1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Ftrace header. For implementation details beyond the random comments 4 * scattered below, see: Documentation/trace/ftrace-design.rst 5 */ 6 7 #ifndef _LINUX_FTRACE_H 8 #define _LINUX_FTRACE_H 9 10 #include <linux/trace_recursion.h> 11 #include <linux/trace_clock.h> 12 #include <linux/jump_label.h> 13 #include <linux/kallsyms.h> 14 #include <linux/linkage.h> 15 #include <linux/bitops.h> 16 #include <linux/ptrace.h> 17 #include <linux/ktime.h> 18 #include <linux/sched.h> 19 #include <linux/types.h> 20 #include <linux/init.h> 21 #include <linux/fs.h> 22 23 #include <asm/ftrace.h> 24 25 /* 26 * If the arch supports passing the variable contents of 27 * function_trace_op as the third parameter back from the 28 * mcount call, then the arch should define this as 1. 29 */ 30 #ifndef ARCH_SUPPORTS_FTRACE_OPS 31 #define ARCH_SUPPORTS_FTRACE_OPS 0 32 #endif 33 34 #ifdef CONFIG_TRACING 35 extern void ftrace_boot_snapshot(void); 36 #else 37 static inline void ftrace_boot_snapshot(void) { } 38 #endif 39 40 #ifdef CONFIG_FUNCTION_TRACER 41 struct ftrace_ops; 42 struct ftrace_regs; 43 /* 44 * If the arch's mcount caller does not support all of ftrace's 45 * features, then it must call an indirect function that 46 * does. Or at least does enough to prevent any unwelcome side effects. 47 * 48 * Also define the function prototype that these architectures use 49 * to call the ftrace_ops_list_func(). 50 */ 51 #if !ARCH_SUPPORTS_FTRACE_OPS 52 # define FTRACE_FORCE_LIST_FUNC 1 53 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip); 54 #else 55 # define FTRACE_FORCE_LIST_FUNC 0 56 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 57 struct ftrace_ops *op, struct ftrace_regs *fregs); 58 #endif 59 #endif /* CONFIG_FUNCTION_TRACER */ 60 61 /* Main tracing buffer and events set up */ 62 #ifdef CONFIG_TRACING 63 void trace_init(void); 64 void early_trace_init(void); 65 #else 66 static inline void trace_init(void) { } 67 static inline void early_trace_init(void) { } 68 #endif 69 70 struct module; 71 struct ftrace_hash; 72 struct ftrace_direct_func; 73 74 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \ 75 defined(CONFIG_DYNAMIC_FTRACE) 76 const char * 77 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, 78 unsigned long *off, char **modname, char *sym); 79 #else 80 static inline const char * 81 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, 82 unsigned long *off, char **modname, char *sym) 83 { 84 return NULL; 85 } 86 #endif 87 88 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) 89 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, 90 char *type, char *name, 91 char *module_name, int *exported); 92 #else 93 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, 94 char *type, char *name, 95 char *module_name, int *exported) 96 { 97 return -1; 98 } 99 #endif 100 101 #ifdef CONFIG_FUNCTION_TRACER 102 103 extern int ftrace_enabled; 104 105 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS 106 107 struct ftrace_regs { 108 struct pt_regs regs; 109 }; 110 #define arch_ftrace_get_regs(fregs) (&(fregs)->regs) 111 112 /* 113 * ftrace_instruction_pointer_set() is to be defined by the architecture 114 * if to allow setting of the instruction pointer from the ftrace_regs 115 * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports 116 * live kernel patching. 117 */ 118 #define ftrace_instruction_pointer_set(fregs, ip) do { } while (0) 119 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ 120 121 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs) 122 { 123 if (!fregs) 124 return NULL; 125 126 return arch_ftrace_get_regs(fregs); 127 } 128 129 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, 130 struct ftrace_ops *op, struct ftrace_regs *fregs); 131 132 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 133 134 /* 135 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are 136 * set in the flags member. 137 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and 138 * IPMODIFY are a kind of attribute flags which can be set only before 139 * registering the ftrace_ops, and can not be modified while registered. 140 * Changing those attribute flags after registering ftrace_ops will 141 * cause unexpected results. 142 * 143 * ENABLED - set/unset when ftrace_ops is registered/unregistered 144 * DYNAMIC - set when ftrace_ops is registered to denote dynamically 145 * allocated ftrace_ops which need special care 146 * SAVE_REGS - The ftrace_ops wants regs saved at each function called 147 * and passed to the callback. If this flag is set, but the 148 * architecture does not support passing regs 149 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the 150 * ftrace_ops will fail to register, unless the next flag 151 * is set. 152 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the 153 * handler can handle an arch that does not save regs 154 * (the handler tests if regs == NULL), then it can set 155 * this flag instead. It will not fail registering the ftrace_ops 156 * but, the regs field will be NULL if the arch does not support 157 * passing regs to the handler. 158 * Note, if this flag is set, the SAVE_REGS flag will automatically 159 * get set upon registering the ftrace_ops, if the arch supports it. 160 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure 161 * that the call back needs recursion protection. If it does 162 * not set this, then the ftrace infrastructure will assume 163 * that the callback can handle recursion on its own. 164 * STUB - The ftrace_ops is just a place holder. 165 * INITIALIZED - The ftrace_ops has already been initialized (first use time 166 * register_ftrace_function() is called, it will initialized the ops) 167 * DELETED - The ops are being deleted, do not let them be registered again. 168 * ADDING - The ops is in the process of being added. 169 * REMOVING - The ops is in the process of being removed. 170 * MODIFYING - The ops is in the process of changing its filter functions. 171 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code. 172 * The arch specific code sets this flag when it allocated a 173 * trampoline. This lets the arch know that it can update the 174 * trampoline in case the callback function changes. 175 * The ftrace_ops trampoline can be set by the ftrace users, and 176 * in such cases the arch must not modify it. Only the arch ftrace 177 * core code should set this flag. 178 * IPMODIFY - The ops can modify the IP register. This can only be set with 179 * SAVE_REGS. If another ops with this flag set is already registered 180 * for any of the functions that this ops will be registered for, then 181 * this ops will fail to register or set_filter_ip. 182 * PID - Is affected by set_ftrace_pid (allows filtering on those pids) 183 * RCU - Set when the ops can only be called when RCU is watching. 184 * TRACE_ARRAY - The ops->private points to a trace_array descriptor. 185 * PERMANENT - Set when the ops is permanent and should not be affected by 186 * ftrace_enabled. 187 * DIRECT - Used by the direct ftrace_ops helper for direct functions 188 * (internal ftrace only, should not be used by others) 189 */ 190 enum { 191 FTRACE_OPS_FL_ENABLED = BIT(0), 192 FTRACE_OPS_FL_DYNAMIC = BIT(1), 193 FTRACE_OPS_FL_SAVE_REGS = BIT(2), 194 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3), 195 FTRACE_OPS_FL_RECURSION = BIT(4), 196 FTRACE_OPS_FL_STUB = BIT(5), 197 FTRACE_OPS_FL_INITIALIZED = BIT(6), 198 FTRACE_OPS_FL_DELETED = BIT(7), 199 FTRACE_OPS_FL_ADDING = BIT(8), 200 FTRACE_OPS_FL_REMOVING = BIT(9), 201 FTRACE_OPS_FL_MODIFYING = BIT(10), 202 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11), 203 FTRACE_OPS_FL_IPMODIFY = BIT(12), 204 FTRACE_OPS_FL_PID = BIT(13), 205 FTRACE_OPS_FL_RCU = BIT(14), 206 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15), 207 FTRACE_OPS_FL_PERMANENT = BIT(16), 208 FTRACE_OPS_FL_DIRECT = BIT(17), 209 }; 210 211 /* 212 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes 213 * to a ftrace_ops. Note, the requests may fail. 214 * 215 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same 216 * function as an ops with IPMODIFY. Called 217 * when the DIRECT ops is being registered. 218 * This is called with both direct_mutex and 219 * ftrace_lock are locked. 220 * 221 * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same 222 * function as an ops with IPMODIFY. Called 223 * when the other ops (the one with IPMODIFY) 224 * is being registered. 225 * This is called with direct_mutex locked. 226 * 227 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same 228 * function as an ops with IPMODIFY. Called 229 * when the other ops (the one with IPMODIFY) 230 * is being unregistered. 231 * This is called with direct_mutex locked. 232 */ 233 enum ftrace_ops_cmd { 234 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF, 235 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER, 236 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER, 237 }; 238 239 /* 240 * For most ftrace_ops_cmd, 241 * Returns: 242 * 0 - Success. 243 * Negative on failure. The return value is dependent on the 244 * callback. 245 */ 246 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd); 247 248 #ifdef CONFIG_DYNAMIC_FTRACE 249 /* The hash used to know what functions callbacks trace */ 250 struct ftrace_ops_hash { 251 struct ftrace_hash __rcu *notrace_hash; 252 struct ftrace_hash __rcu *filter_hash; 253 struct mutex regex_lock; 254 }; 255 256 void ftrace_free_init_mem(void); 257 void ftrace_free_mem(struct module *mod, void *start, void *end); 258 #else 259 static inline void ftrace_free_init_mem(void) 260 { 261 ftrace_boot_snapshot(); 262 } 263 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 264 #endif 265 266 /* 267 * Note, ftrace_ops can be referenced outside of RCU protection, unless 268 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 269 * core data, the unregistering of it will perform a scheduling on all CPUs 270 * to make sure that there are no more users. Depending on the load of the 271 * system that may take a bit of time. 272 * 273 * Any private data added must also take care not to be freed and if private 274 * data is added to a ftrace_ops that is in core code, the user of the 275 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 276 */ 277 struct ftrace_ops { 278 ftrace_func_t func; 279 struct ftrace_ops __rcu *next; 280 unsigned long flags; 281 void *private; 282 ftrace_func_t saved_func; 283 #ifdef CONFIG_DYNAMIC_FTRACE 284 struct ftrace_ops_hash local_hash; 285 struct ftrace_ops_hash *func_hash; 286 struct ftrace_ops_hash old_hash; 287 unsigned long trampoline; 288 unsigned long trampoline_size; 289 struct list_head list; 290 ftrace_ops_func_t ops_func; 291 #endif 292 }; 293 294 extern struct ftrace_ops __rcu *ftrace_ops_list; 295 extern struct ftrace_ops ftrace_list_end; 296 297 /* 298 * Traverse the ftrace_ops_list, invoking all entries. The reason that we 299 * can use rcu_dereference_raw_check() is that elements removed from this list 300 * are simply leaked, so there is no need to interact with a grace-period 301 * mechanism. The rcu_dereference_raw_check() calls are needed to handle 302 * concurrent insertions into the ftrace_ops_list. 303 * 304 * Silly Alpha and silly pointer-speculation compiler optimizations! 305 */ 306 #define do_for_each_ftrace_op(op, list) \ 307 op = rcu_dereference_raw_check(list); \ 308 do 309 310 /* 311 * Optimized for just a single item in the list (as that is the normal case). 312 */ 313 #define while_for_each_ftrace_op(op) \ 314 while (likely(op = rcu_dereference_raw_check((op)->next)) && \ 315 unlikely((op) != &ftrace_list_end)) 316 317 /* 318 * Type of the current tracing. 319 */ 320 enum ftrace_tracing_type_t { 321 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 322 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 323 }; 324 325 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 326 extern enum ftrace_tracing_type_t ftrace_tracing_type; 327 328 /* 329 * The ftrace_ops must be a static and should also 330 * be read_mostly. These functions do modify read_mostly variables 331 * so use them sparely. Never free an ftrace_op or modify the 332 * next pointer after it has been registered. Even after unregistering 333 * it, the next pointer may still be used internally. 334 */ 335 int register_ftrace_function(struct ftrace_ops *ops); 336 int unregister_ftrace_function(struct ftrace_ops *ops); 337 338 extern void ftrace_stub(unsigned long a0, unsigned long a1, 339 struct ftrace_ops *op, struct ftrace_regs *fregs); 340 341 342 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs); 343 #else /* !CONFIG_FUNCTION_TRACER */ 344 /* 345 * (un)register_ftrace_function must be a macro since the ops parameter 346 * must not be evaluated. 347 */ 348 #define register_ftrace_function(ops) ({ 0; }) 349 #define unregister_ftrace_function(ops) ({ 0; }) 350 static inline void ftrace_kill(void) { } 351 static inline void ftrace_free_init_mem(void) { } 352 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 353 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) 354 { 355 return -EOPNOTSUPP; 356 } 357 #endif /* CONFIG_FUNCTION_TRACER */ 358 359 struct ftrace_func_entry { 360 struct hlist_node hlist; 361 unsigned long ip; 362 unsigned long direct; /* for direct lookup only */ 363 }; 364 365 struct dyn_ftrace; 366 367 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 368 extern int ftrace_direct_func_count; 369 int register_ftrace_direct(unsigned long ip, unsigned long addr); 370 int unregister_ftrace_direct(unsigned long ip, unsigned long addr); 371 int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr); 372 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr); 373 int ftrace_modify_direct_caller(struct ftrace_func_entry *entry, 374 struct dyn_ftrace *rec, 375 unsigned long old_addr, 376 unsigned long new_addr); 377 unsigned long ftrace_find_rec_direct(unsigned long ip); 378 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); 379 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); 380 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); 381 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr); 382 383 #else 384 struct ftrace_ops; 385 # define ftrace_direct_func_count 0 386 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr) 387 { 388 return -ENOTSUPP; 389 } 390 static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr) 391 { 392 return -ENOTSUPP; 393 } 394 static inline int modify_ftrace_direct(unsigned long ip, 395 unsigned long old_addr, unsigned long new_addr) 396 { 397 return -ENOTSUPP; 398 } 399 static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr) 400 { 401 return NULL; 402 } 403 static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry, 404 struct dyn_ftrace *rec, 405 unsigned long old_addr, 406 unsigned long new_addr) 407 { 408 return -ENODEV; 409 } 410 static inline unsigned long ftrace_find_rec_direct(unsigned long ip) 411 { 412 return 0; 413 } 414 static inline int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) 415 { 416 return -ENODEV; 417 } 418 static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) 419 { 420 return -ENODEV; 421 } 422 static inline int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) 423 { 424 return -ENODEV; 425 } 426 static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr) 427 { 428 return -ENODEV; 429 } 430 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 431 432 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 433 /* 434 * This must be implemented by the architecture. 435 * It is the way the ftrace direct_ops helper, when called 436 * via ftrace (because there's other callbacks besides the 437 * direct call), can inform the architecture's trampoline that this 438 * routine has a direct caller, and what the caller is. 439 * 440 * For example, in x86, it returns the direct caller 441 * callback function via the regs->orig_ax parameter. 442 * Then in the ftrace trampoline, if this is set, it makes 443 * the return from the trampoline jump to the direct caller 444 * instead of going back to the function it just traced. 445 */ 446 static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, 447 unsigned long addr) { } 448 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 449 450 #ifdef CONFIG_STACK_TRACER 451 452 extern int stack_tracer_enabled; 453 454 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer, 455 size_t *lenp, loff_t *ppos); 456 457 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 458 DECLARE_PER_CPU(int, disable_stack_tracer); 459 460 /** 461 * stack_tracer_disable - temporarily disable the stack tracer 462 * 463 * There's a few locations (namely in RCU) where stack tracing 464 * cannot be executed. This function is used to disable stack 465 * tracing during those critical sections. 466 * 467 * This function must be called with preemption or interrupts 468 * disabled and stack_tracer_enable() must be called shortly after 469 * while preemption or interrupts are still disabled. 470 */ 471 static inline void stack_tracer_disable(void) 472 { 473 /* Preemption or interrupts must be disabled */ 474 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 475 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 476 this_cpu_inc(disable_stack_tracer); 477 } 478 479 /** 480 * stack_tracer_enable - re-enable the stack tracer 481 * 482 * After stack_tracer_disable() is called, stack_tracer_enable() 483 * must be called shortly afterward. 484 */ 485 static inline void stack_tracer_enable(void) 486 { 487 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 488 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 489 this_cpu_dec(disable_stack_tracer); 490 } 491 #else 492 static inline void stack_tracer_disable(void) { } 493 static inline void stack_tracer_enable(void) { } 494 #endif 495 496 #ifdef CONFIG_DYNAMIC_FTRACE 497 498 void ftrace_arch_code_modify_prepare(void); 499 void ftrace_arch_code_modify_post_process(void); 500 501 enum ftrace_bug_type { 502 FTRACE_BUG_UNKNOWN, 503 FTRACE_BUG_INIT, 504 FTRACE_BUG_NOP, 505 FTRACE_BUG_CALL, 506 FTRACE_BUG_UPDATE, 507 }; 508 extern enum ftrace_bug_type ftrace_bug_type; 509 510 /* 511 * Archs can set this to point to a variable that holds the value that was 512 * expected at the call site before calling ftrace_bug(). 513 */ 514 extern const void *ftrace_expected; 515 516 void ftrace_bug(int err, struct dyn_ftrace *rec); 517 518 struct seq_file; 519 520 extern int ftrace_text_reserved(const void *start, const void *end); 521 522 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); 523 524 bool is_ftrace_trampoline(unsigned long addr); 525 526 /* 527 * The dyn_ftrace record's flags field is split into two parts. 528 * the first part which is '0-FTRACE_REF_MAX' is a counter of 529 * the number of callbacks that have registered the function that 530 * the dyn_ftrace descriptor represents. 531 * 532 * The second part is a mask: 533 * ENABLED - the function is being traced 534 * REGS - the record wants the function to save regs 535 * REGS_EN - the function is set up to save regs. 536 * IPMODIFY - the record allows for the IP address to be changed. 537 * DISABLED - the record is not ready to be touched yet 538 * DIRECT - there is a direct function to call 539 * 540 * When a new ftrace_ops is registered and wants a function to save 541 * pt_regs, the rec->flags REGS is set. When the function has been 542 * set up to save regs, the REG_EN flag is set. Once a function 543 * starts saving regs it will do so until all ftrace_ops are removed 544 * from tracing that function. 545 */ 546 enum { 547 FTRACE_FL_ENABLED = (1UL << 31), 548 FTRACE_FL_REGS = (1UL << 30), 549 FTRACE_FL_REGS_EN = (1UL << 29), 550 FTRACE_FL_TRAMP = (1UL << 28), 551 FTRACE_FL_TRAMP_EN = (1UL << 27), 552 FTRACE_FL_IPMODIFY = (1UL << 26), 553 FTRACE_FL_DISABLED = (1UL << 25), 554 FTRACE_FL_DIRECT = (1UL << 24), 555 FTRACE_FL_DIRECT_EN = (1UL << 23), 556 }; 557 558 #define FTRACE_REF_MAX_SHIFT 23 559 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 560 561 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) 562 563 struct dyn_ftrace { 564 unsigned long ip; /* address of mcount call-site */ 565 unsigned long flags; 566 struct dyn_arch_ftrace arch; 567 }; 568 569 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 570 int remove, int reset); 571 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, 572 unsigned int cnt, int remove, int reset); 573 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 574 int len, int reset); 575 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 576 int len, int reset); 577 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 578 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 579 void ftrace_free_filter(struct ftrace_ops *ops); 580 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 581 582 enum { 583 FTRACE_UPDATE_CALLS = (1 << 0), 584 FTRACE_DISABLE_CALLS = (1 << 1), 585 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 586 FTRACE_START_FUNC_RET = (1 << 3), 587 FTRACE_STOP_FUNC_RET = (1 << 4), 588 FTRACE_MAY_SLEEP = (1 << 5), 589 }; 590 591 /* 592 * The FTRACE_UPDATE_* enum is used to pass information back 593 * from the ftrace_update_record() and ftrace_test_record() 594 * functions. These are called by the code update routines 595 * to find out what is to be done for a given function. 596 * 597 * IGNORE - The function is already what we want it to be 598 * MAKE_CALL - Start tracing the function 599 * MODIFY_CALL - Stop saving regs for the function 600 * MAKE_NOP - Stop tracing the function 601 */ 602 enum { 603 FTRACE_UPDATE_IGNORE, 604 FTRACE_UPDATE_MAKE_CALL, 605 FTRACE_UPDATE_MODIFY_CALL, 606 FTRACE_UPDATE_MAKE_NOP, 607 }; 608 609 enum { 610 FTRACE_ITER_FILTER = (1 << 0), 611 FTRACE_ITER_NOTRACE = (1 << 1), 612 FTRACE_ITER_PRINTALL = (1 << 2), 613 FTRACE_ITER_DO_PROBES = (1 << 3), 614 FTRACE_ITER_PROBE = (1 << 4), 615 FTRACE_ITER_MOD = (1 << 5), 616 FTRACE_ITER_ENABLED = (1 << 6), 617 }; 618 619 void arch_ftrace_update_code(int command); 620 void arch_ftrace_update_trampoline(struct ftrace_ops *ops); 621 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); 622 void arch_ftrace_trampoline_free(struct ftrace_ops *ops); 623 624 struct ftrace_rec_iter; 625 626 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 627 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 628 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 629 630 #define for_ftrace_rec_iter(iter) \ 631 for (iter = ftrace_rec_iter_start(); \ 632 iter; \ 633 iter = ftrace_rec_iter_next(iter)) 634 635 636 int ftrace_update_record(struct dyn_ftrace *rec, bool enable); 637 int ftrace_test_record(struct dyn_ftrace *rec, bool enable); 638 void ftrace_run_stop_machine(int command); 639 unsigned long ftrace_location(unsigned long ip); 640 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 641 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 642 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 643 644 extern ftrace_func_t ftrace_trace_function; 645 646 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 647 struct inode *inode, struct file *file); 648 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 649 size_t cnt, loff_t *ppos); 650 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 651 size_t cnt, loff_t *ppos); 652 int ftrace_regex_release(struct inode *inode, struct file *file); 653 654 void __init 655 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 656 657 /* defined in arch */ 658 extern int ftrace_ip_converted(unsigned long ip); 659 extern int ftrace_dyn_arch_init(void); 660 extern void ftrace_replace_code(int enable); 661 extern int ftrace_update_ftrace_func(ftrace_func_t func); 662 extern void ftrace_caller(void); 663 extern void ftrace_regs_caller(void); 664 extern void ftrace_call(void); 665 extern void ftrace_regs_call(void); 666 extern void mcount_call(void); 667 668 void ftrace_modify_all_code(int command); 669 670 #ifndef FTRACE_ADDR 671 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 672 #endif 673 674 #ifndef FTRACE_GRAPH_ADDR 675 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 676 #endif 677 678 #ifndef FTRACE_REGS_ADDR 679 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 680 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 681 #else 682 # define FTRACE_REGS_ADDR FTRACE_ADDR 683 #endif 684 #endif 685 686 /* 687 * If an arch would like functions that are only traced 688 * by the function graph tracer to jump directly to its own 689 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 690 * to be that address to jump to. 691 */ 692 #ifndef FTRACE_GRAPH_TRAMP_ADDR 693 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 694 #endif 695 696 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 697 extern void ftrace_graph_caller(void); 698 extern int ftrace_enable_ftrace_graph_caller(void); 699 extern int ftrace_disable_ftrace_graph_caller(void); 700 #else 701 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 702 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 703 #endif 704 705 /** 706 * ftrace_make_nop - convert code into nop 707 * @mod: module structure if called by module load initialization 708 * @rec: the call site record (e.g. mcount/fentry) 709 * @addr: the address that the call site should be calling 710 * 711 * This is a very sensitive operation and great care needs 712 * to be taken by the arch. The operation should carefully 713 * read the location, check to see if what is read is indeed 714 * what we expect it to be, and then on success of the compare, 715 * it should write to the location. 716 * 717 * The code segment at @rec->ip should be a caller to @addr 718 * 719 * Return must be: 720 * 0 on success 721 * -EFAULT on error reading the location 722 * -EINVAL on a failed compare of the contents 723 * -EPERM on error writing to the location 724 * Any other value will be considered a failure. 725 */ 726 extern int ftrace_make_nop(struct module *mod, 727 struct dyn_ftrace *rec, unsigned long addr); 728 729 /** 730 * ftrace_need_init_nop - return whether nop call sites should be initialized 731 * 732 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't 733 * need to call ftrace_init_nop() if the code is built with that flag. 734 * Architectures where this is not always the case may define their own 735 * condition. 736 * 737 * Return must be: 738 * 0 if ftrace_init_nop() should be called 739 * Nonzero if ftrace_init_nop() should not be called 740 */ 741 742 #ifndef ftrace_need_init_nop 743 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) 744 #endif 745 746 /** 747 * ftrace_init_nop - initialize a nop call site 748 * @mod: module structure if called by module load initialization 749 * @rec: the call site record (e.g. mcount/fentry) 750 * 751 * This is a very sensitive operation and great care needs 752 * to be taken by the arch. The operation should carefully 753 * read the location, check to see if what is read is indeed 754 * what we expect it to be, and then on success of the compare, 755 * it should write to the location. 756 * 757 * The code segment at @rec->ip should contain the contents created by 758 * the compiler 759 * 760 * Return must be: 761 * 0 on success 762 * -EFAULT on error reading the location 763 * -EINVAL on a failed compare of the contents 764 * -EPERM on error writing to the location 765 * Any other value will be considered a failure. 766 */ 767 #ifndef ftrace_init_nop 768 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) 769 { 770 return ftrace_make_nop(mod, rec, MCOUNT_ADDR); 771 } 772 #endif 773 774 /** 775 * ftrace_make_call - convert a nop call site into a call to addr 776 * @rec: the call site record (e.g. mcount/fentry) 777 * @addr: the address that the call site should call 778 * 779 * This is a very sensitive operation and great care needs 780 * to be taken by the arch. The operation should carefully 781 * read the location, check to see if what is read is indeed 782 * what we expect it to be, and then on success of the compare, 783 * it should write to the location. 784 * 785 * The code segment at @rec->ip should be a nop 786 * 787 * Return must be: 788 * 0 on success 789 * -EFAULT on error reading the location 790 * -EINVAL on a failed compare of the contents 791 * -EPERM on error writing to the location 792 * Any other value will be considered a failure. 793 */ 794 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 795 796 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 797 /** 798 * ftrace_modify_call - convert from one addr to another (no nop) 799 * @rec: the call site record (e.g. mcount/fentry) 800 * @old_addr: the address expected to be currently called to 801 * @addr: the address to change to 802 * 803 * This is a very sensitive operation and great care needs 804 * to be taken by the arch. The operation should carefully 805 * read the location, check to see if what is read is indeed 806 * what we expect it to be, and then on success of the compare, 807 * it should write to the location. 808 * 809 * The code segment at @rec->ip should be a caller to @old_addr 810 * 811 * Return must be: 812 * 0 on success 813 * -EFAULT on error reading the location 814 * -EINVAL on a failed compare of the contents 815 * -EPERM on error writing to the location 816 * Any other value will be considered a failure. 817 */ 818 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 819 unsigned long addr); 820 #else 821 /* Should never be called */ 822 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 823 unsigned long addr) 824 { 825 return -EINVAL; 826 } 827 #endif 828 829 /* May be defined in arch */ 830 extern int ftrace_arch_read_dyn_info(char *buf, int size); 831 832 extern int skip_trace(unsigned long ip); 833 extern void ftrace_module_init(struct module *mod); 834 extern void ftrace_module_enable(struct module *mod); 835 extern void ftrace_release_mod(struct module *mod); 836 837 extern void ftrace_disable_daemon(void); 838 extern void ftrace_enable_daemon(void); 839 #else /* CONFIG_DYNAMIC_FTRACE */ 840 static inline int skip_trace(unsigned long ip) { return 0; } 841 static inline void ftrace_disable_daemon(void) { } 842 static inline void ftrace_enable_daemon(void) { } 843 static inline void ftrace_module_init(struct module *mod) { } 844 static inline void ftrace_module_enable(struct module *mod) { } 845 static inline void ftrace_release_mod(struct module *mod) { } 846 static inline int ftrace_text_reserved(const void *start, const void *end) 847 { 848 return 0; 849 } 850 static inline unsigned long ftrace_location(unsigned long ip) 851 { 852 return 0; 853 } 854 855 /* 856 * Again users of functions that have ftrace_ops may not 857 * have them defined when ftrace is not enabled, but these 858 * functions may still be called. Use a macro instead of inline. 859 */ 860 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 861 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 862 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 863 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) 864 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 865 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 866 #define ftrace_free_filter(ops) do { } while (0) 867 #define ftrace_ops_set_global_filter(ops) do { } while (0) 868 869 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 870 size_t cnt, loff_t *ppos) { return -ENODEV; } 871 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 872 size_t cnt, loff_t *ppos) { return -ENODEV; } 873 static inline int 874 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 875 876 static inline bool is_ftrace_trampoline(unsigned long addr) 877 { 878 return false; 879 } 880 #endif /* CONFIG_DYNAMIC_FTRACE */ 881 882 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 883 #ifndef ftrace_graph_func 884 #define ftrace_graph_func ftrace_stub 885 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB 886 #else 887 #define FTRACE_OPS_GRAPH_STUB 0 888 #endif 889 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 890 891 /* totally disable ftrace - can not re-enable after this */ 892 void ftrace_kill(void); 893 894 static inline void tracer_disable(void) 895 { 896 #ifdef CONFIG_FUNCTION_TRACER 897 ftrace_enabled = 0; 898 #endif 899 } 900 901 /* 902 * Ftrace disable/restore without lock. Some synchronization mechanism 903 * must be used to prevent ftrace_enabled to be changed between 904 * disable/restore. 905 */ 906 static inline int __ftrace_enabled_save(void) 907 { 908 #ifdef CONFIG_FUNCTION_TRACER 909 int saved_ftrace_enabled = ftrace_enabled; 910 ftrace_enabled = 0; 911 return saved_ftrace_enabled; 912 #else 913 return 0; 914 #endif 915 } 916 917 static inline void __ftrace_enabled_restore(int enabled) 918 { 919 #ifdef CONFIG_FUNCTION_TRACER 920 ftrace_enabled = enabled; 921 #endif 922 } 923 924 /* All archs should have this, but we define it for consistency */ 925 #ifndef ftrace_return_address0 926 # define ftrace_return_address0 __builtin_return_address(0) 927 #endif 928 929 /* Archs may use other ways for ADDR1 and beyond */ 930 #ifndef ftrace_return_address 931 # ifdef CONFIG_FRAME_POINTER 932 # define ftrace_return_address(n) __builtin_return_address(n) 933 # else 934 # define ftrace_return_address(n) 0UL 935 # endif 936 #endif 937 938 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 939 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 940 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 941 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 942 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 943 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 944 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 945 946 static inline unsigned long get_lock_parent_ip(void) 947 { 948 unsigned long addr = CALLER_ADDR0; 949 950 if (!in_lock_functions(addr)) 951 return addr; 952 addr = CALLER_ADDR1; 953 if (!in_lock_functions(addr)) 954 return addr; 955 return CALLER_ADDR2; 956 } 957 958 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE 959 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 960 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 961 #else 962 /* 963 * Use defines instead of static inlines because some arches will make code out 964 * of the CALLER_ADDR, when we really want these to be a real nop. 965 */ 966 # define trace_preempt_on(a0, a1) do { } while (0) 967 # define trace_preempt_off(a0, a1) do { } while (0) 968 #endif 969 970 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 971 extern void ftrace_init(void); 972 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY 973 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries" 974 #else 975 #define FTRACE_CALLSITE_SECTION "__mcount_loc" 976 #endif 977 #else 978 static inline void ftrace_init(void) { } 979 #endif 980 981 /* 982 * Structure that defines an entry function trace. 983 * It's already packed but the attribute "packed" is needed 984 * to remove extra padding at the end. 985 */ 986 struct ftrace_graph_ent { 987 unsigned long func; /* Current function */ 988 int depth; 989 } __packed; 990 991 /* 992 * Structure that defines a return function trace. 993 * It's already packed but the attribute "packed" is needed 994 * to remove extra padding at the end. 995 */ 996 struct ftrace_graph_ret { 997 unsigned long func; /* Current function */ 998 int depth; 999 /* Number of functions that overran the depth limit for current task */ 1000 unsigned int overrun; 1001 unsigned long long calltime; 1002 unsigned long long rettime; 1003 } __packed; 1004 1005 /* Type of the callback handlers for tracing function graph*/ 1006 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ 1007 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ 1008 1009 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); 1010 1011 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1012 1013 struct fgraph_ops { 1014 trace_func_graph_ent_t entryfunc; 1015 trace_func_graph_ret_t retfunc; 1016 }; 1017 1018 /* 1019 * Stack of return addresses for functions 1020 * of a thread. 1021 * Used in struct thread_info 1022 */ 1023 struct ftrace_ret_stack { 1024 unsigned long ret; 1025 unsigned long func; 1026 unsigned long long calltime; 1027 #ifdef CONFIG_FUNCTION_PROFILER 1028 unsigned long long subtime; 1029 #endif 1030 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 1031 unsigned long fp; 1032 #endif 1033 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 1034 unsigned long *retp; 1035 #endif 1036 }; 1037 1038 /* 1039 * Primary handler of a function return. 1040 * It relays on ftrace_return_to_handler. 1041 * Defined in entry_32/64.S 1042 */ 1043 extern void return_to_handler(void); 1044 1045 extern int 1046 function_graph_enter(unsigned long ret, unsigned long func, 1047 unsigned long frame_pointer, unsigned long *retp); 1048 1049 struct ftrace_ret_stack * 1050 ftrace_graph_get_ret_stack(struct task_struct *task, int idx); 1051 1052 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 1053 unsigned long ret, unsigned long *retp); 1054 1055 /* 1056 * Sometimes we don't want to trace a function with the function 1057 * graph tracer but we want them to keep traced by the usual function 1058 * tracer if the function graph tracer is not configured. 1059 */ 1060 #define __notrace_funcgraph notrace 1061 1062 #define FTRACE_RETFUNC_DEPTH 50 1063 #define FTRACE_RETSTACK_ALLOC_SIZE 32 1064 1065 extern int register_ftrace_graph(struct fgraph_ops *ops); 1066 extern void unregister_ftrace_graph(struct fgraph_ops *ops); 1067 1068 /** 1069 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called 1070 * 1071 * ftrace_graph_stop() is called when a severe error is detected in 1072 * the function graph tracing. This function is called by the critical 1073 * paths of function graph to keep those paths from doing any more harm. 1074 */ 1075 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); 1076 1077 static inline bool ftrace_graph_is_dead(void) 1078 { 1079 return static_branch_unlikely(&kill_ftrace_graph); 1080 } 1081 1082 extern void ftrace_graph_stop(void); 1083 1084 /* The current handlers in use */ 1085 extern trace_func_graph_ret_t ftrace_graph_return; 1086 extern trace_func_graph_ent_t ftrace_graph_entry; 1087 1088 extern void ftrace_graph_init_task(struct task_struct *t); 1089 extern void ftrace_graph_exit_task(struct task_struct *t); 1090 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 1091 1092 static inline void pause_graph_tracing(void) 1093 { 1094 atomic_inc(¤t->tracing_graph_pause); 1095 } 1096 1097 static inline void unpause_graph_tracing(void) 1098 { 1099 atomic_dec(¤t->tracing_graph_pause); 1100 } 1101 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 1102 1103 #define __notrace_funcgraph 1104 1105 static inline void ftrace_graph_init_task(struct task_struct *t) { } 1106 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 1107 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 1108 1109 /* Define as macros as fgraph_ops may not be defined */ 1110 #define register_ftrace_graph(ops) ({ -1; }) 1111 #define unregister_ftrace_graph(ops) do { } while (0) 1112 1113 static inline unsigned long 1114 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 1115 unsigned long *retp) 1116 { 1117 return ret; 1118 } 1119 1120 static inline void pause_graph_tracing(void) { } 1121 static inline void unpause_graph_tracing(void) { } 1122 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1123 1124 #ifdef CONFIG_TRACING 1125 1126 /* flags for current->trace */ 1127 enum { 1128 TSK_TRACE_FL_TRACE_BIT = 0, 1129 TSK_TRACE_FL_GRAPH_BIT = 1, 1130 }; 1131 enum { 1132 TSK_TRACE_FL_TRACE = 1 << TSK_TRACE_FL_TRACE_BIT, 1133 TSK_TRACE_FL_GRAPH = 1 << TSK_TRACE_FL_GRAPH_BIT, 1134 }; 1135 1136 static inline void set_tsk_trace_trace(struct task_struct *tsk) 1137 { 1138 set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 1139 } 1140 1141 static inline void clear_tsk_trace_trace(struct task_struct *tsk) 1142 { 1143 clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 1144 } 1145 1146 static inline int test_tsk_trace_trace(struct task_struct *tsk) 1147 { 1148 return tsk->trace & TSK_TRACE_FL_TRACE; 1149 } 1150 1151 static inline void set_tsk_trace_graph(struct task_struct *tsk) 1152 { 1153 set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 1154 } 1155 1156 static inline void clear_tsk_trace_graph(struct task_struct *tsk) 1157 { 1158 clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 1159 } 1160 1161 static inline int test_tsk_trace_graph(struct task_struct *tsk) 1162 { 1163 return tsk->trace & TSK_TRACE_FL_GRAPH; 1164 } 1165 1166 enum ftrace_dump_mode; 1167 1168 extern enum ftrace_dump_mode ftrace_dump_on_oops; 1169 extern int tracepoint_printk; 1170 1171 extern void disable_trace_on_warning(void); 1172 extern int __disable_trace_on_warning; 1173 1174 int tracepoint_printk_sysctl(struct ctl_table *table, int write, 1175 void *buffer, size_t *lenp, loff_t *ppos); 1176 1177 #else /* CONFIG_TRACING */ 1178 static inline void disable_trace_on_warning(void) { } 1179 #endif /* CONFIG_TRACING */ 1180 1181 #ifdef CONFIG_FTRACE_SYSCALLS 1182 1183 unsigned long arch_syscall_addr(int nr); 1184 1185 #endif /* CONFIG_FTRACE_SYSCALLS */ 1186 1187 #endif /* _LINUX_FTRACE_H */ 1188