diff options
| -rw-r--r-- | include/linux/ftrace.h | 12 | ||||
| -rw-r--r-- | kernel/kallsyms.c | 5 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 77 |
3 files changed, 88 insertions, 6 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e339dac91ee6..ce2c06f72e86 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -58,9 +58,6 @@ struct ftrace_direct_func; const char * ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, unsigned long *off, char **modname, char *sym); -int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, - char *type, char *name, - char *module_name, int *exported); #else static inline const char * ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, @@ -68,6 +65,13 @@ ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, { return NULL; } +#endif + +#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) +int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, + char *module_name, int *exported); +#else static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) @@ -76,7 +80,6 @@ static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *val } #endif - #ifdef CONFIG_FUNCTION_TRACER extern int ftrace_enabled; @@ -207,6 +210,7 @@ struct ftrace_ops { struct ftrace_ops_hash old_hash; unsigned long trampoline; unsigned long trampoline_size; + struct list_head list; #endif }; diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index c6cc293c0e67..834bfdc43235 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -482,6 +482,11 @@ static int get_ksymbol_mod(struct kallsym_iter *iter) return 1; } +/* + * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace + * purposes. In that case "__builtin__ftrace" is used as a module name, even + * though "__builtin__ftrace" is not a module. + */ static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter) { int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end, diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c163c3531faf..31675b209db2 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2764,6 +2764,38 @@ void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) { } +/* List of trace_ops that have allocated trampolines */ +static LIST_HEAD(ftrace_ops_trampoline_list); + +static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops) +{ + lockdep_assert_held(&ftrace_lock); + list_add_rcu(&ops->list, &ftrace_ops_trampoline_list); +} + +static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops) +{ + lockdep_assert_held(&ftrace_lock); + list_del_rcu(&ops->list); +} + +/* + * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols + * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is + * not a module. + */ +#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace" +#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline" + +static void ftrace_trampoline_free(struct ftrace_ops *ops) +{ + if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) && + ops->trampoline) + ftrace_remove_trampoline_from_kallsyms(ops); + + arch_ftrace_trampoline_free(ops); +} + static void ftrace_startup_enable(int command) { if (saved_ftrace_func != ftrace_trace_function) { @@ -2934,7 +2966,7 @@ int ftrace_shutdown(struct ftrace_ops *ops, int command) synchronize_rcu_tasks(); free_ops: - arch_ftrace_trampoline_free(ops); + ftrace_trampoline_free(ops); } return 0; @@ -6178,6 +6210,27 @@ struct ftrace_mod_map { unsigned int num_funcs; }; +static int ftrace_get_trampoline_kallsym(unsigned int symnum, + unsigned long *value, char *type, + char *name, char *module_name, + int *exported) +{ + struct ftrace_ops *op; + + list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) { + if (!op->trampoline || symnum--) + continue; + *value = op->trampoline; + *type = 't'; + strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN); + strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN); + *exported = 0; + return 0; + } + + return -ERANGE; +} + #ifdef CONFIG_MODULES #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) @@ -6514,6 +6567,7 @@ int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, { struct ftrace_mod_map *mod_map; struct ftrace_mod_func *mod_func; + int ret; preempt_disable(); list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) { @@ -6540,8 +6594,10 @@ int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, WARN_ON(1); break; } + ret = ftrace_get_trampoline_kallsym(symnum, value, type, name, + module_name, exported); preempt_enable(); - return -ERANGE; + return ret; } #else @@ -6553,6 +6609,18 @@ allocate_ftrace_mod_map(struct module *mod, { return NULL; } +int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, char *module_name, + int *exported) +{ + int ret; + + preempt_disable(); + ret = ftrace_get_trampoline_kallsym(symnum, value, type, name, + module_name, exported); + preempt_enable(); + return ret; +} #endif /* CONFIG_MODULES */ struct ftrace_init_func { @@ -6733,7 +6801,12 @@ void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) static void ftrace_update_trampoline(struct ftrace_ops *ops) { + unsigned long trampoline = ops->trampoline; + arch_ftrace_update_trampoline(ops); + if (ops->trampoline && ops->trampoline != trampoline && + (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) + ftrace_add_trampoline_to_kallsyms(ops); } void ftrace_init_trace_array(struct trace_array *tr) |