ * the entryfunc should be called directly or not.
+ */
+ __ftrace_graph_entry = entryfunc;
+ ftrace_graph_entry = ftrace_graph_entry_test;
+ update_function_graph_func();
+
+ ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
out:
mutex_unlock(&ftrace_lock);
ftrace_graph_active--;
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = ftrace_graph_entry_stub;
- ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
+ __ftrace_graph_entry = ftrace_graph_entry_stub;
+ ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
unregister_pm_notifier(&ftrace_suspend_notifier);
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
projects / firefly-linux-kernel-4.4.55.git / blobdiff