1 /* 2 * Ftrace header. For implementation details beyond the random comments 3 * scattered below, see: Documentation/trace/ftrace-design.txt 4 */ 5 6 #ifndef _LINUX_FTRACE_H 7 #define _LINUX_FTRACE_H 8 9 #include <linux/trace_clock.h> 10 #include <linux/kallsyms.h> 11 #include <linux/linkage.h> 12 #include <linux/bitops.h> 13 #include <linux/ptrace.h> 14 #include <linux/ktime.h> 15 #include <linux/sched.h> 16 #include <linux/types.h> 17 #include <linux/init.h> 18 #include <linux/fs.h> 19 20 #include <asm/ftrace.h> 21 22 /* 23 * If the arch supports passing the variable contents of 24 * function_trace_op as the third parameter back from the 25 * mcount call, then the arch should define this as 1. 26 */ 27 #ifndef ARCH_SUPPORTS_FTRACE_OPS 28 #define ARCH_SUPPORTS_FTRACE_OPS 0 29 #endif 30 31 /* 32 * If the arch's mcount caller does not support all of ftrace's 33 * features, then it must call an indirect function that 34 * does. Or at least does enough to prevent any unwelcomed side effects. 35 */ 36 #if !ARCH_SUPPORTS_FTRACE_OPS 37 # define FTRACE_FORCE_LIST_FUNC 1 38 #else 39 # define FTRACE_FORCE_LIST_FUNC 0 40 #endif 41 42 /* Main tracing buffer and events set up */ 43 #ifdef CONFIG_TRACING 44 void trace_init(void); 45 void early_trace_init(void); 46 #else 47 static inline void trace_init(void) { } 48 static inline void early_trace_init(void) { } 49 #endif 50 51 struct module; 52 struct ftrace_hash; 53 54 #ifdef CONFIG_FUNCTION_TRACER 55 56 extern int ftrace_enabled; 57 extern int 58 ftrace_enable_sysctl(struct ctl_table *table, int write, 59 void __user *buffer, size_t *lenp, 60 loff_t *ppos); 61 62 struct ftrace_ops; 63 64 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, 65 struct ftrace_ops *op, struct pt_regs *regs); 66 67 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 68 69 /* 70 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are 71 * set in the flags member. 72 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and 73 * IPMODIFY are a kind of attribute flags which can be set only before 74 * registering the ftrace_ops, and can not be modified while registered. 75 * Changing those attribute flags after registering ftrace_ops will 76 * cause unexpected results. 77 * 78 * ENABLED - set/unset when ftrace_ops is registered/unregistered 79 * DYNAMIC - set when ftrace_ops is registered to denote dynamically 80 * allocated ftrace_ops which need special care 81 * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops 82 * could be controlled by following calls: 83 * ftrace_function_local_enable 84 * ftrace_function_local_disable 85 * SAVE_REGS - The ftrace_ops wants regs saved at each function called 86 * and passed to the callback. If this flag is set, but the 87 * architecture does not support passing regs 88 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the 89 * ftrace_ops will fail to register, unless the next flag 90 * is set. 91 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the 92 * handler can handle an arch that does not save regs 93 * (the handler tests if regs == NULL), then it can set 94 * this flag instead. It will not fail registering the ftrace_ops 95 * but, the regs field will be NULL if the arch does not support 96 * passing regs to the handler. 97 * Note, if this flag is set, the SAVE_REGS flag will automatically 98 * get set upon registering the ftrace_ops, if the arch supports it. 99 * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure 100 * that the call back has its own recursion protection. If it does 101 * not set this, then the ftrace infrastructure will add recursion 102 * protection for the caller. 103 * STUB - The ftrace_ops is just a place holder. 104 * INITIALIZED - The ftrace_ops has already been initialized (first use time 105 * register_ftrace_function() is called, it will initialized the ops) 106 * DELETED - The ops are being deleted, do not let them be registered again. 107 * ADDING - The ops is in the process of being added. 108 * REMOVING - The ops is in the process of being removed. 109 * MODIFYING - The ops is in the process of changing its filter functions. 110 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code. 111 * The arch specific code sets this flag when it allocated a 112 * trampoline. This lets the arch know that it can update the 113 * trampoline in case the callback function changes. 114 * The ftrace_ops trampoline can be set by the ftrace users, and 115 * in such cases the arch must not modify it. Only the arch ftrace 116 * core code should set this flag. 117 * IPMODIFY - The ops can modify the IP register. This can only be set with 118 * SAVE_REGS. If another ops with this flag set is already registered 119 * for any of the functions that this ops will be registered for, then 120 * this ops will fail to register or set_filter_ip. 121 * PID - Is affected by set_ftrace_pid (allows filtering on those pids) 122 */ 123 enum { 124 FTRACE_OPS_FL_ENABLED = 1 << 0, 125 FTRACE_OPS_FL_DYNAMIC = 1 << 1, 126 FTRACE_OPS_FL_PER_CPU = 1 << 2, 127 FTRACE_OPS_FL_SAVE_REGS = 1 << 3, 128 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 4, 129 FTRACE_OPS_FL_RECURSION_SAFE = 1 << 5, 130 FTRACE_OPS_FL_STUB = 1 << 6, 131 FTRACE_OPS_FL_INITIALIZED = 1 << 7, 132 FTRACE_OPS_FL_DELETED = 1 << 8, 133 FTRACE_OPS_FL_ADDING = 1 << 9, 134 FTRACE_OPS_FL_REMOVING = 1 << 10, 135 FTRACE_OPS_FL_MODIFYING = 1 << 11, 136 FTRACE_OPS_FL_ALLOC_TRAMP = 1 << 12, 137 FTRACE_OPS_FL_IPMODIFY = 1 << 13, 138 FTRACE_OPS_FL_PID = 1 << 14, 139 FTRACE_OPS_FL_RCU = 1 << 15, 140 }; 141 142 #ifdef CONFIG_DYNAMIC_FTRACE 143 /* The hash used to know what functions callbacks trace */ 144 struct ftrace_ops_hash { 145 struct ftrace_hash *notrace_hash; 146 struct ftrace_hash *filter_hash; 147 struct mutex regex_lock; 148 }; 149 150 void ftrace_free_init_mem(void); 151 #else 152 static inline void ftrace_free_init_mem(void) { } 153 #endif 154 155 /* 156 * Note, ftrace_ops can be referenced outside of RCU protection, unless 157 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 158 * core data, the unregistering of it will perform a scheduling on all CPUs 159 * to make sure that there are no more users. Depending on the load of the 160 * system that may take a bit of time. 161 * 162 * Any private data added must also take care not to be freed and if private 163 * data is added to a ftrace_ops that is in core code, the user of the 164 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 165 */ 166 struct ftrace_ops { 167 ftrace_func_t func; 168 struct ftrace_ops *next; 169 unsigned long flags; 170 void *private; 171 ftrace_func_t saved_func; 172 int __percpu *disabled; 173 #ifdef CONFIG_DYNAMIC_FTRACE 174 struct ftrace_ops_hash local_hash; 175 struct ftrace_ops_hash *func_hash; 176 struct ftrace_ops_hash old_hash; 177 unsigned long trampoline; 178 unsigned long trampoline_size; 179 #endif 180 }; 181 182 /* 183 * Type of the current tracing. 184 */ 185 enum ftrace_tracing_type_t { 186 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 187 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 188 }; 189 190 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 191 extern enum ftrace_tracing_type_t ftrace_tracing_type; 192 193 /* 194 * The ftrace_ops must be a static and should also 195 * be read_mostly. These functions do modify read_mostly variables 196 * so use them sparely. Never free an ftrace_op or modify the 197 * next pointer after it has been registered. Even after unregistering 198 * it, the next pointer may still be used internally. 199 */ 200 int register_ftrace_function(struct ftrace_ops *ops); 201 int unregister_ftrace_function(struct ftrace_ops *ops); 202 void clear_ftrace_function(void); 203 204 /** 205 * ftrace_function_local_enable - enable ftrace_ops on current cpu 206 * 207 * This function enables tracing on current cpu by decreasing 208 * the per cpu control variable. 209 * It must be called with preemption disabled and only on ftrace_ops 210 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 211 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 212 */ 213 static inline void ftrace_function_local_enable(struct ftrace_ops *ops) 214 { 215 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 216 return; 217 218 (*this_cpu_ptr(ops->disabled))--; 219 } 220 221 /** 222 * ftrace_function_local_disable - disable ftrace_ops on current cpu 223 * 224 * This function disables tracing on current cpu by increasing 225 * the per cpu control variable. 226 * It must be called with preemption disabled and only on ftrace_ops 227 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 228 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 229 */ 230 static inline void ftrace_function_local_disable(struct ftrace_ops *ops) 231 { 232 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 233 return; 234 235 (*this_cpu_ptr(ops->disabled))++; 236 } 237 238 /** 239 * ftrace_function_local_disabled - returns ftrace_ops disabled value 240 * on current cpu 241 * 242 * This function returns value of ftrace_ops::disabled on current cpu. 243 * It must be called with preemption disabled and only on ftrace_ops 244 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 245 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 246 */ 247 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops) 248 { 249 WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)); 250 return *this_cpu_ptr(ops->disabled); 251 } 252 253 extern void ftrace_stub(unsigned long a0, unsigned long a1, 254 struct ftrace_ops *op, struct pt_regs *regs); 255 256 #else /* !CONFIG_FUNCTION_TRACER */ 257 /* 258 * (un)register_ftrace_function must be a macro since the ops parameter 259 * must not be evaluated. 260 */ 261 #define register_ftrace_function(ops) ({ 0; }) 262 #define unregister_ftrace_function(ops) ({ 0; }) 263 static inline int ftrace_nr_registered_ops(void) 264 { 265 return 0; 266 } 267 static inline void clear_ftrace_function(void) { } 268 static inline void ftrace_kill(void) { } 269 static inline void ftrace_free_init_mem(void) { } 270 #endif /* CONFIG_FUNCTION_TRACER */ 271 272 #ifdef CONFIG_STACK_TRACER 273 274 #define STACK_TRACE_ENTRIES 500 275 276 struct stack_trace; 277 278 extern unsigned stack_trace_index[]; 279 extern struct stack_trace stack_trace_max; 280 extern unsigned long stack_trace_max_size; 281 extern arch_spinlock_t stack_trace_max_lock; 282 283 extern int stack_tracer_enabled; 284 void stack_trace_print(void); 285 int 286 stack_trace_sysctl(struct ctl_table *table, int write, 287 void __user *buffer, size_t *lenp, 288 loff_t *ppos); 289 290 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 291 DECLARE_PER_CPU(int, disable_stack_tracer); 292 293 /** 294 * stack_tracer_disable - temporarily disable the stack tracer 295 * 296 * There's a few locations (namely in RCU) where stack tracing 297 * cannot be executed. This function is used to disable stack 298 * tracing during those critical sections. 299 * 300 * This function must be called with preemption or interrupts 301 * disabled and stack_tracer_enable() must be called shortly after 302 * while preemption or interrupts are still disabled. 303 */ 304 static inline void stack_tracer_disable(void) 305 { 306 /* Preemption or interupts must be disabled */ 307 if (IS_ENABLED(CONFIG_PREEMPT_DEBUG)) 308 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 309 this_cpu_inc(disable_stack_tracer); 310 } 311 312 /** 313 * stack_tracer_enable - re-enable the stack tracer 314 * 315 * After stack_tracer_disable() is called, stack_tracer_enable() 316 * must be called shortly afterward. 317 */ 318 static inline void stack_tracer_enable(void) 319 { 320 if (IS_ENABLED(CONFIG_PREEMPT_DEBUG)) 321 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 322 this_cpu_dec(disable_stack_tracer); 323 } 324 #else 325 static inline void stack_tracer_disable(void) { } 326 static inline void stack_tracer_enable(void) { } 327 #endif 328 329 #ifdef CONFIG_DYNAMIC_FTRACE 330 331 int ftrace_arch_code_modify_prepare(void); 332 int ftrace_arch_code_modify_post_process(void); 333 334 struct dyn_ftrace; 335 336 enum ftrace_bug_type { 337 FTRACE_BUG_UNKNOWN, 338 FTRACE_BUG_INIT, 339 FTRACE_BUG_NOP, 340 FTRACE_BUG_CALL, 341 FTRACE_BUG_UPDATE, 342 }; 343 extern enum ftrace_bug_type ftrace_bug_type; 344 345 /* 346 * Archs can set this to point to a variable that holds the value that was 347 * expected at the call site before calling ftrace_bug(). 348 */ 349 extern const void *ftrace_expected; 350 351 void ftrace_bug(int err, struct dyn_ftrace *rec); 352 353 struct seq_file; 354 355 extern int ftrace_text_reserved(const void *start, const void *end); 356 357 extern int ftrace_nr_registered_ops(void); 358 359 bool is_ftrace_trampoline(unsigned long addr); 360 361 /* 362 * The dyn_ftrace record's flags field is split into two parts. 363 * the first part which is '0-FTRACE_REF_MAX' is a counter of 364 * the number of callbacks that have registered the function that 365 * the dyn_ftrace descriptor represents. 366 * 367 * The second part is a mask: 368 * ENABLED - the function is being traced 369 * REGS - the record wants the function to save regs 370 * REGS_EN - the function is set up to save regs. 371 * IPMODIFY - the record allows for the IP address to be changed. 372 * DISABLED - the record is not ready to be touched yet 373 * 374 * When a new ftrace_ops is registered and wants a function to save 375 * pt_regs, the rec->flag REGS is set. When the function has been 376 * set up to save regs, the REG_EN flag is set. Once a function 377 * starts saving regs it will do so until all ftrace_ops are removed 378 * from tracing that function. 379 */ 380 enum { 381 FTRACE_FL_ENABLED = (1UL << 31), 382 FTRACE_FL_REGS = (1UL << 30), 383 FTRACE_FL_REGS_EN = (1UL << 29), 384 FTRACE_FL_TRAMP = (1UL << 28), 385 FTRACE_FL_TRAMP_EN = (1UL << 27), 386 FTRACE_FL_IPMODIFY = (1UL << 26), 387 FTRACE_FL_DISABLED = (1UL << 25), 388 }; 389 390 #define FTRACE_REF_MAX_SHIFT 25 391 #define FTRACE_FL_BITS 7 392 #define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1) 393 #define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) 394 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 395 396 #define ftrace_rec_count(rec) ((rec)->flags & ~FTRACE_FL_MASK) 397 398 struct dyn_ftrace { 399 unsigned long ip; /* address of mcount call-site */ 400 unsigned long flags; 401 struct dyn_arch_ftrace arch; 402 }; 403 404 int ftrace_force_update(void); 405 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 406 int remove, int reset); 407 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 408 int len, int reset); 409 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 410 int len, int reset); 411 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 412 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 413 void ftrace_free_filter(struct ftrace_ops *ops); 414 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 415 416 enum { 417 FTRACE_UPDATE_CALLS = (1 << 0), 418 FTRACE_DISABLE_CALLS = (1 << 1), 419 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 420 FTRACE_START_FUNC_RET = (1 << 3), 421 FTRACE_STOP_FUNC_RET = (1 << 4), 422 }; 423 424 /* 425 * The FTRACE_UPDATE_* enum is used to pass information back 426 * from the ftrace_update_record() and ftrace_test_record() 427 * functions. These are called by the code update routines 428 * to find out what is to be done for a given function. 429 * 430 * IGNORE - The function is already what we want it to be 431 * MAKE_CALL - Start tracing the function 432 * MODIFY_CALL - Stop saving regs for the function 433 * MAKE_NOP - Stop tracing the function 434 */ 435 enum { 436 FTRACE_UPDATE_IGNORE, 437 FTRACE_UPDATE_MAKE_CALL, 438 FTRACE_UPDATE_MODIFY_CALL, 439 FTRACE_UPDATE_MAKE_NOP, 440 }; 441 442 enum { 443 FTRACE_ITER_FILTER = (1 << 0), 444 FTRACE_ITER_NOTRACE = (1 << 1), 445 FTRACE_ITER_PRINTALL = (1 << 2), 446 FTRACE_ITER_DO_PROBES = (1 << 3), 447 FTRACE_ITER_PROBE = (1 << 4), 448 FTRACE_ITER_ENABLED = (1 << 5), 449 }; 450 451 void arch_ftrace_update_code(int command); 452 453 struct ftrace_rec_iter; 454 455 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 456 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 457 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 458 459 #define for_ftrace_rec_iter(iter) \ 460 for (iter = ftrace_rec_iter_start(); \ 461 iter; \ 462 iter = ftrace_rec_iter_next(iter)) 463 464 465 int ftrace_update_record(struct dyn_ftrace *rec, int enable); 466 int ftrace_test_record(struct dyn_ftrace *rec, int enable); 467 void ftrace_run_stop_machine(int command); 468 unsigned long ftrace_location(unsigned long ip); 469 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 470 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 471 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 472 473 extern ftrace_func_t ftrace_trace_function; 474 475 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 476 struct inode *inode, struct file *file); 477 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 478 size_t cnt, loff_t *ppos); 479 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 480 size_t cnt, loff_t *ppos); 481 int ftrace_regex_release(struct inode *inode, struct file *file); 482 483 void __init 484 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 485 486 /* defined in arch */ 487 extern int ftrace_ip_converted(unsigned long ip); 488 extern int ftrace_dyn_arch_init(void); 489 extern void ftrace_replace_code(int enable); 490 extern int ftrace_update_ftrace_func(ftrace_func_t func); 491 extern void ftrace_caller(void); 492 extern void ftrace_regs_caller(void); 493 extern void ftrace_call(void); 494 extern void ftrace_regs_call(void); 495 extern void mcount_call(void); 496 497 void ftrace_modify_all_code(int command); 498 499 #ifndef FTRACE_ADDR 500 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 501 #endif 502 503 #ifndef FTRACE_GRAPH_ADDR 504 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 505 #endif 506 507 #ifndef FTRACE_REGS_ADDR 508 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 509 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 510 #else 511 # define FTRACE_REGS_ADDR FTRACE_ADDR 512 #endif 513 #endif 514 515 /* 516 * If an arch would like functions that are only traced 517 * by the function graph tracer to jump directly to its own 518 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 519 * to be that address to jump to. 520 */ 521 #ifndef FTRACE_GRAPH_TRAMP_ADDR 522 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 523 #endif 524 525 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 526 extern void ftrace_graph_caller(void); 527 extern int ftrace_enable_ftrace_graph_caller(void); 528 extern int ftrace_disable_ftrace_graph_caller(void); 529 #else 530 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 531 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 532 #endif 533 534 /** 535 * ftrace_make_nop - convert code into nop 536 * @mod: module structure if called by module load initialization 537 * @rec: the mcount call site record 538 * @addr: the address that the call site should be calling 539 * 540 * This is a very sensitive operation and great care needs 541 * to be taken by the arch. The operation should carefully 542 * read the location, check to see if what is read is indeed 543 * what we expect it to be, and then on success of the compare, 544 * it should write to the location. 545 * 546 * The code segment at @rec->ip should be a caller to @addr 547 * 548 * Return must be: 549 * 0 on success 550 * -EFAULT on error reading the location 551 * -EINVAL on a failed compare of the contents 552 * -EPERM on error writing to the location 553 * Any other value will be considered a failure. 554 */ 555 extern int ftrace_make_nop(struct module *mod, 556 struct dyn_ftrace *rec, unsigned long addr); 557 558 /** 559 * ftrace_make_call - convert a nop call site into a call to addr 560 * @rec: the mcount call site record 561 * @addr: the address that the call site should call 562 * 563 * This is a very sensitive operation and great care needs 564 * to be taken by the arch. The operation should carefully 565 * read the location, check to see if what is read is indeed 566 * what we expect it to be, and then on success of the compare, 567 * it should write to the location. 568 * 569 * The code segment at @rec->ip should be a nop 570 * 571 * Return must be: 572 * 0 on success 573 * -EFAULT on error reading the location 574 * -EINVAL on a failed compare of the contents 575 * -EPERM on error writing to the location 576 * Any other value will be considered a failure. 577 */ 578 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 579 580 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 581 /** 582 * ftrace_modify_call - convert from one addr to another (no nop) 583 * @rec: the mcount call site record 584 * @old_addr: the address expected to be currently called to 585 * @addr: the address to change to 586 * 587 * This is a very sensitive operation and great care needs 588 * to be taken by the arch. The operation should carefully 589 * read the location, check to see if what is read is indeed 590 * what we expect it to be, and then on success of the compare, 591 * it should write to the location. 592 * 593 * The code segment at @rec->ip should be a caller to @old_addr 594 * 595 * Return must be: 596 * 0 on success 597 * -EFAULT on error reading the location 598 * -EINVAL on a failed compare of the contents 599 * -EPERM on error writing to the location 600 * Any other value will be considered a failure. 601 */ 602 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 603 unsigned long addr); 604 #else 605 /* Should never be called */ 606 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 607 unsigned long addr) 608 { 609 return -EINVAL; 610 } 611 #endif 612 613 /* May be defined in arch */ 614 extern int ftrace_arch_read_dyn_info(char *buf, int size); 615 616 extern int skip_trace(unsigned long ip); 617 extern void ftrace_module_init(struct module *mod); 618 extern void ftrace_module_enable(struct module *mod); 619 extern void ftrace_release_mod(struct module *mod); 620 621 extern void ftrace_disable_daemon(void); 622 extern void ftrace_enable_daemon(void); 623 #else /* CONFIG_DYNAMIC_FTRACE */ 624 static inline int skip_trace(unsigned long ip) { return 0; } 625 static inline int ftrace_force_update(void) { return 0; } 626 static inline void ftrace_disable_daemon(void) { } 627 static inline void ftrace_enable_daemon(void) { } 628 static inline void ftrace_module_init(struct module *mod) { } 629 static inline void ftrace_module_enable(struct module *mod) { } 630 static inline void ftrace_release_mod(struct module *mod) { } 631 static inline int ftrace_text_reserved(const void *start, const void *end) 632 { 633 return 0; 634 } 635 static inline unsigned long ftrace_location(unsigned long ip) 636 { 637 return 0; 638 } 639 640 /* 641 * Again users of functions that have ftrace_ops may not 642 * have them defined when ftrace is not enabled, but these 643 * functions may still be called. Use a macro instead of inline. 644 */ 645 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 646 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 647 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 648 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 649 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 650 #define ftrace_free_filter(ops) do { } while (0) 651 #define ftrace_ops_set_global_filter(ops) do { } while (0) 652 653 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 654 size_t cnt, loff_t *ppos) { return -ENODEV; } 655 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 656 size_t cnt, loff_t *ppos) { return -ENODEV; } 657 static inline int 658 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 659 660 static inline bool is_ftrace_trampoline(unsigned long addr) 661 { 662 return false; 663 } 664 #endif /* CONFIG_DYNAMIC_FTRACE */ 665 666 /* totally disable ftrace - can not re-enable after this */ 667 void ftrace_kill(void); 668 669 static inline void tracer_disable(void) 670 { 671 #ifdef CONFIG_FUNCTION_TRACER 672 ftrace_enabled = 0; 673 #endif 674 } 675 676 /* 677 * Ftrace disable/restore without lock. Some synchronization mechanism 678 * must be used to prevent ftrace_enabled to be changed between 679 * disable/restore. 680 */ 681 static inline int __ftrace_enabled_save(void) 682 { 683 #ifdef CONFIG_FUNCTION_TRACER 684 int saved_ftrace_enabled = ftrace_enabled; 685 ftrace_enabled = 0; 686 return saved_ftrace_enabled; 687 #else 688 return 0; 689 #endif 690 } 691 692 static inline void __ftrace_enabled_restore(int enabled) 693 { 694 #ifdef CONFIG_FUNCTION_TRACER 695 ftrace_enabled = enabled; 696 #endif 697 } 698 699 /* All archs should have this, but we define it for consistency */ 700 #ifndef ftrace_return_address0 701 # define ftrace_return_address0 __builtin_return_address(0) 702 #endif 703 704 /* Archs may use other ways for ADDR1 and beyond */ 705 #ifndef ftrace_return_address 706 # ifdef CONFIG_FRAME_POINTER 707 # define ftrace_return_address(n) __builtin_return_address(n) 708 # else 709 # define ftrace_return_address(n) 0UL 710 # endif 711 #endif 712 713 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 714 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 715 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 716 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 717 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 718 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 719 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 720 721 static inline unsigned long get_lock_parent_ip(void) 722 { 723 unsigned long addr = CALLER_ADDR0; 724 725 if (!in_lock_functions(addr)) 726 return addr; 727 addr = CALLER_ADDR1; 728 if (!in_lock_functions(addr)) 729 return addr; 730 return CALLER_ADDR2; 731 } 732 733 #ifdef CONFIG_IRQSOFF_TRACER 734 extern void time_hardirqs_on(unsigned long a0, unsigned long a1); 735 extern void time_hardirqs_off(unsigned long a0, unsigned long a1); 736 #else 737 static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { } 738 static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { } 739 #endif 740 741 #ifdef CONFIG_PREEMPT_TRACER 742 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 743 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 744 #else 745 /* 746 * Use defines instead of static inlines because some arches will make code out 747 * of the CALLER_ADDR, when we really want these to be a real nop. 748 */ 749 # define trace_preempt_on(a0, a1) do { } while (0) 750 # define trace_preempt_off(a0, a1) do { } while (0) 751 #endif 752 753 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 754 extern void ftrace_init(void); 755 #else 756 static inline void ftrace_init(void) { } 757 #endif 758 759 /* 760 * Structure that defines an entry function trace. 761 * It's already packed but the attribute "packed" is needed 762 * to remove extra padding at the end. 763 */ 764 struct ftrace_graph_ent { 765 unsigned long func; /* Current function */ 766 int depth; 767 } __packed; 768 769 /* 770 * Structure that defines a return function trace. 771 * It's already packed but the attribute "packed" is needed 772 * to remove extra padding at the end. 773 */ 774 struct ftrace_graph_ret { 775 unsigned long func; /* Current function */ 776 /* Number of functions that overran the depth limit for current task */ 777 unsigned long overrun; 778 unsigned long long calltime; 779 unsigned long long rettime; 780 int depth; 781 } __packed; 782 783 /* Type of the callback handlers for tracing function graph*/ 784 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ 785 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ 786 787 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 788 789 /* for init task */ 790 #define INIT_FTRACE_GRAPH .ret_stack = NULL, 791 792 /* 793 * Stack of return addresses for functions 794 * of a thread. 795 * Used in struct thread_info 796 */ 797 struct ftrace_ret_stack { 798 unsigned long ret; 799 unsigned long func; 800 unsigned long long calltime; 801 #ifdef CONFIG_FUNCTION_PROFILER 802 unsigned long long subtime; 803 #endif 804 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 805 unsigned long fp; 806 #endif 807 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 808 unsigned long *retp; 809 #endif 810 }; 811 812 /* 813 * Primary handler of a function return. 814 * It relays on ftrace_return_to_handler. 815 * Defined in entry_32/64.S 816 */ 817 extern void return_to_handler(void); 818 819 extern int 820 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, 821 unsigned long frame_pointer, unsigned long *retp); 822 823 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 824 unsigned long ret, unsigned long *retp); 825 826 /* 827 * Sometimes we don't want to trace a function with the function 828 * graph tracer but we want them to keep traced by the usual function 829 * tracer if the function graph tracer is not configured. 830 */ 831 #define __notrace_funcgraph notrace 832 833 #define FTRACE_NOTRACE_DEPTH 65536 834 #define FTRACE_RETFUNC_DEPTH 50 835 #define FTRACE_RETSTACK_ALLOC_SIZE 32 836 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc, 837 trace_func_graph_ent_t entryfunc); 838 839 extern bool ftrace_graph_is_dead(void); 840 extern void ftrace_graph_stop(void); 841 842 /* The current handlers in use */ 843 extern trace_func_graph_ret_t ftrace_graph_return; 844 extern trace_func_graph_ent_t ftrace_graph_entry; 845 846 extern void unregister_ftrace_graph(void); 847 848 extern void ftrace_graph_init_task(struct task_struct *t); 849 extern void ftrace_graph_exit_task(struct task_struct *t); 850 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 851 852 static inline int task_curr_ret_stack(struct task_struct *t) 853 { 854 return t->curr_ret_stack; 855 } 856 857 static inline void pause_graph_tracing(void) 858 { 859 atomic_inc(¤t->tracing_graph_pause); 860 } 861 862 static inline void unpause_graph_tracing(void) 863 { 864 atomic_dec(¤t->tracing_graph_pause); 865 } 866 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 867 868 #define __notrace_funcgraph 869 #define INIT_FTRACE_GRAPH 870 871 static inline void ftrace_graph_init_task(struct task_struct *t) { } 872 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 873 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 874 875 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc, 876 trace_func_graph_ent_t entryfunc) 877 { 878 return -1; 879 } 880 static inline void unregister_ftrace_graph(void) { } 881 882 static inline int task_curr_ret_stack(struct task_struct *tsk) 883 { 884 return -1; 885 } 886 887 static inline unsigned long 888 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 889 unsigned long *retp) 890 { 891 return ret; 892 } 893 894 static inline void pause_graph_tracing(void) { } 895 static inline void unpause_graph_tracing(void) { } 896 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 897 898 #ifdef CONFIG_TRACING 899 900 /* flags for current->trace */ 901 enum { 902 TSK_TRACE_FL_TRACE_BIT = 0, 903 TSK_TRACE_FL_GRAPH_BIT = 1, 904 }; 905 enum { 906 TSK_TRACE_FL_TRACE = 1 << TSK_TRACE_FL_TRACE_BIT, 907 TSK_TRACE_FL_GRAPH = 1 << TSK_TRACE_FL_GRAPH_BIT, 908 }; 909 910 static inline void set_tsk_trace_trace(struct task_struct *tsk) 911 { 912 set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 913 } 914 915 static inline void clear_tsk_trace_trace(struct task_struct *tsk) 916 { 917 clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 918 } 919 920 static inline int test_tsk_trace_trace(struct task_struct *tsk) 921 { 922 return tsk->trace & TSK_TRACE_FL_TRACE; 923 } 924 925 static inline void set_tsk_trace_graph(struct task_struct *tsk) 926 { 927 set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 928 } 929 930 static inline void clear_tsk_trace_graph(struct task_struct *tsk) 931 { 932 clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 933 } 934 935 static inline int test_tsk_trace_graph(struct task_struct *tsk) 936 { 937 return tsk->trace & TSK_TRACE_FL_GRAPH; 938 } 939 940 enum ftrace_dump_mode; 941 942 extern enum ftrace_dump_mode ftrace_dump_on_oops; 943 extern int tracepoint_printk; 944 945 extern void disable_trace_on_warning(void); 946 extern int __disable_trace_on_warning; 947 948 #ifdef CONFIG_PREEMPT 949 #define INIT_TRACE_RECURSION .trace_recursion = 0, 950 #endif 951 952 int tracepoint_printk_sysctl(struct ctl_table *table, int write, 953 void __user *buffer, size_t *lenp, 954 loff_t *ppos); 955 956 #else /* CONFIG_TRACING */ 957 static inline void disable_trace_on_warning(void) { } 958 #endif /* CONFIG_TRACING */ 959 960 #ifndef INIT_TRACE_RECURSION 961 #define INIT_TRACE_RECURSION 962 #endif 963 964 #ifdef CONFIG_FTRACE_SYSCALLS 965 966 unsigned long arch_syscall_addr(int nr); 967 968 #endif /* CONFIG_FTRACE_SYSCALLS */ 969 970 #endif /* _LINUX_FTRACE_H */ 971