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 * TOUCHED - A callback was added since boot up 552 * MODIFIED - The function had IPMODIFY or DIRECT attached to it 553 * 554 * When a new ftrace_ops is registered and wants a function to save 555 * pt_regs, the rec->flags REGS is set. When the function has been 556 * set up to save regs, the REG_EN flag is set. Once a function 557 * starts saving regs it will do so until all ftrace_ops are removed 558 * from tracing that function. 559 */ 560 enum { 561 FTRACE_FL_ENABLED = (1UL << 31), 562 FTRACE_FL_REGS = (1UL << 30), 563 FTRACE_FL_REGS_EN = (1UL << 29), 564 FTRACE_FL_TRAMP = (1UL << 28), 565 FTRACE_FL_TRAMP_EN = (1UL << 27), 566 FTRACE_FL_IPMODIFY = (1UL << 26), 567 FTRACE_FL_DISABLED = (1UL << 25), 568 FTRACE_FL_DIRECT = (1UL << 24), 569 FTRACE_FL_DIRECT_EN = (1UL << 23), 570 FTRACE_FL_CALL_OPS = (1UL << 22), 571 FTRACE_FL_CALL_OPS_EN = (1UL << 21), 572 FTRACE_FL_TOUCHED = (1UL << 20), 573 FTRACE_FL_MODIFIED = (1UL << 19), 574 }; 575 576 #define FTRACE_REF_MAX_SHIFT 19 577 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 578 579 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) 580 581 struct dyn_ftrace { 582 unsigned long ip; /* address of mcount call-site */ 583 unsigned long flags; 584 struct dyn_arch_ftrace arch; 585 }; 586 587 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 588 int remove, int reset); 589 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, 590 unsigned int cnt, int remove, int reset); 591 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 592 int len, int reset); 593 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 594 int len, int reset); 595 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 596 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 597 void ftrace_free_filter(struct ftrace_ops *ops); 598 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 599 600 enum { 601 FTRACE_UPDATE_CALLS = (1 << 0), 602 FTRACE_DISABLE_CALLS = (1 << 1), 603 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 604 FTRACE_START_FUNC_RET = (1 << 3), 605 FTRACE_STOP_FUNC_RET = (1 << 4), 606 FTRACE_MAY_SLEEP = (1 << 5), 607 }; 608 609 /* 610 * The FTRACE_UPDATE_* enum is used to pass information back 611 * from the ftrace_update_record() and ftrace_test_record() 612 * functions. These are called by the code update routines 613 * to find out what is to be done for a given function. 614 * 615 * IGNORE - The function is already what we want it to be 616 * MAKE_CALL - Start tracing the function 617 * MODIFY_CALL - Stop saving regs for the function 618 * MAKE_NOP - Stop tracing the function 619 */ 620 enum { 621 FTRACE_UPDATE_IGNORE, 622 FTRACE_UPDATE_MAKE_CALL, 623 FTRACE_UPDATE_MODIFY_CALL, 624 FTRACE_UPDATE_MAKE_NOP, 625 }; 626 627 enum { 628 FTRACE_ITER_FILTER = (1 << 0), 629 FTRACE_ITER_NOTRACE = (1 << 1), 630 FTRACE_ITER_PRINTALL = (1 << 2), 631 FTRACE_ITER_DO_PROBES = (1 << 3), 632 FTRACE_ITER_PROBE = (1 << 4), 633 FTRACE_ITER_MOD = (1 << 5), 634 FTRACE_ITER_ENABLED = (1 << 6), 635 FTRACE_ITER_TOUCHED = (1 << 7), 636 }; 637 638 void arch_ftrace_update_code(int command); 639 void arch_ftrace_update_trampoline(struct ftrace_ops *ops); 640 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); 641 void arch_ftrace_trampoline_free(struct ftrace_ops *ops); 642 643 struct ftrace_rec_iter; 644 645 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 646 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 647 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 648 649 #define for_ftrace_rec_iter(iter) \ 650 for (iter = ftrace_rec_iter_start(); \ 651 iter; \ 652 iter = ftrace_rec_iter_next(iter)) 653 654 655 int ftrace_update_record(struct dyn_ftrace *rec, bool enable); 656 int ftrace_test_record(struct dyn_ftrace *rec, bool enable); 657 void ftrace_run_stop_machine(int command); 658 unsigned long ftrace_location(unsigned long ip); 659 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 660 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 661 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 662 663 extern ftrace_func_t ftrace_trace_function; 664 665 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 666 struct inode *inode, struct file *file); 667 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 668 size_t cnt, loff_t *ppos); 669 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 670 size_t cnt, loff_t *ppos); 671 int ftrace_regex_release(struct inode *inode, struct file *file); 672 673 void __init 674 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 675 676 /* defined in arch */ 677 extern int ftrace_ip_converted(unsigned long ip); 678 extern int ftrace_dyn_arch_init(void); 679 extern void ftrace_replace_code(int enable); 680 extern int ftrace_update_ftrace_func(ftrace_func_t func); 681 extern void ftrace_caller(void); 682 extern void ftrace_regs_caller(void); 683 extern void ftrace_call(void); 684 extern void ftrace_regs_call(void); 685 extern void mcount_call(void); 686 687 void ftrace_modify_all_code(int command); 688 689 #ifndef FTRACE_ADDR 690 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 691 #endif 692 693 #ifndef FTRACE_GRAPH_ADDR 694 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 695 #endif 696 697 #ifndef FTRACE_REGS_ADDR 698 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 699 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 700 #else 701 # define FTRACE_REGS_ADDR FTRACE_ADDR 702 #endif 703 #endif 704 705 /* 706 * If an arch would like functions that are only traced 707 * by the function graph tracer to jump directly to its own 708 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 709 * to be that address to jump to. 710 */ 711 #ifndef FTRACE_GRAPH_TRAMP_ADDR 712 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 713 #endif 714 715 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 716 extern void ftrace_graph_caller(void); 717 extern int ftrace_enable_ftrace_graph_caller(void); 718 extern int ftrace_disable_ftrace_graph_caller(void); 719 #else 720 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 721 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 722 #endif 723 724 /** 725 * ftrace_make_nop - convert code into nop 726 * @mod: module structure if called by module load initialization 727 * @rec: the call site record (e.g. mcount/fentry) 728 * @addr: the address that the call site should be calling 729 * 730 * This is a very sensitive operation and great care needs 731 * to be taken by the arch. The operation should carefully 732 * read the location, check to see if what is read is indeed 733 * what we expect it to be, and then on success of the compare, 734 * it should write to the location. 735 * 736 * The code segment at @rec->ip should be a caller to @addr 737 * 738 * Return must be: 739 * 0 on success 740 * -EFAULT on error reading the location 741 * -EINVAL on a failed compare of the contents 742 * -EPERM on error writing to the location 743 * Any other value will be considered a failure. 744 */ 745 extern int ftrace_make_nop(struct module *mod, 746 struct dyn_ftrace *rec, unsigned long addr); 747 748 /** 749 * ftrace_need_init_nop - return whether nop call sites should be initialized 750 * 751 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't 752 * need to call ftrace_init_nop() if the code is built with that flag. 753 * Architectures where this is not always the case may define their own 754 * condition. 755 * 756 * Return must be: 757 * 0 if ftrace_init_nop() should be called 758 * Nonzero if ftrace_init_nop() should not be called 759 */ 760 761 #ifndef ftrace_need_init_nop 762 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) 763 #endif 764 765 /** 766 * ftrace_init_nop - initialize a nop call site 767 * @mod: module structure if called by module load initialization 768 * @rec: the call site record (e.g. mcount/fentry) 769 * 770 * This is a very sensitive operation and great care needs 771 * to be taken by the arch. The operation should carefully 772 * read the location, check to see if what is read is indeed 773 * what we expect it to be, and then on success of the compare, 774 * it should write to the location. 775 * 776 * The code segment at @rec->ip should contain the contents created by 777 * the compiler 778 * 779 * Return must be: 780 * 0 on success 781 * -EFAULT on error reading the location 782 * -EINVAL on a failed compare of the contents 783 * -EPERM on error writing to the location 784 * Any other value will be considered a failure. 785 */ 786 #ifndef ftrace_init_nop 787 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) 788 { 789 return ftrace_make_nop(mod, rec, MCOUNT_ADDR); 790 } 791 #endif 792 793 /** 794 * ftrace_make_call - convert a nop call site into a call to addr 795 * @rec: the call site record (e.g. mcount/fentry) 796 * @addr: the address that the call site should call 797 * 798 * This is a very sensitive operation and great care needs 799 * to be taken by the arch. The operation should carefully 800 * read the location, check to see if what is read is indeed 801 * what we expect it to be, and then on success of the compare, 802 * it should write to the location. 803 * 804 * The code segment at @rec->ip should be a nop 805 * 806 * Return must be: 807 * 0 on success 808 * -EFAULT on error reading the location 809 * -EINVAL on a failed compare of the contents 810 * -EPERM on error writing to the location 811 * Any other value will be considered a failure. 812 */ 813 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 814 815 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \ 816 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) 817 /** 818 * ftrace_modify_call - convert from one addr to another (no nop) 819 * @rec: the call site record (e.g. mcount/fentry) 820 * @old_addr: the address expected to be currently called to 821 * @addr: the address to change to 822 * 823 * This is a very sensitive operation and great care needs 824 * to be taken by the arch. The operation should carefully 825 * read the location, check to see if what is read is indeed 826 * what we expect it to be, and then on success of the compare, 827 * it should write to the location. 828 * 829 * When using call ops, this is called when the associated ops change, even 830 * when (addr == old_addr). 831 * 832 * The code segment at @rec->ip should be a caller to @old_addr 833 * 834 * Return must be: 835 * 0 on success 836 * -EFAULT on error reading the location 837 * -EINVAL on a failed compare of the contents 838 * -EPERM on error writing to the location 839 * Any other value will be considered a failure. 840 */ 841 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 842 unsigned long addr); 843 #else 844 /* Should never be called */ 845 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 846 unsigned long addr) 847 { 848 return -EINVAL; 849 } 850 #endif 851 852 /* May be defined in arch */ 853 extern int ftrace_arch_read_dyn_info(char *buf, int size); 854 855 extern int skip_trace(unsigned long ip); 856 extern void ftrace_module_init(struct module *mod); 857 extern void ftrace_module_enable(struct module *mod); 858 extern void ftrace_release_mod(struct module *mod); 859 860 extern void ftrace_disable_daemon(void); 861 extern void ftrace_enable_daemon(void); 862 #else /* CONFIG_DYNAMIC_FTRACE */ 863 static inline int skip_trace(unsigned long ip) { return 0; } 864 static inline void ftrace_disable_daemon(void) { } 865 static inline void ftrace_enable_daemon(void) { } 866 static inline void ftrace_module_init(struct module *mod) { } 867 static inline void ftrace_module_enable(struct module *mod) { } 868 static inline void ftrace_release_mod(struct module *mod) { } 869 static inline int ftrace_text_reserved(const void *start, const void *end) 870 { 871 return 0; 872 } 873 static inline unsigned long ftrace_location(unsigned long ip) 874 { 875 return 0; 876 } 877 878 /* 879 * Again users of functions that have ftrace_ops may not 880 * have them defined when ftrace is not enabled, but these 881 * functions may still be called. Use a macro instead of inline. 882 */ 883 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 884 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 885 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 886 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) 887 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 888 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 889 #define ftrace_free_filter(ops) do { } while (0) 890 #define ftrace_ops_set_global_filter(ops) do { } while (0) 891 892 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 893 size_t cnt, loff_t *ppos) { return -ENODEV; } 894 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 895 size_t cnt, loff_t *ppos) { return -ENODEV; } 896 static inline int 897 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 898 899 static inline bool is_ftrace_trampoline(unsigned long addr) 900 { 901 return false; 902 } 903 #endif /* CONFIG_DYNAMIC_FTRACE */ 904 905 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 906 #ifndef ftrace_graph_func 907 #define ftrace_graph_func ftrace_stub 908 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB 909 #else 910 #define FTRACE_OPS_GRAPH_STUB 0 911 #endif 912 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 913 914 /* totally disable ftrace - can not re-enable after this */ 915 void ftrace_kill(void); 916 917 static inline void tracer_disable(void) 918 { 919 #ifdef CONFIG_FUNCTION_TRACER 920 ftrace_enabled = 0; 921 #endif 922 } 923 924 /* 925 * Ftrace disable/restore without lock. Some synchronization mechanism 926 * must be used to prevent ftrace_enabled to be changed between 927 * disable/restore. 928 */ 929 static inline int __ftrace_enabled_save(void) 930 { 931 #ifdef CONFIG_FUNCTION_TRACER 932 int saved_ftrace_enabled = ftrace_enabled; 933 ftrace_enabled = 0; 934 return saved_ftrace_enabled; 935 #else 936 return 0; 937 #endif 938 } 939 940 static inline void __ftrace_enabled_restore(int enabled) 941 { 942 #ifdef CONFIG_FUNCTION_TRACER 943 ftrace_enabled = enabled; 944 #endif 945 } 946 947 /* All archs should have this, but we define it for consistency */ 948 #ifndef ftrace_return_address0 949 # define ftrace_return_address0 __builtin_return_address(0) 950 #endif 951 952 /* Archs may use other ways for ADDR1 and beyond */ 953 #ifndef ftrace_return_address 954 # ifdef CONFIG_FRAME_POINTER 955 # define ftrace_return_address(n) __builtin_return_address(n) 956 # else 957 # define ftrace_return_address(n) 0UL 958 # endif 959 #endif 960 961 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 962 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 963 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 964 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 965 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 966 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 967 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 968 969 static __always_inline unsigned long get_lock_parent_ip(void) 970 { 971 unsigned long addr = CALLER_ADDR0; 972 973 if (!in_lock_functions(addr)) 974 return addr; 975 addr = CALLER_ADDR1; 976 if (!in_lock_functions(addr)) 977 return addr; 978 return CALLER_ADDR2; 979 } 980 981 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE 982 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 983 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 984 #else 985 /* 986 * Use defines instead of static inlines because some arches will make code out 987 * of the CALLER_ADDR, when we really want these to be a real nop. 988 */ 989 # define trace_preempt_on(a0, a1) do { } while (0) 990 # define trace_preempt_off(a0, a1) do { } while (0) 991 #endif 992 993 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 994 extern void ftrace_init(void); 995 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY 996 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries" 997 #else 998 #define FTRACE_CALLSITE_SECTION "__mcount_loc" 999 #endif 1000 #else 1001 static inline void ftrace_init(void) { } 1002 #endif 1003 1004 /* 1005 * Structure that defines an entry function trace. 1006 * It's already packed but the attribute "packed" is needed 1007 * to remove extra padding at the end. 1008 */ 1009 struct ftrace_graph_ent { 1010 unsigned long func; /* Current function */ 1011 int depth; 1012 } __packed; 1013 1014 /* 1015 * Structure that defines a return function trace. 1016 * It's already packed but the attribute "packed" is needed 1017 * to remove extra padding at the end. 1018 */ 1019 struct ftrace_graph_ret { 1020 unsigned long func; /* Current function */ 1021 int depth; 1022 /* Number of functions that overran the depth limit for current task */ 1023 unsigned int overrun; 1024 unsigned long long calltime; 1025 unsigned long long rettime; 1026 } __packed; 1027 1028 /* Type of the callback handlers for tracing function graph*/ 1029 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ 1030 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ 1031 1032 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); 1033 1034 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1035 1036 struct fgraph_ops { 1037 trace_func_graph_ent_t entryfunc; 1038 trace_func_graph_ret_t retfunc; 1039 }; 1040 1041 /* 1042 * Stack of return addresses for functions 1043 * of a thread. 1044 * Used in struct thread_info 1045 */ 1046 struct ftrace_ret_stack { 1047 unsigned long ret; 1048 unsigned long func; 1049 unsigned long long calltime; 1050 #ifdef CONFIG_FUNCTION_PROFILER 1051 unsigned long long subtime; 1052 #endif 1053 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 1054 unsigned long fp; 1055 #endif 1056 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 1057 unsigned long *retp; 1058 #endif 1059 }; 1060 1061 /* 1062 * Primary handler of a function return. 1063 * It relays on ftrace_return_to_handler. 1064 * Defined in entry_32/64.S 1065 */ 1066 extern void return_to_handler(void); 1067 1068 extern int 1069 function_graph_enter(unsigned long ret, unsigned long func, 1070 unsigned long frame_pointer, unsigned long *retp); 1071 1072 struct ftrace_ret_stack * 1073 ftrace_graph_get_ret_stack(struct task_struct *task, int idx); 1074 1075 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 1076 unsigned long ret, unsigned long *retp); 1077 1078 /* 1079 * Sometimes we don't want to trace a function with the function 1080 * graph tracer but we want them to keep traced by the usual function 1081 * tracer if the function graph tracer is not configured. 1082 */ 1083 #define __notrace_funcgraph notrace 1084 1085 #define FTRACE_RETFUNC_DEPTH 50 1086 #define FTRACE_RETSTACK_ALLOC_SIZE 32 1087 1088 extern int register_ftrace_graph(struct fgraph_ops *ops); 1089 extern void unregister_ftrace_graph(struct fgraph_ops *ops); 1090 1091 /** 1092 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called 1093 * 1094 * ftrace_graph_stop() is called when a severe error is detected in 1095 * the function graph tracing. This function is called by the critical 1096 * paths of function graph to keep those paths from doing any more harm. 1097 */ 1098 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); 1099 1100 static inline bool ftrace_graph_is_dead(void) 1101 { 1102 return static_branch_unlikely(&kill_ftrace_graph); 1103 } 1104 1105 extern void ftrace_graph_stop(void); 1106 1107 /* The current handlers in use */ 1108 extern trace_func_graph_ret_t ftrace_graph_return; 1109 extern trace_func_graph_ent_t ftrace_graph_entry; 1110 1111 extern void ftrace_graph_init_task(struct task_struct *t); 1112 extern void ftrace_graph_exit_task(struct task_struct *t); 1113 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 1114 1115 static inline void pause_graph_tracing(void) 1116 { 1117 atomic_inc(¤t->tracing_graph_pause); 1118 } 1119 1120 static inline void unpause_graph_tracing(void) 1121 { 1122 atomic_dec(¤t->tracing_graph_pause); 1123 } 1124 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 1125 1126 #define __notrace_funcgraph 1127 1128 static inline void ftrace_graph_init_task(struct task_struct *t) { } 1129 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 1130 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 1131 1132 /* Define as macros as fgraph_ops may not be defined */ 1133 #define register_ftrace_graph(ops) ({ -1; }) 1134 #define unregister_ftrace_graph(ops) do { } while (0) 1135 1136 static inline unsigned long 1137 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 1138 unsigned long *retp) 1139 { 1140 return ret; 1141 } 1142 1143 static inline void pause_graph_tracing(void) { } 1144 static inline void unpause_graph_tracing(void) { } 1145 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1146 1147 #ifdef CONFIG_TRACING 1148 enum ftrace_dump_mode; 1149 1150 extern enum ftrace_dump_mode ftrace_dump_on_oops; 1151 extern int tracepoint_printk; 1152 1153 extern void disable_trace_on_warning(void); 1154 extern int __disable_trace_on_warning; 1155 1156 int tracepoint_printk_sysctl(struct ctl_table *table, int write, 1157 void *buffer, size_t *lenp, loff_t *ppos); 1158 1159 #else /* CONFIG_TRACING */ 1160 static inline void disable_trace_on_warning(void) { } 1161 #endif /* CONFIG_TRACING */ 1162 1163 #ifdef CONFIG_FTRACE_SYSCALLS 1164 1165 unsigned long arch_syscall_addr(int nr); 1166 1167 #endif /* CONFIG_FTRACE_SYSCALLS */ 1168 1169 #endif /* _LINUX_FTRACE_H */ 1170