ftrace: Remove global function list and call function directly
Instead of having a list of global functions that are called,
as only one global function is allow to be enabled at a time, there's
no reason to have a list.
Instead, simply have all the users of the global ops, use the global ops
directly, instead of registering their own ftrace_ops. Just switch what
function is used before enabling the function tracer.
This removes a lot of code as well as the complexity involved with it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1fd4b94..8f61ef7 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -62,7 +62,7 @@
#define FTRACE_HASH_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12
-#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
+#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
#ifdef CONFIG_DYNAMIC_FTRACE
#define INIT_REGEX_LOCK(opsname) \
@@ -103,7 +103,6 @@
static DEFINE_MUTEX(ftrace_lock);
-static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
@@ -171,23 +170,6 @@
return cnt;
}
-static void
-ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *op, struct pt_regs *regs)
-{
- int bit;
-
- bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
- if (bit < 0)
- return;
-
- do_for_each_ftrace_op(op, ftrace_global_list) {
- op->func(ip, parent_ip, op, regs);
- } while_for_each_ftrace_op(op);
-
- trace_clear_recursion(bit);
-}
-
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
@@ -237,43 +219,6 @@
return 0;
}
-static void update_global_ops(void)
-{
- ftrace_func_t func = ftrace_global_list_func;
- void *private = NULL;
-
- /* The list has its own recursion protection. */
- global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
-
- /*
- * If there's only one function registered, then call that
- * function directly. Otherwise, we need to iterate over the
- * registered callers.
- */
- if (ftrace_global_list == &ftrace_list_end ||
- ftrace_global_list->next == &ftrace_list_end) {
- func = ftrace_global_list->func;
- private = ftrace_global_list->private;
- /*
- * As we are calling the function directly.
- * If it does not have recursion protection,
- * the function_trace_op needs to be updated
- * accordingly.
- */
- if (!(ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE))
- global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
- }
-
- /* If we filter on pids, update to use the pid function */
- if (!list_empty(&ftrace_pids)) {
- set_ftrace_pid_function(func);
- func = ftrace_pid_func;
- }
-
- global_ops.func = func;
- global_ops.private = private;
-}
-
static void ftrace_sync(struct work_struct *work)
{
/*
@@ -301,8 +246,6 @@
{
ftrace_func_t func;
- update_global_ops();
-
/*
* If we are at the end of the list and this ops is
* recursion safe and not dynamic and the arch supports passing ops,
@@ -314,10 +257,7 @@
(ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
!FTRACE_FORCE_LIST_FUNC)) {
/* Set the ftrace_ops that the arch callback uses */
- if (ftrace_ops_list == &global_ops)
- set_function_trace_op = ftrace_global_list;
- else
- set_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 */
@@ -434,16 +374,9 @@
if (ops->flags & FTRACE_OPS_FL_DELETED)
return -EINVAL;
- if (FTRACE_WARN_ON(ops == &global_ops))
- return -EINVAL;
-
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
return -EBUSY;
- /* We don't support both control and global flags set. */
- if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
- return -EINVAL;
-
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/*
* If the ftrace_ops specifies SAVE_REGS, then it only can be used
@@ -461,10 +394,7 @@
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
- if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
- add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
- ops->flags |= FTRACE_OPS_FL_ENABLED;
- } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
+ if (ops->flags & FTRACE_OPS_FL_CONTROL) {
if (control_ops_alloc(ops))
return -ENOMEM;
add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
@@ -484,15 +414,7 @@
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
- if (FTRACE_WARN_ON(ops == &global_ops))
- return -EINVAL;
-
- if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
- ret = remove_ftrace_list_ops(&ftrace_global_list,
- &global_ops, ops);
- if (!ret)
- ops->flags &= ~FTRACE_OPS_FL_ENABLED;
- } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
+ if (ops->flags & FTRACE_OPS_FL_CONTROL) {
ret = remove_ftrace_list_ops(&ftrace_control_list,
&control_ops, ops);
} else
@@ -2128,15 +2050,6 @@
ftrace_start_up++;
command |= FTRACE_UPDATE_CALLS;
- /* ops marked global share the filter hashes */
- if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
- ops = &global_ops;
- /* Don't update hash if global is already set */
- if (global_start_up)
- hash_enable = false;
- global_start_up++;
- }
-
ops->flags |= FTRACE_OPS_FL_ENABLED;
if (hash_enable)
ftrace_hash_rec_enable(ops, 1);
@@ -2166,21 +2079,10 @@
*/
WARN_ON_ONCE(ftrace_start_up < 0);
- if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
- ops = &global_ops;
- global_start_up--;
- WARN_ON_ONCE(global_start_up < 0);
- /* Don't update hash if global still has users */
- if (global_start_up) {
- WARN_ON_ONCE(!ftrace_start_up);
- hash_disable = false;
- }
- }
-
if (hash_disable)
ftrace_hash_rec_disable(ops, 1);
- if (ops != &global_ops || !global_start_up)
+ if (!global_start_up)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
command |= FTRACE_UPDATE_CALLS;
@@ -3524,10 +3426,6 @@
struct ftrace_hash *hash;
int ret;
- /* All global ops uses the global ops filters */
- if (ops->flags & FTRACE_OPS_FL_GLOBAL)
- ops = &global_ops;
-
if (unlikely(ftrace_disabled))
return -ENODEV;
@@ -4462,6 +4360,34 @@
#endif /* CONFIG_DYNAMIC_FTRACE */
+__init void ftrace_init_global_array_ops(struct trace_array *tr)
+{
+ tr->ops = &global_ops;
+ tr->ops->private = tr;
+}
+
+void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
+{
+ /* If we filter on pids, update to use the pid function */
+ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+ if (WARN_ON(tr->ops->func != ftrace_stub))
+ printk("ftrace ops had %pS for function\n",
+ tr->ops->func);
+ /* Only the top level instance does pid tracing */
+ if (!list_empty(&ftrace_pids)) {
+ set_ftrace_pid_function(func);
+ func = ftrace_pid_func;
+ }
+ }
+ tr->ops->func = func;
+ tr->ops->private = tr;
+}
+
+void ftrace_reset_array_ops(struct trace_array *tr)
+{
+ tr->ops->func = ftrace_stub;
+}
+
static void
ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
@@ -4520,9 +4446,16 @@
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (ftrace_ops_test(op, ip, regs))
+ if (ftrace_ops_test(op, ip, regs)) {
+ if (WARN_ON(!op->func)) {
+ function_trace_stop = 1;
+ printk("op=%p %pS\n", op, op);
+ goto out;
+ }
op->func(ip, parent_ip, op, regs);
+ }
} while_for_each_ftrace_op(op);
+out:
preempt_enable_notrace();
trace_clear_recursion(bit);
}
@@ -5076,8 +5009,7 @@
/* 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,
+ .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_RECURSION_SAFE,
};
static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)