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 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS 245 #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS 246 #else 247 #define FTRACE_OPS_FL_SAVE_ARGS 0 248 #endif 249 250 /* 251 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes 252 * to a ftrace_ops. Note, the requests may fail. 253 * 254 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same 255 * function as an ops with IPMODIFY. Called 256 * when the DIRECT ops is being registered. 257 * This is called with both direct_mutex and 258 * ftrace_lock are locked. 259 * 260 * ENABLE_SHARE_IPMODIFY_PEER - enable 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 registered. 264 * This is called with direct_mutex locked. 265 * 266 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same 267 * function as an ops with IPMODIFY. Called 268 * when the other ops (the one with IPMODIFY) 269 * is being unregistered. 270 * This is called with direct_mutex locked. 271 */ 272 enum ftrace_ops_cmd { 273 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF, 274 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER, 275 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER, 276 }; 277 278 /* 279 * For most ftrace_ops_cmd, 280 * Returns: 281 * 0 - Success. 282 * Negative on failure. The return value is dependent on the 283 * callback. 284 */ 285 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd); 286 287 #ifdef CONFIG_DYNAMIC_FTRACE 288 /* The hash used to know what functions callbacks trace */ 289 struct ftrace_ops_hash { 290 struct ftrace_hash __rcu *notrace_hash; 291 struct ftrace_hash __rcu *filter_hash; 292 struct mutex regex_lock; 293 }; 294 295 void ftrace_free_init_mem(void); 296 void ftrace_free_mem(struct module *mod, void *start, void *end); 297 #else 298 static inline void ftrace_free_init_mem(void) 299 { 300 ftrace_boot_snapshot(); 301 } 302 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 303 #endif 304 305 /* 306 * Note, ftrace_ops can be referenced outside of RCU protection, unless 307 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 308 * core data, the unregistering of it will perform a scheduling on all CPUs 309 * to make sure that there are no more users. Depending on the load of the 310 * system that may take a bit of time. 311 * 312 * Any private data added must also take care not to be freed and if private 313 * data is added to a ftrace_ops that is in core code, the user of the 314 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 315 */ 316 struct ftrace_ops { 317 ftrace_func_t func; 318 struct ftrace_ops __rcu *next; 319 unsigned long flags; 320 void *private; 321 ftrace_func_t saved_func; 322 #ifdef CONFIG_DYNAMIC_FTRACE 323 struct ftrace_ops_hash local_hash; 324 struct ftrace_ops_hash *func_hash; 325 struct ftrace_ops_hash old_hash; 326 unsigned long trampoline; 327 unsigned long trampoline_size; 328 struct list_head list; 329 ftrace_ops_func_t ops_func; 330 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 331 unsigned long direct_call; 332 #endif 333 #endif 334 }; 335 336 extern struct ftrace_ops __rcu *ftrace_ops_list; 337 extern struct ftrace_ops ftrace_list_end; 338 339 /* 340 * Traverse the ftrace_ops_list, invoking all entries. The reason that we 341 * can use rcu_dereference_raw_check() is that elements removed from this list 342 * are simply leaked, so there is no need to interact with a grace-period 343 * mechanism. The rcu_dereference_raw_check() calls are needed to handle 344 * concurrent insertions into the ftrace_ops_list. 345 * 346 * Silly Alpha and silly pointer-speculation compiler optimizations! 347 */ 348 #define do_for_each_ftrace_op(op, list) \ 349 op = rcu_dereference_raw_check(list); \ 350 do 351 352 /* 353 * Optimized for just a single item in the list (as that is the normal case). 354 */ 355 #define while_for_each_ftrace_op(op) \ 356 while (likely(op = rcu_dereference_raw_check((op)->next)) && \ 357 unlikely((op) != &ftrace_list_end)) 358 359 /* 360 * Type of the current tracing. 361 */ 362 enum ftrace_tracing_type_t { 363 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 364 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 365 }; 366 367 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 368 extern enum ftrace_tracing_type_t ftrace_tracing_type; 369 370 /* 371 * The ftrace_ops must be a static and should also 372 * be read_mostly. These functions do modify read_mostly variables 373 * so use them sparely. Never free an ftrace_op or modify the 374 * next pointer after it has been registered. Even after unregistering 375 * it, the next pointer may still be used internally. 376 */ 377 int register_ftrace_function(struct ftrace_ops *ops); 378 int unregister_ftrace_function(struct ftrace_ops *ops); 379 380 extern void ftrace_stub(unsigned long a0, unsigned long a1, 381 struct ftrace_ops *op, struct ftrace_regs *fregs); 382 383 384 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs); 385 #else /* !CONFIG_FUNCTION_TRACER */ 386 /* 387 * (un)register_ftrace_function must be a macro since the ops parameter 388 * must not be evaluated. 389 */ 390 #define register_ftrace_function(ops) ({ 0; }) 391 #define unregister_ftrace_function(ops) ({ 0; }) 392 static inline void ftrace_kill(void) { } 393 static inline void ftrace_free_init_mem(void) { } 394 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 395 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) 396 { 397 return -EOPNOTSUPP; 398 } 399 #endif /* CONFIG_FUNCTION_TRACER */ 400 401 struct ftrace_func_entry { 402 struct hlist_node hlist; 403 unsigned long ip; 404 unsigned long direct; /* for direct lookup only */ 405 }; 406 407 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 408 extern int ftrace_direct_func_count; 409 unsigned long ftrace_find_rec_direct(unsigned long ip); 410 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 411 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 412 bool free_filters); 413 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 414 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); 415 416 void ftrace_stub_direct_tramp(void); 417 418 #else 419 struct ftrace_ops; 420 # define ftrace_direct_func_count 0 421 static inline unsigned long ftrace_find_rec_direct(unsigned long ip) 422 { 423 return 0; 424 } 425 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 426 { 427 return -ENODEV; 428 } 429 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 430 bool free_filters) 431 { 432 return -ENODEV; 433 } 434 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 435 { 436 return -ENODEV; 437 } 438 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr) 439 { 440 return -ENODEV; 441 } 442 443 /* 444 * This must be implemented by the architecture. 445 * It is the way the ftrace direct_ops helper, when called 446 * via ftrace (because there's other callbacks besides the 447 * direct call), can inform the architecture's trampoline that this 448 * routine has a direct caller, and what the caller is. 449 * 450 * For example, in x86, it returns the direct caller 451 * callback function via the regs->orig_ax parameter. 452 * Then in the ftrace trampoline, if this is set, it makes 453 * the return from the trampoline jump to the direct caller 454 * instead of going back to the function it just traced. 455 */ 456 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, 457 unsigned long addr) { } 458 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 459 460 #ifdef CONFIG_STACK_TRACER 461 462 extern int stack_tracer_enabled; 463 464 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer, 465 size_t *lenp, loff_t *ppos); 466 467 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 468 DECLARE_PER_CPU(int, disable_stack_tracer); 469 470 /** 471 * stack_tracer_disable - temporarily disable the stack tracer 472 * 473 * There's a few locations (namely in RCU) where stack tracing 474 * cannot be executed. This function is used to disable stack 475 * tracing during those critical sections. 476 * 477 * This function must be called with preemption or interrupts 478 * disabled and stack_tracer_enable() must be called shortly after 479 * while preemption or interrupts are still disabled. 480 */ 481 static inline void stack_tracer_disable(void) 482 { 483 /* Preemption or interrupts must be disabled */ 484 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 485 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 486 this_cpu_inc(disable_stack_tracer); 487 } 488 489 /** 490 * stack_tracer_enable - re-enable the stack tracer 491 * 492 * After stack_tracer_disable() is called, stack_tracer_enable() 493 * must be called shortly afterward. 494 */ 495 static inline void stack_tracer_enable(void) 496 { 497 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 498 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 499 this_cpu_dec(disable_stack_tracer); 500 } 501 #else 502 static inline void stack_tracer_disable(void) { } 503 static inline void stack_tracer_enable(void) { } 504 #endif 505 506 #ifdef CONFIG_DYNAMIC_FTRACE 507 508 void ftrace_arch_code_modify_prepare(void); 509 void ftrace_arch_code_modify_post_process(void); 510 511 enum ftrace_bug_type { 512 FTRACE_BUG_UNKNOWN, 513 FTRACE_BUG_INIT, 514 FTRACE_BUG_NOP, 515 FTRACE_BUG_CALL, 516 FTRACE_BUG_UPDATE, 517 }; 518 extern enum ftrace_bug_type ftrace_bug_type; 519 520 /* 521 * Archs can set this to point to a variable that holds the value that was 522 * expected at the call site before calling ftrace_bug(). 523 */ 524 extern const void *ftrace_expected; 525 526 void ftrace_bug(int err, struct dyn_ftrace *rec); 527 528 struct seq_file; 529 530 extern int ftrace_text_reserved(const void *start, const void *end); 531 532 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); 533 534 bool is_ftrace_trampoline(unsigned long addr); 535 536 /* 537 * The dyn_ftrace record's flags field is split into two parts. 538 * the first part which is '0-FTRACE_REF_MAX' is a counter of 539 * the number of callbacks that have registered the function that 540 * the dyn_ftrace descriptor represents. 541 * 542 * The second part is a mask: 543 * ENABLED - the function is being traced 544 * REGS - the record wants the function to save regs 545 * REGS_EN - the function is set up to save regs. 546 * IPMODIFY - the record allows for the IP address to be changed. 547 * DISABLED - the record is not ready to be touched yet 548 * DIRECT - there is a direct function to call 549 * CALL_OPS - the record can use callsite-specific ops 550 * CALL_OPS_EN - the function is set up to use callsite-specific ops 551 * 552 * When a new ftrace_ops is registered and wants a function to save 553 * pt_regs, the rec->flags REGS is set. When the function has been 554 * set up to save regs, the REG_EN flag is set. Once a function 555 * starts saving regs it will do so until all ftrace_ops are removed 556 * from tracing that function. 557 */ 558 enum { 559 FTRACE_FL_ENABLED = (1UL << 31), 560 FTRACE_FL_REGS = (1UL << 30), 561 FTRACE_FL_REGS_EN = (1UL << 29), 562 FTRACE_FL_TRAMP = (1UL << 28), 563 FTRACE_FL_TRAMP_EN = (1UL << 27), 564 FTRACE_FL_IPMODIFY = (1UL << 26), 565 FTRACE_FL_DISABLED = (1UL << 25), 566 FTRACE_FL_DIRECT = (1UL << 24), 567 FTRACE_FL_DIRECT_EN = (1UL << 23), 568 FTRACE_FL_CALL_OPS = (1UL << 22), 569 FTRACE_FL_CALL_OPS_EN = (1UL << 21), 570 }; 571 572 #define FTRACE_REF_MAX_SHIFT 21 573 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 574 575 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) 576 577 struct dyn_ftrace { 578 unsigned long ip; /* address of mcount call-site */ 579 unsigned long flags; 580 struct dyn_arch_ftrace arch; 581 }; 582 583 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 584 int remove, int reset); 585 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, 586 unsigned int cnt, int remove, int reset); 587 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 588 int len, int reset); 589 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 590 int len, int reset); 591 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 592 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 593 void ftrace_free_filter(struct ftrace_ops *ops); 594 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 595 596 enum { 597 FTRACE_UPDATE_CALLS = (1 << 0), 598 FTRACE_DISABLE_CALLS = (1 << 1), 599 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 600 FTRACE_START_FUNC_RET = (1 << 3), 601 FTRACE_STOP_FUNC_RET = (1 << 4), 602 FTRACE_MAY_SLEEP = (1 << 5), 603 }; 604 605 /* 606 * The FTRACE_UPDATE_* enum is used to pass information back 607 * from the ftrace_update_record() and ftrace_test_record() 608 * functions. These are called by the code update routines 609 * to find out what is to be done for a given function. 610 * 611 * IGNORE - The function is already what we want it to be 612 * MAKE_CALL - Start tracing the function 613 * MODIFY_CALL - Stop saving regs for the function 614 * MAKE_NOP - Stop tracing the function 615 */ 616 enum { 617 FTRACE_UPDATE_IGNORE, 618 FTRACE_UPDATE_MAKE_CALL, 619 FTRACE_UPDATE_MODIFY_CALL, 620 FTRACE_UPDATE_MAKE_NOP, 621 }; 622 623 enum { 624 FTRACE_ITER_FILTER = (1 << 0), 625 FTRACE_ITER_NOTRACE = (1 << 1), 626 FTRACE_ITER_PRINTALL = (1 << 2), 627 FTRACE_ITER_DO_PROBES = (1 << 3), 628 FTRACE_ITER_PROBE = (1 << 4), 629 FTRACE_ITER_MOD = (1 << 5), 630 FTRACE_ITER_ENABLED = (1 << 6), 631 }; 632 633 void arch_ftrace_update_code(int command); 634 void arch_ftrace_update_trampoline(struct ftrace_ops *ops); 635 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); 636 void arch_ftrace_trampoline_free(struct ftrace_ops *ops); 637 638 struct ftrace_rec_iter; 639 640 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 641 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 642 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 643 644 #define for_ftrace_rec_iter(iter) \ 645 for (iter = ftrace_rec_iter_start(); \ 646 iter; \ 647 iter = ftrace_rec_iter_next(iter)) 648 649 650 int ftrace_update_record(struct dyn_ftrace *rec, bool enable); 651 int ftrace_test_record(struct dyn_ftrace *rec, bool enable); 652 void ftrace_run_stop_machine(int command); 653 unsigned long ftrace_location(unsigned long ip); 654 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 655 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 656 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 657 658 extern ftrace_func_t ftrace_trace_function; 659 660 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 661 struct inode *inode, struct file *file); 662 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 663 size_t cnt, loff_t *ppos); 664 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 665 size_t cnt, loff_t *ppos); 666 int ftrace_regex_release(struct inode *inode, struct file *file); 667 668 void __init 669 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 670 671 /* defined in arch */ 672 extern int ftrace_ip_converted(unsigned long ip); 673 extern int ftrace_dyn_arch_init(void); 674 extern void ftrace_replace_code(int enable); 675 extern int ftrace_update_ftrace_func(ftrace_func_t func); 676 extern void ftrace_caller(void); 677 extern void ftrace_regs_caller(void); 678 extern void ftrace_call(void); 679 extern void ftrace_regs_call(void); 680 extern void mcount_call(void); 681 682 void ftrace_modify_all_code(int command); 683 684 #ifndef FTRACE_ADDR 685 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 686 #endif 687 688 #ifndef FTRACE_GRAPH_ADDR 689 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 690 #endif 691 692 #ifndef FTRACE_REGS_ADDR 693 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 694 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 695 #else 696 # define FTRACE_REGS_ADDR FTRACE_ADDR 697 #endif 698 #endif 699 700 /* 701 * If an arch would like functions that are only traced 702 * by the function graph tracer to jump directly to its own 703 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 704 * to be that address to jump to. 705 */ 706 #ifndef FTRACE_GRAPH_TRAMP_ADDR 707 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 708 #endif 709 710 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 711 extern void ftrace_graph_caller(void); 712 extern int ftrace_enable_ftrace_graph_caller(void); 713 extern int ftrace_disable_ftrace_graph_caller(void); 714 #else 715 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 716 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 717 #endif 718 719 /** 720 * ftrace_make_nop - convert code into nop 721 * @mod: module structure if called by module load initialization 722 * @rec: the call site record (e.g. mcount/fentry) 723 * @addr: the address that the call site should be calling 724 * 725 * This is a very sensitive operation and great care needs 726 * to be taken by the arch. The operation should carefully 727 * read the location, check to see if what is read is indeed 728 * what we expect it to be, and then on success of the compare, 729 * it should write to the location. 730 * 731 * The code segment at @rec->ip should be a caller to @addr 732 * 733 * Return must be: 734 * 0 on success 735 * -EFAULT on error reading the location 736 * -EINVAL on a failed compare of the contents 737 * -EPERM on error writing to the location 738 * Any other value will be considered a failure. 739 */ 740 extern int ftrace_make_nop(struct module *mod, 741 struct dyn_ftrace *rec, unsigned long addr); 742 743 /** 744 * ftrace_need_init_nop - return whether nop call sites should be initialized 745 * 746 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't 747 * need to call ftrace_init_nop() if the code is built with that flag. 748 * Architectures where this is not always the case may define their own 749 * condition. 750 * 751 * Return must be: 752 * 0 if ftrace_init_nop() should be called 753 * Nonzero if ftrace_init_nop() should not be called 754 */ 755 756 #ifndef ftrace_need_init_nop 757 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) 758 #endif 759 760 /** 761 * ftrace_init_nop - initialize a nop call site 762 * @mod: module structure if called by module load initialization 763 * @rec: the call site record (e.g. mcount/fentry) 764 * 765 * This is a very sensitive operation and great care needs 766 * to be taken by the arch. The operation should carefully 767 * read the location, check to see if what is read is indeed 768 * what we expect it to be, and then on success of the compare, 769 * it should write to the location. 770 * 771 * The code segment at @rec->ip should contain the contents created by 772 * the compiler 773 * 774 * Return must be: 775 * 0 on success 776 * -EFAULT on error reading the location 777 * -EINVAL on a failed compare of the contents 778 * -EPERM on error writing to the location 779 * Any other value will be considered a failure. 780 */ 781 #ifndef ftrace_init_nop 782 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) 783 { 784 return ftrace_make_nop(mod, rec, MCOUNT_ADDR); 785 } 786 #endif 787 788 /** 789 * ftrace_make_call - convert a nop call site into a call to addr 790 * @rec: the call site record (e.g. mcount/fentry) 791 * @addr: the address that the call site should call 792 * 793 * This is a very sensitive operation and great care needs 794 * to be taken by the arch. The operation should carefully 795 * read the location, check to see if what is read is indeed 796 * what we expect it to be, and then on success of the compare, 797 * it should write to the location. 798 * 799 * The code segment at @rec->ip should be a nop 800 * 801 * Return must be: 802 * 0 on success 803 * -EFAULT on error reading the location 804 * -EINVAL on a failed compare of the contents 805 * -EPERM on error writing to the location 806 * Any other value will be considered a failure. 807 */ 808 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 809 810 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \ 811 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) 812 /** 813 * ftrace_modify_call - convert from one addr to another (no nop) 814 * @rec: the call site record (e.g. mcount/fentry) 815 * @old_addr: the address expected to be currently called to 816 * @addr: the address to change to 817 * 818 * This is a very sensitive operation and great care needs 819 * to be taken by the arch. The operation should carefully 820 * read the location, check to see if what is read is indeed 821 * what we expect it to be, and then on success of the compare, 822 * it should write to the location. 823 * 824 * When using call ops, this is called when the associated ops change, even 825 * when (addr == old_addr). 826 * 827 * The code segment at @rec->ip should be a caller to @old_addr 828 * 829 * Return must be: 830 * 0 on success 831 * -EFAULT on error reading the location 832 * -EINVAL on a failed compare of the contents 833 * -EPERM on error writing to the location 834 * Any other value will be considered a failure. 835 */ 836 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 837 unsigned long addr); 838 #else 839 /* Should never be called */ 840 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 841 unsigned long addr) 842 { 843 return -EINVAL; 844 } 845 #endif 846 847 /* May be defined in arch */ 848 extern int ftrace_arch_read_dyn_info(char *buf, int size); 849 850 extern int skip_trace(unsigned long ip); 851 extern void ftrace_module_init(struct module *mod); 852 extern void ftrace_module_enable(struct module *mod); 853 extern void ftrace_release_mod(struct module *mod); 854 855 extern void ftrace_disable_daemon(void); 856 extern void ftrace_enable_daemon(void); 857 #else /* CONFIG_DYNAMIC_FTRACE */ 858 static inline int skip_trace(unsigned long ip) { return 0; } 859 static inline void ftrace_disable_daemon(void) { } 860 static inline void ftrace_enable_daemon(void) { } 861 static inline void ftrace_module_init(struct module *mod) { } 862 static inline void ftrace_module_enable(struct module *mod) { } 863 static inline void ftrace_release_mod(struct module *mod) { } 864 static inline int ftrace_text_reserved(const void *start, const void *end) 865 { 866 return 0; 867 } 868 static inline unsigned long ftrace_location(unsigned long ip) 869 { 870 return 0; 871 } 872 873 /* 874 * Again users of functions that have ftrace_ops may not 875 * have them defined when ftrace is not enabled, but these 876 * functions may still be called. Use a macro instead of inline. 877 */ 878 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 879 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 880 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 881 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) 882 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 883 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 884 #define ftrace_free_filter(ops) do { } while (0) 885 #define ftrace_ops_set_global_filter(ops) do { } while (0) 886 887 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 888 size_t cnt, loff_t *ppos) { return -ENODEV; } 889 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 890 size_t cnt, loff_t *ppos) { return -ENODEV; } 891 static inline int 892 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 893 894 static inline bool is_ftrace_trampoline(unsigned long addr) 895 { 896 return false; 897 } 898 #endif /* CONFIG_DYNAMIC_FTRACE */ 899 900 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 901 #ifndef ftrace_graph_func 902 #define ftrace_graph_func ftrace_stub 903 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB 904 #else 905 #define FTRACE_OPS_GRAPH_STUB 0 906 #endif 907 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 908 909 /* totally disable ftrace - can not re-enable after this */ 910 void ftrace_kill(void); 911 912 static inline void tracer_disable(void) 913 { 914 #ifdef CONFIG_FUNCTION_TRACER 915 ftrace_enabled = 0; 916 #endif 917 } 918 919 /* 920 * Ftrace disable/restore without lock. Some synchronization mechanism 921 * must be used to prevent ftrace_enabled to be changed between 922 * disable/restore. 923 */ 924 static inline int __ftrace_enabled_save(void) 925 { 926 #ifdef CONFIG_FUNCTION_TRACER 927 int saved_ftrace_enabled = ftrace_enabled; 928 ftrace_enabled = 0; 929 return saved_ftrace_enabled; 930 #else 931 return 0; 932 #endif 933 } 934 935 static inline void __ftrace_enabled_restore(int enabled) 936 { 937 #ifdef CONFIG_FUNCTION_TRACER 938 ftrace_enabled = enabled; 939 #endif 940 } 941 942 /* All archs should have this, but we define it for consistency */ 943 #ifndef ftrace_return_address0 944 # define ftrace_return_address0 __builtin_return_address(0) 945 #endif 946 947 /* Archs may use other ways for ADDR1 and beyond */ 948 #ifndef ftrace_return_address 949 # ifdef CONFIG_FRAME_POINTER 950 # define ftrace_return_address(n) __builtin_return_address(n) 951 # else 952 # define ftrace_return_address(n) 0UL 953 # endif 954 #endif 955 956 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 957 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 958 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 959 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 960 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 961 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 962 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 963 964 static __always_inline unsigned long get_lock_parent_ip(void) 965 { 966 unsigned long addr = CALLER_ADDR0; 967 968 if (!in_lock_functions(addr)) 969 return addr; 970 addr = CALLER_ADDR1; 971 if (!in_lock_functions(addr)) 972 return addr; 973 return CALLER_ADDR2; 974 } 975 976 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE 977 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 978 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 979 #else 980 /* 981 * Use defines instead of static inlines because some arches will make code out 982 * of the CALLER_ADDR, when we really want these to be a real nop. 983 */ 984 # define trace_preempt_on(a0, a1) do { } while (0) 985 # define trace_preempt_off(a0, a1) do { } while (0) 986 #endif 987 988 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 989 extern void ftrace_init(void); 990 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY 991 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries" 992 #else 993 #define FTRACE_CALLSITE_SECTION "__mcount_loc" 994 #endif 995 #else 996 static inline void ftrace_init(void) { } 997 #endif 998 999 /* 1000 * Structure that defines an entry function trace. 1001 * It's already packed but the attribute "packed" is needed 1002 * to remove extra padding at the end. 1003 */ 1004 struct ftrace_graph_ent { 1005 unsigned long func; /* Current function */ 1006 int depth; 1007 } __packed; 1008 1009 /* 1010 * Structure that defines a return function trace. 1011 * It's already packed but the attribute "packed" is needed 1012 * to remove extra padding at the end. 1013 */ 1014 struct ftrace_graph_ret { 1015 unsigned long func; /* Current function */ 1016 int depth; 1017 /* Number of functions that overran the depth limit for current task */ 1018 unsigned int overrun; 1019 unsigned long long calltime; 1020 unsigned long long rettime; 1021 } __packed; 1022 1023 /* Type of the callback handlers for tracing function graph*/ 1024 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ 1025 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ 1026 1027 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); 1028 1029 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1030 1031 struct fgraph_ops { 1032 trace_func_graph_ent_t entryfunc; 1033 trace_func_graph_ret_t retfunc; 1034 }; 1035 1036 /* 1037 * Stack of return addresses for functions 1038 * of a thread. 1039 * Used in struct thread_info 1040 */ 1041 struct ftrace_ret_stack { 1042 unsigned long ret; 1043 unsigned long func; 1044 unsigned long long calltime; 1045 #ifdef CONFIG_FUNCTION_PROFILER 1046 unsigned long long subtime; 1047 #endif 1048 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 1049 unsigned long fp; 1050 #endif 1051 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 1052 unsigned long *retp; 1053 #endif 1054 }; 1055 1056 /* 1057 * Primary handler of a function return. 1058 * It relays on ftrace_return_to_handler. 1059 * Defined in entry_32/64.S 1060 */ 1061 extern void return_to_handler(void); 1062 1063 extern int 1064 function_graph_enter(unsigned long ret, unsigned long func, 1065 unsigned long frame_pointer, unsigned long *retp); 1066 1067 struct ftrace_ret_stack * 1068 ftrace_graph_get_ret_stack(struct task_struct *task, int idx); 1069 1070 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 1071 unsigned long ret, unsigned long *retp); 1072 1073 /* 1074 * Sometimes we don't want to trace a function with the function 1075 * graph tracer but we want them to keep traced by the usual function 1076 * tracer if the function graph tracer is not configured. 1077 */ 1078 #define __notrace_funcgraph notrace 1079 1080 #define FTRACE_RETFUNC_DEPTH 50 1081 #define FTRACE_RETSTACK_ALLOC_SIZE 32 1082 1083 extern int register_ftrace_graph(struct fgraph_ops *ops); 1084 extern void unregister_ftrace_graph(struct fgraph_ops *ops); 1085 1086 /** 1087 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called 1088 * 1089 * ftrace_graph_stop() is called when a severe error is detected in 1090 * the function graph tracing. This function is called by the critical 1091 * paths of function graph to keep those paths from doing any more harm. 1092 */ 1093 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); 1094 1095 static inline bool ftrace_graph_is_dead(void) 1096 { 1097 return static_branch_unlikely(&kill_ftrace_graph); 1098 } 1099 1100 extern void ftrace_graph_stop(void); 1101 1102 /* The current handlers in use */ 1103 extern trace_func_graph_ret_t ftrace_graph_return; 1104 extern trace_func_graph_ent_t ftrace_graph_entry; 1105 1106 extern void ftrace_graph_init_task(struct task_struct *t); 1107 extern void ftrace_graph_exit_task(struct task_struct *t); 1108 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 1109 1110 static inline void pause_graph_tracing(void) 1111 { 1112 atomic_inc(¤t->tracing_graph_pause); 1113 } 1114 1115 static inline void unpause_graph_tracing(void) 1116 { 1117 atomic_dec(¤t->tracing_graph_pause); 1118 } 1119 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 1120 1121 #define __notrace_funcgraph 1122 1123 static inline void ftrace_graph_init_task(struct task_struct *t) { } 1124 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 1125 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 1126 1127 /* Define as macros as fgraph_ops may not be defined */ 1128 #define register_ftrace_graph(ops) ({ -1; }) 1129 #define unregister_ftrace_graph(ops) do { } while (0) 1130 1131 static inline unsigned long 1132 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 1133 unsigned long *retp) 1134 { 1135 return ret; 1136 } 1137 1138 static inline void pause_graph_tracing(void) { } 1139 static inline void unpause_graph_tracing(void) { } 1140 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1141 1142 #ifdef CONFIG_TRACING 1143 enum ftrace_dump_mode; 1144 1145 extern enum ftrace_dump_mode ftrace_dump_on_oops; 1146 extern int tracepoint_printk; 1147 1148 extern void disable_trace_on_warning(void); 1149 extern int __disable_trace_on_warning; 1150 1151 int tracepoint_printk_sysctl(struct ctl_table *table, int write, 1152 void *buffer, size_t *lenp, loff_t *ppos); 1153 1154 #else /* CONFIG_TRACING */ 1155 static inline void disable_trace_on_warning(void) { } 1156 #endif /* CONFIG_TRACING */ 1157 1158 #ifdef CONFIG_FTRACE_SYSCALLS 1159 1160 unsigned long arch_syscall_addr(int nr); 1161 1162 #endif /* CONFIG_FTRACE_SYSCALLS */ 1163 1164 #endif /* _LINUX_FTRACE_H */ 1165