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