diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 211 |
1 files changed, 117 insertions, 94 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 674add0aafb3..f8db59c3a601 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -86,7 +86,7 @@ struct ftrace_ops ftrace_list_end __read_mostly = { /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; -static int last_ftrace_enabled; +static int __maybe_unused last_ftrace_enabled; /* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; @@ -3065,40 +3065,6 @@ int ftrace_shutdown(struct ftrace_ops *ops, int command) return 0; } -static void ftrace_startup_sysctl(void) -{ - int command; - - if (unlikely(ftrace_disabled)) - return; - - /* Force update next time */ - saved_ftrace_func = NULL; - /* ftrace_start_up is true if we want ftrace running */ - if (ftrace_start_up) { - command = FTRACE_UPDATE_CALLS; - if (ftrace_graph_active) - command |= FTRACE_START_FUNC_RET; - ftrace_startup_enable(command); - } -} - -static void ftrace_shutdown_sysctl(void) -{ - int command; - - if (unlikely(ftrace_disabled)) - return; - - /* ftrace_start_up is true if ftrace is running */ - if (ftrace_start_up) { - command = FTRACE_DISABLE_CALLS; - if (ftrace_graph_active) - command |= FTRACE_STOP_FUNC_RET; - ftrace_run_update_code(command); - } -} - static u64 ftrace_update_time; unsigned long ftrace_update_tot_cnt; unsigned long ftrace_number_of_pages; @@ -7267,9 +7233,6 @@ core_initcall(ftrace_nodyn_init); static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } static inline void ftrace_startup_all(int command) { } -# define ftrace_startup_sysctl() do { } while (0) -# define ftrace_shutdown_sysctl() do { } while (0) - static void ftrace_update_trampoline(struct ftrace_ops *ops) { } @@ -7909,62 +7872,6 @@ int unregister_ftrace_function(struct ftrace_ops *ops) } EXPORT_SYMBOL_GPL(unregister_ftrace_function); -static bool is_permanent_ops_registered(void) -{ - struct ftrace_ops *op; - - do_for_each_ftrace_op(op, ftrace_ops_list) { - if (op->flags & FTRACE_OPS_FL_PERMANENT) - return true; - } while_for_each_ftrace_op(op); - - return false; -} - -int -ftrace_enable_sysctl(struct ctl_table *table, int write, - void *buffer, size_t *lenp, loff_t *ppos) -{ - int ret = -ENODEV; - - mutex_lock(&ftrace_lock); - - if (unlikely(ftrace_disabled)) - goto out; - - ret = proc_dointvec(table, write, buffer, lenp, ppos); - - if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) - goto out; - - if (ftrace_enabled) { - - /* we are starting ftrace again */ - if (rcu_dereference_protected(ftrace_ops_list, - lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) - update_ftrace_function(); - - ftrace_startup_sysctl(); - - } else { - if (is_permanent_ops_registered()) { - ftrace_enabled = true; - ret = -EBUSY; - goto out; - } - - /* stopping ftrace calls (just send to ftrace_stub) */ - ftrace_trace_function = ftrace_stub; - - ftrace_shutdown_sysctl(); - } - - last_ftrace_enabled = !!ftrace_enabled; - out: - mutex_unlock(&ftrace_lock); - return ret; -} - static int symbols_cmp(const void *a, const void *b) { const char **str_a = (const char **) a; @@ -8026,3 +7933,119 @@ int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *a return err; return args.found == args.cnt ? 0 : -ESRCH; } + +#ifdef CONFIG_SYSCTL + +#ifdef CONFIG_DYNAMIC_FTRACE +static void ftrace_startup_sysctl(void) +{ + int command; + + if (unlikely(ftrace_disabled)) + return; + + /* Force update next time */ + saved_ftrace_func = NULL; + /* ftrace_start_up is true if we want ftrace running */ + if (ftrace_start_up) { + command = FTRACE_UPDATE_CALLS; + if (ftrace_graph_active) + command |= FTRACE_START_FUNC_RET; + ftrace_startup_enable(command); + } +} + +static void ftrace_shutdown_sysctl(void) +{ + int command; + + if (unlikely(ftrace_disabled)) + return; + + /* ftrace_start_up is true if ftrace is running */ + if (ftrace_start_up) { + command = FTRACE_DISABLE_CALLS; + if (ftrace_graph_active) + command |= FTRACE_STOP_FUNC_RET; + ftrace_run_update_code(command); + } +} +#else +# define ftrace_startup_sysctl() do { } while (0) +# define ftrace_shutdown_sysctl() do { } while (0) +#endif /* CONFIG_DYNAMIC_FTRACE */ + +static bool is_permanent_ops_registered(void) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (op->flags & FTRACE_OPS_FL_PERMANENT) + return true; + } while_for_each_ftrace_op(op); + + return false; +} + +static int +ftrace_enable_sysctl(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = -ENODEV; + + mutex_lock(&ftrace_lock); + + if (unlikely(ftrace_disabled)) + goto out; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); + + if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) + goto out; + + if (ftrace_enabled) { + + /* we are starting ftrace again */ + if (rcu_dereference_protected(ftrace_ops_list, + lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) + update_ftrace_function(); + + ftrace_startup_sysctl(); + + } else { + if (is_permanent_ops_registered()) { + ftrace_enabled = true; + ret = -EBUSY; + goto out; + } + + /* stopping ftrace calls (just send to ftrace_stub) */ + ftrace_trace_function = ftrace_stub; + + ftrace_shutdown_sysctl(); + } + + last_ftrace_enabled = !!ftrace_enabled; + out: + mutex_unlock(&ftrace_lock); + return ret; +} + +static struct ctl_table ftrace_sysctls[] = { + { + .procname = "ftrace_enabled", + .data = &ftrace_enabled, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = ftrace_enable_sysctl, + }, + {} +}; + +static int __init ftrace_sysctl_init(void) +{ + register_sysctl_init("kernel", ftrace_sysctls); + return 0; +} +late_initcall(ftrace_sysctl_init); +#endif |