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