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